A forecast for extinction debt in the presence of speciation. (21st February 2017)

• Record Type: Journal Article
• Authors: Sgardeli, Vasiliki; Iwasa, Yoh; Varvoglis, Harry; Halley, John M.
• Is Part Of: Journal of theoretical biology. Volume 415(2017)
• Page Start: 48
• Page End: 52
• Publication Date: 2017-02-21
• Subjects: Relaxation process -- Neutral model -- Random fission speciation -- Extinction rates -- Relaxation time; Biology -- Periodicals; Biological Science Disciplines -- Periodicals; Biology -- Periodicals; Biologie -- Périodiques; Theoretische biologie; Biology; Periodicals; 571.05
• DOI: 10.1016/j.jtbi.2016.11.004
• Languages: English
• ISSNs: 0022-5193

Abstract

Abstract: Predicting biodiversity relaxation following a disturbance is of great importance to conservation biology. Recently-developed models of stochastic community assembly allow us to predict the evolution of communities on the basis of mechanistic processes at the level of individuals. The neutral model of biodiversity, in particular, has provided closed-form solutions for the relaxation of biodiversity in isolated communities (no immigration or speciation). Here, we extend these results by deriving a relaxation curve for a neutral community in which new species are introduced through the mechanism of random fission speciation (RFS). The solution provides simple closed-form expressions for the equilibrium species richness, the relaxation time and the species-individual curve, which are good approximation to the more complicated formulas existing for the same model. The derivation of the relaxation curve is based on the assumption of a broken-stick species-abundance distribution (SAD) as an initial community configuration; yet for commonly observed SADs, the maximum deviation from the curve does not exceed 10%. Importantly, the solution confirms theoretical results and observations showing that the relaxation time increases with community size and thus habitat area. Such simple and analytically tractable models can help crystallize our ideas on the leading factors affecting biodiversity loss. Highlights: The neutral relaxation model in the presence of speciation is solved explicitly. The solutions simplify existing results without serious loss of accuracy. Relaxation is faster with rapid speciation and slower for large community size. This result can be used to forecast biodiversity decline after habitat loss.