, Volume 173, Issue 3, pp 1143–1156 | Cite as

Why are some animal populations unaffected or positively affected by roads?

  • Trina Rytwinski
  • Lenore Fahrig
Conservation ecology - Original research


In reviews on effects of roads on animal population abundance we found that most effects are negative; however, there are also many neutral and positive responses [Fahrig and Rytwinski (Ecol Soc 14:21, 2009; Rytwinski and Fahrig (Biol Conserv 147:87–98, 2012)]. Here we use an individual-based simulation model to: (1) confirm predictions from the existing literature of the combinations of species traits and behavioural responses to roads that lead to negative effects of roads on animal population abundance, and (2) improve prediction of the combinations of species traits and behavioural responses to roads that lead to neutral and positive effects of roads on animal population abundance. Simulations represented a typical situation in which road mitigation is contemplated, i.e. rural landscapes containing a relatively low density (up to 1.86 km/km2) of high-traffic roads, with continuous habitat between the roads. In these landscapes, the simulations predict that populations of species with small territories and movement ranges, and high reproductive rates, i.e. many small mammals and birds, should not be reduced by roads. Contrary to previous suggestions, the results also predict that populations of species that obtain a resource from roads (e.g. vultures) do not increase with increasing road density. In addition, our simulations support the predation release hypothesis for positive road effects on prey (both small- and large-bodied prey), whereby abundance of a prey species increased with increasing road density due to reduced predation by generalist road-affected predators. The simulations also predict an optimal road density for the large-bodied prey species if it avoids roads or traffic emissions. Overall, the simulation results suggest that in rural landscapes containing high-traffic roads, there are many species for which road mitigation may not be necessary; mitigation efforts should be tailored to the species that show negative population responses to roads.


Landscape connectivity Landscape fragmentation Landscape structure Population density Road mitigation 



We are grateful to L. Tischendorf for modelling assistance. We also thank the reviewers for their constructive comments. This study was supported by a Natural Sciences and Engineering Research Council of Canada (NSERC) scholarship to T. R. and NSERC and Canada Foundation for Innovation grants to L. F.

Supplementary material

442_2013_2684_MOESM1_ESM.docx (398 kb)
Supplementary material 1 (DOCX 398 kb)


