The impact of land transformation on breeding Blue Swallows Hirundo atrocaerulea Sundevall, in Kwazulu-Natal, South Africa

Abstract

The Blue Swallow is confined to the grassland component of the mistbelt region of KwaZulu-Natal, South Africa, a habitat well suited to intensive agriculture and especially afforestation, due to the high rainfall and deep well-drained soils. The species is listed as amongst the top five Critically Endangered bird species in South Africa and the numbers are dramatically declining. Any further fragmentation of its habitat may well lead to the local extinction of the Blue Swallow. It is in response to these sentiments that this paper investigates the potential influence of land use change, identifies what those changes have been over a 20-year epoch and what the impact on the persistence of Blue Swallow nesting sites has been. To achieve this, the extent and nature of land transformation, adjacent to past and current Blue Swallow nesting sites on five separate study sites in KwaZulu-Natal was investigated, using a Geographical Information System (GIS) as a means of recording the levels of transformation and the change in land use over time. While sample sizes were limited, as a result of dealing with a Critically Endangered species, the data suggest that nest density was positively related to changes in grassland and arable land uses and negatively related to an increase in plantation forestry. A decrease of 55% in active Blue Swallow nest sites coincided with a measured decline in grassland of 46% for the period 1981–2000. It is clear that the current rate of loss of Blue Swallow breeding pairs is critical and without the conservation of primary grassland habitat, the Blue Swallow is heading towards extinction in KwaZulu-Natal. It is recommended that artificial nest site provision and the conservation and sustainable management of the mistbelt grassland biome, both as a vegetation unit worthy of conserving in its own right and in collaboration with surrounding dependant communities, is necessary for the recovery of this charismatic, indicator species.