Conservation Genetics

, Volume 8, Issue 2, pp 455–464 | Cite as

Genetic consequences of habitat fragmentation and loss: the case of the Florida black bear (Ursus americanus floridanus)

  • Jeremy D. Dixon
  • Madan K. Oli
  • Michael C. Wooten
  • Thomas H. Eason
  • J. Walter McCown
  • Mark W. Cunningham
Original Paper


Habitat loss and fragmentation can influence the genetic structure of biological populations. We studied the genetic consequences of habitat fragmentation in Florida black bear (Ursus americanus floridanus) populations. Genetic samples were collected from 339 bears, representing nine populations. Bears were genotyped for 12 microsatellite loci to estimate genetic variation and to characterize genetic structure. None of the nine study populations deviated from Hardy–Weinberg equilibrium. Genetic variation, quantified by mean expected heterozygosity (HE), ranged from 0.27 to 0.71 and was substantially lower in smaller and less connected populations. High levels of genetic differentiation among populations (global FST = 0.224; global RST = 0.245) suggest that fragmentation of once contiguous habitat has resulted in genetically distinct populations. There was no isolation-by-distance relationship among Florida black bear populations, likely because of barriers to gene flow created by habitat fragmentation and other anthropogenic disturbances. These factors resulted in genetic differentiation among populations, even those that were geographically close. Population assignment tests indicated that most individuals were genetically assigned to the population where they were sampled. Habitat fragmentation and anthropogenic barriers to movement appear to have limited the dispersal capabilities of the Florida black bear, thereby reducing gene flow among populations. Regional corridors or translocation of bears may be needed to restore historical levels of genetic variation. Our results suggest that management actions to mitigate genetic consequences of habitat fragmentation are needed to ensure long-term persistence of the Florida black bear.


Florida black bears Genetic variation Gene flow Habitat fragmentation Microsatellites Ursus americanus floridanus 


