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Nestedness patterns and the dual nature of community reassembly in C alifornia streams: a multivariate permutation‐based approach
Author(s) -
Novak Mark,
Moore Jonathan W.,
Leidy Robert A.
Publication year - 2011
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/j.1365-2486.2011.02482.x
Subject(s) - nestedness , metacommunity , ecology , abiotic component , streams , community , extinction (optical mineralogy) , community structure , tributary , ecosystem , biology , species richness , geography , computer science , biological dispersal , population , computer network , paleontology , demography , sociology , cartography
Many factors contribute to the nonrandom processes of extinctions and invasions that are changing the structure of ecological communities worldwide. These factors include the attributes of the species, their abiotic environment, and the interactions and feedbacks between them. The relative importance of these factors has been difficult to quantify. We used nested subset theory and a novel permutation‐based extension of gradient analysis to disentangle the direct and indirect pathways by which these factors affect the metacommunity structure of freshwater fishes inhabiting the streams tributary to the S an F rancisco B ay. Our analyses provide quantitative measures of how species and stream attributes may influence extinction vulnerability and invasion risk, highlight the need for considering the multiple interacting drivers of community change concurrently, and indicate that the ongoing disassembly and assembly of B ay A rea freshwater fish communities are not fully symmetric processes. Fish communities are being taken apart and put back together in only partially analogous trajectories of extinction and invasion for which no single explanatory hypothesis is sufficient. Our study thereby contributes to the forecasting of continued community change and its effects on the functioning of freshwater ecosystems.