Abstract
Amphibians and reptiles are a diverse group of ectothermic vertebrates that occupy a variety of habitats in rangelands of North America, from wetlands to the driest deserts. These two classes of vertebrates are often referred to as herpetofauna and are studied under the field of herpetology. In U.S. rangelands, there are approximately 66 species of frogs and toads, 58 salamanders, 98 lizards, 111 snakes, and 27 turtles and tortoises. Herpetofauna tend to be poorly studied compared with other vertebrates, which creates a challenge for biologists and landowners who are trying to manage rangeland activities for this diverse group of animals and their habitats. Degradation of habitats from human land use and alteration of natural processes, like wildfire, are primary threats to herpetofauna populations. Disease, non-native predators, collection for the pet trade, and persecution are also conservation concerns for some species. Properly managed livestock grazing is generally compatible with herpetofauna conservation, and private and public rangelands provide crucial habitat for many species. Climate change also poses a threat to herpetofauna, but we have an incomplete understanding of the potential effects on species. Dispersal and adaptation could provide some capacity for species to persist on rangelands as climates, disturbance regimes, and habitats change. However, inadequate information and considerable uncertainty will make climate mitigation planning difficult for the foreseeable future. Planning for and mitigating effects of climate change, and interactions with other stressors, is an urgent area for research. Maintaining large, heterogeneous land areas as rangelands will certainly be an important part of the conservation strategy for herpetofauna in North America.
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Keywords
- Amphibia
- Frog
- Grazing
- Herpetofauna
- Land management
- Lizard
- Rangelands
- Reptilia
- Salamander
- Sauropsida
- Snake
- Toad
- Tortoise
- Turtle
- Wildlife
1 General Life History and Population Dynamics
Amphibians and reptiles are diverse classes of vertebrates. Amphibia are organized taxonomically into three orders: Anura (frogs and toads); Caudata or Urodela (salamanders); and Apoda or Gymnophiona (caecilians). Reptilia are organized into four orders: Squamata (lizards and snakes); Testudines (turtles and tortoises); Crocodylia (alligators and their allies); and Rhynchocephalia (tuatara). Amphibians and reptiles were combined historically and studied in the field of herpetology, but their evolutionary history is not so tidy. Modern cladistics even abandons the term reptile in favor of the clade Sauropsida, which includes birds. This chapter, however, follows a traditional taxonomy of amphibians and non-avian reptiles. North America is home to more than 733 amphibian and reptile species (Crother 2017). According to our analyses, there are about 124 amphibian species, composed of frogs and toads (N = 66) and salamanders (N = 58), whose distributions overlap by at least 10% with the rangeland ecoregions described in this book (Table 25.1). The United States (U.S.) is a global hotspot of salamander diversity, but salamanders are much less common in U.S. rangelands. About 89% of U.S. rangeland reptile species are lizards (N = 98) and snakes (N = 111), with the remaining diversity composed of turtles and tortoises (N = 27) (Table 25.2). One crocodilian, the American alligator (Alligator mississippiensis), occurs on the periphery of southeastern U.S. rangelands, but its distribution was below the 10% threshold for inclusion in this chapter. Keep in mind that diversity estimates of herpetofauna are dynamic as new species continue to be discovered or described. For example, using molecular and morphological evidence, two new toad species were described in central Nevada in 2019 (Gordon et al. 2020). Taxonomy of amphibians and reptiles is somewhat unresolved and often disputed, which creates challenges for communication in conservation. In this chapter, we use taxonomy from Crother (2017) and the Integrated Taxonomic Information System (ITIS; www.itis.gov, accessed 13 July 2021). Species counts, however, were generated from distribution maps in the USGS Gap Analysis Project (USGS GAP 2018a), which used an older taxonomy (Crother et al. 2003). Crother (2017) is currently the most widely accepted taxonomy for North America and thus we recommend checking this reference and consulting with state herpetologists for the latest taxonomic information about species in your area.
Some life history characteristics are shared by amphibians and reptiles and these are important to consider when characterizing their ecology and understanding their habitat use patterns in rangelands. First, amphibians and reptiles are both ectothermic, meaning they cannot regulate body temperatures through metabolism. Instead, their body temperature tracks the environmental temperatures of their surroundings, although they can influence this process behaviorally. For example, amphibians and reptiles raise their body temperatures by exposure to solar or thermal radiation. This is accomplished by a variety of mechanisms, especially darkening their skin through pigmentation, basking, and pressing their bodies against warm surfaces. This process, known as behavioral thermoregulation, explains why lizards are frequently seen basking in morning sunlight or hugging rocks on a cool day. This also explains why snakes are often encountered (and unfortunately killed) on asphalt roads. Behavioral thermoregulation allows herpetofauna to accelerate temperature increases for activity and maintain optimal body temperatures for more hours of the day, including into the night. Amphibians and reptiles can also lower their body temperatures by evaporative cooling or re-radiating body heat into a cooler surrounding environment, such as water, shade, or burrows (Figs. 25.1 and 25.2). Spadefoot toads (Spea and Scaphiopus spp.), for example, are some of the most widespread amphibian inhabitants of U.S. rangelands and use a hardened skin spur on their hind feet to dig burrows into sandy soils to escape dangerously hot, dry surface conditions. Thus, amphibians also select specific microsites to maintain preferred body temperatures, but at the expense of water loss and thus strike a fine balance between temperature regulation and dehydration (Bartelt et al. 2010). Scales, shells, and thickened skin protect reptiles from dehydration. These and other anatomical features, traits, and adaptations enable reptiles to use a wider range of terrestrial locations than amphibians to optimize body temperatures to meet physiological needs.
Reproduction and development are life history characteristics where amphibians and reptiles diverge (Pough et al. 1998). Amphibians produce eggs that are not protected by shells and thus must be deposited in water or very moist environments. Like fishes, most frogs and toads fertilize their eggs externally whereby a female deposits her eggs directly into the water and the male releases sperm onto them. Most amphibian embryos develop gills and become free-swimming tadpoles (frogs and toads) or larvae (salamanders). Some terrestrial species of lungless salamanders (family Plethodontidae) skip the larval stage and embryos develop directly into the adult body form, albeit a tiny version. Most tadpoles and larvae go through metamorphosis, which is the developmental transformation from an aquatic, gilled life stage to terrestrial juveniles that have the adult body form and use lungs for respiration. Amphibians are among only a handful of vertebrates that go through metamorphosis (Laudet 2011). The duration of the larval stage and timing of metamorphosis varies considerably by species and is dependent on both genetic and environmental factors. A few salamander species, including tiger salamanders (Ambystoma spp.) which are common in U.S. rangelands (Fig. 25.1), can retain their gills and remain aquatic as sexually mature adults. Finally, all amphibians have retained some capacity to respire through their skin, although this inefficient form of respiration usually only occurs for animals overwintering under water and obligatorily among the lungless salamanders, which lack both lungs and gills.
Like birds and a few mammals, reptiles produce eggs that have multiple membranes external to the embryo and a protective outer shell that is either parchment-like and leathery, or hard and calcified similar to a chicken egg. Reptiles use one of three strategies for reproduction: ovipary, vivipary, and ovovivipary. In ovipary, the egg must be fertilized internally by copulation between the male and female prior to eggshell formation. Oviparous embryos partially develop inside the female and eggs are laid in microsites with specific soil substrate and moisture and temperature conditions for development and hatching. Oviparous reptiles hatch fully formed as miniature adults, although they may carry the remainder of the egg yolk as a ‘sack-lunch’ during their first season. In ovovivipary, embryos may acquire their sustenance from a yolk that remains inside the female during development, or embryos may be connected to the female by a placenta (i.e., true vivipary). Rattlesnakes (Crotalus spp.), boas (Charina spp.), and gartersnakes (Thamnophis spp.) are all ovoviviparous species from U.S. rangelands (Fig. 25.2).
2 Species Status
2.1 Historical Versus Current Distributions
The diversity of rangeland herpetofauna presently found across North America can be linked to the environments their ancestors experienced and numerous vicariance events (Pyron 2014; Modesto et al. 2015; Wollenberg Valero et al. 2019). Over the eons, the configurations, sizes, and positions of drifting continents shaped the habitats available to herpetofauna with changes in latitude (i.e., tropical versus polar conditions), climates, sea levels, and formations of lava flows, mountain ranges, deserts, and inland seas. The uplift of mountain ranges in western North America (e.g., most recently the Cascade Range and Sierra Nevada around 4–7 mya) produced rain shadows that drastically altered the climates and vegetation of western rangelands. These deserts influenced the evolution, speciation, and adaptations of modern rangeland herpetofauna (Bryson et al. 2012; Bouzid et al. 2021). Glacial cycles and the formation and draining of inland lakes (e.g., Bonneville, Missoula) during the past 15,000–25,000 yrs also influenced diversification of the species we know today (Thompson and Russell 2005; Funk et al. 2008; Kimberly and Fender 2020). Vicariance and introgression of rangeland species is ongoing with modern processes like anthropogenically induced climate change and fragmentation of habitat.
Amphibians and reptiles are generally understudied, even in rangelands where diversity is comparable to, or higher than, other vertebrate groups (Qian 2009). Therefore, information about historical distribution is severely lacking. A logical assumption is that the historical distribution of amphibians in rangelands was probably determined by the availability of surface water and we know surface waters have changed dramatically over contemporary times (Qian 2010). Part of that change is attributed to intensive trapping of North American beaver (Castor canadensis) for pelts and draining of wetlands for cropland agriculture and pasture (Gibson and Olden 2014; Grudzinski et al. 2020; Wohl 2021). We suspect that loss of amphibian habitat must have been enormous because beaver activity in the western U.S. today is strongly associated with amphibian occupancy patterns, especially for frogs and toads (Arkle and Pilliod 2015; Hossack et al. 2015; Zero and Murphy 2016). Other novel water sources were American bison (Bison bison) wallows, which must have once been numerous and extensive across the Great Plains (Meagher 1986). Remnant wallows were still found during the 1940s in grasslands where wallows had not been destroyed by cultivation. Some of those remnant wallows were about 6 m (20 ft) wide and 2.5 m (8 ft) deep and were used as breeding sites by Great Plains toads (Anaxyrus cognatus; Bragg 1940). Western chorus frogs (Pseudacris triseriata) and northern cricket frogs (Acris crepitans) started using bison wallows for breeding at the Konza Prairie in Kansas after bison were reintroduced in 1987 (Gerlanc and Kaufman 2003). Similarly, western chorus frog choruses can be heard from bison wallows at Theodore Roosevelt National Park, North Dakota where bison were reintroduced in 1956 (Hossack et al. 2005). Hence, evidence suggests that bison wallows were once important breeding sites for prairie amphibians, even though successful metamorphosis may have only occurred in wetter years that provided sustained surface water, or what is often referred to as hydroperiods that are long enough for successful reproduction (Gerlanc and Kaufman 2003). Bison wallow abundance and distributions in rangelands are certainly much reduced today and we know little about the consequences for prairie amphibians.