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  1. Beier P, Noss RF (1998) Do habitat corridors provide connectivity? Conserv Biol 12:1241–1252CrossRefGoogle Scholar
  2. Boerson MR, Clark JD, King TL (2003) Estimating black bear population density and genetic diversity at Tensas River, Louisiana using microsatellite DNA markers. Wildl Soc Bull 31:197–207Google Scholar
  3. Brady JR, Maehr DS (1985) Distribution of black bears in Florida. Fla Field Nat 13:1–7Google Scholar
  4. Brody AJ, Pelton MR (1989) Effects of roads on black bear movements in western North Carolina. Wildl Soc Bull 17:5–10Google Scholar
  5. Brooker L, Brooker M (2002) Dispersal and population dynamics of the blue-breasted fairy-wren, Malurus pulcherrimus, in fragmented habitat in the Western Australian wheatbelt. Wildl Res 29:225–233CrossRefGoogle Scholar
  6. Cale PG (2003) The influence of social behaviour, dispersal and landscape fragmentation on population structure in a sedentary bird. Biol Conserv 109:237–248CrossRefGoogle Scholar
  7. Cory CB (1896) Hunting and fishing in Florida. Estes and Lauriet Publishing, BostonGoogle Scholar
  8. Craighead FL, Vyse ER (1996) Brown/grizzly bear metapopulations. In: McCullough DR (ed) Metapopulations and wildlife conservation. Island Press, Washington D.C., pp. 325–351Google Scholar
  9. Crooks KR (2002) Relative sensitivities of mammalian carnivores to habitat fragmentation. Conserv Biol 16:488–502CrossRefGoogle Scholar
  10. Csiki I, Lam C, Key A, Coulter E, Clark JD, Pace RM, Smith KG, Rhoads DD (2003) Genetic variation in black bears in Arkansas and Louisiana using microsatellite DNA markers. J Mammal 84:691–701CrossRefGoogle Scholar
  11. Davies KF, Gascon C, Margules CR (2001) Habitat fragmentation: consequences, management, and future research priorities. In: Soule ME, Orians GH (eds) Conservation biology: research priorities for the next decade. Island Press, Washington, pp. 81–97Google Scholar
  12. Dixon JD, Oli MK, Wooten MC, Eason TH, McCown JW, Paetkau D (2006) Effectiveness of a regional corridor in connecting two Florida black bear populations. Conserv Biol 20:155–162PubMedCrossRefGoogle Scholar
  13. Dobey S, Masters DV, Scheick BK, Clark JD, Pelton MR, Sunquist ME (2005) Population ecology of Florida black bears in the Okefenokee-Osceola ecosystem. University of Tennessee, KnoxvilleGoogle Scholar
  14. Dunbar MR, Cunningham MW, Wooding JB, Roth RP (1996) Cryptorchidism and delayed testicular descent in Florida black bears. J Wildl Dis 32:661–664PubMedGoogle Scholar
  15. Ebert D, Haag C, Kirkpatrick M, Riek M, Hottinger JW, Pajunen VI (2002) A selective advantage to immigrant genes in a Daphnia metapopulation. Science 295:485–488PubMedCrossRefGoogle Scholar
  16. Ernest HB, Boyce WM, Bleich VC, May B, Stiver SJ, Torres SG (2003) Genetic structure of mountain lion (Puma concolor) populations in California. Conserv Genet 4:353–366CrossRefGoogle Scholar
  17. Felsenstein J (1993) PHYLIP (Phylogeny Inference Package). Department of Genetics, University of Washington, SeattleGoogle Scholar
  18. Fitch WM, Margolia E (1967) Construction of phylogenetic trees. Science 155:279–284PubMedCrossRefGoogle Scholar
  19. Flather CH, Bevers M (2002) Patchy reaction-diffusion and population abundance: the relative importance of habitat amount and arrangement. Am Nat 159:40–56CrossRefGoogle Scholar
  20. Foster ML, Humphrey SR (1995) Use of highway underpasses by Florida panthers and other wildlife. Wildl Soc Bull 23:95–100Google Scholar
  21. Frankham R (1995) Inbreeding and extinction: a threshold effect. Conserv Biol 9:792–799CrossRefGoogle Scholar
  22. Frankham R (1996) Relationship of genetic variation to population size in wildlife. Conserv Biol 10:1500–1508CrossRefGoogle Scholar
  23. Frankham R, Ballou J, Briscoe D (2002) Introduction to conservation genetics. Cambridge University Press, New YorkGoogle Scholar
  24. Franklin IR (1980) Evolutionary change in small populations. In: Soule ME, Wilcox BA (eds) Conservation biology: an evolutionary – ecological perspective. Sinauer, Sunderland, Massachusetts, pp. 135–150Google Scholar
  25. Gerlach G, Musolf K (2000) Fragmentation of landscape as a cause for genetic subdivision in bank voles. Conserv Biol 14:1066–1074CrossRefGoogle Scholar
