INFLUENCE OF EXOTIC CONIFER PATCHES ON GRASSHOPPER (ORTHOPTERA) ASSEMBLAGES IN A GRASSLAND MATRIX AT A RECREATIONAL RESORT, NATAL, SOUTH-AFRICA

With the scarcity of extensive, pristine land for new nature reserves, it has become increasingly important to reconcile man's activities with nature conservation. Midmar Dam, Natal, South Africa, is a recreational resort that is also a nature conservation area. The impact of specific landscape elements (conifer patches) on grasshopper (mostly Acridoidea) assemblages within a mixed grassland matrix was investigated at this location. Grasshoppers are good indicator species for general grassland insect communities, and are relatively sensitive to landscape disturbance. Microclimatic temperature and humidity bore no significant relationship to grasshopper assemblage trends, although irradiance did at some sites. There was a strong, positive correlation between grasshopper and grass species richness. Exotic cypress Cupressus arizonica Greene patches increased orthopteran species richness and abundance, while exotic pine Pinus roxburghii Sargent and P. elliotti Engelmann patches are detrimental for grasshoppers far into the grass matrix. This impoverishing effect was great enough to be influential in future conservation management decisions relating to the planting of trees for recreational shade.