Between 1780 and 1980, an estimated 53% of 894,355 km2 (221 million acres) of wetlands were intentionally or unintentionally drained in the contiguous United States, especially freshwater emergent marshes that are so important to wildlife (Dahl 1990). In Nevada, for example, over half of its original 1971 km2 (487,000 acres) of wetlands were lost in that 200-yr span. These losses were partially offset by the creation of water impoundments, such as stock ponds and reservoirs, which are common in rangelands. For example, a state-wide inventory in the early twenty-first century found that more than 70% of lentic wetlands in eastern Montana were human-created (Maxell 2009). Both the loss and creation of wetlands has influenced the contemporary distribution of herpetofauna across U.S. rangelands. Species such as the painted turtle (Chrysemys picta; Fig. 25.2), Woodhouse’s toad (Anaxyrus woodhousii), and tiger salamander (Ambystoma spp.) may have increased their distribution in some places because of water impoundments. In other cases, stock ponds may be the only habitat remaining in otherwise cropland-dominated landscapes (Knutson et al. 2004). Regardless, anthropogenic changes in the type, size, and depth of wetlands in rangelands has influenced herpetofauna distributions in all likelihood, and this may have implications for persistence as climates change. The Great Basin, for example, has been getting warmer and drier in the last century resulting in increased isolation of amphibian populations as detectable in the genetic structure of Columbia spotted frogs (Rana luteiventris; Fig. 25.1; Pilliod et al. 2015; Robertson et al. 2018). In the Great Plains, connectivity among > 80,000 playas from Nebraska to Texas may have been reduced beyond levels needed to support movements for many amphibian species (Heintzman and McIntyre 2021). Except for a few aquatic species, such as the painted turtle and common water snake (Nerodia sipedon), that require surface water to meet their life history needs, reptile distributions and threats are more subtle with regard to water.
Reptiles are much more tolerant of aridity than other vertebrates, enabling them to inhabit a diversity of upland habitats (Fig. 25.3) as long as temperatures are not too cold (Qian 2010). In the last several hundred years, however, reptiles and amphibians have been subjected to large scale land use changes, such as cropland agriculture, livestock production, timber harvest, and urbanization, all of which have influenced species distributions to varying extents (Cordier et al. 2021). Conversion of rangelands to hayfields or irrigated croplands is a major modification to potential habitats from the perspective of local herpetofauna (Fig. 25.3). In rangeland landscapes, the interdigitation of cropland fields, right-of-ways, hedgerows, and fencelines alter herpetofauna communities as these modified areas are frequently only inhabited by the more common and adaptable species (Pulsford et al. 2017). Obviously human features on the landscape that destroy habitat for herpetofauna, such as buildings, parking lots, solar installations, roads, railways, and so forth, also have cumulatively large footprints, and their effects extend into surrounding habitats (Averill-Murray et al. 2021).
The frequency distribution of predicted richness for amphibians and reptiles across different land cover types in rangelands of the U.S. Cropland and urban are embedded within rangelands and likely represent conversion of former rangelands. Richness data are from GAP predicted species distributions (USGS GAP 2018a). The vegetation cover types come from the North American Atlas Land Cover 2010 Mapping Project (data grain is 250 × 250 m). Metadata about these cover types can be found at: http://www.cec.org/north-american-environmental-atlas/land-cover-2010-modis-250m/. The y-axis is a count of 30-m pixels for each category and group. The pixel count (y-axis) of the top four land cover types (Cropland, Grassland, Shrubland, Forest) have a different range than the three less common land cover types (Barren, Urban, Water)
Species richness of both amphibians and reptiles tends to be higher in the south than the north (Fig. 25.4). Reptile diversity is greatest below the 37th parallel, which is highlighted by the state boundaries between Colorado and New Mexico as well as Utah and Arizona. This latitude coincidentally defines the average solar insolation on earth: below this line and toward the equator solar insolation is greater than average incoming solar radiation, whereas above the 37th parallel, toward the poles, solar insolation decreases. Below the 37th parallel, there are hotspots of reptile diversity in central and eastern Texas, with over 70 species found there. Moving northward, reptile diversity tapers off in a steady gradient (Kiester 1971). Amphibian diversity also decreases from the equator northward (Wiens 2007), but the Pacific Northwest has an unusually high diversity of salamanders. Similar to reptiles, the Texas–Mexico border area is also a hotspot of amphibian diversity (Fig. 25.4). The warm, dry conditions in the desert regions of the southwestern U.S. are ideal for reptiles, whereas this region has strikingly low amphibian diversity. Utah, for example, may only have one native salamander species, the western tiger salamander (Fig. 25.1; Ambystoma mavortium). The species was thought to also occur in Nevada, but molecular evidence suggests the only salamander populations in Nevada may be the eastern tiger salamander (Ambystoma tigrinum), introduced as bait by fisherman (Johnson et al. 2011). Introduced populations of eastern tiger salamanders have been discovered in other western states as well.
Map of predicted amphibian (upper panel) and reptile (lower panel) species richness in the United States with rangelands delineated based on ecoregions derived from The Nature Conservancy’s Geospatial Conservation Atlas (geospatial.tnc.org), modified using ecotype layers downloaded from the EPA Level III ecoregions in the Central Mixed—Grass Prairie region in Nebraska and Texas. The amphibian and reptile richness data came from the Gap Analysis Project (USGS GAP 2018b, c)
The elevational range of amphibians and reptiles is broad. For example, the sidewinder rattlesnake (Crotalus cerastes) and western threadsnake (Leptotyphlops humilis) are found below sea level in Death Valley, California whereas western fence lizards (Sceloporus occidentalis: Fig. 25.2) and mountain yellow-legged frogs (Rana muscosa) can be found above 3300 m (10,827 ft) in the Sierra Nevada of central California (Stebbins 2003). About the only areas devoid of herpetofauna in rangelands are alkali flats (dry desert lake beds) and alpine zones.
2.2 Population Monitoring
Population monitoring of herpetofauna species is mostly conducted by state and federal agencies, and is usually associated with species listed or petitioned under the Endangered Species Act or those listed as species of greatest conservation need in State Wildlife Action Plans. For amphibians, monitoring focuses almost exclusively on individual breeding sites or groups of sites in a landscape for species that tend to form metapopulations. The gold standard for population monitoring is mark-recapture. Mark-recapture studies involve marking individual animals with a unique identifier so that they can be identified if captured again in subsequent surveys or trapping efforts (Buckland et al. 2000). Common ways of marking animals are with passive integrated transponder (PIT) tags (Fig. 25.5), scale clips, shell notching, and colored paints, inks, and elastomers (Silvy et al. 2012). When conducted over at least three or more years, mark-recapture data can provide valuable estimates of population size and demographic rates. Population demography includes measures of natality or reproduction, recruitment, survival, senescence, and mortality. Demography data can provide more robust measures of trends and responses to environmental stressors or management compared with simple counts of individuals observed (Schmidt 2003). Indirect measures of populations, such as egg mass counts or enumeration of calling frogs and toads (such as with call recorders; Fig. 25.5), can also provide useful information for tracking population trends (Heyer et al. 1994).
Photographs of common field methods used in herpetological field studies, including: a Drift fences with funnel traps; b Line transect surveys, including distance sampling; c Hand capturing (in this case tubing a Great Basin rattlesnake (Crotalus oreganus lutosus) to allow for safe handling; d Radio-telemetry; e Marking individuals for mark-recapture studies (in this case inserting a passive integrative transponder (PIT) tag); f Call recorder for frogs and toads during the breeding season; g Environmental DNA sampling for species detection; and h PIT tag antenna to record the timing and direction of animal movement. Photographs by Todd Esque, Matthew Laramie, Chad Mellison, Amelia Orton-Palmer, Charles R. Peterson, and David Pilliod
Unlike amphibians or turtles that may congregate at water bodies to breed or forage, or snakes that may congregate to breed and overwinter at hibernacula, lizards and tortoises do not congregate and thus must be surveyed intensively over areas spanning hectares to square kilometers. Therefore, for most reptiles, optimal sampling designs include many plots or trapping locations distributed over large areas representing a range or variety of habitats used by a particular species. Search methods and effort must be consistent, or at least accounted for, among surveys and through time. Capture methods vary depending on the target species and include active sampling, such as noosing lizards or visual searching and capturing animals (Fig. 25.5). Sometimes capturing lizards and snakes involves wild chases and long arms to reach animals under rocks or in burrows, while other times it simply involves picking them up, as with tortoises. Passive sampling devices, such as drift fences, pitfall trap arrays, camera traps, or cover boards, are also commonly used and may be necessary for rare, cryptic, or fossorial species. Each method has some sampling bias because of activity patterns and size of target animals and life stages. Many studies are plagued by small sample sizes or high inter-annual variability in capture rates because of strong environmental associations, such as seasonal or annual weather. For community studies, oftentimes one or a few species dominate the capture tally whereas other species are captured too infrequently to even model.
Distance-sampling methods provide population estimates of species over large areas using standardized linear transects traveled by observers (Fig. 25.5; Buckland et al. 2000). This method was adopted to monitor Mojave desert tortoise (Gopherus agassizii; Fig. 25.2) population trends across its range since 1999 and continues today (USFWS 2011). Field teams are tested with tortoise models to calculate their ability to detect tortoises at various distances from the transect line and these correction factors are used to reduce error and improve estimates. Radio-tagged tortoises have also been used for this purpose and for validation of population estimates. Distance-sampling estimates of population size and trends, usually averaged over extensive areas, have provided important contributions to population management of the Mojave desert tortoise in Arizona, California, and Utah.
There are other monitoring approaches that are useful for herpetofauna that involve only presence/non-detection data and some of these methods have become quite sophisticated. Occupancy modeling has proven useful for herpetofauna (Bailey et al. 2014), including indirect measures of species occurrence such as environmental DNA (Fig. 25.5; Burian et al. 2021) and open drift-fences with cameras instead of traps (Martin et al. 2017). Occupancy modeling accounts for imperfect detection, which is important for herpetofauna that are often rare, cryptic, fossorial, or otherwise difficult to detect. After accounting for detection probabilities and measured environmental variables, presence and non-detection data from repeated visits are used to create occupancy probabilities for an area or site.
Studies of herpetofauna movements have revealed the complexity of diel, seasonal, and interannual habitat use patterns and the role of migration and dispersal in population dynamics and gene flow (Cayuela et al. 2020). Understanding movement ecology of herpetofauna is crucial for their conservation (Bailey and Muths 2019; Joly 2019). Juveniles are particularly understudied, although, as in other vertebrates, juveniles may represent one of the most important life stages for dispersal, colonization, and gene flow (Petrovan and Schmidt 2019). Movement studies generally involve tagging or marking individual animals and tracking their locations actively using radio-transmitters, passively using trapping, or opportunistically with surveys (Fig. 25.5). Radio-telemetry can also increase the certainty of population and demographic estimations (e.g., Mitchell et al. 2021). Twenty years of monitoring amphibians across the U.S. by the U.S. Geological Survey’s Amphibian Research and Monitoring Initiative (ARMI) has provided robust evidence that many amphibian populations are at risk of decline or extinction. An analysis of 83 species revealed that amphibian populations are disappearing from 3.7 to 3.8% of formerly occupied sites annually (Adams et al. 2013; Grant et al. 2016). At this rate, by 2035 many amphibian species will be gone from half of the places where they occurred in 2015 (Grant et al. 2016). These declines are due to a combination of factors driven by habitat loss, invasive predators, disease, and climate change. However, the status and trends of individual amphibian populations depend on many factors and not all species are necessarily at risk (Muths et al. 2018). Monitoring of 14 species of frogs and toads in the southeastern U.S. concluded that seven species were increasing (especially the green treefrog, Hyla cinerea, and spring peeper, Pseudacris crucifer; Fig. 25.1), while eight species showed a declining trend between 2001 and 2013 (Villena et al. 2016). Comparable regional or national monitoring programs do not exist for reptiles, except for a few species of highest conservation concern, such as the Mojave desert tortoise. Recent analyses showed only one of five of the recovery areas for Mojave desert tortoises had positive population growth after ~ 15 yr of monitoring, and juvenile tortoise numbers were declining (Allison and McLuckie 2018). These results are mostly inconsistent with recovery goals (USFWS 2011).