  26. Gottelli D, Sillerozubiri C, Applebaum GD, Roy MS, Girman DJ, Garciamoreno J, Ostrander EA, Wayne RK (1994) Molecular genetics of the most endangered canid: the Ethiopian wolf (Canis simensis). Mol Ecol 3:301–312PubMedGoogle Scholar
  27. Griffith B, Scott J, Carpenter J, Reed C (1989) Translocation as a species conservation tool: status and strategy. Science 245:477–480CrossRefGoogle Scholar
  28. Guo SW, Thompson EA (1992) Performing the exact test of Hardy–Weinberg proportion for multiple alleles. Biometrics 48:361–372PubMedCrossRefGoogle Scholar
  29. Harris LD (1984) The fragmented forest: Island biogeography theory and the preservation of biotic diversity. The University of Chicago Press, ChicagoGoogle Scholar
  30. Harrison S, Bruna E (1999) Habitat fragmentation and large-scale conservation: what do we know for sure? Ecography 22:225–232CrossRefGoogle Scholar
  31. Hellborg L, Walker CW, Rueness EK, Stacy JE, Kojola I, Valdmann H, Vila C, Zimmermann B, Jakobsen KS, Ellegren H (2002) Differentiation and levels of genetic variation in northern European lynx (Lynx lynx) populations revealed by microsatellites and mitochondrial DNA analysis. Conserv Genet 3:97–111CrossRefGoogle Scholar
  32. Hellgren EC, Maehr DS (1993) Habitat fragmentation and black bears in the eastern United States. In: Orff EP (ed) Eastern black bear workshop for research and management. Waterville Valley, New Hampshire, pp. 154–165Google Scholar
  33. Hellgren EC, Onorato DP, Skiles JR (2005) Dynamics of a black bear population within a desert metapopulation. Biol Conserv 122:131–140CrossRefGoogle Scholar
  34. Hendry LA, Goodwin TM, Labisky RF (1982) Florida’s vanishing wildlife. Florida Cooperative Extension Service, GainesvilleGoogle Scholar
  35. Hitchings SP, Beebee TJC (1997) Genetic substructuring as a result of barriers to gene flow in urban Rana temporaria (common frog) populations: implications for biodiversity conservation. Heredity 79:117–127PubMedCrossRefGoogle Scholar
  36. Ims RA, Andreassen HP (1999) Effects of experimental habitat fragmentation and connectivity on root vole demography. J Anim Ecol 68:839–852CrossRefGoogle Scholar
  37. Johnson WE, Eizirik E, Roelke-Parker M, O’Brien SJ (2001) Applications of genetic concepts and molecular methods to carnivore conservation. In: Gittleman JL, Funk SM, Macdonald D, Wayne RK (eds) Carnivore conservation. Cambridge University Press, New York, pp. 335–358Google Scholar
  38. Jules ES (1998) Habitat fragmentation and demographic change for a common plant: trillium in old-growth forest. Ecology 79:1645–1656CrossRefGoogle Scholar
  39. Kasbohm JW, Bentzien MM (1998) The status of the Florida black bear. United States Fish and Wildlife Service, Jacksonville, FloridaGoogle Scholar
  40. Keller I, Largiader CR (2003) Recent habitat fragmentation caused by major roads leads to reduction of gene flow and loss of genetic variability in ground beetles. Proc R Soc Lond Ser B-Biol Sci 270:417–423CrossRefGoogle Scholar
  41. Kyle CJ, Strobeck C (2001) Genetic structure of North American wolverine (Gulo gulo) populations. Mol Ecol 10:337– 347PubMedCrossRefGoogle Scholar
  42. Lande R (1995) Mutation and conservation. Conserv Biol 9:782–791CrossRefGoogle Scholar
  43. Larkin JL, Maehr DS, Hoctor TS, Orlando MA, Whitney K (2004) Landscape linkages and conservation planning for the black bear in west-central Florida. Anim Conserv 7:1–12CrossRefGoogle Scholar
  44. Louis EJ, Dempster ER (1987) An exact test for Hardy–Weinberg and multiple alleles. Biometrics 43:805–811PubMedCrossRefGoogle Scholar
  45. Lu Z, Johnson WE, Menotti-Raymond M, Yuhki N, Martenson JS, Mainka S, Shi-Qiang H, Zhihe Z, Li GH, Pan WS, Mao XR, O’Brien SJ (2001) Patterns of genetic diversity in remaining giant panda populations. Conserv Biol 15:1596–1607CrossRefGoogle Scholar
  46. Mader HJ (1984) Animal habitat isolation by roads and agricultural fields. Biol Conserv 29:81–96CrossRefGoogle Scholar
  47. Maehr DS, Layne JE, Land ED, McCown JW, Roof J (1988) Long distance movements of a Florida black bear. Fla Field Nat 16:1–6Google Scholar
