The Vegetation of the Karamoja District, Uganda: An Illustration of Biological Factors in Tropical Ecology

Abstract

Principal plant communities are open grassland in the plains in the south and west and woodland around the mts.; near the centers of settlement in the east, the grasslands and woodlands are replaced by thickets. The thicket growth is due to prolonged and continuous grazing by the excessive population of domestic animals. For miles about settlements compaction of soil by trampling has prevented penetration by rainwater, and, in spite of a well distributed rainfall of 90 cm., the plants are growing under dry conditions. Compaction is relatively of greater importance than in temperate regions, because of the absence of frost. Termites are abundant and may have important soil-building functions. Overgrazing may be seen in parts of E. Africa where there is no domestic stock, along the migration paths of the enormous herds of antelopes. Biological processes are rapid in the tropics, and, although the principles are the same, many factors, human and other, operate upon the biome differently than in temperate regions.