The avifauna of the Catimbau National Park, an important protected area in the Brazilian semiarid

The Catimbau National Park is a protected area, located within the Caatinga Dry Forest, in the central region of the Brazilian state of Pernambuco. This protected area encompasses ~60,000 ha of an exceptional diversity of habitats, resulting in a high avian diversity, including several rare and endemic species. The park is considered an area of high biological importance and of conservation priority. Despite its relevance for conservation, human degradation due to chronic anthropogenic disturbances (hunting, birds trapping, selective logging, and livestock grazing) has modified the park's natural environments. In 2014, we initiated avian inventories within the park, as part of a long-term ecological research (LTER). Although the avifauna of the park has been described before, our systematic surveys allowed us to have a better understating of the park's avifauna and resulted in several additions to the species list. Here, we update and reevaluate the park's avifauna, discuss the presence of resident and migratory species, and include comments on endemic and rare species that occur within the park's boundaries. We sampled the avifauna through systematic surveys (point counts) and opportunistic observations between 2014 and 2017, including both dry and rainy seasons. We recorded a total of 192 species, including 25 species new to the park's list. During our point counts, we detected 117 species in the dry season, whereas 34 were recorded exclusively during the rainy season. Nearly 10% of the park's avifauna (19 species) is represented by migratory species, such as Elaenia chilensis and Turdus amaurochalinus. Catimbau National Park is important for the conservation of the Caatinga avifauna, since it harbors endemic, range-restricted, migratory, and globally threatened species. Therefore, we emphasize that environmental education and ecological restoration projects, allied to enforcing environmental laws are urgent for the maintenance of biodiversity and ecosystem services in the Catimbau National Park. KEY-WORDS: Caatinga, long-term ecological research, migratory birds, Neotropical Dry Forests, ornithological inventory. within the Caatinga, where over 63% of its area has already been modified by human activities (Pennington et al. 2009, Araújo & Silva 2017, Silva & Barbosa 2017) is also evident at the CNP. The park faces many chronic anthropogenic disturbance pressures as a result of the nearly 300 families that live within the park and depend on livestock grazing and logging to survive (Rito et al. 2017, Arnan et al. 2018). Also, the absence of a welldesigned management plan, mandatory by Brazilian law (SNUC 2002), reflects negatively on the overall conservation of the National Park. At present, CNP presents many degraded areas with different histories of human land use (Cruz et al. 2017, MMA 2018a). Given the remarkable habitat heterogeneity found at the park, the relatively large topographic variation (500–1100 m), and the rainfall gradient within such a small area (650–1100 mm/yr), Catimbau National Park was selected to establish a Long-term Ecological Research (LTER) Program (http://www.peldcatimbau.org). The The avifauna of the Catimbau National Park Las-Casas et al. 80 Revista Brasileira de Ornitologia 27(2): 2019 main purpose of Catimbau's LTER site is to evaluate how chronic anthropogenic disturbances and changes in rainfall regime affect the biota. A total of 20 permanent plots were established, covering most of the topographical, environmental, and anthropogenic disturbance gradient, offering a unique opportunity to understand patterns of diversity in many different biological groups (Rito et al. 2017). Each biological group studied relied on a different sample scheme, depending on the spatial scale desired. To study the avifauna, we established 2 km transects around each one of the 20 permanent plots, sampled by 10 point counts, systematically established every 200 m. The avifauna of the CNP is relatively well known due to past surveys (Farias 2009, Sousa et al. 2012). The first ornithologist to present a species list of the park's avifauna, based on non-systematic inventories and opportunistic observations, included 139 species (Farias 2009). A few years later, Sousa et al. (2012) presented a more complete list of the park's avifauna, updating the park's list to 202 species, including important endemic and threatened species, such as Penelope jacucaca and Spinus yarrellii. In this study, we present the results of three years (2014–2017) of systematic surveys conducted around 20 sites distributed throughout the park, and opportunistic observations conducted elsewhere within the park. We also present a new updated list of the avifauna of the CNP, with relevant information about the avian community, with important records of threatened, migratory, and endemic species. We also provide ecological aspects of species richness and patterns of species composition, highlighting the potential threats found in this protected area and its importance for the conservation of Caatinga birds.


