Open AccessAn island view of endemic rarity—Environmental drivers and consequences for nature conservation
Author(s) -
Irl Severin D. H.,
Schweiger Andreas H.,
Medina Félix M.,
FernándezPalacios José M.,
Harter David E. V.,
Jentsch Anke,
Provenzale Antonello,
Steinbauer Manuel J.,
Beierkuhnlein Carl
Publication year - 2017
Publication title -
diversity and distributions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.918
H-Index - 118
eISSN - 1472-4642
pISSN - 1366-9516
DOI - 10.1111/ddi.12605
Subject(s) - endemism , ecology , geography , abiotic component , archipelago , range (aeronautics) , species richness , biology , composite material , materials science
Aim Rarity—an important measure for conservation biogeography—can vary over many orders of magnitude. However, it is unclear which regional‐scale abiotic conditions drive processes affecting rarity of endemic species on islands. To support conservation efforts, we (1) assess the main abiotic drivers of endemic rarity, (2) determine how well existing protected areas ( PA s) coincide with hotspots of endemic rarity and (3) introduce and evaluate a new hypervolume‐based rarity estimator. Location La Palma (Canary Islands). Methods We recorded all present endemic vascular plant species in 1,212 plots covering the entire island. We calculated endemic rarity (corrected range‐rarity richness for endemics) using a rarity estimation approach based on kernel density estimations (hypervolume approach). We performed a sensitivity analysis based on multiple linear regressions and relative importance estimations of environmental drivers to estimate the performance of the hypervolume‐based rarity estimation compared to standard methods (occurrence frequency, convex hulls, alpha hulls). Results Climate variables (mean annual temperature, climatic rarity, precipitation variability) best explained archipelago endemic ( AE ) and single‐island endemic ( SIE ) rarity. Existing PA s covered the majority of AE and SIE rarity, especially national and natural parks as well as the Natura 2000 sites. In our study system, hypervolumes performed better than standard measures of range size. Main conclusion Both AE and SIE rarity on La Palma show a clear spatial pattern, with hotspots of endemic rarity found at high elevations and in rare climates, presumably owing to geographical and climatic constraints and possibly anthropogenic pressure (e.g., land use, introduced herbivores, fire). Areas of high rarity estimates coincide with the distribution and extent of PA s on La Palma, especially since the recent addition of the Natura 2000 sites. The hypervolume approach is a promising tool to estimate species range sizes, and can be applied on all scales where point/plot data are available.