Ecoregions of Zambia

The biomes and ecoregions in the ecology of Zambia are described, listed and mapped here, following the World Wildlife Fund's Global 200 classification scheme for terrestrial ecoregions, and the WWF freshwater bioregion classification for rivers, lakes and wetlands. Zambia is in the Afrotropic biogeographic realm (or ecozone) of the scheme. Three terrestrial biomes are well represented in the country (with an additional one extending a few kilometres over the border). The distribution of the biomes and ecoregions is governed mainly by the physical environment, especially climate.

The main aspects of the physical environment which determine the biomes and ecoregions of Zambia are: climate, specifically rainfall amount, length of the dry season, and temperature, which is related to elevation; and soils and bushfires.

Rainfall amount is the most important determinant of the type and distribution of ecoregions. Zambia experiences good rainfall, extremes of 500 to 1400 mm (most areas fall into the range 700 to ) in a distinct rainy season of four to six months centred on January, when the moist intertropical convergence zone is over the country. The highest rainfall is in the north (about 1200 mm –- all figures are annual amounts), especially the north-west (1400 mm), decreasing towards the south (around 700 mm); the driest areas are in the Luangwa and middle Zambezi valleys (500 mm). None of the country is arid.

The dry season lasts 6–8 months, divided into the cool dry season or winter from April or May to August, followed by the hot dry season, September to November. Most rivers, lakes and swamps are permanent, except in the hotter, drier south. Along the banks of permanent rivers and in the spray of waterfalls are evergreen thickets similar in character to tropical rainforest, relics of a wetter past. In dambos (grasslands found in most of the country) and other marshes, soil water is available throughout the dry season, but they may be rather acidic. Elsewhere, plants and animals are adapted to the long dry season. For plants this includes the deciduous habit (losing leaves to conserve water), very deep root systems, water-storing roots and tubers, waxy leaf cuticles, and drought-resistant seeds. Succulent plants are also widespread, especially in rocky areas. For animals, adaptations to drought are seen in migration and breeding patterns, as well as the ability, found in rodents and reptiles especially, to obtain water requirements from food without the need to drink. Hibernation through the dry season is practiced by some amphibians and invertebrates. The latter may also survive the dry season through drought-resistant forms.

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