3 Habitat Associations
As ectotherms, climate plays an overarching role in the distribution and habitat associations of herpetofauna. In general, amphibians are limited by environmental temperature and precipitation, whereas reptiles are strongly associated with temperature (Buckley and Jetz 2007; Qian 2010). This explains why we see amphibians and reptiles in specific locations or habitats, including relative to seasons and times of day. As previously described, thermoregulation is crucial for physiological functions (e.g., digestion, metabolism) and performance (locomotion) of herpetofauna. Water balance, or hydroregulation, is also a key process underlying physiological and ecological responses. As might be expected, thermoregulation and hydroregulation are closely linked and thus these physiological and behavioral mechanisms often represent decisions or tradeoffs between optimal body temperature and water loss (Rozen-Rechels et al. 2019). A toad or lizard, for example, may tolerate some dehydration when selecting a warm, dry microsite needed to maintain a higher body temperature necessary for dispersal, digestion, or, in the case of a gravid (pregnant) female, embryonic development.
At the regional or landscape level, availability of freshwater is paramount for amphibians and some reptiles, and species assemblages depend on characteristics of wetland habitats and the spatial distribution and configuration of those wetlands (Mushet et al. 2012). Wetland amphibian habitats in rangelands and croplands are often characterized by the amount and complexity of shoreline, depth of water and availability of shallows, solar insolation, water chemistry, hydrology and hydroperiods, amount of emergent vegetation, and characteristics of riparian and floodplain vegetation (Knutson et al. 2004; Swartz and Miller 2019). Depending upon these habitat characteristics, amphibian communities can also be strongly influenced by predation, especially by salmonids (i.e., trout, char), centrarchids (e.g., bass, bluegill, pumpkinseed, sunfish), gartersnakes (Thamnophis spp.), American bullfrogs (Lithobates catesbeianus) and various birds (Pilliod et al. 2012; Ford et al. 2013; Rowe et al. 2019). In terrestrial environments, the structure and composition of vegetation have strong influences on herpetofauna habitats, especially related to the thermal environment, food resources, and cover (Fischer et al. 2004). In general, heterogeneous habitats provide more niches and microsites than homogeneous habitats (Fuhlendorf et al. 2017; Londe et al. 2020). Finally, contextual location is important, such as past land uses, elevation, landform, soils, surrounding habitat, and distance to nearest habitat suitable for survival, reproduction, or development (Kay et al. 2017; Sawatzky et al. 2019).
The majority of reptiles are not similarly constrained by water requirements. Although most temperate reptiles drink surface water, they also can temporarily tolerate hyperosmotic states of dehydration, which often occurs seasonally in arid and semi-arid rangelands. Some water can be obtained from food, but reptiles also have several physiological adaptations and behaviors that limit water loss (Dupoué et al. 2017). Furthermore, the diversity of body forms, low energy requirements, and behavioral adaptations to inclement weather and seasons enables reptiles to inhabit nearly all rangeland habitat types including most mesic and aquatic sites, prairies, shrub steppes and shrublands, savannahs, woodlands, and forest (Fig. 25.3). Thus, reptile habitat associations are incredibly varied. Because most species are ground-dwellers, understory vegetation and leaf litter (or inversely, bare ground) are often cited as important variables predicting reptile species occurrence across rangelands (e.g., Lindenmayer et al. 2018). Shrubs and trees are important for some reptile species and these species may disappear if these habitat elements are removed or lost to wildfire (Cossel 2003; James and M’Closkey 2003).
Some habitat selection by herpetofauna is associated with foraging behavior and mate finding. Some species will travel to and forage in locations with higher amounts of food resources, which often varies seasonally. Snakes and lizards can be classified as either active foragers that seek, and sometimes chase, their prey or sit-and-wait predators that opportunistically grab prey that comes close enough. The diet of snakes varies by species and habitat preferences, but can include small mammals, birds, fish, lizards, amphibians, and some invertebrates. A few snakes eat other snakes. Lizards and adult amphibians generally feed on arthropods (insects and spiders), annelids (segmented worms), and gastropods (slugs). Turtles are omnivorous, eating a variety of invertebrates, amphibians, fish, algae, and plants, whereas tortoises are strictly herbivorous.
4 Rangeland Management
4.1 Livestock Grazing
Excessive livestock grazing can affect amphibians through multiple pathways. First, overgrazing of grasses and forbs during the spring and summer can expose terrestrial amphibians to predators and desiccation in meadows and wetlands by reducing cover and allowing soils to dry (Canals et al. 2011; Pulsford et al. 2019). Second, excessive livestock use in aquatic habitats can increase turbidity and alter water chemistry via deposition of urine and feces (Schmutzer et al. 2008; Smalling et al. 2021). Negative impacts to water quality may affect larval development of amphibians but likely has fewer effects on amphibians compared with other factors such as hydroperiod and predators (Canals et al. 2011; Cole et al. 2016). Larval developmental issues associated with poor water quality, however, may be sublethal and have delayed effects that are only potentially problematic later in an animal’s life (Gray and Smith 2005; Chelgren et al. 2006). These time-lagged and carryover effects are particularly difficult to observe or measure but can have consequences at the population level (Babini et al. 2015; Bionda et al. 2018). And, finally, livestock may cause some direct mortality of individuals from trampling, although this is probably not a major source of mortality at the population level.
Despite these possible impacts from excessive livestock grazing, few studies have documented consistent negative effects of livestock grazing on amphibians and many amphibians breed successfully in stock ponds, even with heavy livestock use. Effects appear to be species-specific and depend upon habitat preferences (Burton et al. 2010). Some of this variability, however, may also be associated with variation in the type of grazers (e.g., cattle, sheep, goats), stocking rates, and timing and duration of grazing. One review of 46 published studies found only 22% demonstrated negative effects on amphibian communities and the remainder had either positive, neutral, or mixed effects (Howell et al. 2019). This meta-analysis indicated that most of the negative consequences of livestock grazing on amphibians occur in closed-canopy habitats whereas well-managed grazing in open habitats is compatible with amphibian conservation objectives. For example, some species, such as tiger salamanders, American toads (Anaxyrus americana), and western toads (A. boreas), thrive in open, shallow water environments even if used by grazing animals (Pyke and Marty 2005; Burton et al. 2010; Barrile et al. 2021a). A study of livestock-grazed meadows on the western slope of the Sierra Nevada Mountains, California found that Yosemite toads (Bufo canorus; Fig. 25.1) occupied pools that tended to be shallower, warmer, and more nitrogen enriched than unoccupied pools, regardless of livestock grazing intensity ranging from heavy to none (Roche et al. 2012). Similarly, Columbia spotted frog populations also do not appear to be impacted by use of breeding ponds by livestock (Adams et al. 2018), even though studies have found that frog survival, recruitment, and reproduction may increase in the first year or two after livestock are fenced out of breeding ponds (Pilliod and Scherer 2015). These short-term benefits to frogs, however, also are known to disappear from ponds as emergent vegetation becomes tall and dense in the absence of any livestock grazing (Pilliod and Scherer 2015).
Livestock may affect reptiles in both negative and positive ways through changes in grazed vegetation, nutrient redistribution, and physical impact of trampling to habitat components (soil, burrows, vegetation). Some research suggests, however, that livestock do not commonly crush reptiles or damage burrows by trampling (Nicholson and Humphreys 1981). In Australia, light to moderate livestock grazing intensities with a wet-season rest supported the most abundant reptile community, but only when compared with heavy, prolonged livestock grazing treatments (Neilly et al. 2018b). Other studies have found that reptile species richness is lower in grazed areas compared with areas where livestock are absent or where livestock have been removed or excluded with fencing (Hellgren et al. 2010; Read and Cunningham 2010). These responses are not universal and depend upon environmental conditions and habitat requirements of species present (Castellano and Valone 2006; Neilly et al. 2021).
Lizards can benefit from habitats opened up by livestock, as they sprint after prey and toward cover from predators, especially when grazing is managed carefully or used to reduce dense stands of invasive annual grasses that dominate formerly open areas and increase fire risk (Barry and Huntsinger 2021). The federally protected blunt-nosed leopard lizard (Gambelia sila; Fig. 25.2), for example, increased 500% in areas grazed by cattle in comparison with ungrazed areas dominated by invasive annual grasses in the San Joaquin Desert of southern California (Germano et al. 2012). Furthermore, the benefit of increased solar insolation for thermoregulation of reptiles and their egg temperatures in grazed habitats may confer benefits to reptiles from livestock grazing (Fabricius et al. 2003). The volume of rangeland research on herpetofauna in the last two decades has helped advance livestock grazing strategies that are compatible with reptile conservation. While more research is needed, we have sufficient credible, defensible information to move forward constructively (Barry and Huntsinger 2021).
4.2 Other Rangeland Management Actions
Water development, especially in arid and semi-arid environments, has likely influenced the distribution of amphibians. The development of springs, such as installing pipes and pumps, to provide livestock drinking water and other uses may alter the spring such that it no longer provides suitable overwintering habitat for some amphibians. Stock ponds and leaky or overflowing troughs, however, also create surface water in locations that may not have had surface water prior to development. Amphibians may use these artificial sources of water on the landscape to hydrate and occasionally breed (Alvarez et al. 2021). Chorus frogs, tiger salamanders, and other species can be found in water troughs or in their spillage areas in some otherwise dry shrublands and grasslands (Scott 1996). These oases also draw in amphibian predators like gartersnakes (Thamnophis spp.). Efforts are underway to help make water developments for livestock more compatible with amphibian and reptile use (Canals et al. 2011).
Vegetation treatments are common throughout rangelands of the western U.S., to improve forage quantity or quality, but also to control or remove non-native plant species, to stabilize soils and reduce erosion, and to rehabilitate recently burned areas, among other intentions (Pilliod et al. 2017). Many of these land treatments have the potential to affect herpetofauna, either positively or negatively (Pilliod et al. 2020). Research on this topic, however, is lacking and thus there are few guidelines to help resource managers design herp-friendly land treatments (but see Pilliod and Wind 2008; Kingsbury and Gibson 2012; Jones et al. 2016).
The thinning and removal of pinyon and juniper trees is a common rangeland management practice in the western U.S., particularly lately in the name of habitat management for the greater sage-grouse (Centrocercus urophasianus). What are often called pinyon-juniper or P-J woodlands are a forest type composed of single leaf‐pinyon pine (Pinus monophylla), Colorado pinyon (P. edulis), western juniper (Juniperus occidentalis), and Utah juniper (J. osteosperma). In the absence of fire and under favorable climatic conditions, these species have expanded their range into grasslands and shrublands, resulting in changes in water availability, soil chemistry, understory vegetation, and animal communities (Miller et al. 2000; Leis et al. 2017). Several lizard species inhabit P-J woodlands and benefit from the woody structure (Morrison and Hall 1999; James and M’Closkey 2003). The lizards use the trees and downed logs for basking, except for the tree lizard (Urosaurus ornatus; Fig. 25.2), which is distinctly arboreal and perches at greater heights than the other species (James and M’Closkey 2002). Arboreality may protect some lizard species from typical effects of livestock grazing (Jones 1981; Neilly et al. 2018a). Felling or burning trees might benefit lizards, like the sagebrush lizard (Sceloporus graciosus), but removing the dead and downed wood as part of fire management, fuel reduction, or habitat management for shrubland and grassland wildlife species could have negative consequences for tree lizards (Morrison and Hall 1999; James and M’Closkey 2003; Evans et al. 2019). Other lizard species are unlikely to be affected by such activities and ground-dwelling lizard species may benefit from such practices (Radke et al. 2008).
