Biodiversity analysis of true bug assemblages (Hemiptera, Heteroptera) in four habitats in the Garraf Natural Park (Barcelona, Spain).

With the aim of gaining insight into true bugs assemblages, and of giving tools to enhance environmental manager tasks, an analysis was made of the alpha and beta diversity of true bug assemblages in the NE Iberian Peninsula. The study took place during the years 1999, 2000, and 2001. The diversity of true bug assemblages among four typical Mediterranean plant communities (dry grassland, calcicolous rosemary scrub, kermes oak scrub, and evergreen oak forest) in a protected natural area was compared. In each plant community, a stratified sampling, taking into account plants with highest coverage percentage, was performed. Collections were performed monthly using direct observation plus beating or sweeping of the entomological net. Objectives were 1) to assess whether true bug assemblages are different in each plant community surveyed, by means of the analysis of their alpha and beta diversity, 2) to assess if any of the four true bug assemblages may be prioritized according to the biodiversity parameters studied. In total, 3,071 specimens, belonging to 12 families and 77 species were identified. Fifty percent of specimens collected belonged to only three species, and ∼33% of species was represented by only one or two individuals. In each Heteroptera assemblage, the distribution pattern of species frequency classes followed a lognormal model. Thirty-five percent of species represented by three or more specimens were found in only one plant community. Abundance, species richness, and diversity were found to be different for each true bug assemblage and along the year. Abundance was highest in the evergreen oak forest and in spring. Species richness and diversity were highest in the kermes oak scrub and in early summer. Nonparametric species richness estimators showed that completeness of species inventory was >80%. In the study zone, true bug diversity may be considered low medium. Our results show that true bugs assemblages are characteristic of specific plant communities, and thus, true bugs fit as candidate monitoring group in environmental and conservation management.