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The positive correlation between avian species richness and human population density in Britain is not attributable to sampling bias
Author(s) -
Evans Karl L.,
Greenwood Jeremy J.D.,
Gaston Kevin J.
Publication year - 2007
Publication title -
global ecology and biogeography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.164
H-Index - 152
eISSN - 1466-8238
pISSN - 1466-822X
DOI - 10.1111/j.1466-8238.2006.00288.x
Subject(s) - species richness , body size and species richness , population density , ecology , population , sampling bias , geography , sampling (signal processing) , density dependence , biology , demography , statistics , mathematics , sample size determination , filter (signal processing) , sociology , computer science , computer vision
Aim To assess whether spatial variation in sampling effort drives positive correlations between human population density and species richness. Location British 10 × 10 km squares. Methods We calculated three measures of species richness from atlas data of breeding birds in Britain: total species richness, species richness standardised for sampling effort, and the number of species only recorded in supplementary casual records in a manner not standardised for survey effort. We then assessed the form of the relationship between these richness estimates and human population density, both with and without taking spatial autocorrelation into account. Results Both total and standardised species richness exhibit similar species richness–human population density relationships; species richness generally increases with human population density, but decreases at the very highest densities. Supplementary species richness is very weakly correlated with human population density. Main conclusions In this example, sampling effort only slightly influences the form of species richness–human population density relationships. The positive correlation between species richness and human population density and any resultant conservation conflicts are thus not artefactual patterns generated by confounding human density and sampling effort.