Pollination services under different grazing intensities

A study was conducted to investigate whether a lack of pollinators, pollination and therefore, a shortage of fruit set of perennial plants is more likely to occur in overgrazed land than farmland without grazing pressure, as this could have considerable effects on the reproduction of certain plant species. The study was conducted at two adjacent BIOTA biodiversity observatories (www.biota-africa.org) in Namaqualand, South Africa. Individuals of certain plant species of the family of Aizoaceae were measured and flower and fruit production recorded. Malaise traps and transect walks were used to document insect diversity. Preliminary results indicate that not all plant species show reduced flower production but that fruit set is indeed compromised on overgrazed land. Insect diversity and abundance is partially reduced under heavy grazing pressure, especially in locations where the vegetation cover is low and dominated by unpalatable plant species. © ICIPE 2004.