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Why Conservation Biology ?

Metapopulations and Conservation. Why Conservation Biology ?. Habitat destruction & fragmentation Overharvesting (MCF) Exotic species Extinction cascades Genetic, spatial, and climate (change) effects. Human population pressure Increased extinction & extinction debt.

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Why Conservation Biology ?

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  1. Metapopulations and Conservation Why Conservation Biology ? • Habitat destruction & fragmentation • Overharvesting (MCF) • Exotic species • Extinction cascades • Genetic, spatial, and climate (change) effects • Human population pressure • Increased extinction & extinction debt

  2. Island Biogeography Revisited Figure 25.8 Bighorn Sheep persistence depends on initial population size Island birds

  3. Population Viability Analysis Table 25.4 Birds on Californian Channel Islands Persistence as a function of initial population size

  4. A line-up of examples of threatened taxa (Table 25.1)

  5. 3 Standard Levels of Threat Figure 25.2

  6. Invasive Species (Exotics) • A consequence of human mobility • Biotic effects on natural species assemblies • Parasite release • Particularly problematic on islands • Introduction of natural enemies may work, but ..

  7. Virulence is subject to natural selection Myxoma virus in rabbits Figure 12.34

  8. Invasive Species (Exotics) • A consequence of human mobility • Biotic effects on natural species assemblies • Parasite release • Particularly problematic on islands • Introduction of natural enemies may work, but .. • The invasive garden ant, Lasius neglectus, in Europe

  9. The interplay of many factors Extinction vortexes towards extinction Figure 25.5

  10. Figure 25.9 Effects of Fragmentation • Genetic erosionand inbreeding • Demographicstochasticity • Edge effects (50 m for birds?)

  11. 25.11 Dynamics of subpopulations Data: 25.12 Checkerspot butterflies Modelling Approaches

  12. 25.14 Mean time to extinction as function of carrying capacity Ve = Variance in r due to environmental conditions 25.15 Cumulative probability of elephant extinction over 1000 years for 6 habitats without culling Analytical and Simulation Approaches

  13. Gorilla extinction with different recolonisation probability 25.16

  14. How to go about in practice ? 25.13 Decision tree Sumatran rhino’s: pE = extinction probability in 30 Years E(pE) = Expected Value $ = Cost

  15. The endemism hotspot approach Figure 25.19 Carsten Rahbek ZMUC

  16. Ongoing Research: Large blue butterfliesin the genus Maculinea • 5 European species Paintings by Richard Lewington

  17. Large blue butterfliesin the genus Maculinea • 5 European species • Parasites of Myrmica ant colonies

  18. Large blue butterfliesin the genus Maculinea • 5 European species • Parasites of Myrmica ant colonies • Dependent on specific host plants Fra: Flora Danica

  19. Large blue butterfliesin the genus Maculinea • 5 European species • Parasites of Myrmica ant colonies • Dependent on specific host plants • Vulnerable, threatened, endangered or locally extinct

  20. The life cycle of Maculinea alcon

  21. ? The European distribution of M. alcon Geographical variation in host use Elmes et al. (1989) Memorabilia Zoologica48, 55-68. Myrmicarubra • Is this due to: • Cryptic species? • Regional host availability? • Local host switching? Myrmica ruginodis Myrmica scabrinodis

  22. Geographical variation in allozymesGadeberg & Boomsma (1997) Journal of Insect Conservation 1, 99-111 Læsø Råbjerg Mile Tved Idom Vejers Fanø Frøslev Gyttegård

  23. Geographical variation in host use Læsø Råbjerg Mile Myrmica rubra M. ruginodis Tved Idom M. scabrinodis Vejers Frøslev Gyttegård

  24. The Main Study Populations • 3 populations studied in detail • Cross-infection experiments • Surface chemistry Læsø Vejers Gyttegård

  25. Laboratory adoption of Maculinea alcon

  26. MacMan: A large EU program on Maculinea butterflies

  27. Issues to be dealt with in a longer course • What are the relative importances of genetic, environmental, and demographic factors for long term persistence of populations ? • Why are long term monitoring studies important? • Why are invasive species (ants particularly) nasty ?

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