This website is on nominally and practically about bird life, but is also more broadly about the health of the planet where birds live.  This is a great resource on how to value the services that ecosystems provide.  Click the banner above to go to the source:

Ecosystem services are the benefits we receive from nature, such as provision of crops or medicinal plants, the control of pests (), the regulation of climate, the reduction of flood risk (), and opportunities for cultural, spiritual and recreational experiences. Some ecosystem services result in ‘goods’ (see Figure), such as crops, which are market-based and so are easy to measure and value. However, others are non-market based, such as benefits to physical and mental health (), and therefore often go unrecognised, being overlooked and undervalued in decision-making ().

The conceptual framework illustrated below is from the same site.