INTRODUCTION
The Caatinga Domain (hereafter, Caatinga) represents the largest patch of Seasonally Dry Tropical Forest in the Neotropics (Pennington et al. 2000). Far from representing a single vegetational type, the Caatinga is highly heterogeneous, presenting a wide diversity of ecosystems and habitats. Different combinations of soil, relief, topography and rainfall regimes create a wide variety of habitats (Egler 1951, Sarmiento 1975, Andrade-Lima 1981, Leal et al. 2003. Much of this variation can be found at one particular protected area in the Caatinga: the Catimbau National Park (hereafter, CNP). This exceptional diversity of habitats results in a high diversity of bird species, including several rare and endemic, which is one of the reasons the park is considered an area of high biological importance and of conservation priority (Devenish et al. 2009, Menezes et al. 2012. Unfortunately, much of the degradation observed within the Caatinga, where over 63% of its area has already been modified by human activities (Pennington et al. 2009 is also evident at the CNP. The park faces many chronic anthropogenic disturbance pressures as a result of the nearly 300 families that live within the park and depend on livestock grazing and logging to survive (Rito et al. 2017, Arnan et al. 2018. Also, the absence of a welldesigned management plan, mandatory by Brazilian law (SNUC 2002), reflects negatively on the overall conservation of the National Park. At present, CNP presents many degraded areas with different histories of human land use (Cruz et al. 2017, MMA 2018a. Given the remarkable habitat heterogeneity found at the park, the relatively large topographic variation (500-1100 m), and the rainfall gradient within such a small area (650-1100 mm/yr), Catimbau National Park was selected to establish a Long-term Ecological Research (LTER) Program (http://www.peldcatimbau.org). The main purpose of Catimbau's LTER site is to evaluate how chronic anthropogenic disturbances and changes in rainfall regime affect the biota. A total of 20 permanent plots were established, covering most of the topographical, environmental, and anthropogenic disturbance gradient, offering a unique opportunity to understand patterns of diversity in many different biological groups (Rito et al. 2017). Each biological group studied relied on a different sample scheme, depending on the spatial scale desired. To study the avifauna, we established 2 km transects around each one of the 20 permanent plots, sampled by 10 point counts, systematically established every 200 m.
The avifauna of the CNP is relatively well known due to past surveys (Farias 2009, Sousa et al. 2012). The first ornithologist to present a species list of the park's avifauna, based on non-systematic inventories and opportunistic observations, included 139 species (Farias 2009). A few years later, Sousa et al. (2012) presented a more complete list of the park's avifauna, updating the park's list to 202 species, including important endemic and threatened species, such as Penelope jacucaca and Spinus yarrellii.
In this study, we present the results of three years (2014-2017) of systematic surveys conducted around 20 sites distributed throughout the park, and opportunistic observations conducted elsewhere within the park. We also present a new updated list of the avifauna of the CNP, with relevant information about the avian community, with important records of threatened, migratory, and endemic species. We also provide ecological aspects of species richness and patterns of species composition, highlighting the potential threats found in this protected area and its importance for the conservation of Caatinga birds.

Study area
The Catimbau National Park (~60,000 ha), created by a federal decree on 13 December 2002, is a protected area located within three municipalities (Buíque, Tupanatinga and Ibimirim) in the central region of the Brazilian state of Pernambuco (between 8 o 24'00'' and 8 o 36'35''S; 37 o 0'30'' and 37 o 1'40''W) (Fig. 1). Climate is classified as tropical semiarid, according to Koeppen's classification; showing a mean annual temperature of 23 o C, with a great inter-annually irregularity in rainfall regimes, which vary from 650 to 1100 mm/year (SNE 2002).
