Species co‐occurrence and phylogenetic structure of terrestrial vertebrates at regional scales

Global Global Ecology Ecology and and Biogeography, Biogeography, (Global (Global Ecol. Ecol. Biogeogr.) Biogeogr. ) (2016) RE S E A RCH PA P E R Species co-occurrence and phylogenetic structure of terrestrial vertebrates at regional scales Chuan Yan 1† , Yan Xie 2† , Xinhai Li 3 , Marcel Holyoak 4 and Zhibin Zhang 1 * State Key Laboratory of Integrated Management on Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing 100101, China, 2 Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing 100101, China, 3 National Zoological Museum of China, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing 100101, China, 4 Department of Environmental Science and Policy, University of California, 1 Shields Avenue, Davis, CA 95616, USA *Correspondence: Zhibin Zhang, State Key Laboratory of Integrated Management on Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing 100101, China. E-mail: zhangzb@ioz.ac. cn The first two authors made equal contributions. A B S TR AC T Aim To determine how taxonomic level and spatial scale affect the phylogenetic structure of species assemblages across four classes of terrestrial vertebrates. Location Mainland China. Methods Using species distribution data from Mammalia, Aves, Reptilia and Amphibia, including 2153 species from 2105 counties and 1632 species from 295 nature reserves across mainland China, we analysed the phylogenetic structure of co-occurring species at multiple taxonomic levels (class, order, family and genus) and spatial scales. Results We found that phylogenetic clustering and unstructured patterns were more frequent than phylogenetic overdispersion in all groups. There was a higher frequency of phylogenetic clustering within classes and orders than within families and genera, while spatial scale had little effect on the frequency of phylogenetic clustering. Birds and mammals showed less frequent clustering patterns than amphibians and reptiles. Main conclusions Phylogenetic clustering in terrestrial vertebrates was pre- dominant over overdispersion at regional scales and higher taxonomic levels. Our results suggest that regional ecological and evolutionary factors, such as environ- mental filtering and speciation relative to extinction or colonization rates, are important in determining species assemblages of animals. Keywords Competitive exclusion, environmental filtering, neutral process, phylogenetic structure, spatial scale, species assemblage, taxonomic level, vertebrates. I N TR O D U C TI O N It has been a great challenge to reveal the ecological and evolu- tionary processes that drive species assembly in nature. An accu- mulation of phylogenetic information has allowed researchers to address this question by examining the phylogenetic structure of natural species assemblages (Webb et al., 2002). Two main phylogenetic structures identified are phylogenetic clustering (closely related species tend to co-occur) and phylogenetic overdispersion (closely related species tend not to co-occur) relative to a null or neutral expectation. The mechanisms pro- posed in the literature to explain these structures include the ecological processes of environmental filtering and competitive exclusion and the evolutionary processes of speciation and extinction (Cavender-Bares et al., 2009; Cardillo, 2011). C 2016 John Wiley & Sons Ltd V © 2016 John Wiley & Sons Ltd Environmental filtering predicts that assemblages will be phylogenetically clustered (Webb et al., 2002; Emerson & Gillespie, 2008) provided that the relevant traits and habitat preferences show a phylogenetic signal, i.e. that closely related species are more similar (Den Boer, 1979; Cavender-Bares et al., 2006). The competitive exclusion hypothesis predicts that com- petition prevents the coexistence of closely related species because they frequently share similar ecological traits and use similar resources (Elton, 1946; Hardin, 1960), which generally results in phylogenetic overdispersion (Emerson & Gillespie, 2008; but see exceptions by Mayfield and Levine, 2010). A third, more recent, view arises from spatial models of neutral commu- nities (Hubbell, 2001), predicting phylogenetically unstructured patterns in local communities (Hubbell, 2001; Kembel & Hubbell, 2006). Lastly, Cardillo (2011) proposed that rapid spe- DOI: DOI: 10.1111/geb.12428 10.1111/geb.12428 http://wileyonlinelibrary.com/journal/geb http://wileyonlinelibrary.com/journal/geb