Prescribed fire practices appear to have minimal effects on herpetofauna in rangelands where it is appropriate. Besides concern about causing mortality from combustion or heat stress (Smith et al. 2001), particularly for turtles and tortoises (Larson 2014), most interest in prescribed fire is related to the role of fire in creating or maintaining heterogeneity in vegetation structure and composition that can sustain or enhance herpetofauna diversity (Wilgers and Horne 2006; Larson 2014). In southern Texas, a short-term study concluded that dormant-season fires had little effect on diversity and abundance of herpetofauna, but growing-season fires tended to increase diversity and abundance of grassland species, such as the six-lined racerunner (Cnemidophorus sexlineatus; Fig. 25.2; Ruthven et al. 2008). Minimal effects of prescribed fire on herpetofauna also have been reported in other rangelands, including California oak woodlands (Vreeland and Tietje 2002). Prescribed fire, grazing, and herbicide treatments have been used for creating or maintaining habitat heterogeneity for herpetofauna in seasonal wetlands, grasslands, and some woodlands, with mixed success (Jones et al. 2000; Larson 2014; Mester et al. 2015; Wilgers et al. 2006). In general, effects seem to be short-lived as plant communities respond to the disturbance and associated changes in nutrients, light availability, and competition. Even where prescribed fire appears to have negative effects on herpetofauna (e.g., Wilgers et al. 2006; Larson 2014), these effects tend not to persist through time. To optimize diversity, management for habitat mosaics may need to involve rotational burning, sometimes coupled with low-intensity cattle-grazing or herbicide treatments (Mester et al. 2015). This approach may allow species-specific responses in relation to changes in vegetation structure and microhabitat conditions (e.g., temperature, moisture of soil or vegetation) that changes through time (Wilgers and Horne 2006). The winners and losers scenario of wildlife response to local rangeland management is a reasonable conservation strategy as long as massive areas are not managed uniformly.
5 Impacts of Disease
Several amphibian and reptile diseases may be influenced by human activities and management practices in rangelands (Gray et al. 2017). One of the most notable amphibian diseases is the amphibian chytrid fungus, Batrachochytrium dendrobatidis or Bd, which causes chytriodiomycosis and is associated with severe population declines in several North American species (Lips 2016; Scheele et al. 2019). In rangelands, Bd is now thought to have contributed to the near extirpation of two toad species in the mid-1970s: the Wyoming toad (Anaxyrus hemiophrys baxteri; Fig. 25.1) and the Yosemite Toad (Kagarise Sherman and Morton 1993; Green and Kagarise Sherman 2001; Fig. 25.1). The Wyoming toad became functionally extinct in the wild by the 1980s (Lewis et al. 1985) and is a case study of the challenges of captive rearing, reintroduction, and species recovery in amphibians (Dreitz 2006). Variants of Bd exist and their pathogenicity are still being studied because not all amphibians in the U.S. are susceptible to Bd, at least under current environmental conditions. Like all wildlife diseases, the contraction of Bd, its prevalence in populations, and its effects on survival and fitness depend on the ecology and evolutionary history of the species with the disease in relation to the environment (Russell et al. 2019). For example, a study of boreal toads (Anaxyrus boreas) in western Wyoming revealed that livestock grazing may influence toad-Bd dynamics by creating warmer microclimates from the reduction of vegetation that allow toads to bask and clear themselves of the disease (Barrile et al. 2021a, b). Batrachochytrium salamandrivorans (Bsal) is a recently discovered disease from Asia that also causes chytridiomycosis. It quickly spread across Europe but has yet to arrive in North America (Waddle et al. 2020). The high diversity of North American salamanders puts the U.S. at extreme risk but, like frogs and toads exposed to Bd, some species may have innate protection, such as skin peptide defenses (Pereira and Woodley 2021).
Besides Bd, ranavirus is a major cause of mortality in some populations of amphibians (and some reptiles and fishes) around the world (Brunner et al. 2015). Ranavirus is not a single virus, but instead a group of iridoviruses first discovered in the northern leopard frog (Lithobates pipiens; Fig. 25.1), a common inhabitant of North American rangelands. Besides leopard frogs, it is known to infect the American bullfrog (Lithobates catesbeianus) and the commercial sale of leopard frogs and bullfrogs to laboratories and schools across America likely contributed to the spread and continental distribution of the viruses. The most widely known member of this group of viruses is the Ambystoma Tigrinum Virus (ATV), which can cause mortality in three species of tiger salamanders found in U.S. rangelands (Picco et al. 2007; Price et al. 2017). Ranaviruses appear to proliferate under periods of stress for the animals, such as changes in water temperature (Brunner et al. 2015). Ranavirus also may be more prevalent in areas where cattle congregate, possibly due to poor water quality caused by elevated turbidity and ammonia which stresses amphibians, particularly tadpoles and larvae (Hoverman et al. 2012). The creation of permanent ponds as water sources for livestock may also attract American Bullfrogs, which are known vectors of amphibian diseases (Yap et al. 2018; Brunner et al. 2019).
Disease in rangeland reptiles is a growing conservation concern (Fitzgerald et al. 2018; Mendoza-Roldan et al. 2021). Disease agents include microscopic bacteria, viruses, protozoans, and mycoses (fungi), frequently called zoonoses (or zoonotic) when they cause disease in humans and livestock (Mendoza-Roldan et al. 2021). Upper Respiratory Tract Disease Syndrome (URTDS), which causes inflammation and erosion of the nasal cavity and sometimes death, was first described in Mojave desert tortoises in California (Jacobson et al. 1991). The discovery of the disease agents of URTDS, Mycoplasma agassizii (Myag) and M. testudineum (Myte), was influential in the listing of the Mojave desert tortoises as Threatened under the Endangered Species Act (Brown et al. 2004; USFWS 2011). Myag and Myte are also found in Texas tortoises (G. berlandieri), gopher tortoises (G. polyphemus), and Sonoran desert tortoises (G. morafkai; Weitzman et al. 2017). Snake Fungal Disease is a rapidly emerging mycosis (Ophidiomyces ophiodiicola) that has now been found throughout the eastern U.S., and in several rangeland reptile species west of the Mississippi River (Lorch et al. 2016; Allender et al. 2020).
Many macroscopic parasites are also disease agents for reptiles, the most well-known including Arachnida (e.g., ticks, mites) and Diptera (flies and mosquitoes). Ticks are known globally as vectors for diseases hosted by reptiles, other wildlife, livestock, and humans. Borrelia spp. are spirochete bacteria carried by ticks and transmitted through the blood of vertebrate hosts. Borrelia spp. are causative agents for Lyme disease (Jacobson 2007; Swei et al. 2011) and Tick-Borne Relapsing Fever (TBRF; Forrester et al. 2015; Bechtel et al. 2021). Lyme disease (B. burgdorfii—Bobu) is the most common vector-born disease in the United States (CDC 2008). In California, western black-legged ticks (Ixodes pacificus) are vectors for Bobu among > 55 vertebrate hosts, including nine lizard species (Swei et al. 2011). About 90% of hosts for nymphal and larval ticks are western fence lizards, but the lizards are not very competent hosts because their blood includes borreliacidal components (i.e., when the lizard blood enters the tick during a meal it kills the Bobu). Regions with abundant lizards may have a lower proportion of Borrelia-infected tick nymphs and larvae (Ginsberg et al. 2021).
6 Ecosystem Threats
6.1 General
Some threats to amphibians, such as wetland habitat loss and degradation, non-native predators, and disease, are common to amphibians around the world (Lemckert et al. 2012; Pilliod et al. 2012; Wake and Koo 2018). Much less is known about specific threats to rangeland-associated amphibians, but several warrant consideration even if scientific evidence for their impacts is ambiguous or lacking (Mims et al. 2020). First, changes to hydrology or hydroperiod associated with water pumping, diversions, and dams are concerns. Stable, predictable water levels and flow rates are crucial for the development of amphibian tadpoles and larvae and the survival of post-metamorphic animals during the dry season and drought (Pilliod et al. 2021). Second, intensive human land use puts amphibians at risk because of clearing of vegetation, road construction, culvert installation, wastewater discharge (e.g., from hydrocarbon extraction, concentrated animal feeding operations), and construction of impervious surfaces (i.e., cement, asphalt). Crop production also is an intensive land use, although amphibian responses can be mixed. Some amphibians will venture into fields during pivot and flood irrigation and be attracted to lights when foraging for insects (Hansen et al. 2019) but, in general, homogenization of vegetation and application of chemicals (i.e., fertilizers, herbicides, insecticides) can be detrimental to amphibians or their habitats. Amphibians that forage in moist crop fields may then avoid these same areas after harvest. Fire and its relationship with changes in climate and invasive plant species is also potentially important, but in need of additional study (Mims et al. 2020).
Reptiles face many of the same threats as amphibians in rangelands, especially loss and isolation of suitable habitats, disease, and pollution from animal wastes and agrichemicals (Fitzgerald et al. 2018). A meta-analysis of 56 studies that reported on how habitat modification affected the abundance of 376 reptile species concluded that mining had the most negative impacts, followed by farming, livestock grazing, and tree plantations (Doherty et al. 2020). The mean effect of logging was neutral. Because of their tendency to bask and forage in areas of human use, reptiles may be more prone to direct mortality from human activities than other animals, although this has been difficult to quantify. A study using carcass detection dogs found that 57% of animals killed during typical agricultural mowing were reptiles, especially lizards (Deak et al. 2021). Invasive plants, especially dense annual grasses that cover open areas of bare ground, are known to interfere with lizard and snake movements and foraging ability in desert rangelands (Rieder et al. 2010; Blakemore 2018). The increased frequency of wildfire caused by these grasses also appears to have negative consequences for some reptile species, either through direct mortality (Jolly et al. 2022) or changes in habitat (Woinarski et al. 1999; Cossel 2003). Some species are also the target of exploitation, such as collection and sale in the illicit internet pet trade, whereas others are simply persecuted because of general fear or hatred of snakes, especially rattlesnakes and other pit vipers (Katzner et al. 2020).
The proliferation of transportation and energy infrastructure across rangeland landscapes further increases herpetofauna road mortality, creates barriers to migration and dispersal, and fragments once continuous habitats (Doherty et al. 2021). Road mortality is considered the leading cause of reptile mortality, especially for snakes (Hill et al. 2019). Roads provide attractive surfaces for thermoregulation and movement and collisions with vehicles are rampant, even on rural rangeland roads (Jochimsen et al. 2014; Hubbard et al. 2016). A study in southeastern Ohio found that the amount of pasture within a 100 m buffer of a roadkill was the strongest predictor of road mortality for 14 snake species (Wagner et al 2021). Fencing reptiles out of roadways comes with its own costs for snakes and turtles, including restricting access to seasonal resources and reducing gene flow among populations (Markle et al. 2017). Newly applied genetic tools and analyses provide insight to the influence of geographic factors like roads and railways on reptiles and amphibians. For example, a railway constructed some 120 yr ago bisected a population of Mojave desert tortoises resulting in differences in genetic diversity on either side of the railway after only about eight generations of tortoises (Dutcher et al. 2020). Roads and other human development certainly continue to play a role in shaping the population genetic structure of herpetofauna through reduced movement of individuals and reduced exchange of genes among populations. More research is needed on appropriate methods to avoid herpetofauna mortality and barriers to movement using overpasses or culverts to provide safe passage routes across roads and railways.
