One for the Potential list:
First coined by Gilpin & Soulé in 1986, the extinction vortex is the term used to describe the process that declining populations undergo when”a mutual reinforcement occurs among biotic and abiotic processes that drives population size downward to extinction” (Brook, Sodhi & Bradshaw 2008).
Although several types of ‘vortices’ were labelled by Gilpin & Soulé, the concept was subsequently simplified by Caughley (1994) in his famous paper on the declining and small population paradigms, but only truly quantified for the first time by Fagan & Holmes (2006) in their Ecology Letters paper entitled Quantifying the extinction vortex.
Fagan and Holmes compiled a small time-series database of ten vertebrate species (two mammals, five birds, two reptiles and a fish) whose final extinction was witnessed via monitoring. They confirmed that the time to extinction scales to the logarithm of population size. In other words, as populations decline, the time elapsing before extinction occurs becomes rapidly (exponentially) smaller and smaller. They also found greater rates of population decline nearer to the time of extinction than earlier in the population’s history, confirming the expectation that genetic deterioration contributes to a general corrosion of individual performance (fitness). Finally, they found that the variability in abundance was also highest as populations approached extinction, irrespective of population size, thus demonstrating indirectly that random environmental fluctuations take over to cause the final extinction regardless of what caused the population to decline in the first place.
What does this mean for conservation efforts? It was fundamentally the first empirical demonstration that the theory of accelerating extinction proneness occurs as populations decline, meaning that all attempts must be made to ensure large population sizes if there is any chance of maintaining long-term persistence. This relates to the minimum viable population size concept that should underscore each and every recovery and target set or desired for any population in trouble or under conservation scrutiny.
ConservationBytes.com 
[…] numbers, population fragmentation, inbreeding and reduced genetic variation can lead to a fatal “extinction vortex”. In this sense, our planet is currently accumulating a large extinction debt that must […]
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[…] Low population sizes, few rhinos living close together and the isolation of viable habitats have combined with fatal consequences for the Sumatran rhino. If females don’t regularly mate, they have a tendency to develop uterine cysts and growths. It was this that left Iman infertile. This is what conservation biologists refer to as an “Allee effect”: the lower a population becomes, the less successful individuals become at reproducing. Ultimately, this leads to an extinction vortex. […]
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[…] Small populations, few rhinos live in close contact and the isolation of viable habitats has combined fatal consequences for the Sumatran rhino. If females do not mate regularly, they have a tendency to develop cysts and uterine growths. That was what left Iman barren. This is what conservation biologists refer to an "Allee effect": the lower a population becomes, the less successful individuals reproduce. Ultimately, this leads to a vortex of extinction. […]
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[…] Low population sizes, few rhinos living close together and the isolation of viable habitats have combined with fatal consequences for the Sumatran rhino. If females don’t regularly mate, they have a tendency to develop uterine cysts and growths. It was this that left Iman infertile. This is what conservation biologists refer to as an “Allee effect”: the lower a population becomes, the less successful individuals become at reproducing. Ultimately, this leads to an extinction vortex. […]
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[…] Low population sizes, few rhinos living close together and the isolation of viable habitats have combined with fatal consequences for the Sumatran rhino. If females don’t regularly mate, they have a tendency to develop uterine cysts and growths. It was this that left Iman infertile. This is what conservation biologists refer to as an “Allee effect”: the lower a population becomes, the less successful individuals become at reproducing. Ultimately, this leads to an extinction vortex. […]
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[…] Low population sizes, few rhinos living close together and the isolation of viable habitats have combined with fatal consequences for the Sumatran rhino. If females don’t regularly mate, they have a tendency to develop uterine cysts and growths. It was this that left Iman infertile. This is what conservation biologists refer to as an “Allee effect”: the lower a population becomes, the less successful individuals become at reproducing. Ultimately, this leads to an extinction vortex. […]
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[…] Low population sizes, few rhinos living close together and the isolation of viable habitats have combined with fatal consequences for the Sumatran rhino. If females don’t regularly mate, they have a tendency to develop uterine cysts and growths. It was this that left Iman infertile. This is what conservation biologists refer to as an “Allee effect”: the lower a population becomes, the less successful individuals become at reproducing. Ultimately, this leads to an extinction vortex. […]
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[…] Low population sizes, few rhinos living close together and the isolation of viable habitats have combined with fatal consequences for the Sumatran rhino. If females don’t regularly mate, they have a tendency to develop uterine cysts and growths. It was this that left Iman infertile. This is what conservation biologists refer to as an “Allee effect”: the lower a population becomes, the less successful individuals become at reproducing. Ultimately, this leads to an extinction vortex. […]
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[…] Low population sizes, few rhinos living close together and the isolation of viable habitats have combined with fatal consequences for the Sumatran rhino. If females don’t regularly mate, they have a tendency to develop uterine cysts and growths. It was this that left Iman infertile. This is what conservation biologists refer to as an “Allee effect”: the lower a population becomes, the less successful individuals become at reproducing. Ultimately, this leads to an extinction vortex. […]
