Effectiveness of genera as a higher-taxon substitute for species in ant biodiversity analyses is not affected by sampling technique

Abstract

Survey costs and a lack of taxonomists are often the main impediments to biodiversity inventories. The use of a higher-taxon approach that is efficient in representing species patterns within a short period of time is one way to overcome these constraints, especially if these responses are consistent at various spatial scales and sampling techniques. Here, we evaluated whether the use of pitfall trapping or Winkler extraction influenced the utility of genus as a surrogate to predict patterns of species richness and composition related to environment. The study sites were spread along 10 degrees of latitude, covering phytophysiognomies with different topographic characteristics. We recorded 450 ant species/morphospecies distributed in 70 genera. Pitfall-traps captured a larger proportion of species (77–98%) and genera (71–100%) per site. Genus was efficient in predicting variations in richness, and assemblage composition detected at the species level, using pitfall-traps or Winkler extractors. The higher-taxon approach saved approximately 40% of the surveys costs. The negative effect of the species-genus ratio was detected only on species composition, but it did not affect the quality of predictions using genera. The results are consistent with the hypothesis that genus can be used as a proxy for broader sets of species independent of sampling technique or environmental heterogeneity. The use of pitfall-traps or Winkler extractors for genus-level identification proved to be cost-efficient and time-efficient and should work well in other regions requiring conservation effort and monitoring programs.