6.2 Climate Change
Changes in climate across U.S. rangelands may alter environmental conditions to such an extent that many, if not all, aspects of herpetofauna ecology will be affected. Observed changes in climate over the last several decades depend on location, especially latitude and elevation, but also continental position relative to mountain ranges (e.g., rain shadows) and the Pacific coast. Depending upon location, rangelands are experiencing warmer winters, shallower snowpacks, earlier springs, warmer nighttime (i.e., minimum) temperatures, longer and warmer growing seasons, shifts in summer monsoons, and longer, more frequent and severe heat waves and droughts (Polley et al. 2013; McCollum et al. 2017). All of these factors tend to be more variable year to year, and less predictable. These environmental changes will affect herpetofauna reproduction, development, and survival. Changes in wetland hydroperiods, earlier peak flows and more variable intermittency in streams, changes in the insulating capacity of snow in winter, changes in the thermal environment during the active season, and changes in the phenology of plants and prey (insects, small mammals) are most worrisome. Animals will adjust their diel and seasonal activity patterns to a point, but not without consequences. For example, some amphibians are breeding earlier and at smaller body sizes compared with a few decades ago (Li et al. 2013), which may expose some populations to higher mortality and stress (e.g., heightened disease risk) and result in population declines (Miller et al. 2018; Muths et al. 2018). Spiny lizards (Sceloporus spp.), which are common in rangelands, may have already experienced widespread population declines associated with climate change. Revisits of 200 sites in Mexico revealed 12% of local populations may have gone extinct since 1975. Using physiological models, the research suggests that thermal niches at these locations may have been altered to the point where lizards can no longer forage adequately to permit viable embryo development (Sinervo et al. 2010). Lizards may be particularly vulnerable to climate change because of their close affiliation with specific soil substrates for thermoregulation and reproduction and relatively limited dispersal abilities, often resulting in small or patchy distributions. Thermal niche modeling suggests that local extinction of lizard populations could reach 39% worldwide and 20% of species may be at risk of extinction by 2080 (Sinervo et al. 2010). Unfortunately, few lizard populations or species are being monitored in rangelands and thus many extinctions may occur quickly and without notice.
Adaptive behavior may enable herpetofauna to cope with climate changes. For example, herpetofauna may find microhabitats that allow them to maintain preferred body temperatures and moisture levels (Long and Prepas 2012). Phenotypic plasticity and genetic adaptation among herpetofauna also may mitigate some of the effects of climate change (Urban et al. 2013) but also may create new challenges. There is concern, for example, that, as temperatures increase, amphibians who rely on terrestrial foraging may need to change their foraging strategies because of the risk of dehydration (Lertzman‐Lepofsky et al. 2020). This effect could be worsened in heavily grazed areas where vegetative cover is reduced (Bartelt et al. 2010). A study in California, however, found that vernal pools that were grazed by livestock dried an average of 50 days per year later than ungrazed pools, probably because of increased evapotranspiration from the abundant vegetation in the ungrazed wetlands (Pyke and Marty 2005). This study demonstrates the complex interactions between grazing and climate change and, in this case, climate mitigation strategies for species like the endangered California tiger salamander (Ambystoma californiense; Pyke and Marty 2005). Predictions for reptiles are no simpler, because we know little about how these animals are able to adjust their basking and foraging behavior or take advantage of microhabitats. Further, livestock grazing in rangelands may ameliorate or exacerbate the effects of climate change in unforeseen ways, including potential changes in the availability and distribution of thermal refuges (Clayton and Bull 2015; Rutschmann et al. 2016).
7 Conservation and Management Actions
Concerns about herpetofauna in the U.S. have stimulated an active community of diverse partners, including federal, state, tribal, NGOs, private landowners, and concerned citizens. These groups and partnerships take many forms. Formal working groups, such as those involved in endangered species conservation, tend to work on single species issues. Examples from U.S. rangelands include the Columbia spotted frog in Nevada and other states (Pilliod, in press). In Nevada, interagency technical teams have met since 1999 and helped the U.S. Fish and Wildlife Service write a conservation plan for this species that balanced species conservation with other rangeland issues. This led to a Conservation Agreement and Strategy for two distinct population segments (Northeast Nevada and Toiyabe subpopulations) that were first implemented in 2003 and then renewed for another 10 yr in 2015 (McAdoo and Mellison 2016). The technical team helps coordinate and implement the conservation plan, recruit assistance from scientists and other stakeholders to evaluate the effectiveness of conservation actions, status, and trends, and change the plan as necessary to meet the stated goals.
Partners in Amphibian and Reptile Conservation (www.parcplace.org, accessed 14 July 2021) is another organization that is bringing conservation issues to the forefront and facilitating creative solutions to pressing conservation challenges in rangelands and elsewhere. PARC is an open conservation community with participation, partnerships, and directions determined by current members at state, regional, and national levels. Most importantly, biologists, natural resource specialists, and land managers from public agencies meet with private landowners, concerned citizens, and industry to foster and implement conservation efforts. Simply put, the group forges proactive partnerships to conserve amphibians, reptiles, and the places they live. This inclusive approach to conservation has proven highly successful because it brings diverse perspectives to the table and garners ownership of conservation approaches. An important set of publications produced by PARC is the habitat management guidelines (HMG’s). Each volume covers a specific region of the country with rangelands mostly represented in the Northwest and Western Canada (Pilliod and Wind 2008), Midwest (Kingsbury and Gibson 2012), and Southwest (Jones et al. 2016). The HMG’s are designed to help managers think about herpetofauna habitat needs from the perspective of specific vegetation types. The guidelines include examples for “maximizing compatibility” whereby landowners and resource managers can contribute to the conservation and stewardship of these animals while managing their land primarily for other uses, such as livestock grazing or farming.
Habitat management guidelines for livestock grazing suggest landowners and managers consider: (1) controlling timing and extent of livestock access to wetlands and streams through fencing, restricted access points, and seasonal use, (2) establishing alternative water sources such as water troughs, (3) carefully developing springs to serve as a source for livestock water without interfering with the spring’s ability to provide water to wildlife and hibernacula for amphibians, and (4) managing grazing to maintain a higher stubble height of herbaceous vegetation that could preserve forage quality while maintaining cover from predators and desiccating conditions. More detailed recommendations can be found in the HMGs and other guidelines that are available for specific species or locations (e.g., Ford et al. 2013).
8 Research/Management Needs
The research and management needs of herpetofauna in rangelands are considerable because they are some of the least-studied vertebrates and many species lack sufficient information to make informed conclusions about status, trends, and threats, much less decisions about effective management and conservation strategies. Throughout this chapter we have highlighted areas of needed research. We encourage researchers and managers to work together to identify the most pressing and relevant issues to improve conservation actions and outcomes for rangeland amphibians and reptiles. Efficient, timely, co-production of scientific information is urgently needed given the current and forthcoming threats to herpetofauna and rangelands. Public–private engagement and diverse stakeholder partnerships may be the best way to incorporate this information effectively into conservation planning and decision making for herpetofauna and other wildlife across our nation’s rangelands.
References
Adams MJ, Miller DAW, Muths E, Corn PS, Campbell Grant EH, Bailey LL, Fellers GM, Fisher RN, Sadinski WJ, Waddle H, Walls SC (2013) Trends in amphibian occupancy in the United States. PLoS ONE 8:e64347
Adams MJ, Pearl CA, Chambert T, McCreary B, Galvan SK, Rowe J (2018) Effect of cattle exclosures on Columbia spotted frog abundance. Wetlands Ecol Manage 26:627–634
Allender MC, Ravesi MJ, Haynes E, Ospina E, Petersen C, Phillips CA, Lovich R (2020) Ophidiomycosis, an emerging fungal disease of snakes: targeted surveillance on military lands and detection in the western US and Puerto Rico. PLoS ONE 15:e0240415
Allison LJ, McLuckie AM (2018) Population trends in Mojave desert tortoises (Gopherus agassizii). Herpetol Conserv Biol 13:433–452
Alvarez JA, Shea MA, Foster SM, Wilcox JT (2021) Use of atypical aquatic breeding habitat by the California tiger salamander. California Fish Wildlife, Special CESA Issue 235–240
Arkle RS, Pilliod DS (2015) Persistence at distributional edges: Columbia spotted frog habitat in the arid Great Basin, USA. Ecol Evol 5:3704–3724
Averill-Murray RC, Esque TC, Allison LJ, Bassett S, Carter SK, Dutcher KE, Hromada SJ, Nussear KE, Shoemaker K (2021) Connectivity of Mojave desert tortoise populations—management implications for maintaining a viable recovery network. U.S. Geological Survey Open-File Report 2021–1033, 23 p. https://doi.org/10.3133/ofr20211033
Babini MS, de Lourdes BC, Salas NE, Martino AL (2015) Health status of tadpoles and metamorphs of Rhinella arenarum (Anura, Bufonidae) that inhabit agroecosystems and its implications for land use. Ecotoxicol Environ Saf 118:118–125
Bailey LL, Muths E (2019) Integrating amphibian movement studies across scales better informs conservation decisions. Biol Cons 236:261–268
Bailey LL, MacKenzie DI, Nichols JD (2014) Advances and applications of occupancy models. Methods Ecol Evol 5:1269–1279
Barrile GM, Chalfoun AD, Walters AW (2021a) Livestock grazing, climatic variation, and breeding phenology jointly shape disease dynamics and survival in a wild amphibian. Biol Cons 261:109247
Barrile GM, Chalfoun AD, Walters AW (2021b) Infection status as the basis for habitat choices in a wild amphibian. Am Nat 197:128–137
Barry S, Huntsinger L (2021) Rangeland land-sharing, livestock grazing’s role in the conservation of imperiled species. Sustainability 13:4466
