methods of maintaining biodiversity Flashcards
maintaining biodiversity
Conservation is the name given to the preservation and careful management of the environment and of natural resources. By conserving the natural habitat in an area, organisms’ chances of survival are maintained, allowing them to reproduce. As a consequence species and genetic diversity can be safeguarded.
There are many different ways in which scientists try to conserve biodiversity. They can be divided into two main categories:
• in situ conservation - within the natural habitat
• ex situ conservation - out of the natural habitat.
Scientists are currently trying to conserve a number of species to prevent their extinction. Species are classified, for the purposes of conservation, according to their abundance in the wild:
• extinct - no organisms of the species exist anywhere in the world
• extinct in the wild - organisms of the species only exist in captivity
• endangered - a species that is in danger of extinction
• vulnerable - a species that is considered likely to become endangered in the near future.
Non-threatened and categories of least concern follow below. Many conservation techniques focus on increasing the numbers of organisms from species that are classified as endangered.
Scientists also promote the practice of sustainable development - economic development that meets the needs of people today, without limiting the ability of future generations to meet their needs.
in situ conservation
In situ conservation takes place inside an organism’s natural habitat.
This maintains not only the genetic diversity of species, but also the evolutionary adaptations that enable a species to adapt continually to changing environmental conditions, such as changes in pest populations or climate. By allowing the endangered species to interact with other species, it also preserves the interdependent relationships present in a habitat, therefore interlinked species may also be preserved. In situ conservation is generally cheaper than ex situ conservation.
Marine (saltwater), aquatic (freshwater) and terrestrial (land) nature reserves are examples of areas that have been specifically designated
for the conservation of wildlife.
wildlife reserves- in situ
Once an area has been designated as a wildlife reserve, active management is required. Active management techniques may include: -controlled grazing - only allowing livestock to graze a particular area of land for a certain period of time to allow species time to recover, or keeping a controlled number of animals in a habitat to maintain it (see below)
• restricting human access - for example, not allowing people to visit a beach during the seal reproductive season, or by providing paths which must be followed to prevent plants being trampled
• controlling poaching - this includes creating defences to prevent access, issuing fines, or more drastic steps such as the removal of rhino horns
• feeding animals - this technique can help to ensure more organisms survive to reproductive age
• reintroduction of species - adding species to areas that have become locally extinct, or whose numbers have decreased significantly
• culling or removal of invasive species - an invasive species is an organism that is not native to an area and has negative effects on the economy, environment, or health. These organisms compete with native species for resources.
-halting succession - succession is a natural process in which early colonising species are replaced over time until a stable mature population is achieved. For example, as a result of natural succession any piece of land left alone for long enough in the UK will develop into woodland. The only way to protect some habitats such as heath-, down- or moorland from becoming woodland is through controlled grazing. In different parts of the country ponies, deer, sheep, and cows eat tree seedlings as they appear, preventing succession from heathland to scrubland to woodland.
This is an important role played by humans in maintaining some of our most beautiful habitats for future generations.
marine conservation zone-in situ
Marine conservation zones are less well established than terrestrial ones. Lundy Island is currently the only statutory marine reserve in England, but there are many other protected areas.
Marine reserves are vital in preserving species-rich areas such as coral reefs, which are being devastated by non-sustainable fishing methods.
The purpose of the marine reserve is not to prevent fisherman from visiting the entire area, but to create areas of refuge within which populations can build up and repopulate adjacent areas. Large areas of sea are required for marine reserves as the target species often move large distances, or breed in geographically different areas.
botanic gardens- ex situ
Ex situ conservation involves the removal of organisms from their natural habitat. It is normally used in addition to in situ measures, ensuring the survival of a species.
Botanic gardens-
Plant species can be grown successfully in botanic gardens. Here the species are actively managed to provide them with the best resources to grow, such as the provision of soil nutrients, sufficient watering, and the removal or prevention of pests.
There are roughly 1500 botanic gardens worldwide, holding 35 000 plant species. Although this is a significant number (more than 10% of the world’s flora), the majority of species are not conserved. Many wild relatives of selectively bred crop species are under-represented amongst the conserved species. These wild species are a potential source of genes, conferring resistance to diseases, pests, and parasites.
seed banks-ex situ
A seed bank is an example of a gene bank - a store of genetic material. seeds are carefully stored so that new plants may be grown in the future. They are dried and stored at temperatures of -20°C to maintain their viability, by slowing down the rate at which they lose their ability to germinate. Almost all temperate seeds, and many tropical seeds, can be stored in this way. Scientists expect that they will remain viable for centuries, providing a back-up against the extinction of wild plants. The Svalbard ‘Doomsday Vault’ in Norway stores seeds in the permafrost and already houses around 800000 species. It will eventually have 3 million different types of seeds and aims to provide a back-up against the extinction of plants in the wild by storing seeds for future reintroduction and research, for breeding and for genetic engineering in the future.
