2 / 2016-10-22 18:02:04

Null model to evaluating of plant diversity distribution across elevation gradient

11579,11580,11581,11582

Abstract:
The study of diversity distribution between local plant communities is interest for plant ecologists. For correct evaluating of variations in diversity, β-diversity is a useful metric. But, β-diversity is somewhat dependent to types of diversity (α-diversity and γ-diversity). In order to, null models especially abundance-based null model can remove this problem and our evaluating from β-diversity become well with randomizations in null models (Mori et.al., 2015). In this study, type of fully constrained of null models is selected. In this type, both richness and occurrence frequency totals are constant because of according to last studies were revealed null models that preserve the species abundance patterns could better reflect empirical patterns of spatial organization of individuals (Cadotte and Davies 2016). Also, for conducting of this model to community data, indices of bray-Curtis, Chord and Sorensen were used. For performing of this method on our data, we placed 239 plots across elevation gradient with stratified random sampling in south range of Hezar Masjed Mountains. This region is located in Khorassan Razavi province in Iran and all of the analyses in this paper were performed with R software version 3.1.3. Results in this study indicated that β-diversity distribution is ascended with elevation increment but, proportion of variation in plant species composition and evenness patterns were more than variation in number of plants species between stands. Also, results with bray-Curtis index were better than others indices for evaluating distance between randomization communities and determining of β-diversity distribution, due to this index is appropriate for abundance data in ecology (Legendre and Legendre 2012). According to our results, abundance-based null model and bray-Curtis index are the most appropriate for evaluating of diversity distribution between plant communities and are conformed to empirical results.

References:
Cadotte M.W. and T.J. Davies (2016) Phylogenies in ecology , a guide to concepts and methods, Princeton university press, 1-252
Legendre P. and L. Legendre (2012) Numerical ecology, Elsevier, 1-990
Mori A.S., Fujii S., Kitagawa R. and D. Koide (2015) Null model approaches to evaluating the relative role of different assembly processes in shaping ecological communities, Oecologia 178:261-273