  1. Benítez-López A, Alkemade R, Verweij PA (2010) The impacts of roads and other infrastructure on mammal and bird populations: a meta-analysis. Biol Conserv 143:1307–1316CrossRefGoogle Scholar
  2. Berven KA (1988) Factors affecting variation in reproductive traits within a population of wood frogs (Rana sylvatica). Copeia 1988:605–615CrossRefGoogle Scholar
  3. Berven KA (2009) Density dependence in the terrestrial stage of wood frogs: evidence from a 21-year population study. Copeia 2009:328–338CrossRefGoogle Scholar
  4. Calvo RN, Silvy NJ (1996) Key deer mortality, U.S. 1. The Florida Keys. Florida DOT report FL-ER-58-96, pp 337–348Google Scholar
  5. Carr LW, Fahrig L (2001) Effect of road traffic on two amphibian species of differing vagility. Conserv Biol 15:1071–1078CrossRefGoogle Scholar
  6. Cudworth NL, Koprowski JL (2010) Microtus californicus (Rodentia: Cricetidae). Mammalian Species 42:230–243CrossRefGoogle Scholar
  7. Dodd NL, Gagnon JW, Boe S, Schweinsburg RE (2007) Assessment of elk highway permeability by using global positioning system telemetry. J Wildl Manage 71:1107–1117CrossRefGoogle Scholar
  8. Dunning JB, Danielson BJ, Pulliam HR (1992) Ecological processes that affect populations in complex landscapes. Oikos 65:169–175CrossRefGoogle Scholar
  9. Dyer SJ, O’Neill JPS, Wasel M, Boutin S (2001) Avoidance of industrial development by woodland caribou. J Wildl Manage 65:531–542CrossRefGoogle Scholar
  10. Eder T (2002) Mammals of Ontario. Lone Pine, EdmontonGoogle Scholar
  11. Eigenbrod F, Hecnar SJ, Fahrig L (2008) The relative effects of road traffic and forest cover on anuran populations. Biol Conserv 141:35–46CrossRefGoogle Scholar
  12. Evink GL (1996) Florida department of transportation initiatives related to wildlife mortality. In: Evink GL, Garrett P, Zeigler D, Berry J (eds) Proceedings of the 1996 International Conference on Wildlife Ecology and Transportation. State of Florida Department of Transportation Environmental Management Office, Tallahassee, FL
  13. Fahrig L, Rytwinski T (2009) Effects of roads on animal abundance: an empirical review and synthesis. Ecol Soc 14:21, Google Scholar
  14. Fahrig L, Pedlar JH, Pope SE, Taylor PD, Wegner JF (1995) Effect of road traffic on amphibian density. Biol Conserv 73:177–182CrossRefGoogle Scholar
  15. Flaherty EA, Smith WP, Pyare S, Ben-David M (2008) Experimental trials of the northern flying squirrel (Glaucomys sabrinus) traversing managed rainforest landscapes: perceptual range and fine-scale movements. Can J Zool 86:1050–1058CrossRefGoogle Scholar
  16. Ford AT, Fahrig L (2008) Movement patterns of eastern chipmunks (Tamias striatus) near roads. J Mammal 89:895–903CrossRefGoogle Scholar
  17. Forero-Medina G, Vieira MV (2009) Perception of a fragmented landscape by neotropical marsupials: effects of body mass and environmental variables. J Trop Ecol 25:53–62CrossRefGoogle Scholar
  18. Forman RTT, Sperling D, Bissonette JA, Clevenger AP, Cutshall CD, Dale VH, Fahrig L, France R, Goldman CR, Heanuem K, Jones JA, Swanson FJ, Turrentine T, Winter TC (2003) Road ecology: science and solutions. Island Press, WashingtonGoogle Scholar
  19. Fuller TK (1989) Population dynamics of wolves in North-central Minnesota. Wildl Monogr 105:1–41Google Scholar
  20. Gagnon JW (2007) Traffic volume alters elk distribution and highway crossings in Arizona. J Wildl Manage 71:2318–2323CrossRefGoogle Scholar
  21. Garland T Jr, Bradley WG (1984) Effects of highway on Mojave desert rodent populations. Am Midl Nat 111:47–56CrossRefGoogle Scholar
  22. Gibbons MM, McCarthy TK (1986) The reproductive output of frogs Rana temporaria (L) with particular reference to body size and age. J Zool 209:579–593CrossRefGoogle Scholar
  23. Hecnar SJ, M’Closkey RT (1996) Regional dynamics and the status of amphibians. Ecology 77:2091–2097CrossRefGoogle Scholar
  24. Hoskin CJ, Goosem MW (2010) Road impacts on abundance, call traits, and body size of rainforest frogs in Northeast Australia. Ecol Soc 14:15,
