1 / 13

Niches versus Neutrality

Niches versus Neutrality. Reviews of Neutral Models Levine & HilleRisLambers (2009) Nature 461:254. Reviews. Hubbel (2001) The Unified Neutral Theory of Biodiversity and Biogeography . Princeton University Press. Zero Sum Multinomial for Species Abundances

jabari
Download Presentation

Niches versus Neutrality

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Niches versus Neutrality Reviews of Neutral Models Levine & HilleRisLambers (2009) Nature 461:254.

  2. Reviews Hubbel (2001) The Unified Neutral Theory of Biodiversity and Biogeography. Princeton University Press. Zero Sum Multinomial for Species Abundances Tuning Parameters, NCM versions of niche-preemption to lognormal species abundances

  3. Reviews Bell, Lechowitz &Waterway (2006) Ecology 87:1378. Niches vs immigration Predicted static patterns similar Experimental results strongly favor niche theory

  4. Reviews McGill, Maure & Weiser (2006) Ecology 87:1411. Review testing neutral theory statistically Available tests fail to support neutrality (only 1 exception) Develop new test to distinguish zero-sum multinomial from lognormal species abundances Neutral theory: Estimating parameters difficult/arbitrary “… overwhelming evidence against neutral theory.”

  5. Reviews Purves & Turnbull (2010) J Animal Ecology 79:1215. Stress implausibility of growth-rate equality assumed by NCM Neutrality highly implausible Similar views: Gotelli & McGill (2006) Ecography 29:793

  6. Niches and Neutrality Currently, neutral models (approx. 10) lack both conceptual strength and empirical support. Neutral models remind us that ecology, as a science, should link pattern (at a given scale) to process (often at a more restricted scale); description and statistical fit model prediction do not validate model.

  7. Niches and Maintenance of Diversity Levine & HilleRisLambers (2009) Nature461:254.

  8. Levine & HilleRisLambers (2009) Maintenance of ecological diversity Functional, economic & aesthetic Coexistence: Competitors’ niches differ; Stabilizes density-dependent dynamics, Per-capitum growth greater when rare Challenge: Neutral theory: here, density-independent growth rates

  9. Levine & HilleRisLambers (2009) Left: Self-Regulation Stronger than Interspecific Effect Higher Growth Rate When Rare Produces Coexistence Right: No Niche Difference, Implying Within-Species and Between-Species Effects Same

  10. Levine & HilleRisLambers (2009) Annuals on Serpentine Soils Sites: 10+ Species Co-Occur Diversity Niche Based? Planted Experimental Communities Each 10 Species Equal Relative Abundances Growth-Rate Differences Reflect Inherent Differences, Density-Variation Controlled

  11. Levine & HilleRisLambers (2009) Species Not Equivalent 2 Orders of Magnitude in Geometric Mean Neutral Model Assumptions: Self-Regulation Equal to Between-Species Effect Discrete-Time Dynamics: Competitive Exclusion

  12. Species Diversity Seed pools control (any niche effects) Niches removed (equal effects) Control (Niche differences) H’ 50% Greater Rare Species 35% Community Niches Removed Rare Species 8% Community Common Species More Common

  13. Self-Regulated Growth: Seed Production Signature of Coexistence via Self-Regulation Niche Differences

More Related