Abundance and guild structure of grasshoppers (Orthoptera: Acridoidea) in communally grazed and protected savanna

Abstract

This study was conducted to determine how savanna grass sward modifications caused by heavy grazing pressure influenced the abundance and guild structure of grasshoppers. Heavily grazed communal land was compared with a lightly grazed area and a mowed airstrip, in adjacent protected land, in the Mpumalanga lowveld, South Africa. Plant species composition, height, aerial cover and greenness of grass in the herbaceous stratum were measured in representative sites. Total grasshopper abundance and relative abundance of grasshopper species were also assessed in each site. Grasshoppers were assigned to feeding and habitat functional groups for comparison among the three areas. The heavily grazed area, characterised by short vegetation and low aerial cover, high greenness of grass, and high frequency of forbs, was inhabited by grasshopper species associated with bare ground or short and/or sparse grass, that were non-graminivorous or soft grass feeders. The lightly grazed area, characterised by tall vegetation and high aerial cover, low greenness of grass, and low frequency of forbs, was inhabited by grasshopper species associated with long and/or thick grass, that were mixed feeders or tough grass feeders. The mowed area, characterised by short vegetation and low aerial cover, low greenness of grass, and low frequency of forbs, exhibited lower grasshopper abundance, species richness, and diversity than either of the grazed areas.

Impacts of high utilisation pressure on biodiversity components inColophospermum mopanesavanna

“…Thus local land degradation or heavy utilisation led to significantly increased plant species richness (Shackleton 2000), decreased woody plant species richness (Shackleton 1993b, Higgins et al 1999, see Ward et al 2000 or increased grass species richness (Shackleton 2000) and diversity (Tefera et al 2010). Other results in the region have shown neither a significant effect of heavy utilisation on richness of woody plant species and forbs (Shackleton 2000) nor on grass species richness (Prendini et al 1996).…”

Grazing and Orthoptera: a review

“…In savannah grassland in South Africa, abundance and guild structure of grasshoppers varied between lightly and heavily grazed areas (Prendini et al 1996). The heavily grazed areas characterized by short vegetation were dominated by grasshopper species associated with short grass and/or bare earth, whereas the lightly grazed grassland with taller and thicker grass had mainly grasshoppers of taller vegetation which were mixed feeders or tough grass feeders (Prendini et al 1996).…”

Dietary composition of birds species at an inland airport in South Africa

“…Die meeste sprinkaansoorte beskik ook oor 'n hoë mate van beweeglikheid en is dus in staat om uit 'n wye verskeidenheid potensiële mikrohabitats te selekteer. 34 Daardeur word hulle opsigtelikheid nie alleen verhoog nie, maar dra dit ook daartoe by dat verskillende fases in hul lewensiklus alomteenwoordig kan wees. Die sporadiese toename in sprinkaangetalle tydens swermvorming, 35 geassosieer met hul hoë voedingswaarde, 36 verseker voorts hul potensiële belang as hoë kwaliteit voedselbron.…”