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Abstract Detail

Recent Topics Posters

Magee, Andrew [1], May, Michael R. [2], Moore, Brian [3].

A meta-analysis exploring the prevalence of density-dependent diversification.

In the past decade, various phylogenetic methods have been developed to detect tree-wide changes in the rate of lineage diversification (speciation – extinction). Application of these methods to empirical data has revealed a pervasive pattern of density-dependent diversification, where diversification rates decrease through time.  The apparent prevalence of this pattern is generally accepted as prima facie evidence of a biological cause for temporal decreases in diversification rate. Specifically, ecological interactions among species—such as competition for limited resources—intensify as the number of species in a growing lineage accumulates, causing the rate of speciation to decrease and/or the rate of extinction to increase. Surprisingly, the empirical prevalence of density-dependent diversification—and the impact of alternative methods used to detect it—have not been carefully studied. In this study, we performed a comprehensive meta-analysis to assess the prevalence of density-dependent diversification: we collected a comprehensive sample of datasets (comprising every previously published study of temporal variation in diversification rates), and subjected these datasets to an exhaustive series of analyses (using all available statistical methods developed to study this problem). Specifically, our sample of datasets includes 436 ultrametric trees (with species diversity data) from 107 published studies, which we analyzed using four statistical phylogenetic methods to detect tree-wide changes in diversification through time, including: (1) the gamma statistic of Pybus and Harvey (2000); (2) the survivorship method of Paradis (1998); (3) the birth-death likelihood method of Rabosky (2006), and; (4) the maximum-likelihood approach of Stadler (2011). We detected tree-wide shifts in diversification rate in 60%–86% of the trees; 2% of these involved rate increases, 98% involved rate decreases. For trees that were inferred to experience temporal decreases in diversification rate, 81%–87% were consistent with models of density-dependent diversification. We discuss inconsistencies in the prevalence of density-dependent diversification detected by the four methods, and consider possible biases that may partly explain these discrepancies. 

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1 - University of California, Davis, Evolution and Ecology, 1 Shields Avenue, Davis, CA, 95616, USA
2 - University of California, Davis, Evolution and Ecology, 2320 Storer Hall, One Shield Avenue, Davis, CA, 95616, USA
3 - University of California, Davis, Department of Evolution & Ecology, Storer Hall, One Shields Avenue, Davis, CA, 956126, USA


Presentation Type: Recent Topics Poster
Session: P
Location: /
Date: Monday, July 28th, 2014
Time: 5:30 PM
Number: PRT029
Abstract ID:1267
Candidate for Awards:None

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