Breeze rustles the dry grass on the high veld under clear skies. It's winter on the South African savanna, but the mild days still bustle with life, in spite of this being the dry season. Water, the ultimate limiting factor, has driven the evolution of a great diversity of life that inhabits this region. The savanna in particular, with its mix of grasses and woody plants, provides a banquet for herbivores, both grazers and browsers, which in turn feed predators large and small. And the variability of water from season to season, and from wet years to drought, was a driving force for a range of adaptations. Most importantly among these is seasonal migration.
For millennia, herds of wildebeest, zebra and other herbivores have migrated in search of available food and water. This in turn has lead other species to adapt their own behaviors. Nile crocodile will lie in wait on established migration routes for the wildebeest to cross a river; calves are sitting ducks, as it were. Nature’s logic might seem askew, but wildebeest numbers, over a million on the Serengeti plains, permit the sacrifice of individuals for the benefit of the herd.
The migration of herbivores is driven, in part, by the cycles of growth and death of grasses, which in turn is driven by the cycles of wet and dry seasons of the tropics. The various grasses and shrubs drove the evolution of different digestive systems. Ruminants developed four-chamber stomachs to permit fermentation followed by regurgitation and chewing the cud. This is familiar from our domestic cows, but is also employed by wildebeest, which translates in Africaans to “wild cattle”, as well as antelopes and a wide array of related species which reach a particularly high diversity on the African savanna. Waterbuck, springbok, blesbok, hartebest, eland, and kudu, among them. Another strategy, employed by zebra and elephants, is hindgut fermentation, a characteristic that gives these animals a unique auditory presence on the savanna. A long digestive track permits these animals to eat continuously and to extract nutrients from the most marginal of sources.
The diversity of herbivores set the stage for a variety of predators which have evolved different strategies, from ambush to coordinated hunting. The charismatic megafauna such as lions and leopards provide opportunities for hyena, jackal, vultures and other carrion eaters. The nutrient cycle is then completed by the detritivores, nature’s recyclers. Fungi, bacteria and the like recycle nutrients necessary for the next seasons grasses and other plants. The circle of life is complete.
Nature is, of course, messy and chaotic. Species adapt to environmental conditions, only to find themselves unfit when the environment changes. In the African savanna the regular occurrence of drought has necessitated that organisms adapt to this reality, or die out. Recent controlled studies cited by Rasmussen indicate that some species can evolve over 6 or 8 generations to environmental changes, but the period is much longer for most species. The rapid rate of human-induced changes to the environment have therefore imperiled species that cannot adapt or evolve, but have created a niche for those that can evolve more rapidly.
Human-induced habitat loss and fragmentation are especially problematic as growing populations and economic exploitation of natural resources lead to ever increasing human-wildlife conflicts. With much of the population of Subsaharan African engaging in subsistence agriculture, the interactions between humans and wildlife are a daily fact of life. Elephants, known for their tremendous capacity to uproot trees and rip branches, present a particular challenge. These “ecosystem engineers” play a valued role in maintaining the natural heterogeneity of the landscape, but are often viewed by humans as destructive. With the need to consume up to 200 kilograms of food per day, the succulent vegetables of a garden plot are like candy to an elephant that can easily push over fences. South Africa’s history of colonization, private landownership and livestock raising has led to a high degree of fragmentation and fencing. Presently there is a move toward removing fences to combine ranches into larger reserves, such as the privately-held Dinokeng Game Reserve, outside Pretoria, South Africa. The reserve hosts the 18,500 hectares of “highveld” savanna and diverse megafauna, and is managed by WEI (Wildlife Ecological Investors), a private South African wildlife firm.
Pollution and contamination poses both direct and indirect impacts to wildlife. A factory that drains toxic materials into a local river is a direct impact. Automobile emissions, dispersed into the lower atmosphere, are and example of indirect impacts. The law of unintended consequences is at play here. African vultures provide a case study, where some areas such as the Dinokeng have seen a dramatic decline in vulture populations. The likely culprit is lead poisoning from hunters using lead-based ammunition. When vultures consume the remains of animals that have been shot by hunters, they ingest the toxic led. This circumstance was the cause of decimation of California Condor and other raptor populations in the 1960s and 1970s.
