3.3 Conservation and regenerationIB Environmental Systems and Societies SL: Revision notes

Arguments for preservation can be based on five kinds of justification:

• Aesthetic: nature's beauty and inspiration.
• Ecological: species and habitats support ecosystem function and services (pollination, flood regulation, carbon storage).
• Economic: resources, tourism and genetic material for medicines and crops.
• Ethical: species have an intrinsic right to exist, and we have a duty to future generations.
• Social: cultural and recreational value, health and wellbeing, and livelihoods of communities.

Species-based conservation tends to use ex situ strategies (outside the natural habitat): captive breeding in zoos, seed banks, botanic gardens. Example: California condor, 22 birds in 1982, all wild birds captured by 1987 and bred, releases from 1992.

Habitat-based conservation tends to use in situ strategies (within the natural habitat): reserves and national parks.

A mixed approach considers both habitat and particular species, e.g. protecting a reserve while breeding and reintroducing a flagship species.

The Convention on Biological Diversity (CBD) is a UN treaty that addresses both species-based and habitat-based conservation. In 2022 its parties set a target to protect at least 30% of land and sea by 2030.

Habitat conservation protects species by conserving their natural environment. This may need protection of wild areas, or active management (for example controlling invasive species or grazing).

Effective reserves depend on understanding the biology of target species (territory, diet, breeding, migration) and the size and shape of the area:

• Larger reserves support larger populations and more species, and have less edge compared with area.
• A circular shape has the lowest edge-to-area ratio, so less edge effect; long narrow shapes have more edge.
• Corridors connect reserves, allowing gene flow and movement.
• Buffer zones around a core area reduce disturbance.

Rewilding regenerates natural processes in ecosystems, by reducing human management and allowing natural processes, often with the return of grazing animals or missing species. At Knepp Estate (England), 1,400 hectares of former farmland have been allowed to regenerate since 2001 with free-roaming cattle, ponies, pigs and deer; nightingales, turtle doves and purple emperor butterflies now breed there.

Conservation and regeneration measures can be used to reverse biodiversity decline and so keep humanity within a safe operating space for the biodiversity planetary boundary.

Perspectives and value systems affect the strategies a society chooses:

• Ecocentric: intrinsic value of nature; favours protection with minimal intervention, e.g. rewilding.
• Anthropocentric: nature is valued for its use to humans; favours managed use and ecosystem services.
• Technocentric: faith in technology and management; favours active interventions such as captive breeding and monitoring.

Different groups (conservationists, farmers, governments) hold different values, which can cause conflict over land use.