Streamside forests reduce nutrient pollution of aquatic ecosystems Donald E. Weller, Thomas E. Jordan, and Matthew E. Baker Smithsonian Environmental Research Center

Ecosystem services Terrestrial –Wildlife habitat –Carbon sequestration –Forest products Aquatic –Aquatic food chain –Control temperature –Pollutant regulation –Nutrient removal

Field studies of nitrogen removal

Distance from field toward stream (m) Nitrate concentration (mg N/l) Mid-Atlantic removal results

National stream and river restoration Riparian restorations > 20,000 projects > $5 billion

Buffer prevalence varies widely

Problems “scaling up”... Watershed results mixed Transect results striking ?

(Mal)adaptive management Knowledge Evaluation Measurement Implementation

Overlay sources and streams on elevation Identify downhill transport pathways transport pathway for 1 pixel Quantify width & aggregate paths Well- buffered pathway Not so well-buffered New geographic analysis sources flowpaths sinks

Prioritizing management efforts

Chesapeake Bay example  321 watersheds  3 physiographic provinces  focus on cropland and buffers  empirical models for stream nitrate

Benefits differ among regions Stream Nutrient Levels <no buffers <current buffers <complete buffer <no cropland

Overall reductions 16% 32% 68%

Policy implications Protect riparian areas –Conserve existing forest buffers –Restore missing forest buffers Outreach and education Focus incentive funding –Regional targeting –Site level targeting Implement adaptive management –Improve models for estimating benefits –Measure outcomes