  25. Jaeger JAG, Fahrig L (2004) Effects of road fencing on population persistence. Conserv Biol 18:165–1657CrossRefGoogle Scholar
  26. Jaeger JAG, Bowman J, Brennan J, Fahrig L, Bert D, Bouchard J, Charbonneau N, Frank K, Gruber B, Tluk von Toschanowitz K (2005) Predicting when animal populations are at risk from roads: an interactive model of road avoidance behavior. Ecol Modell 185:329–348CrossRefGoogle Scholar
  27. Johnson WC, Collinge SK (2004) Landscape effects on black-tailed prairie dog colonies. Biol Conserv 115:487–497CrossRefGoogle Scholar
  28. Kaplan RH, Salthe SN (1979) The allometry of reproduction: an empirical view in salamanders. Am Nat 113:671–689CrossRefGoogle Scholar
  29. Karraker NE, Gibbs JP (2011) Contrasting road effect signals in reproduction of long- versus short-lived amphibians. Hydrobiologia 66:213–218CrossRefGoogle Scholar
  30. Knight RL, Kawashima JY (1993) Responses of raven and red-tailed hawk populations to linear right-of-ways. J Wildl Manage 57:266–271CrossRefGoogle Scholar
  31. Laan R, Verboom B (1990) Effects of pool size and isolation on amphibian communities. Biol Conserv 54:251–262CrossRefGoogle Scholar
  32. Laurian C, Dussault C, Ouellet J-P, Courtois R, Poulin M, Breton L (2008) Behavior of moose relative to a road network. J Wildl Manage 72:1550–1557CrossRefGoogle Scholar
  33. Leeson BF (1996) Highway conflicts and resolutions in Banff National Park, Alberta, Canada. In: Evink GL, Garrett P, Zeigler D, Berry J (eds) Proceedings of the 1996 International Conference on Wildlife Ecology and Transportation. State of Florida Department of Transportation Environmental Management Office, Tallahassee, Florida, USA,
  34. Linzey DW, Packard RL (1977) Ochrotomys nuttalli. Mammalian Species 75:1–6CrossRefGoogle Scholar
  35. Lyon LJ (1983) Road density models describing habitat effectiveness for elk. J For 81:592–595Google Scholar
  36. Mace RD, Waller JS, Manley TL, Lyon LJ, Zurring H (1996) Relationships among grizzly bears, roads, and habitat in the Swan Mountains, Montana. J Appl Ecol 33:1395–1404CrossRefGoogle Scholar
  37. Maehr DS, Land ED, Roelke ME (1991) Mortality patterns of panthers in southwest Florida. Proc Ann Conf SE Fish Wildl Agencies 45:201–207Google Scholar
  38. McGregor R, Bender DJ, Fahrig L (2008) Do small mammals avoid roads because of the traffic? J Appl Ecol 45:117–123CrossRefGoogle Scholar
  39. Mech SG, Zollner PA (2002) Using body size to predict perceptual range. Oiko 98:47–52CrossRefGoogle Scholar
  40. Mech LD, Fritts SH, Raddle GL, Paul WJ (1988) Wolf distribution and road density in Minnesota. Wildl Soc Bull 16:85–87Google Scholar
  41. Meunier FP, Verheyden C, Jouventin P (2000) Use of road-sides by diurnal raptors in agricultural landscapes. Biol Conserv 92:291–298CrossRefGoogle Scholar
  42. Mladenoff DJ, Sickley TA, Haight RG, Wydeven AP (1995) A regional landscape analysis and prediction of favourable gray wolf habitat in the northern Great-Lakes region. Conserv Biol 9:279–294CrossRefGoogle Scholar
  43. Munro KG, Bowman J, Fahrig L (2012) Effect of paved road density on abundance of white-tailed deer. Wildl Res 39:478–487CrossRefGoogle Scholar
  44. Newmark WD, Boshe JI, Sariko HI, Makumbule GK (1996) Effects of a highway on large mammals in Mikumi National Park, Tanzania. Afr J Ecol 34:15–31CrossRefGoogle Scholar
  45. Olden JD, Schooley RL, Monroe JB, Poff NL (2004) Context-dependent perceptual range and their relevance to animal movements in landscapes. J Anim Ecol 73:1190–1194CrossRefGoogle Scholar
  46. Prevedello JA, Forero-Medina G, Vieira MV (2011) Does land use affect perceptual range? Evidence from two marsupials of the Atlantic Forest. J Zool 284:53–59CrossRefGoogle Scholar
  47. Pupin NC (2010) Reproductive biology of an endemic Physalaemus of the Brazilian Atlantic forest, and the trade-off between clutch and egg size in terrestrial breeders of the P. signifier group. Herpetol J 20:147–156Google Scholar
  48. Reh W, Seitz A (1990) The influence of land use on the genetic structure of populations of the common frog Rana temporaria. Biol Conserv 54:239–249CrossRefGoogle Scholar
