Shen et al. 2008 Proposed conservation landscape for Giant Pandas in the Mishan Mtns. China Cons Biol 22:1144-53

1. Shen et al. 2008 Proposed conservation landscape for Giant Pandas in the Mishan Mtns. China Cons Biol 22:1144-53 Core Habitat CH 1,3,5,6,8 25% chance of extinction in 100yrs Recommend CORRIDORS PL1 -4

2. OUTLINE Corridors as a conservation tool benefits costs recent evidence large scale examples

3. MOVEMENT CORRIDORS: CONSERVATION BARGAINS OR POOR INVESTMENTS? Simberloff et al 1992 Conservation Biology 493-504

4. “a wildlife corridor is a linear landscape element which serves as a linkage between historically connected habitat, and is meant to facilitate movement between these natural areas” McEuan 1993

5. Benefits of corridors 1962- species-area relations Corridors increase area linking reserves should increase species richness 1974 - equilibrium theory of island biogeography Corridors increase immigration Equilibrium number of species should increase Corridors may aid dispersal, allow recolonization or rescue of populations, increase genetic diversity, prevent inbreeding reduce stochastic effects ---> general recommendation for reserve design

6. Benefits of corridors Beier 1993,1995 - cougars in southern California 150km2 Hwy 75km2 Santa Ana mountains 2070 km2 - 20 adults

7. Beier 1993, 1995 Radiocollared cougars Movement paths use riparian corridors Mortality around housing developments roads Models found - cougars will not persist in the small patches - population in large patch will not persist without immigration from Palomar Range Concluded A CORRIDOR IS ESSENTIAL

8. Benefits of corridors Maintain pathways for migratory species Eg quetzals in Costa Rica Protected breeding habitat Monteverde Reserve Proposed corridors Low elevation habitat used during non-breeding season

9. Benefits of corridors Maintain connectivity for ecological processeses Eg pollination by bees (Rudbeckia) and butterflies (Lantana) SOURCE Source pollen dusted with dayglo powder Townsend and Levey 2005 Ecol 86: 466-75

10. Benefits of corridors 1 Aid dispersal 2. Allows migration Maintains ecological processes 4. Allows range shifts due to climate change 5. Provision of escape routes from fire 6. Opportunity to avoid predation

11. Simberloff (1992): much cited paper MOVEMENT CORRIDORS: CONSERVATION BARGAINS OR POOR INVESTMENTS? Data on corridor use is limited/ experiments are not rigorous Data on consequences of corridors for demography and genetic structure is sparse Costs of corridors may be better spent on making larger reserves -

12. Hazards of corridors • Corridors may provide avenue for catastrophes (predators, fire, disease) corridors may attract edge-inhabiting predators isolated reserves quarantine disease • Corridors may act as entry route for exotics corridors may favour movement of introduced spp corridors may be reservoir for weeds • Corridors may function as sinks • Corridors with no buffer zone may expose migrants to danger Exposure to domestic animals, roads, etc 5. Corridors may facilitate poaching/trapping

13. Corridors: a philosophical slant Corridors are easily understood. Is it good conservation practise to sell the easiest program in the absence of evidence it is the most effective? Is it beneficial for people to feel that they are doing something important for conservation in the absence of evidence they are doing anything

14. 17 years after Simberloff Do corridors provide connectivity? Approaches do animals/plants use corridors do corridors influence demography do corridors influence genetic structure do corridors influence diversity

15. do animals/plants use corridors? Experimental corridors in S Carolina Corridors promote movement in diverse taxa

16. do animals/plants use corridors? Experimental corridors in S Carolina Obs Birds usually fly parallel to edge Model Predict bird and seed movement in connected/unconnected patches Expt Feed birds-track seeds of wax myrtle

17. do corridors influence demography? Control corridor fragment 5700 individuals 22600 captures Survival higher in corridor linked grids Population sizeless variable in corridor linked grids Coffman et al 2001 Oikos 93: 3-21

18. do corridors influence demography? Mountain pygmy possum Contiguous Fragmented by ski development Males can’t move --> lower female survival and skewed sex ratio + TUNNEL normal sex ratio and survival Females winter at higher elevation Males move to lower elevations

19. do corridors influence genetic structure? • Red squirrels • Deforestation in 19th century --> • Dwindling poplations in small isolated patches • Populations become genetically distinct • Reforestation 1950’s ---> • Kielder forest • links some populations • Genetic data - 1920’s museum skins • - 2001 resampled populations

20. do corridors influence genetic structure? Red squirrels Fragmented Linked by stepping stone corridor Reforestation has allowed genetic mixing of Scottish and Cumbrian populations

21. do corridors influence species diversity? Gilbert et al. 1998 ProcRSoc 265: 577-82 Moss micro-arthropod communities on rocks What is predicted?

22. do corridors influence species diversity? Gilbert et al. 1998 ProcRSoc 265: 577-82 Moss micro-arthropod communities on rocks What is predicted?

23. Corridors and connectivity Diverse taxa do use corridors - reasonable evidence Corridors can influence demography - some evidence Corridors can influence genetic processes - some evidence Corridors can influence diversity - some evidence Despite criticisms Corridors may be best solution to a complex problem

24. Conservation corridors Example 1. The Terai Arc 250 bengal tigers 11 protected areas

25. Conservation corridors Example 1. The Terai Arc 250 bengal tigers WWF+ partners Goal - link the 11 protected areas Khata corridor - 3 km long Links Royal Bardia to Kataniaghat 2001 - restoration commenced community forests and plantations 2004 - Elephant and tiger using corridor

26. Conservation corridors Example 2. The Mesoamerican corridor Wildlife Conservation Society initiative 7 countries Chiapas, Mexico to Darrien Gap, Panama 1996 GIS model linking reserves, remaining forest Progress slow Costa Rica 39 Mexico/Belize 4

27. Corridors- unresolved questions Which spp use corridors? Which benefit How do residency and movement rates differ among taxa “passage” vs “corridor dwellers” How does utilization change with shape, width, length, landscape? Will corridors promote the movement of exotics and disease?

28. Gibert ert al. 1998 Corridors maintain species richness in the fragmented landscapes of a microecosystem. P Roy Soc Lond B 265: 577-582 Damschen, EI et al. 2006 Corridors increase plant species richness at large scales SCIENCE 313: 1284-6 Shepherd, B and Whittington, J 2006. Response of wolves to corridor restoration and human use management ECOLOGY AND SOCIETY 11 Dixon, JD et al. 2006. Effectiveness of a regional corridor in connecting two Florida black bear populations CONSERVATION BIOLOGY 20: 155-162 Martensen et al. 2008. Relative effects of fragment size and connectivity on bird community ib the Atlantic Rainforest BIOLOGICAL CONSERVATION 141: 2184-92 Lees AC and Peres CA 2008 Conservation value of remnant riparian corridors of varying quality for Amazonian birds and mammals Conservation Biology 22 439-449 Beier P et al. 2008 Forks in the road: choices in procedures for designing wildland linkages. CONSERVATION BIOLOGY 22: 836-51

29. Points for discussion Corridors - are benefits taxon specific - how can we examine costs - what do we want them to do - how do we design them