Endemic and Alien Species

The term Endemic Species refers to species or taxa that only occur in a specific region and nowhere else. Endemism is often used as a measure of ecosystem integrity and health. Alien Species are introduced and if invasive can pose a threat to the endemic species.

Endemic Species

The following information is based upon country level data, as no species diversity assessment has been completed for the Limpopo River basin to date.

Botswana

Botswana has more than 900 species of mammals, amphibians, birds and reptiles, and 0,8% of these are endemic to Botswana (Mongabay.com 2009). Some 30,2% of the country is protected, three times the sub-Saharan Africa average of 10,9% (Earth Trends 2009). Botswana has one RAMSAR wetland of international importance: the inland Okavango delta. The Okavango empties into the Kalahari Desert to form the largest inland delta in the world.

Summary of total and endemic species counts in Botswana.

.. = no data
Source: WCMC (1994) Adapted from Mongabay.com 2009; *Earth Trends 2009

Mozambique

Mozambique ratified the Convention of Biological Diversity in 1995 and The Protocol on Biosafety in 2003. Current estimates suggest that over 5 500 species of plants, 580 birds and 200 mammals can be found in Mozambique (CBD 2010b). Protected areas in Mozambique recently expanded to 15 % from an earlier 11 %, with the addition of coastal and marine ecosystem reserves and the Limpopo Transfrontier National Park. Forest cover was estimated to be 62 Mha in 1994 (CBD 2010b), but this is likely have to changed significantly due to pressures from rural and urban populations seeking building materials and fuel.

The number and proportion of endemic and threatened species in Mozambique are shown in the table below.

Summary of total and endemic species counts in Mozambique.

.. = no data
Source: WCMC (1994)

South Africa

South Africa has the third highest level of biological diversity in the world, with 7,5% of the worlds vascular plants, 5,8% of the world’s mammal species, 8% of the world’s bird species, 4,6% of the world’s reptile species, 16% of marine fish species and 5,5% of the world’s recorded insect species (DEAT 2009a).

In South Africa alone, there are 582 protected areas (160 private reserves and 422 areas under national, provincial or local authorities) (DEAT 2009a). The 422 formally protected areas cover some 6% of the land surface area. Although the extent to which viable populations are conserved in such areas is not known, about 74% of plant, 92% of amphibian and reptile, 97% of bird, and 93% of mammal species of South Africa are estimated to be represented (DEAT 2009a). The number and proportion of endemic and threatened species in South Africa are shown in the table below.

Summary of total and endemic species counts in South Africa.

Zimbabwe

Zimbabwe ratified the Convention on Biological Diversity in 1994 and the Protocol on Biosafety in 2005. Biodiversity plays an important role in Zimbabwe's economy, as the nation is heavily reliant on natural resources, including wildlife and tourism. Conservations efforts extend to 17 % of the land area of Zimbabwe, with approximately 15 % of the country contained in national parks, forest reserves and botanical gardens. Threats to biodiversity include land use change, afforestation, mining, dams and urban expansion (CBD 2010b). The number and proportion of endemic and threatened species in Zimbabwe are shown in the table below.

Summary of total and endemic species counts in Zimbabwe.

.. = no data
Source: WCMC (1994), DEAT (2009a)

Alien Species

Alien species and their invasion into non-native ecosystems is one of main drivers behind loss of biodiversity, globally (CBD 2010b). These species are either intentionally or accidentally introduced into an ecosystem and once established begin to threaten the native plant species through a number of mechanisms, including rapid growth and ecosystem degradation.

Ecosystems that have already been modified by human impacts are often more at risk from invasion than pristine ecosystems (CBD 2010b).

In addition to these significant financially-related losses, another direct impact that is felt across southern Africa is the increased use of water by many alien invasive plant species. This is one of the primary drivers behind the South African Working for Water programme, which aims to alleviate poverty through programmes associated with clearing of alien invasive plant communities.

Number of alien species known to be in the countries of the Limpopo River basin (no data presented for Zimbabwe).

.. = no data
Scholes and Biggs 2004

In addition to mechanical/physical plant clearing, Alien plants can be controlled using biological agents, but these so-called bio-control agents must be extensively tested prior to release, as they can have even more negative impacts than the initial invasive plant it was intended to remove/retard, if not properly studied.

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