Ant community in natural fragments of the Brazilian wetland: species–area relation and isolation

Biogeographic theory has been given much attention for its potential application to biodiversity conservation in areas fragmented through anthropic action. The objective of this study was to determine whether ant community structure established in natural woodland fragments immersed in a matrix of natural grasslands could be explained by this theory. We therefore investigated whether the relationship between species richness and both area and isolation that have previously been found in anthropogenically formed forest fragments are applicable to naturally formed forest fragments. The sampling consisted of eight natural woodland fragments with varying areas and degrees of isolation. Sampling was undertaken proportionally to the fragment size, and each sampling point was spaced at least 10 m apart. Ants were collected from each point through arboreal and epigeic “pitfall” traps. In addition, five epigeic traps were placed 100 m from each sampled fragment in the adjacent grassland. A total of 81 ant species were sampled. Total and epigaeic species richness increased with size of area and fragment isolation. However, arboreal ants responded positively only with respect to increasing area, but not with isolation. Moreover, specialist and generalist species richness had a positive relationship with area, but not with isolation. Biogeographic Theory can only be applied to some of the patterns found in the natural fragments in the present study. This positive relationship of ant richness and isolation suggests that these environments bear unique characteristics and therefore, must be regarded as conservation targets. The results obtained in this study suggest the need for further studies, to reinforce the importance of biodiversity conservation of this characteristic habitat in the Pantanal

The species–area relationship in ant ecology

AIM: The positive relationship between species richness and area-the species-area relationship (SAR)-is a key principle in ecology. Previous studies show large variation in the SAR across taxa collectively indicating the necessity of a taxon-focused approach to accurately evaluate biodiversity scaling patterns. Ants are ideal for this given their global distribution and role in ecosystem functioning. Using data from insular ant communities, this study quantified and investigated various attributes of ant SARs and reviewed the SAR literature for ant faunas, world-wide, to identify specific areas for improvement. LOCATION: Islands around the world. TAXON: Ants (Hymenoptera: Formicidae). METHODS: We aggregated data on species richness and island characteristics from previous studies on ant SARs to evaluate effects of climate, biogeographic realm, and latitude on slope values from these studies. A multimodel inference approach was used to determine the form of the different SARs, and whether there were any differences between mainland and insular SARs. We also assessed differences between mainland and insular SAR slopes and intercepts. To seek a general slope coefficient for ants, we used a mixed-effect model. Finally, we tested for potential thresholds in the global insular SAR using piecewise regression models. RESULTS: There was a negative relationship between SAR slopes and precipitation in both mainland and insular SARs, while SAR slopes and intercept values were higher in mainland compared to insular systems. Strong evidence of thresholds emerged in the global insular SAR. Finally, a general slope of 0.16 was observed for insular systems, which is lower than found in previous studies. MAIN CONCLUSIONS: A taxon-focused approach proves to showcase unexpected patterns in the SAR. Ant diversity increases faster across area in mainland areas compared to true islands. The influences of climate and biogeographic realms on the ant SAR warrant deeper study. Our review highlights knowledge gaps in the ant SAR that also extend to other taxa, such as the effects of nonnative species on the SAR.info:eu-repo/semantics/publishedVersio