Learn about conservation of Wild environments, animals and flora.
There are 10 lessons in this course:
Introduction to Wildlife Conservation
Recovery of Threatened Species
Approaches to Conservation of Threatened Wildlife
Planning for Wildlife
Managing Threatened Wildlife Populations
Wildlife Conservation Project
Determine guiding principles of wildlife conservation and the threats to wildlife.
Determine ways to achieve species recovery.
Discuss the principles of habitat conservation
Discuss fragmentation, restoration and the use of protected areas.
Describe and discuss the various approaches used to conserve threatened species and ecosystems.
Explain a range of flora survey techniques developed for conservation purposes.
Differentiate between a variety of different fauna survey techniques.
Discuss fauna survey techniques that have been developed to sample fauna for conservation purposes.
Discuss survey techniques used to conserve wildlife in marine environments.
Discuss different planning tools that are available to help conservation of wildlife in farming, urban and residential planning.
Identify management techniques used in the conservation of different types of wildlife.
Develop a recovery plan for a threatened species of wildlife.
WHAT IS THREATENING WILDLIFE CONSERVATION TODAY?
Habitat fragmentation, as the name suggests it the fragmenting or disruption of continuity of a species’ habitat. This can be caused by natural processes such as geological processes which over time alter the layout of the physical environment. However, in the last 200 years, the major cause of habitat fragmentation is the change in land use by humans.
Habitat patch size and distribution can have significant impacts on the distribution, social structure and the inevitable survival of wildlife populations. With the clearing of land worldwide for cultivation and urban/residential development, wildlife habitats are being broken up into smaller and more isolated patches. This fragmentation can isolate populations from one another, stopping genetic flow and therefore weakening the genetic diversity of species. This can lead to reduced fitness of a population (inbreeding depression) and can make the population more susceptible to the effects of disease and other external factors. An example of this is evident in a small isolated population of African lions in Tanzania. Due to inbreeding depression, the males of this population produced abnormal sperm which then led to their declined reproductive success.
Reduction in habitat size also leads to the increased length of habitat edges. These are the zones between two or more plant communities. Many wildlife species make use of edges. The influence these two habitat types have on one another along this boundary is known as the 'edge effect'. This edge can be beneficial for some species when it provides access to two different habitats in a small area as there are greater resources available per unit of area. These edges can also have a negative impact on some species, particularly when there is a large edge bordering disturbed land. Forest fires, higher rates of predation and infestation by pioneer plant species are more likely to occur along the edges of habitat.
Orangutan Case Study
There are many threats facing Indonesia’s Orangutans, including poaching, the illegal pet trade and most significantly the loss and fragmentation of habitat due to illegal logging and Palm Oil plantations. In 2007 the UN Environment Program warned that if current deforestation trends continue, the Orangutan will be extinct in the wild within 2 decades.
Orangutans were once present over thousands of miles across the rainforests of southeast Asia. Today only 50,000 to 60,000 exist and can only be found in Borneo and Sumatra and this habitat is continually under threat. Deforestation in the forms of illegal logging, slash and burning for plan oil plantations has had devastating consequences on the native Orangutan populations.
Palm Oil Plantations in Indonesia and Malaysia are considered a critical threat to the habitat of Orangutans. These two countries are also the two largest exporters of palm oil in the world. Not only do the plantations remove rainforest habitat, but they also lead to increased fragmentation of surrounding habitat. Orangutans entering palm oil plantations and damaging fruit can also be susceptible to hunting leading to either capture or death.
International Organisations are trying to work with the Indonesian Government and Palm Oil Companies to try to reduce the impact on Orangutans. Wildlife corridors are being created to allow Orangutans to connect with other populations, therefore maintaining genetic diversity.