This protected area is located within the Caatinga Domain, a Seasonally Dry Tropical Forest. Most of the park (70%) is composed of old-growth vegetation in sandy soils, with five main phytophysiognomies with distinct vegetation structure and floras, including i) shrubby-arboreal Caatinga generally located on the leeward slopes and at altitudes between 600 and 800 m a.s.l., ii) shrubby Caatinga with Cerrado elements can be found in many sites of the Chapada São José, both in lower and surrounding areas of the hills and slopes, iii) shrubby Caatinga with elements of rocky fields (campos rupestres) occur in the plateaus and mountain ranges (800 and 1100 m a.s.l.), iv) evergreen arboreal vegetation (brejos de altitude) at the foothills, and v) evergreen shrubby Caatinga located on windward slopes between 600 and 800 m a.s.l. (Rodal et al. 1998, SNE 2002. Systematic and opportunistic methodologies were conducted in these phytophysiognomies, as well as in aquatic environments (lagoons, ponds and temporary pools) found at the CNP (Fig. 2).

Bird survey and analyses
We conducted avian surveys at the CNP between August 2014 and August 2017, including both the dry and the rainy seasons. We surveyed the avifauna using point counts with unlimited detection radius (Ralph et al. 1996, Bibby et al. 2000, Sutherland et al. 2004. CNP hosts 20 LTER permanent sites (plots), spatially established to remain independent from one another and to account for the climatic and land use variation found at the park (Table  1, Fig. 1). Around each of these 20 sites, we established 2 km-long transects, which we sampled conducting point counts, which were systematically distributed every 200 m, totaling 10 point counts per site and 200 in the park. All localities and point-counts were geo-referenced using a Garmin GPS unit (GPSMAP64). We sampled each point count during 10 min, when all birds detected by sight or sound were recorded. Each site was sampled three times, once during the dry season and twice during the rainy season, totaling 600 point counts. Besides our systematic surveys, we conducted opportunistic observations between point counts and throughout the park's entire area.
Birds were identified by sight and sound by an experienced observer (FMGLC). We used binoculars and digital recorders to observe and document species presence in the area. Taxonomy and nomenclature follow the Brazilian Committee of Ornithological Records (Piacentini et al. 2015). Species were classified according to their conservation and distribution status. Patterns of endemism (Caatinga and northeast Brazil endemics) were based on Pacheco (2004) and . Threatened species were defined according to Brazilian (MMA 2018b) and international red lists (IUCN 2019). Migration status follows Somenzari et al. (2018), who revised migratory patterns for Brazilian birds.
For habitat we used the five types as described by    Rodal et al. (1998) andSNE (2002): shrubby-arboreal Caatinga, Caatinga with Cerrado elements, Caatinga with rocky outcrops elements (campos rupestres), evergreen arboreal vegetation and evergreen shrubby Caatinga. The evergreen arboreal vegetation (brejos de altitude) is largely disturbed, especially by agriculture. It presents a typical vegetational composition and can be found in the foothills of the scarpment (~800 m a.s.l.). Habitat categorization for birds was based on our own records, and is applied exclusively for birds detected during this study. Photographs and/or digital recordings were archived at www.wikiaves.com and can be assessed online using the provided voucher numbers (Table 2).
To evaluate sampling effectiveness, we used Chao 1 and Jackknife 1 richness estimators (Magurran 2004), which are based on quantitative data and are known to overcome other estimators in terms of bias and precision (Gotelli & Colwell 2010). The total number of species observed at the point counts was represented by a rarefaction curve. These analyses were performed using the software EstimateS 9.1.0 (Colwell 2011). Opportunistic data were excluded from these analyses.
From our inventory (systematic and opportunistic) most of the species detected are considered residents. Nineteen species recorded at the CNP are considered migratory or partially migratory (  (Table 2) were recorded exclusively during the rainy season and are likely to carry out seasonal displacements within the Caatinga.
During our surveys most species were detected in more than one habitat. Most of the species recorded during our studies were detected in shrubby-arboreal Caatinga (162 species), followed by shrubby Caatinga with Cerrado elements (n = 85 spp.), shrubby Caatinga with elements of rocky fields (n = 59 spp.), evergreen arboreal vegetation (n = 56 spp.), evergreen shrubby Caatinga (n = 89), and 12 species related to aquatic environments.
