Many people’s well-being is improved by biodiversity. For example, commercial and recreational fishers benefit from well-maintained fish populations; indigenous communities benefit from cultural, spiritual, and subsistence practices connected to the natural environment; tourists and recreationists benefit from enhanced bird-watching and other wildlife opportunities; and students benefit from environmental education opportunities.

Individual actions can change biodiversity. For example, boaters can unintentionally transport invasive species — non-native plants, animals, or pathogens that cause harm to natural areas — leading to negative impacts. When invasives attach to boats and boat trailers that are then moved from one body of water to another, the invasives move as well. Once invasives enter a water body, they can compete with native species and change the ecological balance.

Biodiversity can be measured in many ways, including observing how the number of species change over time. Biodiversity can also be measured through multiple indicators (for example, species richness and species distribution); the presence of an indicator species; rare/threatened/endangered species status and location; genetic diversity; and overall habitat preservation/acreage protection.

When biodiversity changes, it can impact many ecosystem benefits. Some examples are:

• Recreationists − people who enjoy bird-watching, wildlife viewing, and nature photography, for example − have the quality of their experience reduced when the diversity, richness, and abundance of flora, fauna, and fungi declines.
• Indigenous people and others − biodiversity can impact people’s health by reducing current and potential future medicines. A plant species may have cultural or subsistence properties for indigenous people, or undiscovered medicinal properties.
• Fishers and aquaculturists are impacted by habitat biodiversity changes that lead to declines in fish stocks and seafood resources.
  

Because biodiversity is complex, its value is derived through specific measures. Quantitative, non-monetary indicators of biodiversity are designed to measure the variety and number of species, genes, ecosystems, or ecosystem functioning. Tracking these measures over time can show how biodiversity is changing.

Policy makers can use cost-benefit analysis to understand which projects provide the most biodiversity benefit. Value can also be observed through ecosystem program payments, as these programs compensate landowners for providing biodiversity through ecosystem maintenance. Economists have used various methods to assign monetary values for biodiversity, including actual expenditures, revealed preferences (hedonic, travel cost), stated preferences (contingent valuation, conjoint analysis), replacement costs, experimental cash market value, and meta-analyses.