The influence of agriculture on the decline of west coast renosterveld, south-western Cape, South Africa: C. McDowell & E. Moll, Journal of Environmental Management, 35(3), 1992, pp 173–192

Abstract

Nearly 85% of South Coast renosterveld, a fire-prone shrubland, has been replaced by agriculture; the remaining areas are small fragments scattered throughout agricultural lands. Because nearly all of the remaining vegetation is required to fulfil a modest reservation target, conservation of these fragments will be central to any implementation plan. To assess the condition and, therefore, the conservation potential of these fragments, we investigated the community patterns, species diversity and representation of biological attributes in 23 renosterveld fragments. Communities in large fragments were more similar to each other than those in small fragments. There were no significant linear relationships between species diversity and fragment area. We found weak fragmentation effects in attribute representation. Numbers of alien graminoid species and total alien species, and frequency of individuals of geophyte species increased with decreasing fragment size. Frequency of individuals and percentage cover of species with seeds that are dispersed for short distances, increased with decreasing fragment size, while percentage cover of perennial graminoids decreased. Small fragments are highly disturbed by grazing, trampling, crop spraying and frequent fires, but retain a similar community structure to large fragments that presumably represent the pre-agricultural matrix vegetation. Therefore, all remnants of renosterveld, irrespective of fragment size, should be considered conservation-worthy.