Diversity of bumblebees, heteropteran bugs and grasshoppers maintained by both: abandonment and extensive management of mountain meadows in three regions across the Austrian and Swiss Alps

Abstract

Context Abandonment of extensively managed meadows is an ongoing global challenge in recent decades, particularly in mountain regions, and directly affects plant diversity. However, the extent to which plant diversity further affects associated insect pollinators or herbivores is little investigated. Objectives We focused on the effects of abandonment of mountain meadows on species richness and assemblages of bumblebees, bugs and grasshoppers. Specifically, we investigated the influence of vegetation cover, flower cover, plant richness and surrounding landscape on the three insect groups.Methods Species richness, abundance and species assemblages of bumblebees, bugs and grasshoppers were surveyed in one Swiss and two Austrian regions: three meadows which had been abandoned for 15-60 years, and three extensively managed meadows (mown once a year, no use of fertilizers). We surveyed bumblebees and bugs by sweep net, and grasshoppers using the time-effective soundscape approach. Results Bumblebee species richness and abundance were significantly higher in managed meadows, whereas bug and grasshopper richness and abundance showed no differences between both management types. Managed and abandoned meadows harboured significantly different species assemblages of bugs and grasshoppers, but not of bumblebees. Increasing flower cover and plant richness increased bumblebee 123Landscape Ecol (2017) 32:1937-1951 DOI 10.1007 richness, but correlated negatively with richness of bugs. Surrounding open landscape positively affected bugs. Caelifera positively correlated with surrounding forest cover and negatively with vegetation cover. Vegetation cover positively affected Ensifera. Conclusions Abandoned and extensively managed meadows are important habitat types for the conservation of the three insect groups, thus suggesting the maintenance of both habitat types within mountain landscapes.

Influence of abandonment on syrphid assemblages in mountainous meadows

“…Abandonment had a negative effect on plant richness, which will decrease syrphid abundance. Our results also supports previous observation that declines in plant species cause a decline of pollinators (Walcher et al., ).…”

“…In European mountains, there is a trend of abandonment in formerly managed meadows (Prévosto et al., ). Managed semidry grassland has often been observed species rich (Walcher et al.,). Thus, such grassland harbor rich natural values (Kampmann, Lüscher, Konold, & Herzog, ) which is one of the attractions for eco‐tourists (Stöcklin, ).…”

“…Managed semidry grassland has often been observed species rich (Walcher et al,2017). Thus, such grassland harbor rich natural values (Kampmann, Lüscher, Konold, & Herzog, 2012) which is one of the attractions for eco-tourists (Stöcklin, 2007).…”

Perceived health benefits of managed and unmanaged meadows in a mountain biosphere reserve – an experimental study in the Austrian Alps

“…Participants perceived the abandoned meadow as having greater biodiversity than the managed one. Whether this is correct is difficult to confirm, but research on flora and fauna biodiversity in Alpine mountain meadows has often observed higher plant biodiversity in extensively managed meadows (Boschi & Baur 2008;Tocco et al 2013;Tasser & Tappeiner 2002), even for that part of the BR (Walcher et al 2017), while results for fauna biodiversity varied between meadow types (Ranta & Vepsäläinen 1981). In addition, the managed meadow of this study had recently been cut and flowering plants were very rare, making it difficult for participants to recognize the plant biodiversity.…”

Why species richness of plants and herbivorous insects do or do not correlate

“…In light of the two hypotheses, we may explain the variation in the correlation between plant–insect species richness among previous studies. First, most previous studies have attempted to explain insect species richness by total plant species richness rather than by utilized plant species richness, and some of them have found no significant relationships between them (Vessby et al 2002; Axmacher et al 2009; Walcher et al 2017). On the contrary, a study on plant and their associated insect species (collected from individuals of the focal plants) showed a significant relationship between their species richness even accounting for geographic and environmental variables (Kemp and Ellis 2017).…”