Bartelt PE, Klaver RW, Porter WP (2010) Modeling amphibian energetics, habitat suitability, and movements of western toads, Anaxyrus (= Bufo) boreas, across present and future landscapes. Ecol Model 221:2675–2686
Bechtel, MJ, Drake KK, Esque TC, Nieto NC, Foster JT, Teglas MB (2021) Borreliosis transmission from ticks associated with desert tortoise burrows: examples of tick-borne relapsing fever in the Mojave Desert. Vector-Borne Zoonotic Diseases, ahead of print. https://doi.org/10.1089/vbz.2021.0005
Bionda CDL, Babini S, Martino AL, Salas NE, Lajmanovich RC (2018) Impact assessment of agriculture and livestock over age, longevity and growth of populations of common toad Rhinella arenarum (anura: Bufonidae), central area of Argentina. Global Ecol Conserv 14:e00398
Blackburn DG, Evans HE, Vitt LJ (1985) The evolution of fetal nutritional adaptations. Fortschritte Der Zoology 30:437–439
Blakemore G (2018) A mechanistic and landscape scale approach quantifying habitat suitability of cheatgrass (Bromus tectorum) engineered habitats for Great Basin reptiles. M.S. thesis, University of Nevada Reno, Reno, NV. http://hdl.handle.net/11714/4517
Bouzid NM, Archie JW, Anderson RA, Grummer JA, Leaché AD (2021) Evidence for ephemeral ring species formation during the diversification history of western fence lizards (Sceloporus occidentalis). Mol Ecol. https://doi.org/10.1111/mec.15836
Bragg AN (1940) Habits, habitat, and breeding of Bufo Cognatus Say. Am Nat 74:322–349
Brown DR, Merritt JL, Jacobson ER, Klein PA, Tully JG (2004) Mycoplasma testudineum sp. nov., from a desert tortoise (Gopherus agassizii) with upper respiratory tract disease. Int J Syst Evol Microbiol 54:1527–1529
Brunner JL, Storfer A, Gray MJ, Hoverman JT (2015) Ranavirus ecology and evolution: from epidemiology to extinction. In: Gray MJ, Chinchar VG (eds) Ranaviruses: lethal pathogens of ectothermic vertebrates. Springer, Switzerland, pp 71–104
Brunner JL, Olson AD, Rice JG, Meiners SE, Le Sage MJ, Cundiff JA, Goldberg CS, Pessier AP (2019) Ranavirus infection dynamics and shedding in American bullfrogs: consequences for spread and detection in trade. Dis Aquat Org 135:135–150
Bryson RW Jr, Jaeger JR, Lemos-Espinal JA, Lazcano D (2012) A multilocus perspective on the speciation history of a North American aridland toad (Anaxyrus punctatus). Mol Phylogenet Evol 64:393–400
Buckland ST, Goudie IBJ, Borchers DL (2000) Wildlife population assessment: past developments and future directions. Biometrics 56:1–12
Buckley LB, Jetz W (2007) Environmental and historical constraints on global patterns of amphibian richness. Proc Royal Soc B: Biol Sci 274(1614):1167–1173
Burian A, Mauvisseau Q, Bulling M, Domisch S, Qian S, Sweet M (2021) Improving the reliability of eDNA data interpretation. Mol Ecol Resour 21:1422–1433
Burton EC, Gray MJ, Schmutzer AC, Miller DL (2010) Differential responses of postmetamorphic amphibians to cattle grazing in wetlands. J Wildl Manag 73:269–277
Canals RM, Ferrer V, Iriarte A, Cárcamo S, San Emeterio L, Villanueva E (2011) Emerging conflicts for the environmental use of water in high-valuable rangelands. Can livestock water ponds be managed as artificial wetlands for amphibians? Ecol Eng 37:1443–1452
Carter SK, Nussear KE, Esque TC, Leinwand IIF, Masters E, Inman RD, Carr NB, Allison LJ (2020) Quantifying development to inform management of Mojave and Sonoran desert tortoise habitat in the American Southwest. Endangered Species Res 42:167–184
Castellano MJ, Valone TJ (2006) Effects of livestock removal and perennial grass recovery on the lizards of a desertified arid grassland. J Arid Environ 66:87–95
Cayuela HA, Teulier L, Martínez-Solano I, Léna J-P, Merilä J, Muths E, Shine R, Quay L, Denoël M, Clobert J, Schmidt BR (2020) Determinants and consequences of dispersal in vertebrates with complex life cycles: a review of pond-breeding amphibians. Q R Biol 95:1–36
CDC [Centers for Disease Control] (2008) Surveillance for Lyme disease—United States, 1992–2006. Morb Mortal Wkly Rep 57:1–9
Chelgren ND, Rosenberg DK, Heppell SS, Gitelman AI (2006) Carryover aquatic effects on survival of metamorphic frogs during pond emigration. Ecol Appl 16:250–261
Clayton J, Bull CM (2015) The impact of sheep grazing on burrows for pygmy bluetongue lizards and on burrow digging spiders. J Zool 297:44–53
Cole EM, Hartman R, North MP (2016) Hydroperiod and cattle use associated with lower recruitment in an r-selected amphibian with a declining population trend in the Klamath Mountains, California. J Herpetol 50:37–43
Cordier JM, Aguilar R, Lescano JN, Leynaud GC, Bonino A, Miloch D, Loyola R, Nori J (2021) A global assessment of amphibian and reptile responses to land-use changes. Biol Cons 253:108863
Cossel Jr JO (2003) Changes in reptile populations in the Snake River Birds of Prey Area, Idaho between 1978–1979 and 1997–1998: the effects of weather, habitat and wildfire. Doctoral dissertation, Idaho State University, Pocatello, Idaho
Crother BI (2017) Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding, 8th edn. Herpetological Circular 43, Society for the Study of Amphibians and Reptiles, University Heights, Ohio. https://ssarherps.org/wp-content/uploads/2017/10/8th-Ed-2017-Scientific-and-Standard-English-Names.pdf
Crother BI, Boundy J, Campbell JA, DeQuiero K, Frost D, Green DM, Highton R, Iverson JB, McDiarmid RW, Meylan PA, Reeder TA, Seidel ME, Sites JW Jr, Tilley SG, Wake DB (2003) Scientific and standard English names of amphibians and reptiles of North America north of Mexico: update. Herpetol Rev 34:196–203
Dahl TE (1990) Wetlands losses in the United States, 1780’s to 1980’s. US Department of the Interior, Fish and Wildlife Service, Washington, DC
Deak G, Katona K, Biro Z (2021) Exploring the use of a carcass detection dog to assess mowing mortality in Hungary. J Vertebr Biol 69:20089
Doherty TS, Balouch S, Bell K, Burns TJ, Feldman A, Fist C, Garvey TF, Jessop TS, Meiri S, Driscoll DA (2020) Reptile responses to anthropogenic habitat modification: a global meta-analysis. Glob Ecol Biogeogr 29:1265–1279
Doherty TS, Hays GC, Driscoll DA (2021) Human disturbance causes widespread disruption of animal movement. Nature Ecol Evol 5:513–519
Dreitz VJ (2006) Issues in species recovery: an example based on the Wyoming toad. Bioscience 56:765–771
Dupoué A, Rutschmann A, Le Galliard JF, Miles DB, Clobert J, DeNardo DF, Brusch GA, Meylan S (2017) Water availability and environmental temperature correlate with geographic variation in water balance in common lizards. Oecologia 185:561–571
Dutcher K, Nussear KE, Vandergast A, Esque TC, Mitelberg A, Heaton J (2020) Genes in space: what Mojave desert tortoise genetics can tell us about landscape connectivity. Conserv Genet 21:289–303
Evans MJ, Newport JS, Manning AD (2019) A long-term experiment reveals strategies for the ecological restoration of reptiles in scattered tree landscapes. Biodivers Conserv 28:2825–2843
Fabricius C, Burger M, Hockey PAR (2003) Comparing biodiversity between protected areas and adjacent rangeland in xeric succulent thicket, South Africa: arthropods and reptiles. J Appl Ecol 40:392–403
Fischer J, Lindenmayer D, Cowling A (2004) The challenge of managing multiple species at multiple scales: reptiles in an Australian grazing landscape. J Appl Ecol 41:32–44
Fitzgerald LA, Walkup DK, Chyn K, Buchholtz E, Angeli N, Parker M (2018) The future for reptiles: advances and challenges in the anthropocene. In: Dellasala DA, Goldstein MI (eds) Encyclopedia of the anthropocene. Elsevier Press, Amsterdam, pp 162–174
Ford LD, Van Hoorn PA, Rao DR, Scott NJ, Trenham PC, Bartolome JW (2013) Managing rangelands to benefit California red-legged frogs and California tiger salamanders. Alameda County Resource, Livermore, California
Forrester JD, Kjemtrup AM, Fritz CL, Marsden-Haug N, Nichols JB, Tengelsen LA, Sowadsky R, DeBess E, Cieslak PR, Weiss J, Evert N (2015) Tickborne relapsing fever—United States, 1990–2011. Centers for Disease Control and Prevention (US). MMWR Morb Mortal Weekly Report 64:58–60
Fuhlendorf SD, Fynn RW, McGranahan DA, Twidwell D (2017) Heterogeneity as the basis for rangeland management. In: Briske DD (ed) Rangeland systems: processes, management and challenges. Springer, Switzerland, pp 169–196
Funk WC, Pearl CA, Draheim HM, Adams MJ, Mullins TD, Haig SM (2008) Range-wide phylogeographic analysis of the spotted frog complex (Rana luteiventris and Rana pretiosa) in northwestern North America. Mol Phylogenet Evol 49:198–210
Gauthier J, Kluge AG, Rowe T (1988) Amniote phylogeny and the importance of fossils. Cladistics 4:105–209
Gerlanc NM, Kaufman GA (2003) Use of bison wallows by anurans on Konza Prairie. Am Midl Nat 150:158–168
Germano DJ, Rathbun GB, Saslaw LR (2012) Effects of grazing and invasive grasses on desert vertebrates in California. J Wildl Manag 76:670–682
Gibson PP, Olden JD (2014) Ecology, management, and conservation implications of North American beaver (Castor canadensis) in dryland streams. Aquat Conserv Mar Freshwat Ecosyst 24:391–409
Ginsberg HS, Hickling GJ, Burke RL, Ogden NH, Beati L, LeBrun RA, Arsnoe IM, Gerhold R, Han S, Jackson K, Maestas L (2021) Why Lyme disease is common in the northern US, but rare in the south: the roles of host choice, host-seeking behavior, and tick density. PLoS Biol 19:e3001066
Gordon MR, Simandle ET, Sandmeier FC, Tracy CR (2020) Two new cryptic endemic toads of Bufo discovered in central Nevada, western United States (Amphibia: Bufonidae: Bufo [Anaxyrus]). Copeia 108:166–183
Grant EHC, Miller DAW, Schmidt BR, Adams MJ, Amburgey SM, Chambert T, Cruickshank SS, Fisher RN, Green DM, Hossack BR, Johnson PTJ, Joseph MB, Rittenhouse TAG, Ryan ME, Waddle JH, Walls SC, Bailey LL, Fellers GM, Gorman TA, Ray AM, Pilliod DS, Price SJ, Saenz D, Sadinski W, Muths E (2016) Quantitative evidence for the effects of multiple drivers on continental-scale amphibian declines. Sci Rep 6:25625
Gray AL, Duffus J, Haman KH, Harris RN, Allender MC, Thompson TA, Christman MR, Sacerdote-Velat A, Sprague LA, Williams JM, Miller DL (2017) Pathogen surveillance in herpetofaunal populations: guidance on study design, sample collection, biosecurity, and intervention strategies. Herpetological Review 48:334–351
Gray MJ, Smith LM (2005) Influence of land use on postmetamorphic body size of playa lake amphibians. J Wildl Manag 69:515–524
Green DE, Kagarise Sherman C (2001) Diagnostic histological findings in Yosemite toads (Bufo canorus) from a die-off in the 1970s. J Herpetol 35:92–103
Grudzinski BP, Cummins H, Vang TK (2020) Beaver canals and their environmental effects. Prog Phys Geogr Earth Environ 44:189–211
Hansen NA, Scheele BC, Driscoll DA, Lindenmayer DB (2019) Amphibians in agricultural landscapes: the habitat value of crop areas, linear plantings and remnant woodland patches. Anim Conserv 22:72–82
Heintzman LJ, McIntyre NE (2021) Assessment of playa wetland network connectivity for amphibians of the south-central Great Plains (USA) using graph-theoretical, least-cost path, and landscape resistance modelling. Landscape Ecol 36:1117–1135
Hellgren EC, Burrow AL, Kazmaier RT, Ruthven DC III (2010) The effects of winter burning and grazing on resources and survival of Texas horned lizards in a thornscrub ecosystem. J Wildl Manag 74:300–309