A total of 28 taxa detected in our surveys are considered range-restricted. Nine species are endemic to the Caatinga, whereas 19 taxa are restricted to the Brazilian northeast (Table 2). Picumnus fulvescens a northeastern endemic and Hylopezus ochroleucus a Caatinga endemic are considered "Near Threatened", with decreasing trends in their populations (IUCN 2019). None of the species is considered threatened by extinction according to the Brazilian MMA (2018b). Three exotic species were recorded (Columba livia, Estrilda astrild and Passer domesticus), mostly in urban and peri-urban areas, but there is no evidence that they represent any threat to autoctonous species.

DISCUSSION
In this study we presented newly quantitative data on the avian assemblage found at the Catimbau National Park. During our quantitave surveys, restricted to 20 sites, we detected ~70% (155 species) of the 192 species. In addition, opportunistic observations included another 37 species of birds, mostly waterbirds that do not occur at or near our sampled sites. In fact, according to species richness estimators, our quantitative surveys detected the vast majority of the species present in our sites, showing the importance of conducting systematic surveys. The CNP avian assemblage (192 species) represented ~35% of bird species registered for the Caatinga Domain (sensu ; n = 548) and 35.8% of the 535 bird species recorded for the state of Pernambuco (Farias & Pereira 2009).
Despite our systematic surveys, we failed to find 34 bird species previously reported for the CNP by Sousa et al. (2012). Among the species we failed to record, 11 are linked to aquatic environments, including three species of herons (Tigrisoma lineatum, Nycticorax nycticorax, and Butorides striata), two of ducks (Cairina moschata and Amazonetta brasiliensis), two common inhabitants of ponds and pools (Podilymbus podiceps and Nannopterum brasilianus), two species of raptors likely occurring in low densities (Buteo nitidus and Buteo albonotatus), two species of hummingbirds (Anthracothorax nigricollis and Polytmus guainumbi), two species of nightbirds (Antrostomus rufus and Chordeiles acutipennis), four species of birds often linked to more humid forests (Herpsilochmus atricapillus, Sittasomus griseicapillus, Synallaxis hypospodia, and Pheugopedius genibarbis), and three species of seedeaters known to have erratic populations elsewhere in the Caatinga (Sporophila lineola, Sporophila leucoptera, and Sporophila bouvreuil).
More important, however, were the apparent absences of three species of conservation concern, including three endemic and threatened species (Crypturellus noctivagus zabele, P. jacucaca, and S. yarrellii) previously reported by Sousa et al. (2012). These species are known to be widely hunted by poachers and for the illegal trade, and their absences may indicate local extinctions. The CNP suffers strong pressure from hunting and illegal trade, particulalry for birds. During the study period hunters and local residents were observed trapping birds within the CNP boundaries, an illegal activity outside and even inside the protected area. We found many endemic avian taxa in captivity, including E. cactorum, Paroaria dominicana, Sporophila albogularis and Icterus jamacaii, but also more widespread species, such as Amazona aestiva and Cyanoloxia brissonii, widely appreciated by the illegal trade. We are afraid that if the scenario of hunting activities, illegal logging, overgrazing by goats and cattle, hunting of wild animals (mainly mammals and birds), and bird trapping continue to occur within the park, other species may also become locally extinct. Species whose populations are locally and regionally small are more susceptible to local extinction (e.g., Pereira & Brito 2005, Pereira & Azevedo-Jr. 2011, Fernandes-Ferreira et al. 2012, Las-Casas et al. 2012, Albuquerque et al. 2017.
