Disentangling the Web of Life

1. Asummaryof: Disentangling the Web of Life JordiBascompte(2009), Science 425:416-419

2. Overview • Incorporating network theory in Ecological Studies • Review • Benefits • Examine interaction patterns vs. species composition

3. Outline • Paper Overview • Entangled Bank • Biodiversity • Architecture • Architecture of Biodiversity • Architecture Influences Robustness • Architecture Influences Network Size • Beyond Species Interactions • Conclusion

4. The Entangled Bank “In the case of every species, many different checks, acting at different periods of life, and during different seasons or years, probably come into play; … When we look at the plants and bushes clothing an entangled bank, we are tempted to attribute their proportional numbers and kinds to what we call chance. But how false a view is this!” http://www.fossilmuseum.net/Evolution/Darwin.htm

5. Outline • Paper Overview • Entangled Bank • Biodiversity • Architecture • Architecture of Biodiversity • Architecture Influences Robustness • Architecture Influences Network Size • Beyond Species Interactions • Conclusion

6. Biodiversity • Definition: • the diversity of plant and animal life in a particular habitat (or in the world as a whole); "a high level of biodiversity is desirable“ • Value: • At the ecosystem level, biodiversity provides the conditions and drives the processes that sustain the global economy – and our very survival as a species • wordnetweb.princeton.edu/perl/webw

7. Biodiversity • Past Studies: • Count species, not their interactions • Assume homogeneous interactions • Need: • Incorporate network theory

8. Outline • Paper Overview • Entangled Bank • Biodiversity • Architecture • Architecture of Biodiversity • Architecture Influences Robustness • Architecture Influences Network Size • Beyond Species Interactions • Conclusion

9. Architecture of Biodiversity • Food Webs = Trophic interactions • Predator/Prey/Herbivore/Plant cmore.soest.hawaii.edu

10. Architecture of Biodiversity • Food Webs = Trophic interactions • Mutualism (pollinations/seed dispersal)

11. Architecture of Biodiversity Montoya, J, S L Pimm, R V Sole (2006) Ecological Networks and their fragility. Nature, 442:doi:10.1038/nature04927

12. Architecture of Biodiversity Montoya, J, S L Pimm, R V Sole (2006) Ecological Networks and their fragility. Nature, 442:doi:10.1038/nature04927

13. Outline • Paper Overview • Entangled Bank • Biodiversity • Architecture • Architecture of Biodiversity • Architecture Influences Robustness • Architecture Influences Network Size • Beyond Species Interactions • Conclusion

14. Architecture Influences Robustness • Biodiversity Threats • species extinctions, • habitat loss • anthropogenic influence • Coextinction avalanches • phylogenetically similar species • trophically unique species

15. Architecture Influences Robustness Rezende, E, J E Lavabre, P R Guimeraes, P Jordano, J Bascompte (2007) Non-random coextinctions in phylogenetically structures in multualistic networks.Nature, 448:925-928.

16. Architecture Influences Robustness Petchey, O, A Eklof, C Borrvall and B Ebenman (2008)Trophically Unique Species Are Vulnerable to Cascading Extinction. The American Naturalist, 171:569-579

17. Architecture Influences Robustness Trophic Modules Network Motifs

18. Outline • Paper Overview • Entangled Bank • Biodiversity • Architecture • Architecture of Biodiversity • Architecture Influences Robustness • Architecture Influences Network Size • Beyond Species Interactions • Conclusion

19. Architecture Influences Network Size • Size: Number of species that can be supported by a network • example

20. Architecture Influences Network Size • Challenges linking architecture & function • population dynamics network topology • multiple interaction types • species invasions, climate change, and other challenges

21. Outline • Paper Overview • Entangled Bank • Biodiversity • Architecture • Architecture of Biodiversity • Architecture Influences Robustness • Architecture Influences Network Size • Beyond Species Interactions • Conclusion

22. Beyond Species Interactions • Other types of ecological networks • Habitat Fragments

23. Beyond Species Interactions • Other types of ecological networks • Genetic variation in space

24. Outline • Paper Overview • Entangled Bank • Biodiversity • Architecture • Architecture of Biodiversity • Architecture Influences Robustness • Architecture Influences Network Size • Beyond Species Interactions • Conclusion

25. Conclusion • Networks useful descriptors of ecological systems • Assessment of perturbations/predictions • Enable heterogeneous studies • Show generalities among disparate systems

26. Thanks