As the world population steadily increases, and the demand for land, water, and natural resources becomes more and more intense, our wildlife is becoming threatened due to loss of habitat, over exploitation, and other human induced factors. Biodiversity is important – not only is it essential to maintaining healthy ecosystems, but humans can actually benefit from many of the species that are being lost, and without them the world is worse off. Plant and animal species are interlinked in an intricate web of life that is finely balanced. This system – or ecosystem, as it is commonly referred to – is made up of various components, some living (biotic components), some non-living (abiotic components), which all function together like clockwork. All species have a role to play in their ecosystem, and when they disappear, the system starts functioning less effectively, often with negative spin offs to other organisms within that ecosystem.
Factors that Cause Species Loss
There are a number of factors that can cause wildlife to become endangered, including: habitat loss, habitat modification, or reduction or removal of resources that are essential for the survival of certain species; human disturbance, especially during the breeding season; overexploitation, either directly, or indirectly as a result of non-target by-catch of exploited species (common in most fisheries); or species may decline as a result of direct and indirect effects of environmental toxins.
Overexploitation of fish and wildlife is one of the most common causes of species decline. Harvesting of fish and wildlife becomes unsustainable when more animals are harvested than what are replaced through reproduction.
As the world’s human population rises, so too does the demand for food, placing increasing pressure on dwindling fish and wildlife resources. In many cases, unsustainable harvesting of wildlife is motivated by greed, as there are high financial rewards to be had in exchange. While the target species may be harvested for food to feed the masses, very often it is harvested to the point of extinction purely for man’s pleasure. In the case of wild captured species to supply the exotic pet trade, many pet owners are blissfully unaware that their exotic pet was wild caught, or bred from stock that was captured in the wild. Yet others believe that they are justified in owning a rare bird or animal, their rationale being that captive stocks will preserve a species that would otherwise go extinct – completely oblivious to the fact that they are contributing to the cause.
Animals are very often annihilated to the point of extinction for their body parts, which may be highly sought after for medicinal or aphrodisiac purposes (rhino horn and shark fins), or which may be highly valued for ornamental purposes (ivory). These animals are usually illegally poached, often involving gross cruelty in the methods used, with only the horn, tusk, or fin being removed, while the animal is left dead, or dying, where it was poached. As the bigger the horn, tusk, or fin, the bigger the prize money, usually animals with the largest appendages are targeted. These animals also tend to make up the prime breeding stock, which has a double-whammy effect on the population; not only are prize animals removed from the population, but they are no longer available to reproduce and add to that population. This is one of the fundamental reasons for species decline and extinction, especially in long-lived species that only reach sexual maturity – and consequently only breed – later in life. Furthermore, ruthless poachers will mercilessly kill a rhino cow with a calf at her side, leaving the calf to die a slow death from starvation – if it is not attacked by predators first. This results in not one, but effectively two individuals that are removed from the population. All for the sake of some ground up horn to enhance the sexual prowess of men from distant lands – very sad.
Wildlife in Africa, and other countries, is not only being exploited by people from afar. In Africa the bushmeat trade is growing considerably, as many human populations face food shortages due to drought and famine. Wild animals are hunted using snares, traps, spears and guns, and are being exploited to the point of extinction. Some of these animals are also captured for the exotic pet market, and as many inhabit tropical rainforests, they are already under threat due to habitat loss from encroaching human activities and global warming.
Loss of habitat is the number one cause of species decline worldwide. Animals require suitable habitat to breed and raise their young, to provide protection from weather and predators, and to forage or hunt prey. When trees and plants are decimated, the animals living there are at risk if they cannot move to a suitable habitat nearby. Endemic species, which only occur in a certain area, are most at risk. These species are usually totally dependent on a unique habitat for their survival, which is the reason why they are not found anywhere else in the world. Endemic species are often specially adapted to living in certain conditions, but are unable to readily adapt to survive in other habitats.
There are a number of human activities that can cause habitat loss. These include clearing for urban development or agriculture; mining activities; and deforestation as a result of logging for wood and paper. Nature can also mess with nature. Natural events, such as wildfires caused by lightning strikes, droughts, floods, hurricanes, and fierce storms, can all destroy habitats, and while they may recover over time, the wildlife that is dependent on them for survival may need to move to alternative habitat in order to survive. While many of us are quick to point fingers at unscrupulous loggers for the wanton destruction of forest habitats, we may actually be inadvertently contributing to the decimation of forest ecosystems and placing endangered species in peril. The World Wildlife Fund (WWF) recently reported that Asia Pulp and Paper (APP), who are responsible for turning an estimated 5 million acres – the equivalent of 4 million football fields, or an area larger than the state of Massachusetts – of tropical forest in Sumatra, Indonesia, into pulp since they began operating there in 1984, have been supplying U.S. supermarket chains, restaurants, and schools with toilet paper and tissue paper. The forests that they are destroying are the last refuge for critically endangered species, such as Sumatran tigers, elephants, and orangutans. These habitats are literally being flushed down the loo – but who knew…?
A natural habitat may also be deteriorated by pollutants, which may kill organisms outright, change the dynamics of the habitat, or may have more subtle, but long-lasting, effects on certain species. Very often toxic pollutants go unnoticed because they don’t cause mass mortality of species, however, the long-term effects may be even more dramatic. Pesticides and pollutants that affect the hormones and reproductive functioning of animals can have serious long-term effects on population growth and survival. The loss of just one species, be it a primary pollinator, an apex predator, or a seemingly insignificant organism at the bottom of the food chain, can radically affect the whole ecosystem.
