Connectivity measures: a review

Springer Science and Business Media LLC - Tập 23 - Trang 879-890 - 2008
Pavel Kindlmann1, Francoise Burel2
1Institute of Systems Biology and Ecology, AS CR, Ceske Budejovice, Czech Republic
2CNRS, UMR ECOBIO, Université de Rennes 1, Rennes Cedex, France

Tóm tắt

One of the central problems in contemporary ecology and conservation biology is the drastic change of landscapes induced by anthropogenic activities, resulting in habitat loss and fragmentation. For many wild living species, local extinctions of fragmented populations are common and recolonization is critical for regional survival. Successful recolonization depends on the availability of dispersing individuals and the degree of landscape connectivity. The obvious implications of landscape connectivity for conservation biology have led to a proliferation of connectivity measures. However, general relationships between landscape connectivity and landscape structure are lacking, and so are the relationships between different connectivity metrics. Consequently, there is a need to develop landscape metrics that more accurately characterize the landscape with an emphasis on the underlying processes. Here we review various definitions of landscape connectivity, explain their mathematical connotations, and make some unifying conclusions and suggestions for future research.

Tài liệu tham khảo

Adler FR, Nuernberger B (1994) Persistence in patchy irregular landscapes. Theor Popul Biol 45:41–75. doi:10.1006/tpbi.1994.1003 Anderson GS, Danielson BJ (1997) The effects of landscape composition and physiognomy on metapopulation size: the role of corridors. Landsc Ecol 12:261–271. doi:10.1023/A:1007933623979 Andreassen HP, Halle S, Ims RA (1996a) Optimal width of movement corridors for root voles: not too narrow and not too wide. J Appl Ecol 33:63–70. doi:10.2307/2405016 Andreassen HP, Ims RA, Stenseth NC (1996b) Discontinuous habitat corridors: effects on male root vole movements. J Appl Ecol 33:555–560. doi:10.2307/2404984 Ault TR, Johnson CR (1998) Spatially and temporally predictable fish communities on coral-reefs. Ecol Monogr 68:25–50 Baars MA (1979) Patterns of movement of radioactive carabid beetles. Oecologia 44:125–140. doi:10.1007/BF00346411 Bascompte J, Solé R (1996) Habitat fragmentation and extinction thresholds in explicit models. J Anim Ecol 65:465–473. doi:10.2307/5781 Bélisle M (2005) Measuring landscape connectivity the challenge of behavioral landscape ecology. Ecology 86:1988–1995. doi:10.1890/04-0923 Bennett AF, Henein K, Merriam G (1994) Corridor use and the elements of corridor quality: chipmunks and fencerows in a farmland mosaic. Biol Conserv 68:155–166. doi:10.1016/0006-3207(94)90347-6 Benton TG, Vickery JA, Wilson JD (2003) Farmland biodiversity: is habitat heterogeneity the key? Trends Ecol Evol 18:182–188. doi:10.1016/S0169-5347(03)00011-9 Bevers M, Flather C (1999) Numerically exploring habitat fragmentation effects on populations using cell-based coupled map lattices. Theor Popul Biol 65:465–473 Bonner J (1994) Widlife’s roads to nowhere? New Sci 143:30–34 Brachet S, Olivieri I, Godelle B, Klein E, Frascaria-Lacoste N, Gouyon P (1999) Dispersal and metapopulation viability in a heterogeneous landscape. J Theor Biol 198:479–495. doi:10.1006/jtbi.1999.0926 Briers RA (2002) Incorporating connectivity into reserve selection procedures. Biol Conserv 103:77–83. doi:10.1016/S0006-3207(01)00123-9 Brooker L, Brooker M, Cale P (1999) Animal dispersal in fragmented habitat: measuring habitat connectivity, corridor use and dispersal