The effects of agriculture on farmland bird assemblages on the Agulhas Plain, Western Cape, South Africa

Coastal Fynbos on the Agulhas Plain of the Western Cape, South Africa, has been transformed extensively by crop and pastoral agriculture. Many bird species, e.g. sunbirds, nightjars and mousebirds have consequently been affected negatively by the reduction of suitable habitat for daily requirements. However, populations of certain bird species, especially granivores and omnivores, such as sparrows, larks and pipits, as well as Egyptian Geese and Helmeted Guineafowl have proliferated on the Agulhas Plain. This study investigates the effects of agricultural development on overall bird diversity on the Agulhas Plain. In 1998, twice monthly transect counts at 13 farmland sites recorded 106 bird species. Fifteen species occurred at 75% or more of the sites. Highest avian diversity was recorded at the sites with a mixture of crops and Coastal Fynbos (Mixed regime). A small number of species, e.g. sunbirds, are reliant on the natural Coastal Fynbos for their survival. With the exception of the Mixed regime that gained 50 species, all the other agricultural regimes reflected a loss of diversity when compared with Fynbos. To provide more suitable habitat for a greater diversity of birds, mixed landscapes should be maintained, and further destruction of natural Fynbos habitat should be prevented.