Assessing ant assemblages: pitfall trapping versus nest counting (Hymenoptera, Formicidae)

Abstract

Pitfall trapping and nest counting are the most common census methods for ant assemblages. We examined the concordance between pitfall catches and nest counts on dry grassland. Spearman rank correlations and non-metric multidimensional scaling of the Bray Curtis similarity index revealed moderate concordance between the data collated by the two methods, but overall method-related differences were considerable. The dissimilarity was influenced by the type of land management, but not by trapping period or plot shape. Trapping success depended on nest density, ground vegetation cover and species-specific traits (inhabited stratum, colony size, foraging distance). Even when these factors were taken into account, the convertibility of pitfall trap and nest density values was unsatisfactory: the census method proved to be crucial in designing ant-ecological studies and interpreting literature data.

Species diversity and nestedness of ant assemblages in an urban environment

“…The relative species richness of the urban ant fauna in Warsaw is similar to that recorded in some other European cities. In Sofia, the percentage of species found in the city of the total number recorded for Bulgaria is 30% (Antonova & Penev, 2006), in Vienna, relative to the whole of Austria, it is also 30% (Schlick-Steiner & Steiner, 1999). In another Austrian city, Linz and two German cities, Mainz and Cologne, however the recorded percentages are 21%, 21% and 20%, respectively (Lippke & Cölln, 1991;Dauber & Eisenbeis, 1997;Ambach, 1999).…”

Effect of the colour of pitfall traps on their capture efficiency of carabid beetles (Coleoptera: Carabidae), spiders (Araneae) and other arthropods

“…In this context, one has to keep in mind the general problems associated with using pitfall traps as census method for ants (cf. Agosti et al, 2000;Majer, 1997;Schlick-Steiner et al, 2006;Steiner et al, 2005).…”

The ant (Hymenoptera: Formicidae) communities of the central interior of British Columbia: Adaptations to a temperature-constrained environment.

“…They are especially popular with entomologists working with epigaeic invertebrates because they are inexpensive, easy to install, and sample 24 hrs a day (Agosti et al 2000;Schlick-Steiner et al 2006). A great number of design variations have been reported on in the literature, assessing, for example, the effects of variations in trap diameter (Abenspergtraun and Steven 1995;Work et al 2002;Borgelt and New 2005), collecting fluid (Greenslade and Greenslade 1971;Lemieux and Lindgren 1999;Koivula et al 2003), lids (Phillips and Cobb 2005), and surrounding habitat structure (Koivula et al 2003;Phillips and Cobb 2005).…”

“…Ideally, ecological samples will allow for estimates of absolute abundance that, in turn, can be used to assess population densities and parameters such as biomass or life history tables (Schlick-Steiner et al 2006). Unfortunately, this normally requires unit area or habitat area searches that often provide little data for large effort (Southwood and Henderson 2000).…”

“…This is contrasted with sampling methodologies intended to estimate the absolute abundance of populations per unit area or volume. It is frequently assumed, or forgotten, that trapping bias may skew species abundances as compared to their actual densities within a given habitat (Lang 2000;Schlick-Steiner et al 2006).…”