mortality. Conserv Ecol 3:4 Brotons L, Mönkkönen M, Martin JL (2003) Are fragments islands? Landscape context and density-area relationships in boreal forest birds. Am Nat 162:343–357. doi:10.1086/376887 Bowne DR, Bowers MA (2004) Interpatch movements in spatially structured populations: a literature review. Landsc Ecol 19:1–20. doi:10.1023/B:LAND.0000018357.45262.b9 Bunn AG (2000) Landscape connectivity: a focal species approach using graph theory. Master’s Project Report, Duke University, USA Bunn AG, Urban DL, Keitt TH (2000) Landscape connectivity: a conservation application of graph theory. J Environ Manage 59:265–278. doi:10.1006/jema.2000.0373 Cabeza M (2003) Habitat loss and connectivity of reserve networks in probability approaches to reserve design. Ecol Lett 6:665–672. doi:10.1046/j.1461-0248.2003.00475.x Calabrese JM, Fagan WF (2004) A comparison-shopper’s guide to connectivity metrics. Front Ecol Environ 2:529–536 Castellón TD, Sieving KE (2006) An experimental test of matrix permeability and corridor use by an endemic understory bird. Conserv Biol 20:135–145. doi:10.1111/j.1523-1739.2006.00332.x Chardon JP, Adriaensen F, Matthysen E (2003) Incorporating landscape elements into a connectivity measure: a case study for the speckled wood butterfly (Pararge aegeria L). Landsc Ecol 18:561–573. doi:10.1023/A:1026062530600 Collinge SK (2000) Effects of grassland fragmentation on insect species loss, colonization, and movement patterns. Ecology 81:2211–2226 Collinge SK, Forman RTT (1998) A conceptional model of land conversion processes–predictions and evidence from a microlandscape experiment with grassland insects. Oikos 82:66–84. doi:10.2307/3546918 Danielson BJ, Hubbard MW (2000) The influence of corridors on the movement behavior of individual Peromyscus polionotus in experimental landscapes. Ecology 15:323–331 Dawson D (1994) Are habitat corridors conduits for animals and plants in a fragmented landscape? A review of the scientific evidence. English Nature Research Report 94. English Nature, Peterborough Debinski DM, Holt RD (2000) A survey and overview of habitat fragmentation experiments. Conserv Biol 14:342–355. doi:10.1046/j.1523-1739.2000.98081.x Demers MN, Simpson JW, Boerner REJ, Silva A, Berns L, Artigas F (1995) Fencerows, edges, and implications of changing connectivity illustrated by two contiguous Ohio landscapes. Conserv Biol 9:1159–1168. doi:10.1046/j.1523-1739.1995.9051159.x Doak DF, Marino PC, Kareiva PM (1992) Spatial scale mediates the influence of habitat fragmentation on dispersal success: implications for conservation. Theor Popul Biol 41:315–336. doi:10.1016/0040-5809(92)90032-O Dorner B, Lertzman K, Fall J (2002) Landscape pattern in topographically complex landscapes: issues and techniques for analysis. Landsc Ecol 17:729–743. doi:10.1023/A:1022944019665 Duelli P, Studer M, Marchand I, Jakob S (1990) Population movements of arthropods between natural and cultivated areas. Biol Conserv 54:193–207. doi:10.1016/0006-3207(90)90051-P Dytham C (1995) The effect of habitat destruction pattern on species persistence: a cellular model. Oikos 74:340–344. doi:10.2307/3545665 Fahrig L, Merriam G (1985) Habitat patch connectivity and population survival. Ecology 66:1762–1768. doi:10.2307/2937372 Fahrig L (1992) Relative importance of spatial and temporal scales in a patchy environment. Theor Popul Biol 41:300–314. doi:10.1016/0040-5809(92)90031-N Fahrig L, Merriam G (1994) Conservation of fragmented populations. Conserv Biol 8:50–59. doi:10.1046/j.1523-1739.1994.08010050.x Ferrari JR, Lookingbill TR, Neel MC (2007) Two