Landscape connectivity, habitat structure and activity of bat guilds in farmland‐dominated matrices

Abstract

Summary1. Agricultural intensification has caused a decline in structural elements in European farmland, where natural habitats are increasingly fragmented. The loss of habitat structures has a detrimental effect on biodiversity and affects bat species that depend on vegetation structures for foraging and commuting. 2. We investigated the impact of connectivity and configuration of structural landscape elements on flight activity, species richness and diversity of insectivorous bats and distinguished three bat guilds according to species-specific bioacoustic characteristics. We tested whether bats with shorter-range echolocation were more sensitive to habitat fragmentation than bats with longer-range echolocation. We expected to find different connectivity thresholds for the three guilds and hypothesized that bats prefer linear over patchy landscape elements. 3. Bat activity was quantified using repeated acoustic monitoring in 225 locations at 15 study plots distributed across the Swiss Central Plateau, where connectivity and the shape of landscape elements were determined by spatial analysis (GIS). Spectrograms of bat calls were assigned to species with the software BATIT by means of image recognition and statistical classification algorithms. 4. Bat activity was significantly higher around landscape elements compared to open control areas. Short-and long-range echolocating bats were more active in well-connected landscapes, but optimal connectivity levels differed between the guilds. Species richness increased significantly with connectivity, while species diversity did not (Shannon's diversity index). Total bat activity was unaffected by the shape of landscape elements. 5. Synthesis and applications. This study highlights the importance of connectivity in farmland landscapes for bats, with shorter-range echolocating bats being particularly sensitive to habitat fragmentation. More structurally diverse landscape elements are likely to reduce population declines of bats and could improve conditions for other declining species, including birds. Activity was highest around optimal values of connectivity, which must be evaluated for the different guilds and spatially targeted for a region's habitat configuration. In a multispecies approach, we recommend the reintroduction of structural elements to increase habitat heterogeneity should become part of agri-environment schemes.

Factors driving population recovery of the greater horseshoe bat (Rhinolophus ferrumequinum) in the UK: implications for conservation

“…Moreover, these actions must also promote the creation of a dense and connected network of green linear features (hedgerows and tree lines) for foraging and commuting purposes. Given that agricultural intensification has led to a major loss of landscape connectivity and complexity, which has been unfavourable for bat communities (Frey-Ehrenbold et al 2013), these recommendations will also be highly beneficial for other bat species (Boughey et al 2011b;Ashrafi et al 2013;Heim et al 2015). This case study based on a lightintolerant bat species also highlights another major challenge for bat conservationists: the impact of light pollution on photophobic species at a landscape scale.…”

Bats in the Anthropogenic Matrix: Challenges and Opportunities for the Conservation of Chiroptera and Their Ecosystem Services in Agricultural Landscapes

“…Within agricultural areas, bat activity increases with proximity to natural areas (Estrada et al 1993;Verboom and Huitema 1997;Boughey et al 2011) and in less fragmented landscapes (Fuentes-Montemayor et al 2011;Frey-Ehrenbold et al 2013) or in landscapes with more natural elements such as hedgerows and woodlots (Verboom and Huitema 1997).…”

The understory bat community in a fragmented landscape in the lowlands of the Los Tuxtlas, Veracruz, Mexico

“…Still another possibility is that they may be an indicator of the responses of bats to the habitat fragmentation of the Los Tuxtlas landscape. We know that species use of various landscape elements depends on the spatial-temporal distribution of resources, connectivity, and configuration of structural landscape elements (Frey-Ehrenbold et al 2013;Montaño et al 2015). Either enhancement or decline in species richness can be anticipated.…”