Definition
Ecosystem Services are the benefits provided to people which are derived from the structure and/or function of an ecosystem. They are diverse and include provisioning, regulating, cultural and supporting services. Often taken for granted, an ecosystem service is often identified once it has been removed or threatened.
While many components articulate basic aspects of the system in question, Ecosystem Services are defined by their utility to humans. It is therefore important to consider the beneficiaries of the services (i.e., who potentially benefits from the occurrence of those services) in their designation. Because the potential beneficiaries vary from place to place, ecosystem services vary from place to place. In addition to the direct beneficiaries, ecosystems typically have an “existence value” which is the value to society due to the presence of the ecosystem.
Representative Components
There a many varied examples we could cite, but popular Ecosystem Services include:
- Groundwater recharge
- Water quality (pollution sequestration, filtration)
- Community benefit (recreational opportunities) – identify community that benefits
- Carbon fixation
- Education
- Natural hazard minimization/reduction
- Food provisioning
Utility
Ecosystem services represent a universal currency that can be used to evaluate across different types of ecosystems. The same service can be provided by different ecosystems. On the other hand, not every service is performed by every ecosystem.
Ecosystem services can be used in an equivalency analysis to determine the amount of out-of-kind mitigation needed for an impact by quantifying the amount of service provided in the impacted area and the proposed mitigation area, and the amount of service “lift” to be provided by the mitigation project. This could be done for a single service, or for a suite of services. If a suite of services is used, there would have to be a method for combining them (e.g., basing the size of the mitigation project on the mean of the service increases, or the lowest service lift).
Assessment of ecosystem services should include identification of the beneficiary humans communities, the characteristics of those human communities (e.g., demographics, composition, density), the ease/ability of the beneficiary community to access the services, and the degree/intensity of the services provided.
Relevance
Ecosystem services represent aspects of natural resources that provide value to people. As such, they may help build support for a mitigation project.
Ecosystem services have not traditionally been included in the analyses of impacts or specification of mitigation. Although mitigation services are discussed fairly extensively in the 2008 Mitigation Rule, they generally are not included in mitigation analyses (Ruhl et al. 2009).
Historic ecosystem losses have often preferentially impacted underserved or underrepresented communities because ecosystem services have not been explicitly considered. Moreover, mitigation banks (the preferred method of compensation under the 2008 mitigation rule) have the potential to concentrate services away from the communities impacted by ecosystem losses. Consideration of ecosystem functions can help remedy this disconnect.
Research Needs & Hurdles
The main hurdle for assessing function is that we rarely observe or measure functions in the field, which would entail experimentation. Instead, we observe indicators or biotic or abiotic features or attributes that are correlated with underlying processes occurring at the site. Furthermore, the relationship between an indicator or set of indicators and an underlying function is often not well understood; in fact, in many cases, it is not linear. Also, in out-of-kind mitigation cases, the functions assessed at a mitigation site might be different in type and degree relative to functions at the impact site. For example, floodplain storage at an impact site with a low-order stream at the top of a watershed would typically be less than a mitigation site located in a high-order stream with well-developed floodplains closer to the outlet of the watershed. As another example, tidal attenuation occurring at a salt marsh impact site would not occur in open water habitat.
Hurdles here are numerous, including:
- Consistent terminology around a standard set of ecosystem functions necessary to produce ecosystem services – relationship between functions and services.
- Structured classification and assessment tools or models that produce quantifiable outcomes of ecosystem services.
- Process for establishing defensible benchmarks, categories, or thresholds
- Process for identifying beneficiaries and relating services to specific community benefits.
- Standard data and metadata formats for inclusion of ES information into tracking systems.
Example/Representative Metrics
Each service will have one or more metrics that could be used to assess it. Some examples discussed included:
- Movement hours per person day (Human mental/physical health)
- Surfing days (e.g. cultural practices, use of resource/area both traditionally and contemporarily)
- fishing/harvest days per year (food production and availability)
- Visitors per year (recreational opportunities/accessibility)
- School visit days (educational opportunities)
- Water Quality (improvement or maintenance; dissolved oxygen, nitrogen concentrations, fecal indicator bacteria concentrations)
- Flood damage reduction
- Storm damage reduction
- Erosion reductionEmployment opportunities
- Disaster protection (classically from floods, storms, and fires)
- Carbon flux (g C m-2 d–1; carbon sequestration)
- Water supply (groundwater recharge)
- Vector-borne/infectious diseases
Please bear with us and please check back very soon…