measures of landscape-graph connectivity: assessment across gradients in area and configuration. Landsc Ecol 22:1315–1323. doi:10.1007/s10980-007-9121-7 Fischer M (2001) Landscape dynamics can accelerate metapopulation extinction. Trends Ecol Evol 16:225–226. doi:10.1016/S0169-5347(01)02175-9 FitzGibbon SI, Putland DA, Goldizen AW (2007) The importance of functional connectivity in the conservation of a ground-dwelling in an urban Australian landscape. Landsc Ecol 22:1513–1525. doi:10.1007/s10980-007-9139-x Forman RTT (1983) Corridors in a landscape: their ecological structure and function. Ekol CSSR 2:375–387 Gaines MS, McGlenaghan LR (1980) Dispersal in small mammals. Annu Rev Ecol Syst 11:163–196. doi:10.1146/annurev.es.11.110180.001115 Gardner RH, Milne BT, Turner MG, O’Neill RV (1987) Neutral models for the analysis of broad-scale landscape pattern. Landsc Ecol 1:19–28. doi:10.1007/BF02275262 Gelling M, Macdonald DW, Mathews F (2007) Are hedgerows the route to increased farmland small mammal density? Use of hedgerows in British pastoral habitats. Landsc Ecol 22:1019–1032. doi:10.1007/s10980-007-9088-4 Girvetz EH, Greco SE (2007) How to define a patch: a spatial model for hierarchically delineating organism-specific habitat patches. Landsc Ecol 22:1131–1142. doi:10.1007/s10980-007-9104-8 Goodwin BJ (2003) Is landscape connectivity a dependent or independent variable? Landsc Ecol 18:687–699. doi:10.1023/B:LAND.0000004184.03500.a8 Goodwin BJ, Fahrig L (2002a) Effect of landscape structure on the movement behaviour of a specialized goldenrod beetle, Trirhabda borealis. Can J Zool 80:25–34. doi:10.1139/z01-196 Goodwin BJ, Fahrig L (2002b) How does landscape structure influence landscape connectivity? Oikos 99:552–570. doi:10.1034/j.1600-0706.2002.11824.x Grashof-Bokdam C (1997) Forest species in an agricultural landscape in the Netherlands–effects of habitat fragmentation. J Veg Sci 8:21–28. doi:10.2307/3237238 Graves TA, Farley S, Goldstein MI, Servheen C (2007) Identification of functional corridors with movement characteristics of brown bears on the Kenai Peninsula, Alaska. Landsc Ecol 22:765–772. doi:10.1007/s10980-007-9082-x Green DG (1994) Connectivity and complexity in landscapes and ecosystems. Pac Conserv Biol 1:194–200 Gustafson EJ (1998) Quantifying landscape spatial pattern: what is the state of the art? Ecosystems (NY, Print) 1:143–156. doi:10.1007/s100219900011 Gustafson EJ, Gardner RH (1996) The effect of landscape heterogeneity on the probability of patch colonization. Ecology 77:94–107. doi:10.2307/2265659 Haddad NM (1999) Corridor use predicted from behaviours at habitat boundaries. Am Nat 153:215–227. doi:10.1086/303163 Haddad NM (2000) Corridor length and patch colonization by a butterfly, Junonia coenia. Conserv Biol 14:738–745. doi:10.1046/j.1523-1739.2000.99041.x Hanski I (1999a) Metapopulation ecology. Oxford series in ecology and evolution. Oxford University Press, Oxford Hanski I (1999b) Habitat connectivity, habitat continuity, and metapopulations in dynamic landscapes. Oikos 87:209–219. doi:10.2307/3546736 Hanski I, Ahlo J, Moilanen A (2000) Estimating the parameters of survival and migration of individuals in metapopulations. Ecology 81:239–251 Hansson L (1991) Dispersal and connectivity in metapopulations. Biol J Linn Soc 42:89–103. doi:10.1111/j.1095-8312.1991.tb00553.x Hargis CD, Bissonette JA, David JL (1998) The behavior of landscape metrics commonly used in the study of habitat fragmentation. Landsc Ecol 13:167–186. doi:10.1023/A:1007965018633 Hastings A (1980) Disturbance, coexistence, history, and