3 Biodiversity and Conservation
Learn how biodiversity and species diversity are described, how ecosystems benefit people, which pressures threaten biodiversity, and how conservation approaches protect and restore nature.
and
encompasses variation within species, among species, and among ecosystems. describes both the kinds of species in a community and how evenly individuals are distributed among them.
is the number of species in a community. Two communities can have the same but differ in : a community dominated by one species is less even than one in which individuals are more evenly distributed.
For example, a forest containing many native tree, insect, bird, and fungi species has greater than a plantation containing mostly one tree species. Diversity can help an ecological community withstand disturbances because, if one species declines, others may continue performing similar ecological roles. The degree of this resilience depends on the species and ecosystem involved; does not guarantee that an ecosystem will resist every change.
are benefits people receive from ecosystems. They are commonly grouped into four categories:
: Goods such as food, fresh water, timber, and medicines.
: Processes such as pollination, water purification, flood reduction, and climate regulation.
: Recreational, spiritual, educational, and aesthetic benefits.
: Underlying processes, including nutrient cycling and soil formation, that help ecosystems function and sustain other services.
A wetland, for example, can provide habitat for diverse species, store floodwater, filter some pollutants, and offer opportunities for recreation. These benefits depend on ecological relationships and ecosystem condition, not simply on the presence of one species.
Threats to
The major direct pressures on include:
Land- and sea-use change: Habitat loss, degradation, and fragmentation, such as when forests are cleared or wetlands are drained.
Direct exploitation: Harvesting or capturing organisms faster than populations can recover.
Climate change: Shifts in temperature, rainfall, ocean conditions, and extreme events that alter habitats and species’ ranges.
Pollution: Contaminants, excess nutrients, plastics, and other pollutants that harm organisms or disrupt ecosystem processes.
: Organisms introduced beyond their natural range that can spread and harm native species or ecosystems.
These pressures can interact. For instance, fragmented habitat may make it harder for a species to move as the climate changes. Underlying causes of the pressures can include patterns of production and consumption, economic incentives, technology, and governance.
Approaches and Trade-offs
protects and maintains or restores the ecosystems and ecological processes on which it depends. Effective approaches often combine several methods:
Protect habitats in place through protected areas and other effective measures.
Connect and restore habitats so populations can persist, move, and recover.
Use natural resources sustainably, keeping harvest and land use within ecological limits.
Reduce pressures such as pollution, habitat destruction, and the spread of invasive species.
Support species recovery, including carefully managed breeding or seed storage when needed.
Include local and Indigenous communities in decisions that affect their lands, knowledge, livelihoods, and resources.
A plan should consider both species and the broader ecosystem. Protecting a species without addressing habitat change or other pressures affecting it may not be enough. decisions can involve trade-offs: choices about land, water, and resource use can affect both human communities and nature. Planning should therefore consider ecological evidence and people’s needs.
Key Connections
includes both the number of species and their relative abundance. supports such as food, clean water, flood regulation, and benefits. Habitat change, overexploitation, climate change, pollution, and are major pressures on . protects and restores habitats, reduces these pressures, promotes sustainable use, and involves the people affected by decisions.