Direct exploitation Flashcards
(4 cards)
What kind of species are most at risk from overexploitation?
Large vertebrates - particularly ungulates, primates and other large mammals - are favoured in terms of hunting. The impact of size can be seen in the median body sizes of 0.7 kg, 0.44 kg and 0.06 kg of animals that, respectively, have gone extinct in the Anthropocene, are threatened or are not threatened.
Why are tropical forests (e.g. in Africa) being harvested from particularly unsustainably?
Rapidly increasing human populations in developing tropical countries puts pressure on the food system, including sources of wild meat, which may be used as food for subsistence or as a delicacy. The population of Africa increased 8-fold in the 20th century. In addition, productivity of tropical forests for wild meat is 10 times less than open habitats such as savanna.
Other than potential extinctions, how might hunting / harvesting affect wild species populations?
Due to taxonomic bias and size bias in hunting, the threat is unequal across species / is not random. There are many cases where e.g. trophy hunting, size of fishing nets, etc. has led to a selection pressure against large individuals, and further evolutionary changes (e.g. increased proportion of tuskless female elephants; decrease in mean age at sexual maturation for wild cod).
What might the drivers be for overexploitation of wild populations?
Economic forces are the main drivers for exploitation of wild meat, either because it is cheaper than buying meat from livestock, or because there is a demand from urban populations for wild meat delicacies that may be a source of income for rural communities. Also, people feed on what is available e.g. hunting in reserves increases when fish catch decreases due to supply or restrictions.
