The Importance of Biodiversity

Biodiversity matters for several connected reasons. The detailed ethical and economic arguments are covered in later lessons; this lesson gives the overview.1. Ecosystem stability. In a diverse ecosystem, each species interacts with many others through food webs, pollination and nutrient cycling. If one species declines, others can take over its role, so the ecosystem is more stable and recovers better from disturbance such as disease, drought or climate change. A community with few species is more easily disrupted. For example, a large monoculture crop can be wiped out by a single pest or disease.2. Genetic resources. High genetic diversity within a species gives it a better chance of surviving environmental change, because some individuals are likely to have alleles that suit the new conditions. Wild relatives of crop plants carry alleles, such as those for disease resistance and drought tolerance, that can be bred into crops.3. Resources for humans. Organisms provide food, timber, fibres and fuel. Many medicines come from living things: aspirin was developed from a chemical in willow bark, and vincristine, a drug used to treat childhood leukaemia, comes from the Madagascar periwinkle. Many species that could provide new medicines have not yet been studied.4. Ecosystem services and wellbeing. Ecosystems purify water, form soil, pollinate crops and regulate climate. People also value wildlife for enjoyment, recreation and tourism.5. Ethical reasons. Many people believe every species has a right to exist and that humans have a duty to protect it.When a species becomes extinct, all these benefits are lost permanently.