competition for space. Theor Popul Biol 18:363–373. doi:10.1016/0040-5809(80)90059-3 Hein S, Gombert J, Hovestadt T, Poethke H-J (2003) Movement patterns of the bush cricket Platycleis albopunctata in different types of habitat: matrix is not always matrix. Ecol Entomol 28:432–438. doi:10.1046/j.1365-2311.2003.00531.x Heino M, Hanski I (2001) Evolution of migration rate in a spatially realistic metapopulation model. Am Nat 157:495–511. doi:10.1086/319927 Henein K, Merriam G (1990) The elements of connectivity where corridor quality is variable. Landsc Ecol 4:157–170. doi:10.1007/BF00132858 Hess GR (1996) Linking extinction to connectivity and habitat destruction in metapopulation models. Am Nat 148:226–236. doi:10.1086/285922 Hjermann DO, Ims RA (1996) Landscape ecology of the wart-biter Decticus verrucivorus in a patchy landscape. J Anim Ecol 65:768–780. doi:10.2307/5675 Hof J, Flather CH (1996) Accounting for connectivity and spatial correlation in the optimal placement of wildlife habitat. Ecol Modell 88:143–155. doi:10.1016/0304-3800(95)00082-8 Hunter MD (2002) Landscape structure, habitat fragmentation, and the ecology of insects. Agric For Entomol 4:159–166. doi:10.1046/j.1461-9563.2002.00152.x Huxel GA, Hastings A (1998) Population size dependence, competitive coexistence and habitat destruction. J Anim Ecol 67:446–453. doi:10.1046/j.1365-2656.1998.00208.x Ims RA, Andreassen HP (1999) Effects of experimental habitat fragmentation and connectivity on root vole demography. J Anim Ecol 68:839–852. doi:10.1046/j.1365-2656.1999.00336.x Johnson AR, Milne BT, Wiens JA (1992a) Diffusion in fractal landscapes: simulations and experimental studies of tenebrionid beetle movements. Ecology 73:1968–1993. doi:10.2307/1941448 Johnson AR, Wiens JA, Milne BT, Crist TO (1992b) Animal movements and population dynamics in heterogeneous landscapes. Landsc Ecol 7:63–75. doi:10.1007/BF02573958 Jonsen ID, Taylor PD (2000) Fine-scale movement behaviors of calopterygid damselflies are influenced by landscape structure: an experimental manipulation. Oikos 88:553–562. doi:10.1034/j.1600-0706.2000.880312.x Jordan F, Magura T, Tóthmérész B, Vasas V, Kodobocz V (2007) Carabids (Coleoptera: Carabidae) in a forest patchwork: a connectivity analysis of the Bereg Plain landscape graph. Landsc Ecol 22:1527–1539. doi:10.1007/s10980-007-9149-8 Kareiva P (1985) Finding and losing host plants by Phyllotreta: patch size and surrounding habitat. Ecology 66:1809–1816. doi:10.2307/2937376 Kareiva PM, Shigesada N (1983) Analyzing insect movement as a correlated random walk. Oecologia 56:234–238. doi:10.1007/BF00379695 Keymer JE, Marquet PA, Velasco-Hernandez JX, Levin SA (2000) Extinction thresholds and metapopulation persistence in dynamic landscapes. Am Nat 156:478–494. doi:10.1086/303407 Klausmeier CA (1998) Extinction in multispecies and spatially explicit models of habitat destruction. Am Nat 152:303–310. doi:10.1086/286170 Knaapen JP, Scheffer M, Harms B (1992) Estimating habitat isolation in landscape planning. Landsc Urban Plan 23:1–16. doi:10.1016/0169-2046(92)90060-D Krummel JR, Gardner RH, Sugihara G, O’Neill RV, Coleman PR (1987) Landscape patterns in a disturbed environment. Oikos 48:321–324. doi:10.2307/3565520 Laan R, Verboom B (1990) Effects of pool size and isolation on amphibian communities. Biol Conserv 54:251–262. doi:10.1016/0006-3207(90)90055-T Levin SA (1974) Dispersion and population interactions. Am Nat 108:207–225. doi:10.1086/282900 Lima SL, Zollner PA (1996) Towards a behavioral ecology of ecological landscapes. Trends Ecol Evol 