Habitat Degradation and Loss
Habitat degradation can be defined as the slow decline or attrition of habitat suitability. The process of habitat degradation can eventually lead to habitat loss. It is a key threatening process affecting many species worldwide and is believed to be the main cause of species extinction and endangerment on a global scale. Around 60% of ecosystems on earth are now considered degraded or unsustainable due to human activity. This includes both terrestrial and marine ecosystems.
Habitat degradation can be split into two types.
- The reduction in the availability of food resources (eg. over fishing leading to the endangerment of the Seal Lion of the US east coast) or
- The availability of shelter (eg. the reduction in Mountain Ash tree hollows available to Leadbeaters Possum in Victoria, Australia).
These two factors combined can result in the reduced abundance of a species within its natural habitat.
Habitat degradation is one of the major processes impacting both plant and animal species worldwide. It has the direct impact of loss of biodiversity, removing habitat for species forcing them to adjoining habitats and sometimes resulting in local population extinctions. Habitat degradation and loss can also have the flow on effects of increased erosion downstream and eutrophication of waterways, higher predation rates and increased competition in surrounding habitats, putting pressure on these habitats.
The loss of habitat is the major impact leading to the endangerment of many species worldwide. Human populations are continually transforming land with approximately half of the earth’s land area already transformed for human use. This can be divided into 11% for farming and forestry, 26% for livestock pasture and the remaining 63% for development such as housing, industry, services and transport. Forest cover has changed worldwide decreasing by around 670,000 km2 between 1980 and 1995. Although countries such as North America are experiencing forest growth, the quality of forest habitat is declining.
Two thirds of the world’s rivers have been changed and flow has been regulated. Many of the wetlands worldwide have been drained or filled. In countries such as Central and South America, the rate of wetland loss is still quite high.
Effects of habitat loss
Many ecologists have identified links between area size and species richness. Therefore, the loss of habitat can not only affect individual species but species richness. Trends identified between species richness and area size are:
- Extinction rates are greater on small islands
- Larger areas contain more individuals.
- Speciation (evolution of new species) is more likely in larger areas
- There are more “core” areas within large areas that are less affected by environmental disturbances and edge effects.
- Increased diversity of habitat in larger areas will result in greater species-area relationship.
Habitat loss and degradation is a significant issue facing conservationists and will be discussed in greater detail in later lessons.
The degradation and erosion of soil is considered by leading ecologists to be the second largest global environmental problem after population growth. The conversion of land to cropping across the world has had a major impact on soil quality. This is a significant issue in areas where the soil is not suitable for cropping in the first place.
When plants (trees and shrubs) are cleared from a site, soil is exposed to sunlight and the eroding effects of wind and water. Soil aeration is increased and the rate of weathering increases. Apart from erosion, the proportion of organic matter in the soil gradually decreases, through the action of microbes in the soil which use it as a source of energy ‑ unless the new land use provides some replacement.
Soil erosion, which is the movement of soil particles from one place to another by wind or water, is considered to be a major environmental problem. Erosion has been going on through most of earth's history and has produced river valleys and shaped hills and mountains. Such erosion is generally slow, but human activity has caused a rapid increase in the rate at which soil is eroded (i.e. a rate faster than natural weathering of bedrock can produce new soil). This has resulted in a loss of productive soil from crop and grazing land as well as layers of infertile soils being deposited on formerly fertile crop lands. Erosion also has the environmental effects of the formation of gullies, siltation of lakes and streams as well as causing land slips. Humans have the capacity for major destruction of our landscape and soil resources. They also have the tools and knowledge to combat this problem. One simple soil conservation technique is the use of cover crops by farmers to retain soil during periods when the soil is not under crop.
Pollution can take many forms (eg. water, air, soil) and have various devastating impacts on individuals and diversity. Some of these impacts are difficult to ascertain. For example, it will not be known for many years what the actual extent of the BP Oil Spill in the Gulf of Mexico in 2010 will have on marine and bird life that are dependent on the surrounding environment.
