**5.2 Anthropogenic drivers**

Human activities are considered to be the main driver of agrobiodiversity erosion by population numbers, use of land, and of peoples' lifestyles, causes damage to habitats for various species. The global biodiversity decline by 30% is driven by land use through food production followed by 20% overexploitation of natural resources such as overharvesting, overhunting and overfishing for food, timber and medicines. The activities by rural communities of Tanzania in similar context affect agrobiodiversity. For instance, the study conducted in 1997 in the Udzungwa Scarp Forest Reserve of Tanzania, found human activities threatening the biodiversity [44]. This tells the fact that, biodiversity takes convert if progressively is exposed to human alterations of natural habitats, and abiotic and biotic environments are both changing swiftly, often unpredictably, and species and populations are progressively more subjected to stressful environmental situations [43]. Industrial pollution and the use of agro-chemicals have revealed to interrupt biodiversity dramatically. Large-scale destruction of natural habitats has triggered large populations of various species to become fragmented, resulting in small 'remnant' populations that become increasingly isolated. Subdivision of large populations in combination with limited gene

*Perspective Chapter: Traditional African Vegetables Agrobiodiversity – Livelihood Utilization… DOI: http://dx.doi.org/10.5772/intechopen.109070*

flow between the fragments has significant ecological and genetic consequences. Ecologically, habitat fragmentation will have demographic effects as small populations are progressively more affected by demographic and environmental stochasticity greatly increasing their extinction chance. The biodiversity needs to be explored and documented due to the fact that it consists of some of the species which are rare, endemic and threatened in such a way that they need protection and conservation measures [44].
