Premium
Multi‐scale sampling boosts inferences from beta diversity patterns in coastal forests of South Africa
Author(s) -
Olivier Pieter I.,
Aarde Rudi J.
Publication year - 2014
Publication title -
journal of biogeography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 158
eISSN - 1365-2699
pISSN - 0305-0270
DOI - 10.1111/jbi.12303
Subject(s) - nestedness , beta diversity , biological dispersal , sampling (signal processing) , niche , ecology , alpha diversity , scale (ratio) , tree (set theory) , biology , species diversity , species richness , geography , mathematics , cartography , population , demography , filter (signal processing) , sociology , computer science , computer vision , mathematical analysis
Aim We used a hierarchical fractal‐based sampling design to test how sampling grain influences (1) beta diversity of and (2) inferences from the modelled contribution of niche‐ versus dispersal‐based assembly processes in structuring tree and bird assemblages. Location Coastal forest fragments, South Africa. Methods We surveyed 103 tree plots and 267 bird points within eight forest fragments and partitioned beta diversity (β sor ) into its turnover (β sim ) and nestedness (β nes ) components. We evaluated how sampling at fine, intermediate and coarse scales influenced beta diversity components, and compared how tree and bird beta diversity responded to sampling grain variation. We then explored the relative contributions of niche‐ and dispersal‐based assembly processes in explaining spatial turnover as a function of sampling grain and/or study taxon, by using multiple regression modelling on distance matrices and variance partitioning. Results The β sor of trees and birds was mainly explained by β sim at all sampling scales. For both taxonomic groups, β sor and β sim decreased as sampling scale increased. Beta diversity differed among trees and birds at fine, but not at coarse, sampling scales. Dispersal‐based assembly processes were the best predictors of community assembly at fine scales, whereas niche‐based assembly processes were the best predictors at coarse scales. However, most of the variation in tree community composition was explained at fine scales (by dispersal‐based assembly processes), while most of the variation in bird community composition was explained at coarse scales (by niche‐based assembly processes). Main conclusions Our study shows that inferences from beta diversity are scale dependent. By matching the grain of the data with the grain at which predictor variables and associated processes are likely to operate, multi‐scale sampling approaches can help improve planning for biodiversity conservation and should be part of initiatives aimed at ecological conservation plans.