Status and Trends of Biodiversity
Overview
Zimbabwe is characterised by three phytogeographic regions, the Zambesian, the Afromontane and the East African coastal. The Zambesian region covers over 95% of the country. The Eastern Highlands form part of the Afromontane region and have the highest level of endemism, notably in the Chimanimani Mountains. The Zambesian phytogeographic region comprises five woodland types – miombo, mopane, teak, acacia and Terminalia/Combretum. Many tree species in these woodlands are economically important and are used for timber, poles, firewood, fruit and medicines. The total flora of Zimbabwe comprises 5930 taxa.
During the national Red Data listing for Zimbabwe, 504 taxa were formally assessed, of which 211 were regarded as threatened. There are 232 species or subspecies that are believed to be endemic or near-endemic to Zimbabwe. A number of these rare and threatened species lie outside formally protected areas. The major areas of endemism in the country are the Chimanimani Mountains, the Great Dyke and the dambos of the central watershed area. Table 1 shows the habitats of the plant species on the Red Data List. Seven species are listed as extinct, while 54 are listed as critically endangered (Table 2). Those reported as extinct are Triceratella drummondii, Agraecopsis trifurca, Angraecum stella-africae, Oeceoclades decaryana, Polystachya pubescens, Platycerium alcicorne and Encephalartos chimanimaniensis.
Moist forest: 138 listed taxa; 94 threatened taxa; 44.3% of total threatened taxa. Dry forest: 12 listed taxal 6 threatened taxa; 2.8% of total threatened taxa. Moist woodland: 41 listed taxa; 25 threatened taxa; 11.8% of total threatened taxa. Dry woodland: 64 threatened taxa; 22 threatened taxa; 10.4% of total threatened taxa. Rock and outcrops: 31 listed taxa; 14 threatened taxa; 6.6% of total threatened taxa. Grasslands: 130 listed taxa; 37 threatened taxa; 17.5% of total threatened taxa. Dambos: 24 listed taxa; 2 threatened taxa; 0.9% of total threatened taxa. Wetlands: 13 listed taxa; 3 threatened taxa; 1.4% of total threatened taxa. Disturbed: 1 listed taxa; 1 threatened taxa; 0.5% of total threatened taxa. Unknown: 63 listed taxa; 12 threatened taxa; 5.7% of total threatened taxa.
Total number of RDL: 504 taxa. Genera: 257 taxa. Families: 84 taxa. Endemic/near endemic taxa: 224 taxa. Strict endemic taxa: 178 taxa. Threatened taxa (extinct, critically endangered, endangered, vulnerable): 211 taxa. Lower risk taxa: 162 taxa. Extinct: 7 taxa. Critically endangered: 54 taxa. Endangered: 29 taxa. Vulnerable: 121 taxa. Lower risk near threatened: 91 taxa. Lower risk least concern: 71 taxa. Data Deficient: 131 taxa.
The major threat to forest species is collectors, afforestation and land conversion to agriculture. Other threats to species survival in Zimbabwe are habitat loss due to human activities such as deforestation, mining, dams and urban expansion.
There are no systems for the protection of these species and chances of degradation are high especially with the land reform programme. Innovative systems for their protection also need to be developed and enforced. There is thus an urgent need to re-examine the representativeness of protected areas and the appropriateness of current management regimes with a view to extending the protected areas to comprehensively address pressing issues of biodiversity loss and habitat fragmentation outside protected areas. Fig 1 shows 27 sites that are being recommended for protection as special areas of endemism or representatives of certain vegetation/species types on former privately owned land.
The status and conservation of many plant species in Zimbabwe remains poorly documented. It is therefore prudent that such an exercise be carried out so that the status of almost 90% of the plant species is documented.
Animal diversity is very high in Zimbabwe and consists of 175 mammal species, 600 bird species and 264 reptile and amphibian species. Total bird species number fluctuates within and across years due to migration, but there is a general decline in bird populations associated with the disappearance of their specialized habitats. The most common wild animals found in Zimbabwe include elephant, lion, giraffe, hippopotamus, buffalo, zebra, impala, cheetah, leopard, kudu, ostrich, bushbuck, duiker, eland, reedbuck, sable, steenbok, tsessebe, warthog, waterbuck, wild beast, hyena, pangolin, wild dogs, crocodile, tortoise, crab, snails, earth worms, frogs, ants, monkeys, baboons, birds, owls, snakes, lizards and butterflies. The most widely monitored wildlife species are those of economic importance as well as ecological key indicator species.
The crocodile (Crocodylus niloticus) is the only reptile that has been extensively studied due to its economic importance, while the python (Python sebae) is the only protected reptile in the country. Some causes of biodiversity loss include population pressure and land tenure systems, fire, drought and frost, and the negative impact of high density of elephants. The diversity of Zimbabwe’s aquatic flora and fauna is directly related to the type and distribution of its wetlands. These wetlands include floodplains, riparian wetlands, dambos, pans, swamps and artificial impoundments. Of the 123 fish species occurring in the country, only a few economically and biologically important ones have been monitored. Causes of aquatic biodiversity change include interbasin transfer, reservoir formation, pollution, hybridization, and anthropogenic activities.
Wildlife Population on Parks Estates:According to the Parks and Wildlife Authority the population of elephants stands at more than twice the ecological carrying capacity in the core range within the protected areas. Having exceeded the carrying capacity of the areas, the elephants are threatening the habitats of many other species and biodiversity in general. Although populations of many other wildlife species have been doing well outside protected areas, they still face uncertainty in the former game farms, as some new farmers may prefer land use forms other than game farming. A Wildlife Based Land Use Policy was developed by Ministry of Environment and Tourism to facilitate the continuation of wildlife production as a land use in former conservancies and game farms.
Both the black and white rhinoceros continue to increase although they face serious risk from reduced protection and habitat loss in the interim period during change of ownership and land use associated with resettlement in conservancies. However several "safe" areas are still available in secure conservancies and the proposed Gonarezhou Intensive Protection Zone (IPZ) in the Gonarezhou National Park.
Number and Extent of Protected Areas
15% of the country is protected as National Parks, Forest Reserves and Botanic Gardens. Conservancies (private farmland and combined holdings managed for wildlife) make up approximately 17% of the country.
Percentage of Forest Cover
Zimbabwe’s land area is classified in the following categories: 0.03% is moist forest (tropical rainforest), 0.4% is Forest Plantation, 65.92% is indigenous woodland (including bushland), 4.85% is grassland, 27.47% is cultivated land, 0.36% is settlement and 0.97% is rock outcrop and water body.
