Gbarakoro N. Tambeke
African arthropod species are threatened by unsustainable agriculture, over-exploitation of edible species, invasive species and pollution. These drivers of arthropod biodiversity threats has caused not only biodiversity loss but also decline in ecosystem functions leading to low agricultural crop production, food security, and poverty. The causes of arthropod diversity threats and effects in Africa, and some approaches made to salvage the threats are examined in this paper. Desertification, habitat fragmentation and land-use conversion of forested land for developmental projects are major factors that destroy arthropod species habitats. Unsustainable agricultural practices such as non-target insect pest control services, waste water irrigation systems, and casual farming practices all pose serious threats to biodiversity as they reduce ecologically beneficial organisms, cause depletion of nutrients, and eutrophication. In West Africa, casual-farming practice that depend on its water source from the waste water irrigation due to the absence of regular water supply is another contributing factor. This untreated waste water contained in municipal waste water open channels contain chemicals which cause biodiversity threats. Excessive application of agrochemicals in agro-ecosystems cause alteration of soil pH and nutrient levels and reduce soil fauna biodiversity. The black soot generated from petroleum refining activities in Africa cover the surfaces of leaves and reduce herbivorous insect biodiversity leading to reduction in leaf fall and frass with insufficient input of nutrients into the soil, causing biodiversity loss of organisms that depend on such energy input. High concentration of Total Petroleum Hydrocarbons (TPH) and exotic species introduced during clean-up of hydrocarbon pollution and over-exploitation of food insects beyond their regeneration capacity cause biodiversity loss. Non-maintenance of ecosystem health, creation of malnutrition, poverty and agricultural down-turn are some effects of arthropod biodiversity threats in Africa. Some efforts aimed at addressing arthropod biodiversity threats are suggested.
Keywords: Arthropod biodiversity threats, casual-farming, unsustainable agriculture, black soot, ecosystem function.