Human population growth and the extinction of the tsetse fly

Agricultural expansion is a major cause of biodiversity loss worldwide, in Africa, biologists have observed that the populations of some tsetse specie s, which transmit human and livestock trypanosomosis, decline or disappear as human populations grow and farmers clear fly habitat for cultivation. Th e objectives of this paper are to synthesize the available information conc erning human and tsetse populations and to develop a model to estimate the future effect of human populations on tsetse populations. A spatial, GIS mo del was developed to estimate future impacts using a combination of fine-re solution human population data for the years 1960, 1980, 2000, 2020, and 20 40; field data on the relationships between human and tsetse population den sities; and the distribution of different types of tsetse fly. By 2040, man y of the 23 species of tsetse By will begin to disappear and the area of la nd infested and number of people in contact with flies will also decline. H owever, none of the species of flies will be under threat of extinction by human agricultural activities in the near term. An area of Africa larger th an Europe will remain infested by tsetse and under threat of trypanosomosis for the foreseeable future. (C) 2000 Elsevier Science B.V. All rights rese rved.