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Overpopulation
Overpopulation or overabundance is a phenomenon in which a species' population becomes larger than the carrying capacity of its environment. This may be caused by increased birth rates, lowered mortality rates, reduced predation or large scale migration, leading to an overabundant species and other animals in the ecosystem competing for food, space, and resources. The animals in an overpopulated area may then be forced to migrate to areas not typically inhabited, or die off without access to necessary resources. Judgements regarding overpopulation always involve both facts and values. Animals often are judged overpopulated when their numbers cause impacts that people find dangerous, damaging, expensive, or otherwise harmful. Societies may be judged overpopulated when their human numbers cause impacts that degrade ecosystem services, decrease human health and well-being, or crowed other species out of existence. Background In ecology, overpopulation is a concept used primaril ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biodiversity Loss
Biodiversity loss includes the worldwide extinction of different species, as well as the local reduction or loss of species in a certain habitat, resulting in a loss of biological diversity. The latter phenomenon can be temporary or permanent, depending on whether the environmental degradation that leads to the loss is reversible through ecological restoration/ecological resilience or effectively permanent (e.g. through land loss). The current global extinction (frequently called the sixth mass extinction or Anthropocene extinction), has resulted in a biodiversity crisis being driven by human activities which push beyond the planetary boundaries and so far has proven irreversible. Even though permanent global species loss is a more dramatic and tragic phenomenon than regional changes in species composition, even minor changes from a healthy stable state can have dramatic influence on the food web and the food chain insofar as reductions in only one species can adversely affect th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population
Population typically refers to the number of people in a single area, whether it be a city or town, region, country, continent, or the world. Governments typically quantify the size of the resident population within their jurisdiction using a census, a process of collecting, analysing, compiling, and publishing data regarding a population. Perspectives of various disciplines Social sciences In sociology and population geography, population refers to a group of human beings with some predefined criterion in common, such as location, race, ethnicity, nationality, or religion. Demography is a social science which entails the statistical study of populations. Ecology In ecology, a population is a group of organisms of the same species who inhabit the same particular geographical area and are capable of interbreeding. The area of a sexual population is the area where inter-breeding is possible between any pair within the area and more probable than cross-breeding with in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carrying Capacity
The carrying capacity of an environment is the maximum population size of a biological species that can be sustained by that specific environment, given the food, habitat, water, and other resources available. The carrying capacity is defined as the environment's maximal load, which in population ecology corresponds to the population equilibrium, when the number of deaths in a population equals the number of births (as well as immigration and emigration). The effect of carrying capacity on population dynamics is modelled with a logistic function. Carrying capacity is applied to the maximum population an environment can support in ecology, agriculture and fisheries. The term carrying capacity has been applied to a few different processes in the past before finally being applied to population limits in the 1950s. The notion of carrying capacity for humans is covered by the notion of sustainable population. At the global scale, scientific data indicates that humans are living beyon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
English Nature
English Nature was the United Kingdom government agency that promoted the conservation of wildlife, geology and wild places throughout England between 1990 and 2006. It was a non-departmental public body funded by the Department for Environment, Food and Rural Affairs (DEFRA) and gave statutory advice, grants and issued licences. The Nature Conservancy Council (NCC) (formerly the Nature Conservancy) was established by the National Parks and Access to the Countryside Act 1949 to cover nature conservation issues across the whole of Great Britain. The NCC was split into four by the Environmental Protection Act 1990—its English duties being given to English Nature. In Scotland, its functions were merged with those of the Countryside Commission for Scotland to form Scottish Natural Heritage, and similarly in Wales there was a merger to form the Countryside Council for Wales. A much smaller body, the Joint Nature Conservation Committee (JNCC), supported all three agencies. The Engl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forage
Forage is a plant material (mainly plant leaves and stems) eaten by grazing livestock. Historically, the term ''forage'' has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used more loosely to include similar plants cut for fodder and carried to the animals, especially as hay or silage. While the term ''forage'' has a broad definition, the term ''forage crop'' is used to define crops, annual or biennial, which are grown to be utilized by grazing or harvesting as a whole crop. Common forages Grasses Grass forages include: *'' Agrostis'' spp. – bentgrasses **''Agrostis capillaris'' – common bentgrass **''Agrostis stolonifera'' – creeping bentgrass *''Andropogon hallii'' – sand bluestem *''Arrhenatherum elatius'' – false oat-grass *'' Bothriochloa bladhii'' – Australian bluestem *''Bothriochloa pertusa'' – hurricane grass *''Brachiaria decumbens'' – Surinam grass *''Brachiaria humidicola'' – ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Deer
