Conservation of arthropod diversity in montane wetlands: effect of altitude, habitat quality and habitat fragmentation on butterflies and grasshoppers

Abstract

Summary 0[ The patterns of arthropod diversity were investigated in 13 montane wetlands in Switzerland[ These di}ered in altitude\ management regime "cattle!grazing vs[ mowing#\ vegetation structure "index combining vegetation height and density# and degree of habitat fragmentation[ 1[ The general arthropod diversity was determined by net sampling at 09 sampling points per site[ The diversity of grasshoppers and butter~ies was measured by counting species richness at the site and species density "species richness per unit area# on transects[ The species richness of grasshoppers and butter~ies was found to be more sensitive to the geographical attributes of the site whereas species density was more a}ected by the habitat quality[ 2[ Grasshopper diversity decreased within the observed altitudinal range "799Ð0399 m# and was higher at grazed sites\ whereas butter~y diversity was higher at mown sites[ Arthropod diversity but not abundance of arthropods was positively related to the vegetation structure[ 3[ The species richness of butter~ies was negatively in~uenced by the degree of habitat fragmentation] both the size of habitat as well as the area of wetland habitats within 3 km were related positively to the number of specialist wetland butter~ies[ 4[ Late mowing as well as low!density cattle!grazing are appropriate management actions to maintain arthropod diversity in montane wetlands[ In order to establish site!speci_c management plans\ the biology of the present target species as well as the historical context should be considered[ 5[ We suggest that the best protection for the species examined in this study would be a network of wetland sites managed using a variety of traditional\ non!intensive methods[ This can only be achieved by coordinated planning of conservation measures among sites[ Key!words] biodiversity\ global change\ management strategies\ metapopulation structure[ Journal of Applied Ecology "0888# 25\ 252Ð262

Food Availability for Insectivores in Grasslands – Arthropod Abundance in Pastures, Meadows and Fallow Land

“…None of the studied habitat types offered plenty of food all the time, a fact that supports the importance of differences in grassland usage on a local scale, if the arthropod abundance and therefore the food supply for insectivores should be optimised Wetterstein and Schmid, 1999). Noteworthy the abundance of arthropods, especially of larger individuals, was on average higher in pastures and extensively used meadows than in fallow land and intensively used meadows.…”

“…However, different aspects of grassland management are mainly discussed from the view of insect conservation (e.g. Carvell, 2002;Wetterstein and Schmid, 1999;Vulliamy, 2006;Sjödin, 2007;Radlmair and Dolek, 2002). Intensive application of fertilizers and frequent mowing or heavy grazing have indeed a negative impact on many arthropod species (von Nordheim, 1992; von Wingerden et al, 1992;Benton et al, 2003) and this may have consequences also for species depending on arthropods as food (Vickery, 2001).…”

Arthropod Colonisation of Trees in Fragmented Landscapes Depends on Species Traits

“…Habitat fragmentation is a primary cause of biodiversity loss (Saunders et al 1991, Kruess & Tscharntke 1994, Wettstein & Schmid 1999, but fragmentation effects on biodiversity vary greatly between studies (Debinski & Holt 2000, Fahrig 2003. This is partly because a range of different processes are subsumed under the term habitat fragmentation (Fahrig 2003, Lindenmayer & Fischer 2007.…”

Rangeland Management for Pollinators

“…A Swiss study found that although grazing was an effective management tool for limiting succession, (i.e., slowing the conversion of open grassland to shrubland or woodland) responses to grazing varied greatly among butterfl y species. 9 The authors suggest that any management regime be attentive to historical and species-specifi c characteristics of the species at the site, and that a diversity of management techniques be used on a regional scale in order to preserve the greatest diversity of insect pollinator habitat.…”