Biodiversity conservation is an extraordinary challenge that must be addressed through a better understanding of biodiversity itself, changes in human behavior and beliefs, and various conservation strategies.
The number of species on the planet, or in any geographical area, is the result of a balance of two evolutionary processes: speciation and extinction. When speciation rates begin to exceed extinction rates in , species numbers will increase. Similarly, when extinction rates begin to exceed speciation rates, the opposite happens.
Throughout the history of life on Earth, as reflected in the fossil record, these two processes fluctuated. There are many smaller but still dramatic events that the extinction, but the five mass extinctions have attracted the majority of research into their causes. Series of major extinction events across the entire fossil record (542 million years ago).
Most scientists now agree that the main causes of these extinctions were the impact of a large asteroid on what is now the Yucatan Peninsula and the subsequent release of energy and global climate changes.
The dodo bird is one of the oldest and best-known examples. The dodo bird had lived in the forests of Mauritius, and became extinct around 1662. The dodo bird was hunted to extinction in by sailors for its flesh and was easy prey. Introduced pigs, rats and dogs brought to the island by European ships also killed dodo hatchlings and eggs.
Steller’s sea cow became extinct in 1768; It was related to the manatee and probably once lived on the northwest coast of North America. The Steller’s manatee was discovered by Europeans in 1741 and hunted for its meat and oil. The last Steller manatee was killed in 1768 in Cincinnati, Ohio, in 1914.
This species once migrated in the millions in but has declined in numbers due to overhunting of and habitat loss due to clearing of forests for farmland.
These are just a few of the species extinctions recorded over the past 500 years. Conservation of Nature (IUCN) maintains a list of extinct and endangered species, the Red List. The list is not exhaustive but describes 380 vertebrates that became extinct after 1500 AD .C., of which 86 have become extinct due to overhunting or overfishing.
Estimates of extinction rates are complicated by the fact that most extinction rates are likely to be unobserved. People often notice the extinction of animals, especially if they have been hunted or otherwise used. But there are many organisms that are less obvious (not necessarily less valuable) to humans and many that are not described.
The background extinction rate is estimated at about 1 per million species years (E/MSY). A million-year species could be a species surviving a million years or a million species surviving a year. For example, if there are 10 million species, we would expect 10 of those species to disappear in a year. This is the background rate.
A contemporary estimate of the extinction rate uses written records of extinctions. First, many extant species would not be described until much later than this time and their loss would therefore go unnoticed. Second, we know the number is higher than written documentation suggests because it is an extinct species. are now described using skeletal remains that have never been mentioned in written history. the estimated extinction rate is close to 100 E/MSY. The projected rate by the end of the century is 1,500 E/MSY.
A 90 percent reduction in habitat from 100 km2 to 10 km2 reduces the number of compatible species by about 50 percent. A second approach to estimating extinction rates over time is to correlate the loss of species with habitat loss and is based on measuring forest cover loss and understanding species-area relationships.
Similarly, as the area of habitat decreases, the number of species observed will also decrease. This type of relationship is also evident in the relationship between an island’s area and the number of species found on the island: as one increases, the other also increases, although not in a straight line.
Estimates of extinction rates based on habitat loss and species-area relationships have suggested that with around 90% habitat loss, 50% of the species are expected to disappear. Forest area reduced from 100 km2 to 10 km2, an increase of 90, reducing the number of species by about 50%.
Species range estimates have led to estimates of current species extinction rates of around 1000 E/EMS and higher.
Today, major efforts to conserve biodiversity include legislative approaches to regulating human and commercial behavior, the separation of protected areas, and habitat restoration.
Laws were enacted to protect species around the world. The agreement and supporting national legislation provide a legal framework for “species transported across nations’ borders. to protect them from being captured or killed when the purpose is international trade. The species protected by the treaty number about 33,000. The scope of the agreement is limited as it relates only to the international movement of organizations or parts of organizations. It is also limited by the ability or willingness of various countries to enforce the treaty and accompanying legislation.
Many countries have laws protecting endangered species and regulating hunting and fishing. The ESA and similar ones in other countries are a useful tool but suffer from the fact that it is often difficult to list a species or implement an effective management plan once it is listed.
It’s illegal to disturb, kill, or transfer parts of protected species (much of the hunting of birds in the past was for their feathers). Examples of protected species include northern cardinals, red-tailed hawks and black vultures.
Global warming a major contributor to biodiversity loss. Governments are worried about the impact of anthropogenic global warming, especially on their economies and food resources. Since greenhouse gas emissions know no national borders, efforts to reduce them are international.
A biodiversity hotspot is a protection concept developed by Norman Myers in 1988. Hotspots are geographic areas that harbor a large number of endemic species. The purpose of the concept was to identify key locations on the planet for conservation efforts, a sort of conservation triage. The original hotspot criteria included the presence of at least 1,500 endemic plant species and 70% of the area disturbed by human activity. There are now 36 biodiversity hotspots with a whopping endemic species, including half of all endemic species in the world. Although these cover only 2.3% of the Earth’s surface, 42% of the world’s vertebrate species and 50% of the plants are endemic to these hotspots. Extensive research has been carried out into optimal nature conservation projects to preserve biodiversity.
A large reserve is better than the same area of several smaller reserves because there are more core habitats outside the reserve boundaries unaffected by less hospitable ecosystems. In addition to the physical specifications of a reserve, there are a number of regulations governing the use of a reserve. This can include anything from logging, mineral mining, regulated hunting, human settlement, and non-destructive human recreation. Uses are driven by political pressure rather than protection considerations.
Climate change will inevitably pose problems of the location of reserves as species within them migrate to higher latitudes as the habitat of the reserve becomes less favorable. Accounting for expected changes from global warming is underway, but will only be as effective as the accuracy of climate predictions.
Wolves are killing elk and coyotes and providing more abundant resources for detritivores. The reduction in elk populations has allowed the replanting of riparian areas (areas along the banks of a stream or river), which has increased biodiversity in that habitat. The reduction of coyote populations by wolves has increased the number of prey species previously killed by coyotes. In this habitat, the wolf is a key species, a species essential to maintaining diversity within an ecosystem. Removing a keystone species from an ecological community leads to a breakdown in diversity.
Effective restoration of a key species can have the effect of restoring community biodiversity. Ecologists have advocated identifying key species where possible and focusing conservation efforts on those species.
Zoo and breeding programs contribute to conserving many endangered species.