Land pollution is the general degradation of the land surfaces, usually due to human activities and the misuse of resources. The most severe type of land pollution is land contamination. Sources of land pollution include:
- Coal-fired power plants
- Oil Refineries
- Chemical Plants
- Plastic Factories
- Improper disposal of nuclear and toxic waste
- Accumulation of waste
- Misuse of agricultural chemicals (herbicides and pesticides)
The effects of land pollution for humans, plants and animals can include health issues such as deformities and cancer.
Air pollution is the accumulation of substances in the atmosphere at such concentrations that can endanger health or negatively impact living organisms. The major sources of air pollution are:
- Power and heat generation (eg. coal combustion)
- Incineration of solid wastes
- Industrial processes
- Exhaust fumes from vehicles
- Acid rain
- Tobacco smoke
The major air pollutants are carbon monoxide, hydrocarbons, nitrogen oxide, sulphur dioxide, particulates and photochemical oxidants.
Water pollution is an issue in both our rivers and in the ocean. There are many causes of water pollution including introduction of effluent, heavy metals, agricultural fertilisers high in nutrients such as nitrates and phosphates and siltation.
Eutrophication is defined as the process by which a body of water acquires a high concentration of nutrients. This is becoming a large problem in marine environments due to the excessive amounts of organic matter entering waterways. These are sourced from sewage, livestock, agricultural fertilisers, soil eroding from deforestation and upwelling of deep ocean waters. Eutrophication is particularly harmful to coral reefs. As corals have evolved in the lowest nutrient environments in the world, small increases in nutrients can then rapidly increase algal growth which in turn smothers and kills the coral underneath.
Pollution and degradation of marine and coastal environments is mainly caused by land-based activities. The main pollution pressures are derived from human settlement, population growth and urbanisation along coastal areas. These produce pollution in the forms of:
- Excess sediment, phosphorous and nitrogen
- Storm water discharge
- Marine debris
- Estuarine pollution
Sea Grasses and Coral Reef habitats are important breeding and foraging habitats for aquatic creatures. These habitats are being degraded by the dumping of dredge wastes and discharge of silt from adjacent coastal rivers. These are reducing the amount of light available to sea grass and coral therefore limiting their ability to grow.
Other factors contributing to the degradation of many marine ecosystems include:
- agricultural activities in river catchments leading to fine sediment and chemical runoff
- trawling by commercial fishermen
- pollution from urban runoff
- pollution from cruise ships
- increased water vessel traffic
- nutrient runoff leading to eutrophication and algal blooms.
- noise disturbance
Overexploitation is the unsustainable harvesting of a resource, either plant or animal to a point of diminishing returns. If overexploitation of a species continues it can lead to local extinctions. The overexploitation of species worldwide has led to reduced genetic diversity and relative species abundance.
Overexploitation has led to the extinction of many species worldwide including the Passsenger Pigeon in the US, the Moa in New Zealand and the Giant Lemur of Madagascar. Hunting is still a major threat to mammals, fish and birds worldwide. The Wildlife Conservation Society of the United States, estimate that more than 1 million metric tonnes of wild meat (bush meat) is coming out of Africa’s tropical forests each year. Those mammals that are at the greatest risk of extinction are large and slow to reproduce, such as elephants and large antelopes. Large and conspicuous birds are also more likely to be in danger of extinction. These include pheasants and megapodes (eg. the Malleefowl of Australia).
Some marine experts estimate that almost 90% of the world’s large marine fish have gone from our oceans. In many places, pressure from overfishing and related environmental problems have forced governments to limit or completely eliminate fishing until fish populations are able to recover.
Overexploitation usually occurs for three reasons – meat, fur/hides and live trade. One example of overexploitation for meat is whaling in the 20th Century. During this time, the number of whales that were taken worldwide rose to around 66,000 individuals per year. During this period, many species were reduced to extremely low population numbers and some were on the verge of extinction. The International Whaling Commission was established in 1946 to control the amount of whales being taken. This was due to growing concern that the number being taken was unsustainable and would lead to the death of the industry itself. Many species have recovered since this time, however others are still taken under the guise of “scientific research”.
