Mapping ecosystem services

Ecosystem services can be defined as benefits that humans obtain from ecosystems, and are divided into four categories (Millennium Ecosystem Assessment (Program), 2005), as shown below, which can be evaluated globally. Many ecosystem services have been reduced in the recent past, most notably fisheries, water supply and purification, waste treatment, natural hazard protection, regulation of air quality, regulation of regional and local climate, among others.

Ecosystem services. Adapted from (Millennium Ecosystem Assessment (Program), 2005)

For my thesis I decided to work with ecosystem services instead of biodiversity since not enough georeferenced information was available. I found an assessment of the ecosystem services of the ecosystems on Galapagos Islands that have been evaluated by their trend (improved, improving, mixed or deteriorating) and the importance (high, medium high, medium low and low). After giving these descriptive values a numeric value, and assigning that final value to terrestrial ecosystems on Galapagos, I got the following map as a result.

Note that the orange-red area is the highest value ecosystem - the humid zone, the orange area is the second-highest value - the arid zone, while the pale yellow is the lowest value ecosystem - the transitional zone.

References: Millennium Ecosystem Assessment (Program). (2005). Ecosystems and human well-being: synthesis. Washington, DC: Island Press.