Relations between species rarity, vulnerability, and range contraction for a beetle group in a densely populated region in the Mediterranean biodiversity hotspot.
Rarity is often considered an indication of species extinction risk, and it is frequently used to obtain measures of species vulnerability. However, there is no strong evidence of a correlation between species vulnerability and threat. Moreover, there is no consensus about how rarity should be measured. I used a multidimensional characterization of species rarity to calculate a vulnerability index for tenebrionid beetles inhabiting an Italian region in the Mediterranean biodiversity hotspot. I used different metrics to examine 3 dimensions of rarity: species range, ecology, and population. Species with rarity values below the median were scored as rare for each dimension. I combined rarity scores into a vulnerability index. I then correlated species vulnerability with range trends (expanded vs. contracted). Different measures of the same rarity dimension were strongly correlated and produced similar vulnerability scores. This result indicates rarity-based vulnerability estimates are slightly affected by the way a certain rarity dimension is measured. Vulnerability was correlated with range trends; species with the highest vulnerability had the strongest range contraction. However, a large number of common species also underwent range contraction in the last 50 years, and there was no clear relation between range contraction and their ecology. This indicates that in general human-induced environmental changes affected species irrespective of their assumed vulnerability and that focusing only on rare species may severely bias perceptions of the extent of species decline.
Azorean Biodiversity Group (CITA-A) and Platform for Enhancing Ecological Research & Sustainability (PEERS) Universidade dos Açores; Departamento de Ciências Agrárias, Pico da Urze, 9700-04, Angra do Heroísmo, Terceira, Açores, Portugal; Department of Biotechnology and Biosciences, University of Milano Bicocca, Piazza della Scienza 2, 20126, Milan, Italy.
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Fattorini
D063147:Animal Distribution; D000818:Animals; D044822:Biodiversity; D001517:Coleoptera / Q000502:physiology*; D003247:Conservation of Natural Resources; D056727:Endangered Species; D004777:Environment; D053476:Extinction, Biological; D007558:Italy; D019083:Mediterranean Region; D011156:Population Density; D012189:Retrospective Studies; D013045:Species Specificity
Coleoptera; Italia; Italy; Kattan index; Tenebrionidae; conservación de insectos; insect conservation; índice de Kattan