The survival of bird populations is threatened by habitat loss, with a reduction in plants and insects numbers. Habitat protection and restoration is often a key requirement in the conservation of bird species.

There has been a major shift of emphasis of zoos from recreation to conservation. Information gathered through research undertaken at zoos assists in conservation and management decisions. Captive breeding programmes conducted in zoological parks produce individuals for release into the wild in reintroduction programmes, so boosting wild populations.

Streams, lakes and oceans exist in a fragile balance. Predators maintain the population of the species they prey upon at the level which the environment can support. If humans are to harvest from these ecosystem, the effect of removing animals from the ecosystem must be understood.

Invertebrates have suffered a lack of attention from conservation professionals and the general public in the past. Scientists, however, are gaining a better understanding of the role of invertebrates in natural systems and the need to protect them. Habitat loss is one of the main threats to invertebrate populations. Over collecting of some invertebrate groups, such as beetles and butterflies, can also pose a threat.

Many species of mammals have undergone a decline in distribution and population size over the last few decades, due to habitat loss and fragmentation. Mammals often attract more public interest than other groups of animals, due to the larger species such as elephants and the big cats. There are, however, many small, inconspicuous mammals also in need of conservation.

All life depends on plants. Threats to plant communities range from the destruction of large areas of trees through logging, to pollution from fertilisers, car exhausts, factory emissions and sewage. Increased fertility as a result of fertiliser pollution and nitrogen deposition results in a decline in the diversity of plant species with vegetation becoming increasingly dominated by fewer, more competitive species

Over the last few decades, many reptiles and amphibians have declined in numbers, with some species becoming extinct. These declines are often attributable to human activity such as deforestation, draining of wetlands, and pollution.

Many biologically rich areas are essential resources for local people. Habitat and species conservation and the needs of local people cannot be addressed separately, as this may lead to poverty, resentment and lack of co-operation by locals. Linking biodiversity conservation with people's needs, through sustainable development, involves the combining of environmental stewardship with economic development and providing for the needs of local people.