Scaling local abundance determinants in mediterranean dung beetles
Article first published online: 9 MAR 2011
© 2011 The Authors. Insect Conservation and Diversity © 2011 The Royal Entomological Society
Insect Conservation and Diversity
Volume 5, Issue 2, pages 106–117, March 2012
How to Cite
NUMA, C., LOBO, J. M. and VERDÚ, J. R. (2012), Scaling local abundance determinants in mediterranean dung beetles. Insect Conservation and Diversity, 5: 106–117. doi: 10.1111/j.1752-4598.2011.00137.x
- Issue published online: 13 MAR 2012
- Article first published online: 9 MAR 2011
- Accepted 5 February 2011 First published online X Month 20XX Editor: Simon R. Leather Associate editor: Alan Gange
- Abundance models;
- Cabañeros National Park;
- landscape connectivity;
- landscape scale;
- species traits
Abstract. 1. We study the factors that contribute to the variation in the local abundance of dung beetle species inhabiting Cabañeros National Park, a Mediterranean reserve in Central Spain. The relative roles of five different groups of explanatory variables (climatic, local-scale vegetation, landscape-scale vegetation, landscape connectivity and trophic resources) were assessed for 27 sampling sites established by a nested hierarchical sampling design that considered three regional landscapes (woodland, scrubland, grassland) and three local habitat types (forest, scrub, pasture) within each landscape.
2. Connectivity variables related to the spatial configuration of closed vegetation and distance to patches of open or closed vegetation were the best predictors of the species abundance. Precipitation was the most important climatic variable, whereas grassland area at the local- or landscape-scale and woodland area at the landscape-scale were the most important vegetation variables. Dung resources variables had the lowest explanatory ability.
3. More than 60% of the models explained more than 70% of the total variability. Observed and predicted abundance were highly and positively correlated and the mean percentage of absolute predictive errors was approximately 50%. Low-abundance observations had higher predictive errors and model accuracies seemed to be lower for species with narrow distributional ranges and presence in a high number of sampling localities.
4. Mediterranean ecosystems contain a diverse assemblage of dung beetle species whose composition and abundance are influenced by a variety of factors operating across different spatial scales. The most important variables are the spatial configuration and the habitat connectivity around each locality.