The millenium ark: How long a voyage, how many staterooms, how many passengers?

Abstract

Barring holocausts, demographic forecasts suggest a "demographic winter" lasting 500-1,OOO years and eliminating most habitat for wildlife in the tropics. About 2,000 species of large, terrestrial animals may have to be captively bred if they are to be saved from extinction by the mushrooming human population. Improvements in biotechnology may facilitate the task of protecting these species, but it probably will be decades at least before cryotechnology per se is a viable alternative to captive breeding for most species of endangered wildlife. We suggest that a principle goal of captive breeding be the maintenance of 90% of the genetic variation in the source (wild) population over a period of 200 years. Tables are provided that permit the estimation of the ultimate minimum size of the captive group, given knowledge of the exponential growth rate of the group, and the number of founders. In most cases, founder groups will have to be above 20 (effective) individuals.

Genetic Effects of a Persistent Bottleneck on a Natural Population of Ornate Box Turtles (Terrapene ornata)

“…Based on the actual allele frequencies, the IL population would retain about 71% of the observed number of alleles and 92% of the observed heterozygosity if its population size remained constant at 75 for the next 200 years. In order to achieve the conservation recommendation of maintaining 90% of genetic diversity for a 200-year period (Soule et al 1986), the population size would need to be increased to approximately 300.…”

“…Our simulation results demonstrated that the IL population would lose 30% of its observed number of alleles in the next 200 years if the population size remained at 75 (Table 3). To maintain 90% of the observed number of alleles over a 200-year period, as recommended by Soule et al (1986), a population size of 300 is required. One cautionary finding of our simulation study is that only 150 individuals are required to maintain the same level of genetic diversity under a traditional discrete-generation model ( Table 3).…”

Valuing Species: The Continuities between Non-Market and Market Valuations in Biodiversity Conservation

“…It is not that genes and ecosystems don't garner significant attention as loci of value in biodiversity conservation, but rather that value at these levels is often calibrated in relation to the value of relevant species categories. This is apparent in the case of genetic diversity, which is valued in biodiversity conservation to the degree that it is useful for propagating valued species (Friese 2015), a point underlined by the framing of the value of preserving diverse genetic types in living populations or frozen 'gene banks' as an 'insurance policy' for endangered species (Soulé et al 1986). Ecosystems, meanwhile, are increasingly being valued for the 'services' they provide for human society and economy (see Helm 2015).…”

Microsatellite variability reveals significant genetic differentiation of giant pandas (Ailuropoda melanoleuca) in the Minshan A habitat

“…It is very difficult for small isolated populations to maintain long-term survival even though excellent habitat or few human disturbances occur (Pimm and Raven, 2000;Loucks et al, 2001;Zhang et al, 2002;Yang et al, 2007). Currently, although a series of steps has been carried out to expand panda habitats and prompt the linkages between the protected areas (Soule et al, 1986;Xiao et al, 2008), the ecological degradation of panda habitats continues to worsen (Liu et al, 2001;Lü et al, 2001;Xiao et al, 2008).…”