How landscape structure, land‐use intensity and habitat diversity affect components of total arthropod diversity in agricultural landscapes

Abstract

Summary 1.Agricultural intensification poses a serious threat to biodiversity as a consequence of increased land-use intensity, decreased landscape heterogeneity and reduced habitat diversity. Although there is interest in the preservation of total species richness of an agricultural landscape ( γ diversity), the effects of intensification have been assessed primarily by species richness at a local scale ( α diversity). This ignores species richness between local communities ( β diversity), which is an important component of total species richness. 2. In this study, measures of land-use intensity, landscape structure and habitat diversity were related to γ , α and β diversity of wild bees (Apoidea), carabid beetles (Carabidae), hoverflies (Syrphidae), true bugs (Heteroptera) and spiders (Araneae) within 16 local communities in 24 temperate European agricultural landscapes. 3. The total landscape species richness of all groups was most strongly affected by increased proximity of semi-natural habitat patches. Bees also decreased in landscapes with a high intensity of farmland management, demonstrating additive effects of both factors. 4. Separating total species diversity into components, the decrease in total species richness could be attributed primarily to a decrease in species diversity between local communities. Species richness of the local communities of all investigated groups decreased with increasing land-use intensity and, in the case of spiders, decreasing proximity of the semi-natural habitat patches. 5. The effect of increased habitat diversity appeared to be of secondary importance to total species richness but caused a shift in the relative contribution of α and β diversity towards the latter. 6. Synthesis and applications . This study demonstrates that the effects of agricultural change operate at a landscape level and that examining species diversity at a local level fails to explain the total species richness of an agricultural landscape. The coincidence of patterns of β diversity with those of γ diversity emphasizes that such information is of crucial importance for the implementation and evaluation of restoration programmes aiming to restore sustainable countryside diversity. As local extinction processes in highly fragmented landscapes shape biodiversity, priority should be given to the conservation of diverse agricultural landscape remnants in Europe.

Spatially Heterogeneous Perturbations Homogenize the Regulation of Insect Herbivores

“…Loss of apex arthropod predators (Hendrickx et al 2007;Shochat et al 2008), however, can have similar effects, with reduced predation increasing herbivore abundance but also lowering richness if one or a few herbivores dominate (Holt 1977;Oliver et al 2009). There may also be strong interactions between human-induced changes to resources and predators: nutrient enrichment may drive consumer birth rates that far exceed predator-driven herbivore mortality or may cause system instability by creating top-heavy feeding webs (Polis et al 1997;McCann 2011;Shurin et al 2012;Tunney et al 2012).…”

A spatial scale assessment of habitat effects on arthropod communities of an oceanic island

“…In arthropods (see Chust et al, 2004;Holland et al, 2004;Clough et al, 2005;Gaucherel et al, 2007;Gonzá lez-Mejias et al, 2007;Hendrickx et al, 2007;Driscoll, 2008), such analysis can help to identify the spatial scales at which a predictor variable influences species richness and abundance of local communities.…”

The role of remote sensing in the development of SMART indicators for ecosystem services assessment

“…The identification and classification of these macro structures by remote sensing is possible (e.g., Yang and Prince 2000;Ozesmi and Bauer 2002;Silvestri et al 2003;Mumby et al 2004;Harris and Bryant 2009) and quantitative assessments of biodiversity populations have also been made using the species-area relationship and extent of habitat derived from remote sensing (Turner et al 2003;Jha et al 2005). Other examples of the link between specific species and landscape indicators have been reported by Dormann et al (2007) and Hendrickx et al (2007). However, a reliable indication of the status and trends of biodiversity and ecosystem service provision beyond habitat mapping and based on remote sensing data, requires more research effort to validate the results.…”