Seed banks don’t work for all plants. Some seeds die when dried and frozen, and sadly the seeds of most tropical rainforest trees fall into this category.
captive breeding programmes-ex situ
Captive breeding programmes produce offspring of species in a human-controlled environment. These are often run and managed by zoos and aquatic centres. For example, The National Marine Aquarium in South West England is playing an important role in the conservation of sea horse species. Several species are now solely represented by animals in captivity.
Scientists working on captive breeding programmes aim to create a stable, healthy population of a species, and then gradually reintroduce the species back into its natural habitat. The Arabian Oryx is an example of a species that was extinct in the wild before its reintroduction.
Captive breeding programmes provide the animals with shelter, an abundant supply of nutritious food, an absence of predators and veterinary treatment. Suitable breeding part be impemen (which can vetesed to artificially inseminate females) can be imported from other zoos if not available within the zoo’s own population.
Maintaining genetic diversity within a captive breeding population can be difficult. As only a small number of breeding partners are available, problems related to inbreeding can occur. To overcome this, an international catalogue is maintained, detailing genealogical data
on individuals. Mating can thus be arranged to ensure that genetic diversity is maximised. Techniques such as artificial insemination, embryo transfer and long-term cryogenic storage of embryos allow new genetic lines to be introduced without having to transport the adults to new locations, and do not require the animals cooperation.
Some organisms born in captivity may not be suitable for release in the wild. These are some of the reasons:
• Diseases - there may be a loss of resistance to local diseases in captive-bred populations. Also, new diseases might exist in the wild, to which captive animals have yet to develop resistance.
-Behaviour - some behaviour is innate, but much has to be learned through copying or experience. In an early case of reintroduction, a number of monkeys starved because they had no concept of having to search for food - they had become domesticated. Now food is hidden in cages, rather than just supplied, so that the animals learn to look for it.
• Genetic races - the genetic make-up of captive animals can become so different from the original population that the two populations cannot interbreed.
• Habitat - in many cases the natural habitat must first be restored to allow captive populations to be reintroduced. If only a small suitable habitat exists it is likely that there are already as many individuals as the habitat can support. The introduction of new individuals can lead to stress and tension as individuals fight for limited territory and resources such as food.
conservation agreements-ex situ
To conserve biodiversity successfully, local, and international cooperation is required to ensure habitats and individual species are preserved. Animals do not respect a country’s boundaries. Therefore, to increase the chances of a species’ survival, cross-border protections should be offered.
international union for the conservation of nature -ex situ
Intergovernmental organisations, such as the International Union for the Conservation of Nature (IUCN), assist in securing agreements between nations. At least once a year the IUCN publishes the Red List, detailing the current conservation status of threatened animals.
Countries can then work together to conserve these species. The IUCN was also involved in the establishment of the Convention on International Trade in Endangered Species (CITES). This treaty regulates the international trade of wild plant and animal specimens and their products. As the trade in wild animals and plants crosses borders between countries, the effort to regulate it requires international cooperation to safeguard certain species from over-exploitation. Today, more than 35000 species of animals and plants are protected by this treaty.
the rio convention-ex situ
In 1992, an historic meeting of 172 nations was held in Rio de Janeiro, which became known as the Earth Summit. The summit resulted in some new agreements between nations in the Rio Convention:
The Convention on Biological Diversity (CBD) requires countries to develop national strategies for sustainable development, thus ensuring the maintenance of biodiversity.
The United Nations Framework Convention on Climate Change
(UNFCCC) is an agreement between nations to take steps to stabilise greenhouse gas concentrations within the atmosphere.
• The United Nations Convention to Combat Desertification
(UNCCD) aims to prevent the transformation of fertile land into desert and reduce the effects of drought through programmes of international cooperation.
Each convention contributes to maintaining biodiversity. They are intrinsically linked, operating in many ecosystems and addressing interdependent issues.
countryside stewardship scheme-ex situ
Many conservation schemes are set up at a more local level. An example is the Countryside Stewardship Scheme in England.
The scheme, which operated from 1991-2014, offered governmental payments to farmers and other land managers to enhance and conserve the English landscape. Its general aim was to make conservation a part of normal farming and land management practice.
Specific aims of the scheme included:
• sustaining the beauty and diversity of the landscape
• improving, extending and creating wildlife habitats restoring neglected land and conserving archaeological and historic features
• improving opportunities for countryside enjoyment.
This scheme has now been replaced by the Environmental Stewardship Scheme, which operates similarly.