Inter-specific Competition for a Limiting Resource
Inter-specific competition is competition between two or more species for a limiting resource such as food and/or nesting sites. When demand is more than the supply, the stronger, more competitive species will out-compete weaker species for resources, often negatively impacting the weaker species by reducing population growth rates and population size. An example in marine ecosystems are seals and seabirds, who often compete for the same food source (anchovy, pilchards, round-herring), and also for nesting/breeding sites on offshore islands. As seals are much larger and fiercer competitors, seabirds, such as the endangered African penguin, may be outcompeted. Very often species that are vulnerable to competition also face other threats as well. The African penguin population has plummeted as a result of multiple factors: increased competition from seals, other seabirds, and man (overfishing), for limited resources; decreased ocean productivity due to global warming; over exploitation of eggs, and guano (that provided ideal breeding habitat on exposed islands), in the past; fatalities following oil spills, and diseases such as avian malaria; all of which have contributed to a steady decline in population numbers, and will ultimately lead to the extinction of this species if the situation is not reversed.
Global Warming & Climate Change
Global warming is having a profound effect on many ecosystems, which are literally changing shape before our eyes. This obviously has a direct impact on the animals that live in these habitats, and are dependent upon them for food, shelter, and breeding habitat. Global warming and climate change will ultimately cause more habitat loss over time, as the planet gets hotter, ice melts, sea levels rise, and weather and rainfall patterns change. More frequent and more severe droughts are turning once productive landscapes into barren deserts, while other areas are being swamped as a result of extreme storms, flooding, and/or rising sea levels. Changes in land and sea temperatures affect productivity both on land and in the oceans, which can negatively impact food availability, and the ability of our planet to sustain life in abundance, as the knock on effects are felt up the food chain.
Global warming is a consequence of human activities: on the one hand we are contributing heavily to the greenhouse effect by burning fossil fuels, which are largely responsible for the increase in carbon dioxide emissions; on the other, large scale deforestation has removed the Earth’s natural mechanism to absorb carbon dioxide from the atmosphere. Not only are forests essential for animals that live there; they act as the lungs of our planet by absorbing carbon dioxide from the atmosphere, which is processed into carbon during photosynthesis, and released as oxygen, which all animals, including humans, need to survive. It seems crazy that we are so hell bent on self-destruction!
Protection of Endangered Species
There are many conservation organizations around the world that fund research on endangered species, as well as initiatives to ensure their protection. Organizations such as the World Wildlife Fund (WWF) and Birdlife International raise money to fund research projects, which provide a better understanding of the underlying issues that cause a species to be at risk, as well as any mitigating measures that can be undertaken to reduce the rate of decline. In addition, they run educational campaigns to enhance awareness of endangered species, and the factors that are causing their demise, and also encourage financial and volunteer support of their programs. Data gathered from research programs may be utilized in conservation management tools such as the IUCN Red List of Threatened Species, which is a list of endangered species compiled by the International Union for the Conservation of Nature (IUCN) according to the current conservation status of a species. Categories include vulnerable, threatened, or endangered.
Monitoring the Trade of Endangered Species
‘CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora) is an international agreement between governments. Its aim is to ensure that international trade in specimens of wild animals and plants does not threaten their survival’. To control the trade in endangered species across international borders, threatened species are listed on one of three CITES categories, depending on the level of restrictions imposed on the trade of a particular species. While CITES provides the framework for the proper management of the trade in wildlife, poaching is rife, and consequently international trade in wildlife needs to be policed. TRAFFIC is an international monitoring network that works closely with CITES to monitor the trade in wildlife. TRAFFIC strives to ensure that the ‘trade in wild plants and animals is managed at sustainable levels without damaging the integrity of ecological systems and in such a manner that it makes a significant contribution to human needs, supports local and national economies and helps to motivate commitments to the conservation of wild species and their habitats’.
Captive Breeding Programs
When wild populations have been reduced to a level where that population is no longer viable, a captive breeding program may be initiated in an effort to boost the numbers of endangered species. Captive breeding programs have been used with mixed success on a variety of animals, including Siberian tigers, Iberian lynx, cheetah and other wild cats; endangered rhinos; and a variety of endangered bird species. Where there is sufficient habitat, and conditions in the wild allow, captive bred individuals may be released into the wild to boost wild stocks, or they may be reintroduced to areas where they no longer occur. Alternatively, they may be held in captivity at various international institutions to facilitate a wider captive breeding program, in an effort to maintain an adequate gene pool to prevent inbreeding.
Endangered wild species that are in demand as pets, are often bred in captivity to meet this demand. While this does reduce the demand for, and consequently the pressure on, wild stocks, this needs to be controlled. Breeders of exotic species may require permits for owning, breeding, and transporting these species, and some method of identification to identify individuals as captive bred (for example bird rings, or microchips) is generally also required.
Why is Biodiversity Important?
Natural ecosystems function as a tightly knit web of life, with all the living and non-living components of the system playing a vital role in the effective functioning of the system. Biodiversity is essential to keep these ecosystems functioning smoothly as a unit. By removing any of the components that make up the whole, we are jeopardizing the health and welfare of the entire system, and all life that is dependent upon it.
Humans too are dependent on healthy ecosystems – and the rich biodiversity of species these contain. Nature provides us with all the resources we require to survive: food, water, oxygen, fertile soil, medicines, shelter, protection from the elements and adverse weather conditions, as well as recreational opportunities that keep us sane in an insane world. Yet, biodiversity is being threatened by human activities on a scale that is almost incomprehensible, and which will ultimately not only affect the welfare of other living creatures, but humankind too.