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[…] go extinct. As strong selection causes the species to dwindle, it enters what is referred to as the ‘extinction vortex’. Without genetic diversity, they can’t adapt: thus, more individuals die off, causing more […]
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[…] numbers, population fragmentation, inbreeding and reduced genetic variation can lead to a fatal “extinction vortex”. In this sense, our planet is currently accumulating a large extinction debt that must […]
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[…] numbers, population fragmentation, inbreeding and reduced genetic variation can lead to a fatal extinction vortex. In this sense, our planet is currently accumulating a large extinction debt that must eventually […]
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[…] numbers, population fragmentation, inbreeding and reduced genetic variation can lead to a fatal extinction vortex. In this sense, our planet is currently accumulating a large extinction debt that must eventually […]
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[…] numbers, population fragmentation, inbreeding and reduced genetic variation can lead to a fatal extinction vortex. In this sense, our planet is currently accumulating a large extinction debt that must eventually […]
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[…] Following population genetic theory, we can make several predictions for the future genetic health of isolated trees. The first is that the genetic diversity of trees inhabiting small isolated fragments will decrease over time, as the pool and diversity of individuals decreases. The second prediction is that individuals inhabiting small isolated patches will become more genetically different from each other over time due to a reduction in the exchange of genes via pollen and seed, a process termed genetic drift. It is this gene exchange, or gene flow, that maintains the genetic connection between individuals and populations. The third prediction is that individuals will become more inbred over time as individuals are forced to mate with related individuals. Remember your cousin living up the street? The key problem with inbreeding is that it can increase the frequency of some maladaptive characters – remember your neighbour with that genetic condition? This reduction in vigour of populations due to inbreeding is known as inbreeding depression. These three forces, loss of genetic diversity, increasing genetic differences and increasing inbreeding, can also interact synergistically to drive the populations inhabiting such genetic ghettos towards an extinction vortex. […]
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[…] numbers, population fragmentation, inbreeding and reduced genetic variation can lead to a fatal “extinction vortex”. In this sense, our planet is currently accumulating a large extinction debt that must […]
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[…] numbers, population fragmentation, inbreeding and reduced genetic variation can lead to a fatal “extinction vortex”. In this sense, our planet is currently accumulating a large extinction debt that must […]
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[…] Extinctions rarely happen instantly, but the conspiracy of declining numbers, population fragmentation, inbreeding and reduced genetic variation can lead to a fatal “extinction vortex“. […]
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[…] numbers, population fragmentation, inbreeding and reduced genetic variation can lead to a fatal “extinction vortex”. In this sense, our planet is currently accumulating a large extinction debt that must […]
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[…] this could make Cheetahs perilously vulnerable to an “extinction vortex”. The vortex starts with a population crash, perhaps from a newly-introduced disease, habitat […]
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[…] be unable to recover naturally as other processes start to take hold. This has since been termed an Extinction Vortex, and it pushes declining populations into greater decline. The point at which it comes into effect […]
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[…] in multiple populations declining, genetic diseases and extinction, related in a concept called the extinction vortex. Coral reefs, as a major part of the world’s oceanic ecosystems, are already stating […]
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I like your extinction vortex graphic – where did you get it?
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[…] Tomando en cuenta que esto se puede aplicar a todos los demás genes y que la interacción entre ellos llega a ser mucho más compleja, estaríamos hablando de mermas en rasgos que participan en la supervivencia o reproducción, resultando en una menor capacidad de adaptarse a los cambios ambientales. A todo esto le sumamos la endogamia que acelera todo este proceso de erosión génica. Como la selección natural opera de manera menos eficiente en poblaciones reducidas, se van acumulando mutaciones desfavorables. Llega un punto donde la población está condenada, cayendo por un círculo vicioso, más bien representado por un espiral, llamado “Vortex de extinción”. […]
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[…] The poor record of species over-exploitation by humans arising from the Tragedy of the Commons (Hardin 1968) is compounded by this new information. This anthropogenic Allee effect (Courchamp et al. 2006) provides a novel example mechanism for how small populations are driven ever-downward because low densities ensure declining fitness. Many species may follow the same general rules, from bluefin tuna, Napoleon wrasse lips and shark fins, to reptile skins and Tibetan antelope woollen shawls. Gault and colleagues warn that as the human population continues to expand and more people enter the luxury-goods market, more wildlife species will succumb to this Allee effect-driven extinction vortex. […]
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See also http://www.mongabay.com/09vortex.htm and http://en.wikipedia.org/wiki/Extinction_vortex
CJA Bradshaw
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