Aspects of the biology and conservation status of the blue crane Antropoides paradiseus, and the Ludwig's Neotis ludwigii and Stanley's N. Denhami Stanleyi bustards in southern Africa

Abstract

The cranes (Gruidae) and bustards (Otididae) are highly threatened taxa. Many species are on the brink of extinction due to anthropogenic factors. On the positive side, several species show a remarkable ability to adapt to man-modified environments. If the cranes and bustards are to survive through the coming century, research on the aspects of their biology directly relevant to understanding their conservation requirements is a high priority. Without a reliable and relevant base of knowledge, no successful conservation management plan can be devised for each threatened species. This thesis presents information on three threatened members of these taxa in southern Africa, the Blue Crane Anthropoides paradiseus, and Ludwig's Neolis ludWigii and Stanley's N. denhami stanleyi Bustards. This information furthers our understanding of their conservation status. The thesis begins with a detailed review of the phylogeny, general biology and conservation status of cranes. This is necessitated by the absence of any thorough and recent review being available. The review provides a point of reference for the research results on the Blue Crane presented in the following seven chapters. Research on the Blue Crane largely focuses on the southwestern Cape and Karoo regions. The past and present distribution of the species in southern Africa is outlined and related to various vegetation types and the effect of various anthropogenic influences. Its colonization of the southwestern Cape is a particularly interesting finding. The abundance of the species in various parts of South Africa is discussed, largely based on road counts and bird atlas data. The total population size in South Africa is estimated and the previously unrecognised importance to the species of the southern Cape coastal plain between Botrivier and Mossel Bay is highlighted. The scarcity of Blue Cranes in the western part of the southwestern Cape, compared with the southern part, is quantified. The reasons for this anomolous dichotomy in abundance betweep these two superficially similar areas are unclear and worthy of further investigation.