Species richnessSpecies richness is the number of different species represented in an ecological community, landscape or region. Species richness is simply a count of species, and it does not take into account the abundances of the species or their relative abundance distributions. Species richness is sometimes considered synonymous with species diversity, but the formal metric species diversity takes into account both species richness and species evenness. Depending on the purposes of quantifying species richness, the individuals can be selected in different ways.
River ecosystemRiver ecosystems are flowing waters that drain the landscape, and include the biotic (living) interactions amongst plants, animals and micro-organisms, as well as abiotic (nonliving) physical and chemical interactions of its many parts. River ecosystems are part of larger watershed networks or catchments, where smaller headwater streams drain into mid-size streams, which progressively drain into larger river networks. The major zones in river ecosystems are determined by the river bed's gradient or by the velocity of the current.
Insular biogeographyInsular biogeography or island biogeography is a field within biogeography that examines the factors that affect the species richness and diversification of isolated natural communities. The theory was originally developed to explain the pattern of the species–area relationship occurring in oceanic islands. Under either name it is now used in reference to any ecosystem (present or past) that is isolated due to being surrounded by unlike ecosystems, and has been extended to mountain peaks, seamounts, oases, fragmented forests, and even natural habitats isolated by human land development.
Ruzizi RiverThe Ruzizi (also sometimes spelled Rusizi) is a river, long, that flows from Lake Kivu to Lake Tanganyika in Central Africa, descending from about to about above sea level over its length. The steepest gradients occur over the first , where hydroelectric dams have been built. Further downstream, the Ruzizi Plain, the floor of the Western Rift Valley, has gentle hills, and the river flows into Lake Tanganyika through a delta, with one or two small channels splitting off from the main channel.
BiotopeA biotope is an area of uniform environmental conditions providing a living place for a specific assemblage of plants and animals. Biotope is almost synonymous with the term "habitat", which is more commonly used in English-speaking countries. However, in some countries these two terms are distinguished: the subject of a habitat is a population, the subject of a biotope is a biocoenosis or "biological community". It is an English loanword derived from the German Biotop, which in turn came from the Greek bios (meaning 'life') and topos ('place').
Endangered species recovery planAn endangered species recovery plan, also known as a species recovery plan, species action plan, species conservation action, or simply recovery plan, is a document describing the current status, threats and intended methods for increasing rare and endangered species population sizes. Recovery plans act as a foundation from which to build a conservation effort to preserve animals which are under threat of extinction. More than 320 species have died out and the world is continuing a rate of 1 species becoming extinct every two years.
Edge effectsIn ecology, edge effects are changes in population or community structures that occur at the boundary of two or more habitats. Areas with small habitat fragments exhibit especially pronounced edge effects that may extend throughout the range. As the edge effects increase, the boundary habitat allows for greater biodiversity. Urbanization is causing humans to continuously fragment landscapes and thus increase the edge effect. This change in landscape ecology is proving to have consequences.
Limnic eruptionA limnic eruption, also known as a lake overturn, is a very rare type of natural disaster in which dissolved carbon dioxide () suddenly erupts from deep lake waters, forming a gas cloud capable of suffocating wildlife, livestock,and humans. A limnic eruption may also cause tsunami or seiche as the rising displaces water. Scientists believe earthquakes, volcanic activity, and other explosive events can serve as triggers for limnic eruptions. Lakes in which such activity occurs are referred to as limnically active lakes or exploding lakes.
Fish killThe term fish kill, known also as fish die-off, refers to a localized die-off of fish populations which may also be associated with more generalized mortality of aquatic life. The most common cause is reduced oxygen in the water, which in turn may be due to factors such as drought, algae bloom, overpopulation, or a sustained increase in water temperature. Infectious diseases and parasites can also lead to fish kill. Toxicity is a real but far less common cause of fish kill.
Conservation-reliant speciesConservation-reliant species are animal or plant species that require continuing species-specific wildlife management intervention such as predator control, habitat management and parasite control to survive, even when a self-sustainable recovery in population is achieved. The term "conservation-reliant species" grew out of the conservation biology undertaken by The Endangered Species Act at Thirty Project (launched 2001) and its popularization by project leader J. Michael Scott.