11:131–135. doi:10.1016/0169-5347(96)81094-9 Lindenmayer DB, Nix HA (1993) Ecological principles for the design of wildlife corridors. Conserv Biol 7:627–630. doi:10.1046/j.1523-1739.1993.07030627.x Mader HJ (1984) Animal habitat isolation by roads and agricultural fields. Biol Conserv 29:81–96. doi:10.1016/0006-3207(84)90015-6 Mader HJ, Schell C, Kornacker P (1990) Linear barriers to arthropod movements in the landscape. Biol Conserv 54:209–222. doi:10.1016/0006-3207(90)90052-Q Marquet PA, Velasco-Hernández JX (1997) A source-sink patch occupancy metapopulation model. Rev Chil Hist Nat 70:371–380 Matthysen E, Adriaensen F, Dhondt AA (1995) Dispersal distances of nuthatches, Sitta europea, in a highly fragmented forest habitat. Oikos 72:375–381. doi:10.2307/3546123 Mauremooto JR, Wratten SD, Worner SP, Fry GLA (1995) Permeability of hedgerows to predatory carabid beetles. Agric Ecosyst Environ 52:141–148. doi:10.1016/0167-8809(94)00548-S McCulloch CE, Cain ML (1989) Analyzing discrete movement data as a correlated random walk. Ecology 70:383–388. doi:10.2307/1937543 Merriam G (1984) Connectivity: a fundamental ecological characteristic of landscape pattern. In: Brandt J, Agger P (eds) Proceedings of first international seminar on methodology in landscape ecology research and planning, vol I. Roskilde Universitessforlag GeoRue, Roskilde, Denmark, pp 5–15 Merriam G (1991) Corridors and connectivity: animal populations in heterogeneous environments. In: Saunders D, Hobbs RJ (eds) Nature conservation 2: the role of corridors. Surrey Beatty and Sons, Chipping Norton, New South Wales, pp 133–142 Merriam G, Saunders DA (1993) Corridors in restoration of fragmented landscapes. In: Saunders D, Hobbs RJ (eds) Nature conservation 2: the role of corridors. Surrey Beatty and Sons, Chipping Norton, New South Wales, pp 71–87 Metzger J-P, Décamps H (1997) The structural connectivity threshold: an hypothesis in conservation biology at the landscape scale. Acta Oecol 18:1–12. doi:10.1016/S1146-609X(97)80075-6 Michel N, Burel F, Legendre P, Butet A (2007) Role of habitat and landscape in structuring small mammal assemblages in hedgerow networks of contrasted farming landscapes in Brittany, France. Landsc Ecol 22:1241–1253. doi:10.1007/s10980-007-9103-9 Moilanen A, Hanski I (1998) Metapopulation dynamics: effect of habitat quality and landscape structure. Ecology 79:2503–2515 Moilanen A, Hanski I (2001) On the use of connectivity measures in spatial ecology. Oikos 95:147–151. doi:10.1034/j.1600-0706.2001.950116.x Moilanen A, Nieminen M (2002) Simple connectivity measures in spatial ecology. Ecology 83:1131–1145 Nichols JD, Kendall WL (1995) The use of multi-state capture-recapture models to address questions in evolutionary ecology. J Appl Stat 22:835–846. doi:10.1080/02664769524658 Noss RF (1993) Wildlife corridors. In: Smith DS, Hellmund PC (eds) Ecology of greenways: design and function of linear conservation areas. University of Minnesota Press, Minneapolis, MN, pp 43–68 Ockinger E, Smith HG (2007) Do corridors promote dispersal in grassland butterflies and other insects? Landsc Ecol 23:27–40. doi:10.1007/s10980-007-9167-6 O’Neill RV, Milne BT, Turner MG, Gardner RH (1988) Resource utilization scales and landscape pattern. Landsc Ecol 2:63–69. doi:10.1007/BF00138908 Orbach R (1986) Dynamics of fractal networks. Science 231:814–819. doi:10.1126/science.231.4740.814 Pain G, Baudry J, Burel F (2000) Landpop: un outil d’étude de la structure spatiale des populations animales fragmentées. Geomatique 10:89–106 Pither J, Taylor PD (1998) An experimental assessment