Heyer R, Donnelly MA, Foster M, Mcdiarmid R (eds) (1994) Measuring and monitoring biological diversity: standard methods for amphibians. Smithsonian Institution, Washington, DC
Hill JE, DeVault TL, Belant JL (2019) Impact of the human footprint on anthropogenic mortality of North American reptiles. Acta Oecologica 101:103486
Hossack BR, Corn PS, Pilliod DS (2005) Lack of significant changes in the herpetofauna of Theodore Roosevelt National Park, North Dakota, since the 1920s. Am Midl Nat 154:423–432
Hossack BR, Gould WR, Patla DA, Muths E, Daley R, Legg K, Corn PS (2015) Trends in Rocky Mountain amphibians and the role of beaver as a keystone species. Biol Cons 187:260–269
Hoverman JT, Gray MJ, Miller DL, Haislip NA (2012) Widespread occurrence of ranavirus in pond-breeding amphibian populations. EcoHealth 9:36–48
Howell HJ, Mothes CC, Clements SL, Catania SV, Rothermel BB, Searcy CA (2019) Amphibian responses to livestock use of wetlands: new empirical data and a global review. Ecol Appl 29:e01976
Hubbard KA, Chalfoun AD, Gerow KG (2016) The relative influence of road characteristics and habitat on adjacent lizard populations in arid shrublands. J Herpetol 50:29–36
Jacobson ER (2007) Chapter 10 Bacterial diseases of reptiles. In: Jacobson ER (ed) Infectious diseases and pathology of reptiles: color atlas and text. CRC Press, New York, NY, pp 461–526
Jacobson ER, Gaskin JM, Brown MB, Harris RK, Gardiner CH, LaPointe JL, Adams JP, Reggiardo C (1991) Chronic upper respiratory tract disease of free-ranging desert tortoises, Xerobates agassizii. J Wildl Dis 27:296–316
James SE, M’Closkey RT (2002) Patterns of microhabitat use in a sympatric lizard assemblage. Can J Zool 80:2226–2234
James SE, M’Closkey TR (2003) Lizard microhabitat and fire fuel management. Biol Cons 114:293–297
Jochimsen DM, Peterson CR, Harmon LJ (2014) Influence of ecology and landscape on snake road mortality in a sagebrush-steppe ecosystem. Anim Conserv 17:583–592
Johnson JR, Thomson RC, Micheletti SJ, Shaffer HB (2011) The origin of tiger salamander (Ambystoma tigrinum) populations in California, Oregon, and Nevada: introductions or relicts? Conserv Genet 12:355–370
Joly P (2019) Behavior in a changing landscape: using movement ecology to inform the conservation of pond-breeding amphibians. Front Ecol Evol 7:155
Jolly CJ, Dickman CR, Doherty TS, van Eeden LM, Geary WL, Legge SM, Woinarski JC, Nimmo DG (2022) Animal mortality during fire. Global Change Biology
Jones B, Fox SF, Leslie DM, Engle DM, Lochmiller RL (2000) Herpetofaunal responses to brush management with herbicide and fire. Rangel Ecol Manage 53:154–158
Jones KB (1981) Effects of grazing on lizard abundance and diversity in western Arizona. Southwestern Naturalist 26:107–115
Jones LL, Halama KJ, Lovich RE (2016) Habitat management guidelines for amphibians and reptiles of the Southwestern United States. Partners in Amphibian and Reptile Conservation, Technical Publication HMG-5, Birmingham, Alabama
Kagarise Sherman C, Morton ML (1993) Population declines of Yosemite toads in the eastern Sierra Nevada of California. J Herpetol 27:186–198
Katzner TE, Carlisle JD, Poessel SA, Thomason EC, Pauli BP, Pilliod DS, Belthoff JR, Heath JA, Parker KJ, Warner KS, Hayes HM, Aberg MC, Ortiz PA, Amdor SM, Alsup SE, Coates SE, Miller TA, Duran ZK (2020) Illegal killing of non-game wildlife and recreational shooting in conservation areas. Conserv Sci Pract e279
Kay GM, Mortelliti A, Tulloch A, Barton P, Florance D, Cunningham SA, Lindenmayer DB (2017) Effects of past and present livestock grazing on herpetofauna in a landscape-scale experiment. Conserv Biol 31:446–458
Kiester AR (1971) Species density of North American amphibians and reptiles. Syst Zool 20:127–137
Kingsbury BA, Gibson J (2012) Habitat management guidelines for amphibians and reptiles of the Midwestern United States, 2nd edn. Partners in amphibian and reptile conservation, Birmingham, Alabama
Kimberly DA, Fender CL (2020) Amphibians and reptiles of Antelope Island, Great Salt Lake, Utah. In: Baxter BK, Butler JK (eds) Great salt lake biology: a terminal lake in a time of change. Springer, Switzerland, pp 345–367
Knutson MG, Richardson WB, Reineke DM, Gray BR, Parmelee JR, Weick SE (2004) Agricultural ponds support amphibian populations. Ecol Appl 14:669–684
Larson DM (2014) Grassland fire and cattle grazing regulate reptile and amphibian assembly among patches. Environ Manage 54:1434–1444
Laudet V (2011) The origins and evolution of vertebrate metamorphosis. Curr Biol 21:R726–R737
Leis SA, Blocksome CE, Twidwell D, Fuhlendorf SD, Briggs JM, Sanders LD (2017) Juniper invasions in grasslands: research needs and intervention strategies. Rangelands 39:64–72
Lemckert F, Hecnar SJ, Pilliod DS (2012) Loss and modification of habitat. In: Heatwole H, Wilkinson JW (eds) Conservation and decline of amphibians: ecological aspects, effect of humans, and management. Amphibian biology series, vol 10. Surrey Beatty and Sons. NSW, Australia, pp 3291–3342
Lertzman-Lepofsky GF, Kissel AM, Sinervo B, Palen WJ (2020) Water loss and temperature interact to compound amphibian vulnerability to climate change. Glob Change Biol 26:4868–4879
Lewis DL, Baxter GT, Johnson KM, Stone MD (1985) Possible extinction of the Wyoming toad, Bufo hemiophrys baxteri. J Herpetol 19:166–168
Li Y, Cohen JM, Rohr JR (2013) Review and synthesis of the effects of climate change on amphibians. Integr Zool 8:145–161
Lindenmayer DB, Blanchard W, Crane M, Michael D, Sato C (2018) Biodiversity benefits of vegetation restoration are undermined by livestock grazing. Restor Ecol 26:1157–1164
Lips KR (2016) Overview of chytrid emergence and impacts on amphibians. Philos Trans Royal Soc B: Biol Sci 371(1709):20150465
Londe DW, Dwayne Elmore R, Davis CA, Fuhlendorf SD, Luttbeg B, Hovick TJ (2020) Structural and compositional heterogeneity influences the thermal environment across multiple scales. Ecosphere 11:e03290
Long ZL, Prepas EE (2012) Scale and landscape perception: the case of refuge use by Boreal Toads (Anaxyrus boreas boreas). Can J Zool 90:1015–1022
Lorch JM, Knowles S, Lankton JS, Michell K, Edwards JL, Kapfer JM, Staffen RA, Wild ER, Schmidt KZ, Ballmann AE, Blodgett D, Farrell TM, Glorioso BM, Last LA, Price SJ, Schuler KL, Smith CE, Wellehan JFX Jr, Blehert DS (2016) Snake fungal disease: an emerging threat to wild snakes. Philos Trans R Soc B 371:20150457
Lovreglio R, Meddour-Sahar O, Leone V (2014) Goat grazing as a wildfire prevention tool: a basic review. iForest 7:260–268
Markle CE, Gillingwater SD, Levick R, Chow-Fraser P (2017) The true cost of partial fencing: evaluating strategies to reduce reptile road mortality. Wildl Soc Bull 41:342–350
Martin SA, Rautsaw RM, Robb F, Bolt MR, Parkinson CL, Seigel RA (2017) Set AHDriFT: applying game cameras to drift fences for surveying herpetofauna and small mammals. Wildl Soc Bull 41:804–809
Maxell BA (2009) State-wide assessment of status, predicted distribution, and landscape-level habitat sustainability of amphibians and reptiles in Montana. PhD dissertation, University of Montana, Missoula, MT
McAdoo K, Mellison C (2016) Case study: successful collaboration for Columbia spotted frog conservation in northern and central Nevada. Fact Sheet 16-10. University of Nevada Cooperative Extension, Reno, Nevada
McCollum DW, Tanaka JA, Morgan JA, Mitchell JE, Fox WE, Maczko KA, Hidinger L, Duke CS, Kreuter UP (2017) Climate change effects on rangelands and rangeland management: affirming the need for monitoring. Ecosystem Health Sustain 3:e01264
Meagher M (1986) Bison bison. Mammalian Species 266:1–8
Mendoza-Roldan JA, Mendoza-Roldan MA, Otranto D (2021) Reptile vector-borne diseases of zoonotic concern. Int J Parasitol Parasites Wildlife 15:132–142
Mester B, Szalai M, Mérő T, Puky M, Lengyel S (2015) Spatiotemporally variable management by grazing and burning increases marsh diversity and benefits amphibians: a field experiment. Biol Cons 192:237–246
Miller DA, Grant EHC, Muths E, Amburgey SM, Adams MJ, Joseph MB, Waddle JH, Johnson PT, Ryan ME, Schmidt BR, Calhoun DL (2018) Quantifying climate sensitivity and climate-driven change in North American amphibian communities. Nat Commun 9:1–15
Miller RF, Svejcar TJ, Rose JA (2000) Impacts of western juniper on plant community composition and structure. J Range Manag 53:574–585
Mims MC, Moore CE, Shadle EJ (2020) Threats to aquatic taxa in an arid landscape: Knowledge gaps and areas of understanding for amphibians of the American Southwest. Wiley Interdiscip Rev Water 7:e1449
Mitchell CI, Shoemaker KT, Esque TC, Vandergast AG, Hromada SJ, Dutcher KE, Heaton JS, Nussear KE (2021) Integrating telemetry data at several scales with spatial capture-recapture to improve density estimates for a rare and elusive reptile. Ecography 12:e03689
Modesto SP, Scott DM, MacDougall MJ, Sues H-D, Evans DC, Reisz RR (2015) The oldest parareptile and the early diversification of reptiles. Proc R Soc B 282:20141912
Morrison ML, Hall LS (1999) Habitat characteristics of reptiles in pinyon-juniper woodland. Great Basin Naturalist 59:288–291
Mushet DM, Euliss NH Jr, Stockwell CA (2012) A conceptual model to facilitate amphibian conservation in the northern Great Plains. Great Plains Res 22:45–58
Muths E, Chambert T, Schmidt BR, Miller DAW, Hossack BR, Joly P, Grolet O, Green DM, Pilliod DS, Cheylan M, Fisher R, McCaffery RM, Adams MJ, Palen W, Arntzen JW, Garwood J, Gellers G, Thirion JM, Besnard A, Campbell Grant EH (2018) Heterogeneous responses of amphibian populations to climate change complicates conservation planning. Sci Rep 7:17102
Neilly H, Nordberg EJ, VanDerWal J, Schwarzkopf L (2018a) Arboreality increases reptile community resistance to disturbance from livestock grazing. J Appl Ecol 55:786–799
Neilly H, O’Reagain P, Vanderwal J, Schwarzkopf L (2018b) Profitable and sustainable cattle grazing strategies support reptiles in tropical savanna rangeland. Rangel Ecol Manage 71:205–212
Neilly H, Ward M, Cale P (2021) Converting rangelands to reserves: Small mammal and reptile responses 24 years after domestic livestock grazing removal. Austral Ecol. https://doi.org/10.1111/aec.13047
Nicholson L, Humphreys K (1981) Sheep grazing at the Kramer Study Plot, San Bernadino County, CA. In: Hashagan KA (ed) Proceedings of the 1981 desert tortoise council symposium, Riverside, CA, pp 163–194
Pereira KE, Woodley SK (2021) Skin defenses of North American salamanders against a deadly salamander fungus. Anim Conserv 24:552–567
Petrovan SO, Schmidt BR (2019) Neglected juveniles; a call for integrating all amphibian life stages in assessments of mitigation success (and how to do it). Biol Cons 236:252–260
Picco AM, Brunner JL, Collins JP (2007) Susceptibility of the endangered California tiger salamander, Ambystoma californiense, to ranavirus infection. J Wildl Dis 43:286–290
Pilliod DS (In press) Successful outcomes in species conservation: a case study of the Columbia spotted frog (Rana luteiventris). In: Walls SC, O’Donnell KM (eds) Strategies for conservation success in herpetology, Society for the Study of Amphibians and Reptiles, University Heights, Ohio, pp 41–52
Pilliod DS, Wind E (2008) Habitat management guidelines for amphibians and reptiles of the northwestern United States and western Canada. Partners in Amphibian and Reptile Conservation, Birmingham, Alabama
