Useful model organisms, indicators, or both? Ground beetles (Coleoptera, Carabidae) reflecting environmental conditions

Abstract

Classic studies have successfully linked single-species abundances, life-history traits, assemblage structures and biomass of carabid beetles to past and present, human-caused environmental impacts and variation in ‘natural’ conditions. This evidence has led many to suggest carabids to function as ‘indicators’ − a term that bears multiple meanings. Here, a conservation-oriented definition for an indicator is used, carabid indicator potential from seven views is evaluated, and ways to proceed in indicator research are discussed. (1) Carabid species richness poorly indicates the richness and abundance of other taxa, which underlines the importance of using multiple taxa in environmental assessments. The ability of assemblage indices and specialist or functional-group abundances to reflect rare species and habitats should be examined in detail. (2) Experimental evidence suggests that carabids may potentially serve as keystone indicators. (3) Carabids are sensitive to human-altered abiotic conditions, such as pesticide use in agro-ecosystems and heavy metal contamination of soils. Carabids might thus reflect ecological sustainability and ‘ecosystem health’. (4) Carabid assemblages host abundant species characteristic of particular habitat types or successional stages, which makes them promising dominance indicators. (5) Carabids reflect variation in ‘natural’ conditions, but vegetation and structural features are more commonly adopted as condition indicators. Carabids nevertheless provide yet another, equally accurate, view on the structure of the environment. (6) Carabids may function as early-warning signalers, as suggested by recent studies linking climate and carabid distributions. (7) Carabids reflect natural and human-caused disturbances and management, but the usefulness of these responses for conservation purposes requires further research. In summary, European carabids appear useful model organisms and possibly indicators because they are diverse, taxonomically and ecologically well-known, efficiently reflect biotic and abiotic conditions, are relevant at multiple spatial scales, and are easy to collect in sufficiently large numbers to allow statistical analyses. The assumption that carabid responses would reflect rare environmental conditions or the responses of rare and threatened species ‒ crucial information for conservationists and managers ‒ has not yet been critically evaluated. Even if it holds, the usefulness will be context dependent: species and their populations vary, conditions vary, questions put forward vary, and assessment goals vary.

Recovery of ground-dwelling assemblages during reforestation with native oak depends on the mobility and feeding habits of the species

“…5b). early phase, within 1-3 years after the clear-felling (Szyszko,423 1983; Niemelä et al, 2007;Koivula, 2011;Schwerk and Szyszko, 424 2011 shaping local diversity of ground beetles (Koivula, 2011). Namely, phases with a closed tree canopy (Niemelä et al, 1993(Niemelä et al, , 2007Elek 480 et al, 2001;Magura et al, 2002Magura et al, , 2003Magura et al, , 2006Pohl et al, 2007; requirements in these stands due to their ecological flexibility.…”

Do traditional land rehabilitation processes improve habitat quality and function? Life-history traits of ground beetles (Coleoptera, Carabidae) say no.

“…Carabid beetles (Coleoptera Carabidae) have found application, confirmed by numerous studies, as bioindicators of environmental disturbances and as a target for conservation efforts (12,13). As a group whose ecology and taxonomy are well known, characterized by high sensitivity to environmental changes, carabids are often chosen for studies on disturbances, e.g.…”

NEON terrestrial field observations: designing continental‐scale, standardized sampling

“…Additionally, they are common prey for small mammals, birds, reptiles, amphibians, and other larger arthropods and so form an important link in ecosystem food webs (Lö vei and Sunderland 1996). Given these factors, their straightforward collection, and their sensitivity to local community differences, ground beetles have been used extensively as indicator taxa (Rainio and Niemela 2003, Kotze et al 2011, Koivula 2011. Longitudinal studies of ground beetle collections will enable inferences about invertebrate diversity under varying climate and land-use regimes.…”