The trade in animal parts has meant that many species are still vulnerable to high rates of exploitation. Bear Bile farming in China has seen the overexploitation of over 7000 Asiatic bears for the Traditional Chinese Medicine market. The bear’s gallbladders are milked of bile through surgically implanted tubes. It is believed that around half of the bears on these farms die due to infections and other complications.
Overexploitation in the fishing industry has been a concern for many years with many believing the industry to be unsustainable. Concerns with over fishing include:
- The increased capacity to exploit fish stocks due to increased demand and effort and improvement in fishing technology
- Significant decline in fish stocks observed on a global scale
- Destruction and degradation of spawning and nursery grounds through fishing practices and human developments on land
- The lack of monitoring of some fishing industries and the limited information on many species fished.
- Removal of long-lived slow growing species
- Changes in the structure of fish populations
- Unsound fishing practices undertaken, such as trawling
- The impact of recreational fishing and boating on fish populations.
An invasive species is one that occurs in a particular environment at a level beyond its normal distribution as a result of human activities. They can compromise the indigenous wildlife and affect agricultural and horticultural values of an area. Invasive species can take many forms such as:
- Disease, fungi and parasites - White Pine Blister Rust Fungus of Asia was introduced into North American and is now attacking ancient Gnarled Limber and Bristlecone Pines in Colorado’s Rocky Mountains. There is no known cure for the fungus which penetrates pine needles and covers branches eventually girdling tree trunks.
- Feral animals – The European Red Fox (Vulpes vulpes) was introduced into Australia in 1855 for recreational hunting. It rapidly adapted to the Australian landscape, establishing itself by the 1870s. It has been able to adapt to various habitats in Australia ranging from urban to alpine and arid areas. It has played a major role in the decline of ground-nesting birds, smaller mammals and reptiles. The only successful control measures to maintain population numbers is the use of fencing and broad scale poisoning programs.
- Insects and other invertebrates – The Western Corn Root worm larvae (Diabrotica virgifera virgifera) was accidentally introduced into Serbia in the 1990s and has since wreaked havoc on maize yields across Europe. The native of Central America has caused immense damage in Europe, feeding on plants and impairing fertilisation during heavy infestations.
- Introduced marine pests – The Northern Pacific Seastar is considered a serious pest in Australia due to its negative impact on native marine systems and marine industries including shellfish farming. They are prodigious predators, eating a wide range of native animals and the population is growing at an alarming rate. It has been directly linked to the decline of the endangered spotted handfish (Brachionichthys hirsutus) in Tasmania, preying on the egg masses and sea squirts that handfish require for spawning.
- Weeds – Japanese Knotweed (Fallopia japonica) is considered a pest species in North America and Europe. The large plant native to Japan, China and Korea has an invasive root system that has been responsible for damaging buildings, flood mitigation, roads, retaining walls and architectural sites. It forms thick, dense colonies that inhibit the growth of native vegetation and is considered the worst invasive species of eastern United States.
Invasive or Introduced species have many impacts not only on native species but humans as well. The various impacts of invasive species can be divided into three main groups:
- Ecological impacts –predation, competition for food and shelter, habitat degradation and spread of disease.
- Economic impacts – many industries are negatively impacted by invasive species including agriculture, forestry and tourism. In Australia alone, the overall direct economic impact of pest animals is conservatively estimated at $740 million annually.
- Social impacts – these flow from economic to ecological impacts. Direct social impacts can include distress from wild dog attacks on livestock and domestic animals or personal injuries through vehicle collisions with feral animals.
Invasive (or “exotic”) species can take many forms and can have devastating on individual species, ecosystems and biodiversity. Invasive species are considered the second largest threat to biodiversity behind habitat destruction. In the US alone, invasive species are believed to be the cause of endangerment of around 49% of endangered species.
