The gap between what we measure and what we want to know about ecosystem services in streams to link to human values

Background/Question/Methods

We evaluate national stream monitoring data based on its capacity to link stream ecosystems to analyses of human well-being. As a nation we invest substantially in monitoring, but may miss opportunities to collect information that effectively connect ecosystems with benefits studies. Further, appropriately defined biophysical information could help communicate stream status for broad audiences, and may contribute to a Green GDP. We base our analysis on “Final Ecosystem Goods and Services” (FEGS). This conceptual construct views ecosystems as systems of production. An ecological production function links changes in stressors to changes in FEGS.   FEGS are defined as ecological features people perceive as being directly relevant to their welfare, as opposed to the larger set of essential intermediate ecological processes and features on which the FEGS depend.   We identified metrics of FEGS for streams in a multidisciplinary workshop (http://www.epa.gov/nheerl/arm/streameco/index.html). We compare the workshop listing of FEGS to the available stream metrics of national extent.  Our evaluation focuses not only on metrics, but also on their representation in time and space.   We present a specific example of our gap analysis for recreational angling, and also provide more general conclusions examining other beneficiaries.

Results/Conclusions

For recreational anglers, FEGS entail 1) Something about the fish: presence and abundance of recreationally relevant fish, taxa and sizes, and 2) Something about the fishing site: overall sensory appeal.   Nationally consistent and representative data for fish assemblages use a sample of  fish collected during summer low flow.  If these data represent recreational fish, then the current biophysical data collection suffices. Nationally available stream data also include a measure of site appeal. If a fish sample taken during summer low flow represents the presence of recreationally relevant fish at other seasons, then the temporal character of the data is sufficient. Considering spatial representation, national monitoring samples are spatially dispersed, approximately one sample site for every 1,000 km of stream. Thus, the data provide no crucial information on local scarcity.   Looking beyond this example, we identify gaps in information for other beneficiaries. Notably, in our coarse screen, the gap is often a temporal or spatial one, rather than a biophysical one. Such gaps may be addressed by modeling rather than by monitoring. Last, we note other gaps such as the quality of the characterization of the location and extent of the nation’s perennial streams.