  48. Maehr DS, Hoctor TS, Quinn LJ, Smith JS (2001) Black bear habitat management guidelines for Florida. Florida Fish and Wildlife Conservation Commission, TallahasseeGoogle Scholar
  49. Maehr DS, Smith JS, Cunningham MW, Barnwell ME, Larkin JL, Orlando MA (2003) Spatial characteristics of an isolated Florida black bear population. Southeast Nat 2:433–446CrossRefGoogle Scholar
  50. Mansfield KG, Land ED (2002) Cryptorchidism in Florida panthers: prevalence, features, and influence of genetic restoration. J Wildl Dis 38:693–698PubMedGoogle Scholar
  51. Mantel N (1967) The detection of disease clustering and a generalized regression approach. Cancer Res 27:209–220PubMedGoogle Scholar
  52. Marshall HD, Ritland K (2002) Genetic diversity and differentiation of Kermode bear populations. Mol Ecol 11:685–697PubMedCrossRefGoogle Scholar
  53. McCown JW, Kubilis PS, Eason TH, Scheick BK (2004) Black bear movements and habitat use relative to roads in Ocala national forest. Florida Fish and Wildlife Conservation Commission, TallahasseeGoogle Scholar
  54. McCoy J, Johnston K (2000) Using ArcGIS spatial analyst. ESRI Publishing, Redlands, CaliforniaGoogle Scholar
  55. McDaniel J (1974) Florida report on black bear management and research. In: Pelton MR, Conley D (eds) Proceedings of the second eastern workshop on black bear management and research. Gatlinburg, Tennessee, pp. 157–162Google Scholar
  56. Meffe GK, Carroll CR (1997) Principles of conservation biology. Sinauer, Sunderland, MassachusettsGoogle Scholar
  57. Michalakis Y, Excoffier L (1996) A generic estimation of population subdivision using distances between alleles with special interest to microsatellite loci. Genetics 142:1061–1064PubMedGoogle Scholar
  58. Miller CR, Waits LP (2003) The history of effective population size and genetic diversity in the Yellowstone grizzly (Ursus arctos): implications for conservation. Proc Natl Acad Sci USA 100:4334–4339PubMedCrossRefGoogle Scholar
  59. Mills LS, Allendorf FW (1996) The one-migrant-per-generation rule in conservation and management. Conserv Biol 10:1509–1518CrossRefGoogle Scholar
  60. Moyer MA, McCown JW, Eason TH, Oli MK (2006) Does genetic relatedness influence space use pattern? A test on Florida black bears. J Mammal 87:255–261CrossRefGoogle Scholar
  61. Noss RF, Quigley HB, Hornocker MG, Merrill T, Paquet PC (1996) Conservation biology and carnivore conservation in the Rocky mountains. Conserv Biol 10:949–963CrossRefGoogle Scholar
  62. O’Brien SJ (1994) A role for molecular genetics in biological conservation. Proc Natl Acad Sci USA 91:5748–5755PubMedCrossRefGoogle Scholar
  63. Paetkau D (2003) An empirical exploration of data quality in DNA-based population inventories. Mol Ecol 6:1375–1387CrossRefGoogle Scholar
  64. Paetkau D, Strobeck C (1994) Microsatellite analysis of genetic variation in black bear populations. Mol Ecol 3:489–495PubMedGoogle Scholar
  65. Paetkau D, Calvert W, Stirling I, Strobeck C (1995) Microsatellite analysis of population structure in Canadian polar bears. Mol Ecol 4:347–354PubMedGoogle Scholar
  66. Paetkau D, Waits LP, Clarkson PL, Craighead L, Strobeck C (1997) An empirical evaluation of genetic distance statistics using microsatellite data from bear (Ursidae) populations. Genetics 147:1943–1957PubMedGoogle Scholar
  67. Paetkau D, Shields GF, Strobeck C (1998) Gene flow between insular, coastal and interior populations of brown bears in Alaska. Mol Ecol 7:1283–1292PubMedCrossRefGoogle Scholar
  68. Paetkau D, Amstrup SC, Born EW, Calvert W, Derocher AE, Garner GW, Messier F, Stirling I, Taylor MK, Wiig O, Strobeck C (1999) Genetic structure of the world’s polar bear populations. Mol Ecol 8:1571–1584PubMedCrossRefGoogle Scholar
  69. Pritchard JK, Stephens M, Donnelly P (2000) Inference of population structure using multilocus genotype data. Genetics 155:945–959PubMedGoogle Scholar
  70. Proctor MF, McLellan BN, Strobeck C (2002) Population fragmentation of grizzly bears in southeastern British Columbia, Canada. Ursus 13:153–160Google Scholar
  71. Raymond M, Rousset F (1995) Genepop (Version-1.2) population genetics software for exact tests and ecumenicism. J Hered 86:248–249Google Scholar
  72. Reed DH, Frankham R (2003) Correlation between fitness and genetic diversity. Conserv Biol 17:230–237CrossRefGoogle Scholar
