Living organisms face a constant barrage of external stresses or threats to wildlife that challenge their ability to survive and reproduce. If a species is unable to successfully cope with these threats through adaptation, they may face extinction.
A constantly changing physical environment requires organisms to adapt to new temperatures, climates, and atmospheric conditions. Living things must also deal with unexpected events such as volcanic eruptions, earthquakes, meteor strikes, fires, and hurricanes.
Threatening processes are practices that are reducing or will reduce the biodiversity and ecological integrity of a regional ecosystem and its wildlife. Processes that are threats to wildlife include:
1. Inappropriate grazing and fire regimes
Grazing pressure from domestic stock and introduced animals (such as rabbits) can have a negative impact on habitat of native animals. Changes in the frequency and intensity of fire can cause wildlife populations to decline. Some species depend on a suitable fire regime for successful regeneration and survival.
2. Invasive plants and animals
The global movement of goods and people are directly contributing to the introduction of plants and animals to areas where they do not naturally occur. These species taken to new environments may fail to survive but some thrive and become invasive. This process, together with habitat destruction, has been a major cause of extinction of native species in many Natural Reserve Areas.
3. Invasive species
- animals
- plants
- introduced marine pests
- diseases, fungi and parasites
Invasive animals
Introduced pest animals place considerable pressure on native wildlife. While some impacts have been well documented, the true impact of invasive animals on environment is unknown and difficult to quantify. Invasive species such as foxes and feral cats, prey on native fauna and have been implicated in the decline or extinction of at least 17 native species. Cane toads compete for food, shelter and breeding sites with native animals. This is thought to be an important factor in the decline of many native animals, particularly the decline in number of some native frogs.
Invasive plants
Weeds can degrade native vegetation and have a detrimental impact on biodiversity. The loss and degradation of native plant and animal habitat by invasion of escaped garden plants, including aquatic plants is listed as a key threatened process and has had a listing advice developed.
Aquarium and other aquatic plants can carry pathogens that can devastate native populations of plants and animals.
Marine pests
There are a number of non-native marine pests (reported in Australian waters most of which were introduced accidentally by shipping and aquaculture activities. Some, including several crabs, mussels, seastars and seaweeds have been found to have a significant impact on marine ecosystems.
Diseases, fungi and parasites
Diseases, fungi and parasites can reduce the ability of native plant and animal species to reproduce or survive. Due to their reduced or restricted populations and the impacts of other threatening processes, threatened species can be particularly vulnerable to introduced diseases, fungi and parasites.
Man-Made Threats
Man-made threats can be classified into the following general categories:
- Land clearing: Loss of natural habitat through land clearing for pastoral purposes, urban development and agriculture can threaten native wildlife and their habitat. Land clearing causes species decline and habitat loss, exacerbates other threatening processes, and reduces the resilience of threatened species to survive future challenges such as climate change.
- Collection: Collecting native plants and plant parts is another threat to some of the native plants. Some ferns, tree ferns, cycads and orchids are seriously threatened by collecting. Even common plants like grasstrees and staghorn are at risk. Individual plants can be damaged when stems, fruits and flowers are removed. Collecting a plant’s seeds reduces the prospects for successful regeneration.
- Habitat Destruction & Fragmentation: The destruction or splitting up of once continuous habitat to enable humans to use the land for agriculture, development of towns and cities, construction of dams, or other purposes.
- Climate Change: – Human activities such as the burning of fossil fuels, have altered the Earth’s atmosphere and have resulted in global climate changes.
- Introduction of Exotic Species:Accidental and intentional introduction of non-native species into regions never before occupied by the species have resulted in the extinction of numerous endemic species.
- Pollution:Pollutants (pesticides, herbicides, etc.) released into the environment are ingested by a wide variety of organisms.
- Over-Exploitation of Resources: Exploitation of wild populations for food has resulted in population crashes (over-fishing, for example).
- Hunting, Poaching, Illegal Trade of Endangered Species:Some endangered species are targeted for their value on illegal markets.
- Accidental Deaths: Car hits, window collisions (birds), collisions with ships (whales).
Specific Threats in Zambian GMAs
The advent of wildlife conservation demarcated National Parks as sanctuaries for wildlife devoid of human occupation and GMAs as areas where humans and wildlife are supposed to co-exist. The co-existence of people and wildlife has been a subject of concern in the management of wildlife in the GMAs by wildlife managers.
In some situations, however, human interactions with wildlife are negative. Wild animals eat livestock and damage crops, and they at times injure or kill humans, leading to a conflict. Human-Wildlife Conflict (HWC) is a face-off between people and wildlife over space or resources. Typically, conflict involves wildlife that consumes pasture or crops, or attacks domestic stock or even humans who kill wildlife in reprisal.
A set of global trends has contributed to the escalation of HWC worldwide. These can be grouped into human population growth, landuse transformation, increasing wildlife population as a result of conservation programmes and climatic factors.
Human Population Growth
Demographic and social changes that have taken place move people in direct contact with wildlife: as human populations grow, settlements expand into and around protected areas (IUCN, 1976), as well as in urban and sub-urban areas. In LGMA for example, human population growth has been on the increase in most Chiefdoms, however, in the year 1963, Chiefs Malama, Msoro, Jumbe, and Mkhanya recorded a decrease in population.
This could be attributed to migration of the people to other parts of the GMA. Thus in the years 1990 and 2000, population had increased considerably in almost all the Chiefdoms leading to the expansion and spread of human settlements into wildlife habitats. This has led into the constriction of species into wildlife habitats, and constriction of species into marginal habitat patches and direct competition with local communities.
- Trophy hunting is the primary land use in mostGMAs and is practised over a vast area. There are no effective restrictions on human settlement in GMAs and there are large and expanding human populations in many of them, and associated high levels of illegal hunting and habitat loss
Habitat destruction is exacerbated by shifting agriculture, burning for charcoal production, cutting for firewood for small-scale tobacco farming, and the development of mines in some GMAs.