of landscape connectivity. Oikos 83:166–174. doi:10.2307/3546558 Poole KG (1997) Dispersal patterns of lynx in the northwest territories. J Wildlife Manage 61:497–505. doi:10.2307/3802607 Ricketts TH (2001) The matrix matters: effective isolation in fragmented landscapes. Am Nat 157:87–99. doi:10.1086/320863 Rosenberg DK, Noon BR, Meslow EC (1997) Biological corridors: form, function and efficacy. Bioscience 47:677–687. doi:10.2307/1313208 Ruckelshaus M, Hartway C, Kareiva PM (1997) Assessing the data requirements of spatially explicit dispersal models. Conserv Biol 11:1298–1306. doi:10.1046/j.1523-1739.1997.96151.x Sakai HF, Noon BR (1997) Between-habitat movement of dusky-footed woodrats and vulnerability to predation. J Wildlife Manage 61:343–350. doi:10.2307/3802590 Saunders DA, Hobbs RJ (1991) Nature conservation 2: the role of corridors. Surrey Beatty and Sons, Chipping Norton, New South Wales Saunders DA, Hobbs RJ, Arnold GW (1993) The Kellerberrin project on fragmented landscapes: a review of current information. Biol Conserv 64:185–192. doi:10.1016/0006-3207(93)90320-Z Schooley RL, Wiens JA (2003) Finding habitat patches and directional connectivity. Oikos 102:559–570. doi:10.1034/j.1600-0706.2003.12490.x Schumaker N (1996) Using landscape indices to predict habitat connectivity. Ecology 77:1210–1225. doi:10.2307/2265590 Stauffer D, Aharony A (1991) Introduction to percolation theory, 2nd edn. Taylor and Francis, London, UK Swanson FJ, Kratz TK, Caine N, Woodmansee RG (1998) Landform effects on ecosystem patterns and processes. Bioscience 38:92–98. doi:10.2307/1310614 Swart J, Lawes MJ (1996) The effect of habitat patch connectivity on samango monkey (Cercopithecus mitis) metapopulation persistence. Ecol Modell 93:57–74. doi:10.1016/0304-3800(95)00211-1 Sweeney S, Jurek M, Bednar M (2007) Using place names to interpret former floodplain connectivity in the Morava River, Czech Republic. Landsc Ecol 22:1007–1018. doi:10.1007/s10980-007-9085-7 Taylor PD, Fahrig L, Henein K, Merriam G (1993) Connectivity is a vital element of landscape structure. Oikos 68:571–573. doi:10.2307/3544927 Thies C, Steffan-Dewenter I, Tscharntke T (2003) Effects of landscape context on herbivory and parasitism at different spatial scales. Oikos 101:18–25. doi:10.1034/j.1600-0706.2003.12567.x Tiebout HM, Anderson RA (1997) A comparison of corridors and intrinsic connectivity to promote dispersal in transient successional landscapes. Conserv Biol 11:620–627. doi:10.1046/j.1523-1739.1997.95270.x Tilman D, Lehman D, Yin C (1997) Habitat destruction, dispersal, and deterministic extinction in competitive communities. Am Nat 149:407–435. doi:10.1086/285998 Tischendorf L (1997) Corridors as conduits for small animals: attainable distances depending on movement pattern, boundary reaction and corridor width. Oikos 79:603–611. doi:10.2307/3546904 Tischendorf L (2001) Can landscape indices predict ecological processes consistently? Landsc Ecol 16:235–254. doi:10.1023/A:1011112719782 Tischendorf L, Fahrig L (2000a) How should we measure landscape connectivity?. Landsc Ecol 15:633–641. doi:10.1023/A:1008177324187 Tischendorf L, Fahrig L (2000b) On the usage and measurement of landscape connectivity. Oikos 90:7–19. doi:10.1034/j.1600-0706.2000.900102.x Tischendorf L, Fahrig L (2001) On the use of connectivity measures in spatial ecology: a reply. Oikos 95:152–155. doi:10.1034/j.1600-0706.2001.950117.x Tischendorf L, Irmler U, Hingst R (1998) A simulation experiment on the potential of hedgerows as movement corridors for forest carabids. Ecol Modell 