Mapping species richness of endemic macroinvertebrates by overlapping distribution maps

Inventory-based approaches (i.e., those that directly relate species richness to explanatory variables) do not work on the medium and local scale that was studied in this paper; even when ecologically-meaningful environmental predictors were used. The use of an alternative approach (Taxon-based diversity mapping) is proposed. This approach starts by modelling the probability of occurrence of twelve target endemic species using environmental variables as predictors. Next, it projects the probability of occurrence from 48 sampled sites to a grid of 532 1-km2 units. Finally, the approach estimates endemic species richness at these 532 1-km2 units by overlapping the twelve maps inferred. We also propose a new approach whose purpose is to detect possible false absences and unstable presences. These doubtful observations were excluded from ecological niche modelling. In addition to species richness, the patterns experienced by species composition were analysed. Species composition experienced strong changes (i.e., large turnover), while species richness remained constant. This stasis in species richness is neither related to low environmental variability (both the biotic and abiotic scenarios are diverse) nor to the lack of species-environment relationships (not only species composition but also species-specific responses are correlated with environment). The area studied is environmentally diverse and species turnover of the macroinvertebrate community was moderate to large. Species composition was significantly correlated with environment (minimum temperature). The predicted number of target endemic species per cell in 92% of the studied area fell between 3 and 5. Therefore Taxonbased diversity mapping has been confirmed as a valid alternative to conventional inventory-based diversity mapping. Additionally, the new procedure proposed here for dealing with noisy presence/absence data produces more accurate distributional maps of individual species.

Bibliographic Details

Main Authors:	Palmer, Miquel, Pons, Guillem X., Outerelo, Raimundo, Vives Noguera, Eduardo, Bellés, Xavier, García, Lluc, Linde, Marta, Gómez-Pujol, Lluís, March, David
Other Authors:	Govern de les Illes Balears
Format:	artículo biblioteca
Published:	Societat d'Història Natural de les Balears 2012
Subjects:	Distribution maps, Occurrence patterns, Spatial structure, GLZ modelling, Species richness,
Online Access:	http://hdl.handle.net/10261/99448
Tags:	Add Tag No Tags, Be the first to tag this record!