On the other hand, we recorded 25 species that were not previously recorded at the CNP (Table 2), including two aquatic species (Tachybaptus dominicus and Himantopus mexicanus), three species of raptors (Heterospizias meridionalis, Urubitinga urubitinga, Parabuteo unicinctus); some austral and intratropical migrants (M. cinereus, Serpophaga subcristata, T. savana, and Piranga flava), whose movements are poorly known; a boreal unreported fron the park; migrant (Falco peregrinus); two species of exotic birds (Columba livia and Estrilda astrild), previously unreported from the park; and one endemism that likely went undersampled in the past (Herpsilochmus sellowi). These results suggest that the core avian assemblage of the CNP is likely very well established by now, and that future records will likely result from more nomadic aquatic species, austral and northern migrants, and possibly some widespread species that have not yet been recorded in the park. Species richness and avian composition may also vary according to differences in the methods applied, sampling effort, nocturnal observations (Vizentin-Bugoni et al. 2015), as well as the conservation status of the areas (Sayer et al. 2017, Bovo et al. 2018.
These results also suggest that the Caatinga bird assemblage composition presents some clear interannual variation, particularly for aquatic and low density species . During the rainy season at the CNP, there was an increment in bird species richness, with the presence of migratory birds, including both longdistance and intratropical migrants (e.g., Ruiz-Esparza et al. 2011, Las-Casas et al. 2012. Most of the bird species found at the CNP occured in shrubby arboreal Caatinga, which is the main phytophisiognomy found within the park boundaries. On the other hand, many species of birds can be found in more than one habitat (Table 2), a pattern that is common among birds in the Caatinga. Most of the species included in the park's list are not forest dependent, being able to explore different habitats . However, some species may be considered forest specialists. In the CNP species such as Leptotila rufaxilla and Ortalis araucuan were restricted to more humid habitats such as evegreen forests, a type of vegetation nowadays very uncommon within the park. This type of vegetation was transformed in areas of plantations and pastures (e.g., Pedra do Cachorro) and the remaining tracts of evergreen forests is very fragmented and present different levels of disturbances.
We also noticed that some bird species at the CNP prefer well-conserved and/or forested habitats and rarely occur in disturbed environments (Pereira & Azevedo-Jr. 2011, Las-Casas et al. 2012. This was the case of P. superciliaris, Trogon curucui, Piculus chrysochloros, Micrastur ruficollis, H. sellowi, H. ochroleucus, C. trochilirostris, Dendroplex picus and S. ruficapillus. In contrast, other species were only observed in disturbed and open areas, such as Athene cunicularia, Suiriri suiriri bahiae and Xolmis irupero niveus. Species such as Sarcoramphus papa, Geranoaetus melanoleucus, Hydropsalis longirostris, Hirundinea ferruginea and Knipolgeus nigerrimus were associated to the CNP's rocky walls. Some of those rare species were those more dependent on forested habitats and more sensitive to disturbance, preferring isolated sites with very low human interference such as P. superciliaris, Claravis pretiosa, M. ruficollis, C. trochilirostris and S. ruficapillus. The Caatinga is the largest block of tropical Dry forests found within South America (Silva & Souza 2018) and is one of the most threatened in the Neotropics, with less than 10% of its original extent (Banda et al. 2016). In Brazil, habitat conservation is uneven among biomes (Jenkins & Joppa 2009, Oliveira & Bernard 2017 and the Caatinga represents the least protected one, with only 1.3% of the total area officially included in protected areas that receive full protection (MMA 2017).
Besides the anthropogenic pressures found within this protected area, such as bird hunting, trapping and cattle grazing, our results demonstrate that the CNP still harbors a valuable Caatinga avian diversity with the presence of range-restricted, endemic, threatened, and migratory species, highlighting its importance for bird conservation. But we emphasize the need of effective management inside and outside the park's boundaries, since pressures inside the reserve may usually reflect those occurring around (Laurance et al. 2012). Despite being fragmented, patches of Caatinga remain well-connected, which may facilitate recolonizations and community regeneration (Antongiovanni et al. 2018). Thus, the maintenance, management and expansion of protected area networks continue to be one of the most important tools for biodiversity conservation (Las-Casas et al. 2012, Oliveira & Bernard 2017, Antongiovanni et al. 2018.
The exceptional natural features of the park, allied to a rich avifauna could provide an economic opportunity through the development of birdwatching, offering new job opportunities. We emphasize that actions such as environmental education and ecological restoration projects, allied to inspection are urgent for the maintenance of the biodiversity and ecosystem services at the CNP.