The red deer (''Cervus elaphus'') is one of the largest deer species. A male red deer is called a stag or hart, and a female is called a hind. The red deer inhabits most of Europe, the Caucasus Mountains region, Anatolia, Iran, and parts of western Asia. It also inhabits the Atlas Mountains of Northern Africa; its early ancestors are thought to have crossed over to Morocco, then to Algeria, Libya and Tunisia via the Strait of Gibraltar, becoming the only species of true deer (Cervidae) to inhabit Africa. Red deer have been introduced to other areas, including Australia, New Zealand, the United States, Canada, Peru, Uruguay, Chile and Argentina. In many parts of the world, the meat (venison) from red deer is used as a food source. Red deer are ruminants, characterized by a four-chambered stomach. Genetics, Genetic evidence indicates that the red deer, as traditionally defined, is a species group, rather than a single species, though exactly how many species the group includes rem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Competitive Exclusion Principle
In ecology, the competitive exclusion principle, sometimes referred to as Gause's law, is a proposition that two species which compete for the same limited resource cannot coexist at constant population values. When one species has even the slightest advantage over another, the one with the advantage will dominate in the long term. This leads either to the extinction of the weaker competitor or to an evolutionary or behavioral shift toward a different ecological niche. The principle has been paraphrased in the maxim "complete competitors can not coexist". History The competitive exclusion principle is classically attributed to Georgy Gause, although he actually never formulated it. The principle is already present in Darwin's theory of natural selection. Throughout its history, the status of the principle has oscillated between ''a priori'' ('two species coexisting ''must'' have different niches') and experimental truth ('we find that species coexisting do have different niches' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planetary Boundaries
Planetary boundaries is a concept highlighting human-caused perturbations of Earth systems making them relevant in a way not accommodated by the environmental boundaries separating the three ages within the Holocene epoch. Crossing a planetary boundary comes at the risk of abrupt environmental change. The framework is based on scientific evidence that human actions, especially those of industrialized societies since the Industrial Revolution, have become the main driver of global environmental change. According to the framework, "transgressing one or more planetary boundaries may be deleterious or even catastrophic due to the risk of crossing thresholds that will trigger non-linear, abrupt environmental change within continental-scale to planetary-scale systems." The normative component of the framework is that human societies have been able to thrive under the comparatively stable climatic and ecological conditions of the Holocene. To the extent that these Earth system proces ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wild Horse
The wild horse (''Equus ferus'') is a species of the genus ''Equus'', which includes as subspecies the modern domesticated horse (''Equus ferus caballus'') as well as the endangered Przewalski's horse (''Equus ferus przewalskii''). The European wild horse known as the tarpan that went extinct in the late 1800s has previously been classified as a subspecies of wild horse (''Equus ferus ferus''), but more recent studies have cast doubt on whether those horses were truly wild or if they actually were feral horses or hybrids.Tadeusz Jezierski, Zbigniew Jaworski: ''Das Polnische Konik. Die Neue Brehm-Bücherei Bd. 658'', Westarp Wissenschaften, Hohenwarsleben 2008, Przewalski's horse had reached the brink of extinction but was reintroduced successfully into the wild. The tarpan became extinct in the 19th century but is theorized to have been present on the steppes of Eurasia at the time of domestication. However, other subspecies of ''Equus ferus'' may have existed and could have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Columbidae
Columbidae () is a bird family consisting of doves and pigeons. It is the only family in the order Columbiformes. These are stout-bodied birds with short necks and short slender bills that in some species feature fleshy ceres. They primarily feed on seeds, fruits, and plants. The family occurs worldwide, but the greatest variety is in the Indomalayan and Australasian realms. The family contains 344 species divided into 50 genera. Thirteen of the species are extinct. In English, the smaller species tend to be called "doves" and the larger ones "pigeons". However, the distinction is not consistent, and does not exist in most other languages. Historically, the common names for these birds involve a great deal of variation between the terms. The bird most commonly referred to as just "pigeon" is the domestic pigeon, which is common in many cities as the feral pigeon. Doves and pigeons build relatively flimsy nests, often using sticks and other debris, which may be placed on bra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gray Squirrel
Gray squirrel or grey squirrel may refer to several species of squirrel indigenous to North America: *The eastern gray squirrel (''Sciurus carolinensis''), from the eastern United States and southeastern Canada; introduced into the United Kingdom, Ireland, western North America, Italy, and South Africa *The western gray squirrel (''Sciurus griseus''), from the western United States *The Arizona gray squirrel (''Sciurus arizonensis''), from the southwestern United States and adjacent Mexico *The Mexican gray squirrel The Mexican gray squirrel (or red-bellied squirrel) (''Sciurus aureogaster'') is a tree squirrel in the genus ''Sciurus'' native to Guatemala and eastern and southern Mexico. It has been introduced to the Florida Keys. The alternate name shou ... (''Sciurus aureogaster''), from southern Mexico and Guatemala; introduced into the Florida Keys {{Animal common name Sciurus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elephant
Elephants are the largest existing land animals. Three living species are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. They are the only surviving members of the family Elephantidae and the order Proboscidea. The order was formerly much more diverse during the Pleistocene, but most species became extinct during the Late Pleistocene epoch. Distinctive features of elephants include a long proboscis called a trunk, tusks, large ear flaps, pillar-like legs, and tough but sensitive skin. The trunk is used for breathing, bringing food and water to the mouth, and grasping objects. Tusks, which are derived from the incisor teeth, serve both as weapons and as tools for moving objects and digging. The large ear flaps assist in maintaining a constant body temperature as well as in communication. African elephants have larger ears and concave backs, whereas Asian elephants have smaller ears, and convex or level backs. Elephants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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