  73. Rice WR (1989) Analyzing tables of statistical tests. Evolution 43:223–225CrossRefGoogle Scholar
  74. Roelke ME, Martenson JS, Obrien SJ (1993) The consequences of demographic reduction and genetic depletion in the endangered Florida panther. Curr Biol 3:340–350PubMedCrossRefGoogle Scholar
  75. Rogers LL (1987) Factors influencing dispersal in the black bear. In: Chepko-Sade BD, Halpin ZT (eds) Mammalian dispersal patterns: the effects of social structure on population genetics. University of Chicago Press, Chicago, pp. 75–84Google Scholar
  76. Saccheri I, Kuussaari M, Kankare M, Vikman P, Fortelius W, Hanski I (1998) Inbreeding and extinction in a butterfly metapopulation. Nature 392:491–494CrossRefGoogle Scholar
  77. Schwartz CC, Franzmann AW (1992) Dispersal and survival of subadult black bears from the Kenai Peninsula, Alaska. J Wildl Manage 56:426–431Google Scholar
  78. Schwartz MK, Mills LS, McKelvey KS, Ruggiero LF, Allendorf FW (2002) DNA reveals high dispersal synchronizing the population dynamics of Canada lynx. Nature 415:520–522PubMedCrossRefGoogle Scholar
  79. Sherwin WB, Moritz C (2000) Managing and monitoring genetic erosion. In: Young AG, Clarke GM (eds) Genetics, demography, and viability of fragmented populations. Cambridge University Press, New York, pp. 9–34Google Scholar
  80. Simek SL, Jonker SA, Scheick BK, Endries MJ, Eason TH (2005) Statewide assessment of road impacts on bears in six study areas in Florida. Florida Fish and Wildlife Conservation Commission, TallahasseeGoogle Scholar
  81. Slatkin M (1993) Isolation by distance in equilibrium and nonequilibrium populations. Evolution 47:264–279CrossRefGoogle Scholar
  82. Spong G, Hellborg L (2002) A near-extinction event in lynx: do microsatellite data tell the tale? Conserv Ecol, 6, Art. No. 15Google Scholar
  83. Taberlet P, Camarra JJ, Griffin S, Uhres E, Hanotte O, Waits LP, DuboisPaganon C, Burke T, Bouvet J (1997) Noninvasive genetic tracking of the endangered Pyrenean brown bear population. Mol Ecol 6:869–876PubMedCrossRefGoogle Scholar
  84. Vos CC, Antonisse-De Jong AG, Goedhart PW, Smulders MJM (2001) Genetic similarity as a measure for connectivity between fragmented populations of the moor frog (Rana arvalis). Heredity 86:598–608PubMedCrossRefGoogle Scholar
  85. Waits LP (1999) Molecular genetic applications for bear research. Ursus 11:253–260Google Scholar
  86. Walker CW, Vila C, Landa A, Linden M, Ellegren H (2001) Genetic variation and population structure in Scandinavian wolverine (Gulo gulo) populations. Mol Ecol 10:53–63PubMedCrossRefGoogle Scholar
  87. Warrillow J, Culver M, Hallerman E, Vaughan M (2001) Subspecific affinity of black bears in the White River National Wildlife Refuge. J Hered 92:226–233PubMedCrossRefGoogle Scholar
  88. Weir BS, Cockerham CC (1984) Estimating F-statistics for the analysis of population structure. Evolution 38:1358–1370CrossRefGoogle Scholar
  89. Westemeier RL, Brawn JD, Simpson SA, Esker TL, Jansen RW, Walk JW, Kershner EL, Bouzat JL, Paige KN (1998) Tracking the long-term decline and recovery of an isolated population. Science 282:1695–1698PubMedCrossRefGoogle Scholar
  90. Wooding JB (1993) Management of the black bear in Florida, a staff report to the commissioners. Florida Game and Fresh Water Fish Commission, TallahasseeGoogle Scholar
  91. Woods JG, Paetkau D, Lewis D, McLellan BN, Proctor M, Strobeck C (1999) Genetic tagging of free-ranging black and brown bears. Wildl Soc Bull 27:616–627Google Scholar

Copyright information

© Springer Science+Business Media B.V. 2006

Authors and Affiliations

  • Jeremy D. Dixon
    • 1
    • 2
  • Madan K. Oli
    • 2
  • Michael C. Wooten
    • 3
  • Thomas H. Eason
    • 4
  • J. Walter McCown
    • 5
  • Mark W. Cunningham
    • 5
  1. 1.Florida Fish and Wildlife Conservation CommissionOlusteeUSA
  2. 2.Department of Wildlife Ecology and ConservationUniversity of FloridaGainesvilleUSA
  3. 3.Department of Biological SciencesAuburn UniversityAuburnUSA
  4. 4.Florida Fish and Wildlife Conservation CommissionTallahasseeUSA
  5. 5.Florida Fish and Wildlife Conservation CommissionGainesvilleUSA

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