106:107–118. doi:10.1016/S0304-3800(97)00186-5 Travis JM, Dytham C (1999) Habitat persistence, habitat availability and the evolution of dispersal. Proc R Soc Lond B Biol Sci 266:723–728. doi:10.1098/rspb.1999.0696 Travis JM, French DR (2000) Dispersal functions and spatial models: expanding our dispersal toolbox. Ecol Lett 3:163–165. doi:10.1046/j.1461-0248.2000.00141.x Treml EA, Halpin PN, Urban DL, Pratson LF (2007) Modeling population connectivity by ocean currents, a graph-theoretic approach for marine conservation. Landsc Ecol 23:19–36. doi:10.1007/s10980-007-9138-y Turner MG (1989) Landscape ecology: the effect of pattern on process. Annu Rev Ecol Syst 20:171–197. doi:10.1146/annurev.es.20.110189.001131 Turner MG, Ruscher CL (1988) Changes in landscape patterns in Georgia, USA. Landsc Ecol 1:241–251. doi:10.1007/BF00157696 van Langevelde F (2000) Scale of habitat connectivity and colonization in fragmented nuthatch populations. Ecography 23:614–622. doi:10.1034/j.1600-0587.2000.230512.x Verboom B, Van Apeldoorn RC (1990) Effects of habitat fragmentation on the Red Squirrel (Sciurus vulgaris L). Landsc Ecol 4:171–176. doi:10.1007/BF00132859 Vos CC, Chardon JP (1998) Effects of habitat fragmentation and road density on the distribution pattern of the moor frog Rana arvalis. J Appl Ecol 35:44–56. doi:10.1046/j.1365-2664.1998.00284.x Vos CC, Stumpel HP (1995) Comparison of habitat-isolation parameters in relation to fragmented distribution patterns in the tree frog (Hyla arborea). Landsc Ecol 11:203–214. doi:10.1007/BF02071811 Vos CC, Verboom J, Opdam PFM, Ter Braak CJF (2001) Toward ecologically scaled landscape indices. Am Nat 157:24–41. doi:10.1086/317004 Walker RS, Novaro AJ, Branch LC (2007) Functional connectivity defined through cost-distance and genetic analyses: a case study for the rock-dwelling mountain vizcacha (Lagidium viscacia) in Patagonia, Argentina. Landsc Ecol 22:1303–1314. doi:10.1007/s10980-007-9118-2 Wallin H, Ekbom BS (1988) Movements of carabid beetles (Coleoptera: Carabidae) inhabiting cereal fields: a field tracing study. Oecologia 77:39–43. doi:10.1007/BF00380922 Wegner JF, Merriam G (1990) Use of spatial elements in a farmland mosaic by a woodland rodent. Biol Conserv 54:263–276. doi:10.1016/0006-3207(90)90056-U White GC, Burnham KP (1999) Program MARK: survival rate estimation from both live and dead encounters. Bird Study 46:S120–S139 Wiegand T, Moloney KA, Naves J, Knauer F (1999) Finding the missing link between landscape structure and population dynamics: a spatially explicit perspective. Am Nat 154:605–627 Wiens JA, Crawford CS, Gosz JR (1985) Boundary dynamics: a conceptual framework for studying landscape ecosystems. Oikos 45:412–427. doi:10.2307/3565577 Wiens JA, Stenseth NC, Van Horne B, Ims RA (1993) Ecological mechanisms and landscape ecology. Oikos 66:369–380. doi:10.2307/3544931 Wiens JA, Schooley RL, Weeks RD (1997) Patchy landscapes and animal movements: do beetles percolate? Oikos 78:257–264. doi:10.2307/3546292 With KA, Crist TO (1995) Critical thresholds in species’ responses to landscape structure. Ecology 76:2446–2459. doi:10.2307/2265819 With KA, King AW (1999) Dispersal success on fractal landscapes: a consequence of lacunarity thresholds. Landsc Ecol 14:73–82. doi:10.1023/A:1008030215600 With KA, Gardner RH, Turner MG (1997) Landscape connectivity and population distributions in heterogeneous landscapes. Oikos 78:151–169. doi:10.2307/3545811 Zollner PA, Lima SL (1999) Illumination and the perception of remote habitat patches by white-footed mice. Anim Behav 58:489–500. doi:10.1006/anbe.1999.1186