The three diagrams show. See main article: Warder Clyde Allee. Positive density-dependence. Translations . Determining whether an Allee effect results from low numbers (n) or low densities (6) of individuals may be thought of in terms of isolated patches or islands of habitat. Examples. Noun . Positive density-dependence, density-dependent facilitation, or the Allee effect describes a situation in which population growth is facilitated by increased population density.. On distingue deux formes de l'effet Allee : l'effet Allee élémentaire (component Allee effect) et l'effet Allee démographique [3], [4]. Wikipedia . Allee effects, population size and population density. 37 relations. The FTA model is underpinned by demographic and ecological phenomena and processes such as the Allee effect, ‘gene surfing’, ‘high-density blocking’ and ‘priority effects’ —whereby early-colonising lineages can reach high densities and thus hinder the success of late-arriving colonisers—which have been suggested to strongly influence spatial biodiversity patterns. This could come about through multiple mechanisms. The Allee effect is a phenomenon in biology characterized by a correlation between population size or density and the mean individual fitness (often measured as per capita population growth rate) of a population or species.. History and background. For dioecious (separate sex) obligatory parasites, mated female worms are required to complete a transmission cycle. Allee effect (plural Allee effects) The negative population growth observed at low population densities. It was demonstrated that kinesis is beneficial for assimilation of both patches and fluctuations of food distribution. negative population growth observed at low population densities. Allee-effekten är ett biologiskt fenomen som visar korrelationen mellan mellan populationens storlek eller densitet beroende på individernas fitness. Många omvärldsfaktorer som rädsla, tillgången på föda och antal artfränder i ett begränsat område kan påverka en individs genomsnittliga fitness, vilket även påverkar populationens tillväxt. Un effet Allee élémentaire est observé quand un composant de la valeur sélective individuelle, par exemple le taux de survie ou de reproduction, est positivement corrélé à … 1999). The Allee effect is a phenomenon in biology characterized by a correlation between population size or density and the mean individual fitness (often measured as per capita population growth rate) of a population or species. Etymology . アリー効果は、生態学において、個体群密度の増加によって個体群に属する個体の適応度が増加する現象のことである。 アメリカの生態学者であるウォーダー・クライド・アリー（Warder Clyde Allee）によって提唱されたことから、アリー効果と呼ばれる。. Allee Effect The allee effect is defined as a “positive relationship between any component of individual fitness and either numbers or density of conspecifics” (Stephens et al. Allee effect. This concept was first described by Warder Clyde Allee in the 1930’s. The Allee effect is a phenomenon seen in population biology when a small population grows faster when the organisms are at high population density than it would if the population was at low density. The models of kinesis were tested with typical situations. Kinesis may delay invasion and spreading of species with the Allee effect. Allee effect explained. The general idea is that for smaller populations, the reproduction and survival rates of individuals increase with population density, although this effect usually disappears as increased intraspecific competition occurs. The Allee effect was first written on extensively by its namesake Warder Clyde Allee. From Warder Clyde Allee, American ecologist. From the Wikipedia article: “Allee saw ecologists as ‘social healers’ who were able to provide a naturalistic foundation for ethics through their research” One of the most famous examples of a possible Allee effect involves the passenger pigeon (Ectopistes migratorius).