Biodiversity is defined by the CBD as:
the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems.Article 2, Convention on Biological Diversity
Countries that have signed the CBD are required to implement policies that protect biodiversity at a variety of levels, principally:
- Ecosystems with rich biodiversity, large numbers of threatened or endemic species, that are important for migrating species; have social, economic, cultural or scientific significance, or support key processes such as evolutionary processes
- Species and communities of species that are threatened, related to domesticated or cultivated species, have medicinal, agricultural, or other economic, social, cultural or scientific significance, and indicator species
- Genotypes with social, scientific or economic significance
Image © Jeremy Barker
Biodiversity is of great importance to humans, not least for the following reasons:
- It is a source of harvestable goods include food, medicines and building materials;
- It is essential for regulation of natural processes and the earth's life support systems; e.g. carbon sequestration, soil formation, purification of water
- It is essential for pollination of commercially valuable crops, biological control of pests and diseases
- It is a source of spiritual and religious enrichment and wellbeing.
- It is the basis for evolution and adaptation to changing environments, making it essential for survival of life.
Biodiversity values include:
- Economic values: biodiversity goods and products are sold for income or used as inputs to other economic activities, for example ecotourism. Replacement or substitution of the services provided by biodiversity (e.g. engineered flood defence to replace coastal protection by dunes or mangroves) often requires large financial investment.
- Social values: employment, health, quality of life, social security, appreciation
- Instrinsic values: the anthropocentric or utilitarian view is that biodiversity has no value except insofar as it has currently recognised benefits for people (including the appreciation of the very existence of biodiversity). The non-utilitarian philosophy is that biodiversity has intrinsic value in its own right, irrespective of its contribution to human wellbeing. Both views are used in political decision-making and should be respected in IA.
Biodiversity is generally considered to be under threat from human activities, with certain issues identified as being of particular concern:
- Decline in ecosystem services required for human-well-being (consider the impact of the loss of pollinators, for example [1]
- Impact on the poorest and failure to attain MDGs
- Loss of resilience
- Loss of unique species & habitats
- Continuing and universal decline
These problems are driven directly and indirectly by human development, key causes being:
- Direct drivers:
- Habitat conversion
- Climate change
- Invasive species
- Over-exploitation
- Pollution (nitrogen and phosphorus)
- Indirect drivers:
- Economic activity
- Demographics (population growth)
- Social and political factors
- Cultural and religious factors
Ecosystems are of critical importance for biodiversity conservation. The function of an ecosystem both supports and is supported by its biodiversity components - a wetland cannot function without plants to take up nutrients and animals and bacteria to release nutrients. Whatever we do, our activities have some impact on the functionality of the ecosystems around us, to a greater or lesser degree. Because of this, it is essential to consider the potential impacts of a proposed development on the ecosystems that come under it's footprint.