In Australia, species that have been introduced by humans such as foxes and the cane toad have lead to environmental disaster in some areas. Foxes have lead to the extinction of some ground nesting birds, whilst the cane toad competes with native frogs and is toxic to many of the species they prey on them such as water birds and reptiles.
Climate change is largely due to greenhouse gases produced through human activity. Greenhouse gases reduce the amount of heat being released into space and absorb heat from the sun in the atmosphere. Changes in climate include increased average air and ocean temperatures, melting of snow and ice and rising sea levels. Ocean circulation and atmospheric changes have also altered global rainfall and wind patterns. During the last 100 years, the global average surface temperature increased by about 0.7°C. Although this increase seems small, it has a large impact on the earth’s climate.
Climate change has social, economical and environmental impacts. Countries such as Australia are more vulnerable to climate change due to the arid nature of the continent. Two of the major changes are:
Hydrological changes - changes in the hydrological cycle at regional and global scales. This contributes to the reduced amount of water stored as ice in glaciers and changes in rainfall patterns.
Biological changes – changes in the range of plant and animal species to higher latitudes and altitudes. Changes in species composition and abundance as well as flowering timing and migration.
Population Isolation/Conservation Genetics
Conservation Genetics is the combination of the studies of ecology, genetic variation, molecular biology, mathematical modelling and evolutionary taxonomy. At the centre of this study is the knowledge of population genetics. Genetic variation is essential to the breeding success and future existence of populations. Some species have high genetic variation or high heterozygosity, whilst others have low genetic variation (low heterozygosity).
The knowledge of a population’s genetic variation is important in conservation biology to help manage populations. There can be three causes of low genetic variation – inbreeding, genetic drift and genetic neighbourhoods (the size of an area in which mates can be chosen at random). Reduced genetic variation can greatly inhibit the growth of a population and can threaten the recovery of endangered species.
Diseases can affect plants, animals and the function of ecosystems. In the past, disease attacks on wildlife were not considered to be a significant issue. Today, scientists have identified diseases as one of the contributing factors to species decline worldwide. Habitat conditions and the impact of disease are closely related. Those animals that are under stress due to pressures on habitat are more likely to succumb to disease.
One example is the occurrence of Chlamydia in the Koala (Phascolarctos cinereus) of Australia. It is believed that Chlamydia occurs naturally in many koala populations. However, symptoms of the disease may not present themselves until the animal is placed under stress. Koalas living in urban areas generally show more symptoms of chlamydial infection than those in non-urban areas.
Extinction and Disease
With relation to species extinction, extinctions caused by disease are difficult to identify retrospectively. They are generally not a common agent for extinction on a large-scale. However, disease has been responsible in the past for local extinctions.
Disease carried by domestic and wild animals can act as vectors for pathogens that affect many species, including humans, such as Foot and Mouth Disease. The disease can be spread by droplet infection or it can be airborne. This makes the disease highly infectious and tight controls need to be in place if any clinical symptoms of the disease are diagnosed in livestock or wildlife populations.
Density and Disease
The density of animal populations is also related to their susceptibility to disease. As available habitat is reduced along with habitat quality, wildlife populations become more concentrated. This can put added stress on populations, increasing their vulnerability to disease.
Diseases may cause serious losses in small populations of endangered species. For example, the already endangered Whooping Crane captive breeding population of 39 suffered a major loss of 7 animals to an insect-borne virus. Although this number seems small, it is 18% of the breeding population, reducing the genetic pool further.
Impacts of Disease Control Measures
Controlling disease, can inadvertently and directly impact wildlife and natural systems. For example, along the eastern seaboard of the United States, many marshes were drained to control the spread of disease by mosquitoes. In turn this control measure destroyed wetland vegetation, therefore reducing available wildlife habitat. When choosing control methods for disease is important that all impacts of control are considered prior to implementation.