Hunting and other consumptive uses of wildlife is a complex topic. Legal hunting, may or may not be ecologically sustainable. The degree to which laws are designed to support wildlife conservation is to a large degree a function of the levels of social and political development of the country in question. This also influences the degree of enforcement of such laws. Corruption is endemic in many Subsaharan countries which compromises the rule of law. Ethical questions arise with “canned” hunting operations which raise lions and other high profile species for “hunting” in confined spaces. This is a type of trophy hunting which targets the oldest and largest animals, seems to epitomize a gratuitous view of nature as man's dominion for whatever amusement or thrill-seeking or perceived need one can think of.
Poaching is the most pressing and damaging consumptive use of wildlife, and is a persistent problem in South Africa, the Congo and other parts of Subsaharan Africa. In its simplest form, poaching is illegal hunting or trapping of animals. Animals may be taken for for bushmeat (i.e., wildlife hunted for food), or poached for the international trade in exotic animals. Although regulated by the Convention on International Trade in Endangered Species or CITES, poachers have resorted to to increasingly sophisticated methods. This is motivated by the value of poached animals and animal products for domestic and international markets. For example, a live rhino may be sold to game reserves for 400,000 South African rand, whereas a rhino horn is worth 4 times that on the black market. Indeed, some assert the poaching is enabled by organized criminal networks with connections to the highest levels of government (the author met with several individuals who described connections between the Gupta family in India and officials in the South African government of Joseph Zuma, considered to be presiding over the most corrupt government in Subsaharan Africa.
The effective conservation of Africa’s diverse wildlife requires active management. Loss and fragmentation of habitat and the other threats described above, necessitate a variety of human interventions. In the case of South Africa, the high degree of fencing has created a circumstance that limits migration routes and creates captive populations under private ownership, with the geographic of animals range dictated by the property size. Indeed, the wildlife itself is considered “owned” by the largely white landowners. The recognized value of wildlife, for tourism and hunting, has led to efforts to repopulate areas with mega-fauna, including both prey and predator species. This in turn has created a market for these species which can be purchased at wildlife auctions. Sadly, this has also produces demand for breeding animals which are often raised in sub-standard conditions, with limited space to roam. The film Blood Lions documents the breeding of lions for “canned hunting”, in which cubs are separated from their mothers within a week of being born to encourage the return to estrus, thereby artificially shortening the natural cycle of pregnancy, birth and weening. Such circumstances raise concerns for both the health of the animal, as well as their ethical treatment. Such considerations are distinct, yet related, to those of effective wildlife and ecosystem management.
For a particular property or game reserve, as they are commonly called in South Africa, effective ecosystem management requires determining sustainable population of predators and prey. With respect to the herbivore populations, there is a need to understand the plant species of preference and their relative abundance. Elephants are a particular concern as a result of their inherent value as among our most intelligent and sentient cousins in the animal kingdom, but also as a result of their tremendous capacity to consume, alter, and disturb trees. There is abundant evidence that this “destruction” has a multitude of ecological benefits, such as creating habitat for rodents and other species. Nonetheless, the damage they inflict on the botanical super-structure, including many economically and socially valued species to humans, means that conflict with humans is inevitable.
In the interest of effective conservation and wildlife management, at Dinokeng WEI has established a number of science research projects, working in cooperation with OpWall (Operation Wallacea), a UK-based ecological research and education business. With the aid of OpWall student volunteers, various projects are undertaken to better understand the ecological factors that effect wildlife on the reserve. In the process, students learn field methods and ecological principles, while collected and analyzing data. Game transects, motion-sensitive wildlife cameras, bird point counts and gridded habitat assessment plots are methods of sampling used to better understand the flora and fauna. For example, habitat assessments involve identifying grasses and woody trees and shrubs, along with age, size and extent of wildlife grazing or browsing. When combined with the population of browsers and grazers, a picture of the health of the reserve emerges. This may in turn help to determine the carrying capacity of the reserve for particular species.
The dawn of the 21st century heralds a species extinction crisis of unparalleled proportions. Scientists now consider us to be in a period of the sixth mass extinction of in Earth’s 4.6 billion year history. This period, dubbed the Anthropocene, is the result of human activities that are destroying habitats, depleting resources, contaminating air and water and warming the climate. Man’s remarkably creative capacities may yet find solutions to this looming crisis, but only if we can temper the juggernaut of boundless consumption and exploitation of the natural world, learning that human well-being is inseparable from nature.
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