Pilliod DS, Scherer RD (2015) Managing habitat to slow or reverse population declines of the Columbia spotted frog in the Northern Great Basin. J Wildl Manag 79:579–590
Pilliod DS, Griffiths RA, Kuzmin SL (2012) Ecological impacts of non-native species. In: Heatwole H, Wilkinson JW (eds) Conservation and decline of amphibians: ecological aspects, effect of humans, and management. Amphibian biology series, vol 10. Surrey Beatty and Sons, NSW, Australia, pp 3343–3382
Pilliod DS, Arkle RS, Robertson JM, Murphy MA, Funk WC (2015) Effects of changing climate on aquatic habitat and connectivity for remnant populations of a wide-ranging frog species in an arid landscape. Ecol Evol 5:3979–3994
Pilliod DS, Welty JL, Toevs GR (2017) Seventy-five years of vegetation treatments on public rangelands in the Great Basin of North America. Rangelands 39:1–9
Pilliod DS, Jeffries MI, Arkle RS, Olson DH (2020) Reptiles under the conservation umbrella of the Greater Sage-Grouse. J Wildl Manag 84:478–491
Pilliod DS, Hausner MB, Scherer RD (2021) From satellites to frogs: quantifying ecohydrological change, drought mitigation, and population demography in desert meadows. Sci Total Environ 758:143632
Polley HW, Briske DD, Morgan JA, Wolter K, Bailey DW, Brown JR (2013) Climate change and North American rangelands: trends, projections, and implications. Rangel Ecol Manage 66:493–511
Pough HF, Andrews RM, Cadle JE, Crump ML, Savitzky AH, Wells KD (1998) Herpetology. Prentice Hall, Upper Saddle River, New Jersey
Price SJ, Ariel E, Maclaine A, Rosa GM, Gray MJ, Brunner JL, Garner TW (2017) From fish to frogs and beyond: impact and host range of emergent ranaviruses. Virology 511:272–279
Pulsford SA, Driscoll DA, Barton PS, Lindenmayer DB (2017) Remnant vegetation, plantings and fences are beneficial for reptiles in agricultural landscapes. J Appl Ecol 54:1710–1719
Pulsford SA, Barton PS, Driscoll DA, Lindenmayer DB (2019) Interactive effects of land use, grazing and environment on frogs in an agricultural landscape. Agr Ecosyst Environ 281:25–34
Pyke CR, Marty J (2005) Cattle grazing mediates climate change impacts on ephemeral wetlands. Conserv Biol 19:1619–1625
Pyron RA (2014) Biogeographic analysis reveals ancient continental vicariance and recent oceanic dispersal in amphibians. Syst Biol 63:779–797
Qian H (2009) Global comparisons of beta diversity among mammals, birds, reptiles, and amphibians across spatial scales and taxonomic ranks. J Syst Evol 47:509–514
Qian H (2010) Environment–richness relationships for mammals, birds, reptiles, and amphibians at global and regional scales. Ecol Res 25:629–637
Radke N, Wester D, Perry G, Rideout-Hanzak S (2008) Short-term effects of prescribed fire on lizards in mesquite-ashe juniper vegetation in central Texas. Appl Herpetol 5:281–292
Read JL, Cunningham R (2010) Relative impacts of cattle grazing and feral animals on an Austral arid zone reptile and small mammal assemblage. Austral Ecol 35:314–324
Rieder JP, Newbold TA, Ostoja SM (2010) Structural changes in vegetation coincident with annual grass invasion negatively impacts sprint velocity of small vertebrates. Biol Invasions 12:2429–2439
Robertson JM, Murphy MA, Pearl CA, Adams MJ, Páez-Vacas MI, Haig SM, Pilliod DS, Storfer A, Funk WC (2018) Regional variation in drivers of connectivity for two frog species (Rana pretiosa and R. luteiventris) from the US Pacific Northwest. Mol Ecol 27:3242–3256
Roche LM, Allen-Diaz B, Eastburn DJ, Tate KW (2012) Cattle grazing and Yosemite toad (Bufo canorus Camp) breeding habitat in Sierra Nevada meadows. Rangel Ecol Manage 65:56–65
Rowe JC, Duarte A, Pearl CA, McCreary B, Galvan SK, Peterson JT, Adams MJ (2019) Disentangling effects of invasive species and habitat while accounting for observer error in a long-term amphibian study. Ecosphere 10:e02674
Rozen-Rechels D, Dupoué A, Lourdais O, Chamaillé-Jammes S, Meylan S, Clobert J, Le Galliard JF (2019) When water interacts with temperature: ecological and evolutionary implications of thermo-hydroregulation in terrestrial ectotherms. Ecol Evol 9:10029–10043
Russell RE, Halstead BJ, Mosher BA, Muths E, Adams MJ, Grant EHC, Fisher RN, Kleeman PM, Backlin AR, Pearl CA, Honeycutt RK, Hossack BR (2019) Effect of amphibian chytrid fungus (Batrachochytrium dendrobatidis) on apparent survival of frogs and toads in the western USA. Biol Cons 236:296–304
Ruthven DC, Kazmaier RT, Janis MW (2008) Short-term response of herpetofauna to various burning regimes in the south Texas plains. Southwestern Naturalist 53:480–487
Rutschmann A, Miles DB, Le Galliard JF, Richard M, Moulherat S Sinervo, B, Clobert J (2016) Climate and habitat interact to shape the thermal reaction norms of breeding phenology across lizard populations. J Animal Ecol 85:457–466
Sawatzky ME, Martin AE, Fahrig L (2019) Landscape context is more important than wetland buffers for farmland amphibians. Agr Ecosyst Environ 269:97–106
Scheele BC, Pasmans F, Skerratt LF, Berger L, Martel A, Beukema W, Acevedo AA, Burrowes PA, Carvalho T, Catenazzi A, De la Riva I (2019) Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity. Science 363(6434):1459–1463
Schmidt B (2003) Declining amphibian populations: the pitfalls of count data in the study of diversity, distribution, dynamics and demography. Herpetol J 14:167–174
Schmutzer AC, Gray MJ, Burton EC, Miller DL (2008) Impacts of cattle on amphibian larvae and the aquatic environment. Freshw Biol 53:2613–2625
Scott NJ (1996) Evolution and management of North American grassland herpetofauna. In: Frey DN (ed) Ecosystem disturbance and wildlife conservation in western grasslands: a symposium proceedings, U.S. Department of Agriculture—Forest Service, Rocky Mountain Forest and Range Research Station, Fort Collins, Colorado, pp 40–53
Silvy NJ, Lopez RR, Peterson MJ (2012) Techniques for marking wildlife. The Wildlife Techniques Manual 1:230–257
Sinervo B, Mendez-De-La-Cruz F, Miles DB, Heulin B, Bastiaans E, Villagrán-Santa Cruz M, Lara-Resendiz R, Martínez-Méndez N, Calderón-Espinosa ML, Meza-Lázaro RN, Gadsden H (2010) Erosion of lizard diversity by climate change and altered thermal niches. Science 328(5980):894–899
Smalling KL, Rowe JC, Pearl CA, Iwanowicz LR, Givens CE, Anderson CW, McCreary B, Adams MJ (2021) Monitoring wetland water quality related to livestock grazing in amphibian habitats. Environ Monit Assess 193:1–17
Smith LJ, Holycross AT, Painter CW, Douglas ME (2001) Montane rattlesnakes and prescribed fire. Southwestern Naturalist 54–61
Stebbins RC (2003) Western reptiles and amphibians, 3rd edn. Houghton Mifflin Company, New York, New York
Swartz TM, Miller JR (2019) Managing farm ponds as breeding sites for amphibians: key trade-offs in agricultural function and habitat conservation. Ecol Appl 29:e01964
Swei A, Ostfeld RS, Lane RS, Briggs CJ (2011) Impact of the experimental removal of lizards on Lyme disease risk. Proc Royal Soc B Biol Sci 278:2970–2978
Thompson MD, Russell AP (2005) Glacial retreat and its influence on migration of mitochondrial genes in the long-toed salamander (Ambystoma macrodactylum) in western North America. In: Elewa AMT (ed) Migration of organisms. Springer, Berlin, pp 205–246
Urban MC, Richardson JL, Freidenfelds NA (2013) Plasticity and genetic adaptation mediate amphibian and reptile responses to climate change. Evol Appl 7:88–103
USFWS [U.S. Fish and Wildlife Service] (2011) Revised recovery plan for the Mojave population of the desert tortoise (Gopherus agassizii). U.S. Fish and Wildlife Service, California and Nevada Region, Sacramento
USGS GAP (2018a) U.S. geological survey—gap analysis project (GAP) species habitat maps CONUS_2001: U.S. Geological Survey data release, https://doi.org/10.5066/F7V122T2
USGS GAP (2018b) U.S. geological survey—gap analysis project (GAP) amphibian species habitat richness: U.S. Geological Survey, https://doi.org/10.3133/sir20195034. Data available at: https://doi.org/10.5066/P9YW3ZQ2
USGS GAP (2018c) U.S. geological survey—gap analysis project (GAP) reptile species habitat richness: U.S. Geological Survey, https://doi.org/10.3133/sir20195034. Data available at: https://doi.org/10.5066/P9YW3ZQ2
Villena OC, Royle JA, Weir LA, Foreman TM, Gazenski KD, Grant EH (2016) Southeast regional and state trends in anuran occupancy from calling survey data (2001–2013) from the North American Amphibian Monitoring Program. Herpetol Conserv Biol 11:373–385
Vreeland JK, Tietje WD (2002) Numerical response of small vertebrates to prescribed fire in California oak woodland. The role of fire in nongame wildlife management and community restoration: traditional uses and new directions. General technical report NE-GTR-288. US Forest Service, Newton Square, Pennsylvania, pp 100–110
Waddle JH, Grear DA, Mosher BA, Grant EH, Adams MJ, Backlin AR, Barichivich WJ, Brand AB, Bucciarelli GM, Calhoun DL, Chestnut T (2020) Batrachochytrium salamandrivorans (Bsal) not detected in an intensive survey of wild North American amphibians. Sci Rep 10(13012):1–7
Wagner RB, Brune CR, Popescu VD (2021) Snakes on a lane: Road type and edge habitat predict hotspots of snake road mortality. J Nat Conserv 61:125978
Wake DB, Koo MS (2018) Amphibians. Curr Biol 28:R1237–R1241
Weitzman CL, Gov R, Sandmeier FC, Snyder SJ, Tracy CR (2017) Co-infection does not predict disease signs in Gopherus tortoises. Royal Soc Open Sci 4:171003
Wiens JJ (2007) Global patterns of diversification and species richness in amphibians. Am Nat 170:S86–S106
Wilgers DJ, Horne EA (2006) Effects of different burn regimes on tallgrass prairie herpetofaunal species diversity and community composition in the Flint Hills, Kansas. J Herpetol 40:73–84
Wilgers DJ, Horne EA, Sandercock BK, Volkmann AW (2006) Effects of rangeland management on community dynamics of the herpetofauna of the tallgrass prairie. Herpetologica 4:378–388
Wohl E (2021) Legacy effects of loss of beavers in the continental United States. Environ Res Lett 16:025010
Woinarski JC, Brock C, Fisher A, Milne D, Oliver B (1999) Response of birds and reptiles to fire regimes on pastoral land in the Victoria River District, Northern Territory. Rangeland J 21:24–38
Wollenberg Valero KC, Marshall JC, Bastiaans E, Caccone A, Camargo A, Morando M, Niemiller ML, Pabijan M, Russello MA, Sinervo B, Werneck FP, Sites JW Jr, Wiens JJ, Steinfartz S (2019) Patterns, mechanisms and genetics of speciation in reptiles and amphibians. Genes 10:646
Yap TA, Koo MS, Ambrose RF, Vredenburg VT (2018) Introduced bullfrog facilitates pathogen invasion in the western United States. PLoS ONE 13(4):e0188384
Zero VH, Murphy MA (2016) An amphibian species of concern prefers breeding in active beaver ponds. Ecosphere 7:e01330. https://doi.org/10.1002/ecs2.1330
Acknowledgements
We thank Michelle Jeffries for her help developing the tables and figures used. Steve Hromada, Bryce Maxell, and an anonymous reviewer provided helpful comments. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
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Pilliod, D.S., Esque, T.C. (2023). Amphibians and Reptiles. In: McNew, L.B., Dahlgren, D.K., Beck, J.L. (eds) Rangeland Wildlife Ecology and Conservation . Springer, Cham. https://doi.org/10.1007/978-3-031-34037-6_25
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