  49. Reijnen R, Foppen R, Meeuwsen H (1996) The effects of traffic on the density of breeding birds in Dutch agricultural grasslands. Biol Conserv 75:255–260CrossRefGoogle Scholar
  50. Roedenbeck IA, Köhler W (2006) Effekte der Landschaftszerschneidung auf die Unfallhufigkeit und Bestandsdichte von Wildtierpopulationen. Natursch Landschaftsplan 38:314–322Google Scholar
  51. Roland A (2002) On the ecology of home range in birds. Rev Ecol-Terre Vie 57:53–73Google Scholar
  52. Rowland MM, Wisdom MJ, Johnson BK, Kie JG (2000) Elk distribution and modeling in relation to roads. J Wildl Manage 64:672–684CrossRefGoogle Scholar
  53. Rytwinski T, Fahrig L (2007) Effect of road density on abundance of white-footed mice. Landscape Ecol 22:1501–1512CrossRefGoogle Scholar
  54. Rytwinski T, Fahrig L (2011) Reproductive rates and body size predict road impacts on mammal abundance. Ecol Appl 21:589–600PubMedCrossRefGoogle Scholar
  55. Rytwinski T, Fahrig L (2012) Do species life history traits explain population responses to roads? A meta-analysis. Biol Conserv 147:87–98CrossRefGoogle Scholar
  56. Schooley RL, Wiens JA (2003) Finding habitat patches and directional connectivity. Oikos 102:559–570CrossRefGoogle Scholar
  57. Sielecki LE (2007) The evolution of wildlife exclusion systems on highways in British Columbia. In: Irwin C.L, Nelson D, McDermott KP (eds), Proceedings of the 2007 International Conference on Ecology and Transportation. Center for Transportation and the Environment, North Carolina State University, Raleigh, NC,
  58. Simms DA (1979) Studies of an ermine population in southern Ontario. Can J Zool 57:824–832CrossRefGoogle Scholar
  59. Stewart KM, Bowyer RT, Kie J (2010) Spatial distributions of mule deer and North American elk: resources partitioning in a sage-steppe environment. Am Midl Nat 163:400–412CrossRefGoogle Scholar
  60. Thiel RP (1985) Relationship between road densities and wolf habitat suitability in Wisconsin. Am Midl Nat 113:404–407CrossRefGoogle Scholar
  61. van der Grift EA, Verboom J, Pouwels R (2004) Assessing the impact of roads on animal population viability. In: Irwin CL, Garrett P, McDermott KP (eds) Proceedings of the 2003 International Conference on Ecology and Transportation. Center for Transportation and the Environment, North Carolina State University, Raleigh, NC,
  62. van Dyke FG, Brocke RH, Shaw HG (1986) Use of road track counts as indices of mountain lion presence. J Wildl Manage 50:102–109CrossRefGoogle Scholar
  63. Waller JS, Servheen C (2005) Effects of transportation infrastructure on grizzly bears in northwestern Montana. J Wildl Manage 69:985–1000CrossRefGoogle Scholar
  64. Wilbur HM (1977) Propagule size, number, and dispersion pattern in Ambystoma and Asclepias. Am Nat 111:43–68CrossRefGoogle Scholar
  65. Wilbur HM (1980) Complex life-cycles. Annu Rev Ecol Evol Syst 11:67–93CrossRefGoogle Scholar
  66. Wilensky U (1999) Netlogo. Center for Connected Learning and Computer-Based Modeling, Northwestern University, Evanston, IL,
  67. Yeomans RS (1995) Water-finding in adult turtles: random search or oriented behaviour? Anim Behav 49:977–987CrossRefGoogle Scholar
  68. Yerger RW (1953) Home range, territoriality, and populations of the chipmunk in central New York. J Mammal 34:448–458CrossRefGoogle Scholar
  69. Zabel CJ, McKelvey K, Ward JP Jr (1995) Influence of primary prey on home-range size and habitat-use patterns of northern spotted owls (Strix occidentalis caurina). Can J Zool 73:433–439CrossRefGoogle Scholar
  70. Zollner PA (2000) Comparing the landscape level perceptual abilities of forest sciurids in fragmented agricultural landscapes. Landscape Ecol 15:523–533CrossRefGoogle Scholar
  71. Zollner PA, Lima SL (1999) Illumination and the perception of remote habitat patches by white-footed mice. Anim Behav 58:489–500PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  1. 1.Geomatics and Landscape Ecology Research Laboratory (GLEL), Ottawa-Carleton Institute of BiologyCarleton UniversityOttawaCanada

Personalised recommendations