Ex-situ strategies

A conservation strategy that entails the removal of germplasm resources (seed, pollen, sperm, individual organisms), from their original habitat or natural environment. Keeping components of biodiversity alive outside of their original habitat or natural environment.

For centuries, gardens, zoos and menageries have been repositories for valuable plants and animals. Botanical gardens, zoological parks and aquariums have a vital role as many plant and animal species face an increasingly threatened and uncertain future in the wild. A new approach is a gene bank and there are two types:

• laboratory gene banks for conservation of sperm
• natural gene bank for conservation of endangered species

At the International Workshop for Core Collections held in Brazil in 1992, it was proposed that in situ or field gene banks should be established for biodiversity conservation areas (e.g. protected areas where traditional agriculture is practised, etc.). These would serve as core collections for plant species associated with individual conservation areas, giving rise to an in situ core collection strategy.

Restoration of species and populations

Reintroduction of captive-bred species is often the justification for many ex situ conservation efforts. Three basic approaches are used to establish a new population of plants and animals:

1. Reintroduction programmes to release captive-bred species back into the wild into an area where they historically inhabited, thus re-populating it. The objective of such programmes is to create a new population in the original environment.
2. Augmentation programs seek to release individuals into an existing population to increase its size and genetic diversity, but this can sometimes result in the introduction of disease and the reduction of genetic fitness of the existing population. It may be necessary where genetic diversity has been severely eroded.
3. Introduction programs establish animal or plant populations outside their historic ranges. This may be appropriate where habitat conditions in historic ranges are severely degraded and the species can no longer survive there. Also where the factor causing the loss of the species is still present, making a reintroduction programme impossible.

Ecosystem and landscape restoration

Restoration ecology is one of the newest and most challenging disciplines in ecology, although some ecological restoration efforts have been going on for decades.

Ecosystem restoration has mainly been practised on extremely degraded sites such as mine sites, spoil heaps and municipal dumps. Frequently, restoration involves the replacement of the plant community, generally by plantings and taking care of perennial species in the hope that fauna will return. Increasing efforts are also being made to re-establish animal and soil communities as part of the reintroduction process.

Landscape restoration aims at improving the design of the existing system by increasing the habitat area and connectivity and by providing buffer zones around existing fragments to protect them from external influences.

The aim is to produce a landscape with elements of the remaining natural ecosystems interspersed with restored ecosystems that fulfil some conservation objectives, and production systems that are sustainable and do not compromise the long-term persistence of the conservation areas. Landscape restoration has to consider the many characteristics of natural landscapes that may have conservation significance.