Zoos can play a large role in conserving endangered species by;
1. Conducting research
2. Running captive breeding programmes
3. Reintroducing species into the wild
4. Educating people
Research enables scientists to understand the role of a species in an ecosystem. By understanding the niche, food web, reproductive behaviour, habitat, feeding relationships etc scientists can suggest effective methods of conserving species.
Captive breeding programmes are used to reintroduce species to the wild, build up population numbers and maintain genetic diversity. In a small population many alleles are lost between generations because an individual only passes on 50% of their alleles. E.g.
R = Red, r = white
If the parents only have 2 children and they are both Red (RR) then the r allele has been lost. This is genetic drift and is a big cause of the loss of genetic diversity in an endangered species.
To avoid this studbooks are kept (basically, a family tree for the captive animals) so that only non-related animals are bred with each other. This decreases the change of genetic drift and also decreases the change of genetic disease.
Wild animals are often introduced to captive breeding programmes to avoid these problems
Reintroducing species into the wild has some success, but depends greatly on the species. As a general rule of thumb, the more advanced the species the more difficult reintroduction is. This is because animals need to learn specific behaviours e.g. how to hunt, how to reproduce, how / where to find shelter, group behaviours. Breeding animals in captive environments that mimic the wild has more success because it allows some of these behaviours to be learned in captivity. Feeding the animals in the wild also helps survival rates.
Educating people is essential to conservation. Often just doing something slightly differently will have a big impact on conserving a species e.g. building roads with tunnels under them for badgers.