A1 Refereed original research article in a scientific journal
Species richness correlates of raw and standardized co-occurrence metrics
Authors: Ulrich W, Kubota Y, Kusumoto B, Baselga A, Tuomisto H, Gotelli NJ
Publisher: WILEY
Publication year: 2018
Journal: Global Ecology and Biogeography
Journal name in source: GLOBAL ECOLOGY AND BIOGEOGRAPHY
Journal acronym: GLOBAL ECOL BIOGEOGR
Volume: 27
Issue: 4
First page : 395
Last page: 399
Number of pages: 5
ISSN: 1466-822X
eISSN: 1466-8238
DOI: https://doi.org/10.1111/geb.12711
Self-archived copy’s web address: https://research.utu.fi/converis/portal/Publication/31007843
Abstract
Measuring beta-diversity and changes in species composition across multiple sites and environments is a major research focus in macroecology, and a variety of metrics have been proposed to quantify species co-occurrence patterns in a species x site occurrence matrix. However, indices of beta-diversity and species co-occurrence are often statistically dependent on the number of species in an assemblage. We compared the results of several common co-occurrence metrics with patterns generated by a spatially explicit neutral model simulation. We found that all measures of co-occurrence and beta-diversity, whether raw, rescaled or standardized by a null model expectation, were highly correlated with the total species richness of the landscape. The one important exception were the effect sizes of the fixed-fixed null model algorithm, which preserves row and column sums of the original matrix during matrix randomization. Our results call for a careful interpretation of meta-analyses of assemblages that differ widely in species richness. At a minimum, observed species richness should be used as a statistical covariate in regression analyses, and results of the fixed-fixed algorithm should be compared carefully with the results of other randomization tests.
Measuring beta-diversity and changes in species composition across multiple sites and environments is a major research focus in macroecology, and a variety of metrics have been proposed to quantify species co-occurrence patterns in a species x site occurrence matrix. However, indices of beta-diversity and species co-occurrence are often statistically dependent on the number of species in an assemblage. We compared the results of several common co-occurrence metrics with patterns generated by a spatially explicit neutral model simulation. We found that all measures of co-occurrence and beta-diversity, whether raw, rescaled or standardized by a null model expectation, were highly correlated with the total species richness of the landscape. The one important exception were the effect sizes of the fixed-fixed null model algorithm, which preserves row and column sums of the original matrix during matrix randomization. Our results call for a careful interpretation of meta-analyses of assemblages that differ widely in species richness. At a minimum, observed species richness should be used as a statistical covariate in regression analyses, and results of the fixed-fixed algorithm should be compared carefully with the results of other randomization tests.
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