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Selecting for extinction: nonrandom disease‐associated extinction homogenizes amphibian biotas
Author(s) -
Smith Kevin G.,
Lips Karen R.,
Chase Jonathan M.
Publication year - 2009
Publication title -
ecology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.852
H-Index - 265
eISSN - 1461-0248
pISSN - 1461-023X
DOI - 10.1111/j.1461-0248.2009.01363.x
Subject(s) - amphibian , extinction (optical mineralogy) , biodiversity , ecology , biology , local extinction , homogenization (climate) , habitat , fauna , vertebrate , geography , population , biological dispersal , paleontology , biochemistry , demography , sociology , gene
Studying the patterns in which local extinctions occur is critical to understanding how extinctions affect biodiversity at local, regional and global spatial scales. To understand the importance of patterns of extinction at a regional spatial scale, we use data from extirpations associated with a widespread pathogenic agent of amphibian decline, Batrachochytrium dendrobatidis ( Bd ) as a model system. We apply novel null model analyses to these data to determine whether recent extirpations associated with Bd have resulted in selective extinction and homogenization of diverse tropical American amphibian biotas. We find that Bd ‐associated extinctions in this region were nonrandom and disproportionately, but not exclusively, affected low‐occupancy and endemic species, resulting in homogenization of the remnant amphibian fauna. The pattern of extirpations also resulted in phylogenetic homogenization at the family level and ecological homogenization of reproductive mode and habitat association. Additionally, many more species were extirpated from the region than would be expected if extirpations occurred randomly. Our results indicate that amphibian declines in this region are an extinction filter, reducing regional amphibian biodiversity to highly similar relict assemblages and ultimately causing amplified biodiversity loss at regional and global scales.