Limnetica 31

The southeastern Iberian Peninsula is a semi-arid region recognised as an area of high aquatic biodiversity. Water beetles (Coleoptera) and water bugs (Hemiptera) are two of the region’s most thoroughly studied insect groups. An exhaustive database of aquatic beetles and bugs from the Region of Murcia (SE Spain) and a set of 33 variables were employed for two related purposes: a) to describe the sampling effort conducted in the study area on these groups in order to identify zones with reliable inventories and b) with this information as a base, to forecast the distribution of species richness for each group. Theoretical estimates were based on the Clench function applied to the accumulated number of samples and were constructed with general linear models (GLM). The following results were obtained: 1) the percentage of grid cells that can be considered to be well sampled in the study area (143 10 × 10 km UTM grid cells) is approximately 14 % for beetles and 22 % for bugs; 2) well-surveyed cells are evenly distributed according to the previously defined physioclimatic subareas, which enable the use of these grid cells for modelling the richness distribution; and 3) a more accurate picture of the actual richness patterns for both groups is shown by the analysis. These results were combined to identify key areas where future sampling efforts must be focused.