The USDA Farm Service Agency (FSA) is contracting with the STRIPS team to evaluate the performance of prairie strips in comparison to traditional filter and buffer strip implementations supported by the Conservation Reserve Program (CRP).
Under CRP, environmentally sensitive cropland is replaced with native and non-native grasses, trees, restored wetlands, riparian buffers, and grass filters. It is well established that whole crop fields converted into grass, trees, and wetlands types provide multiple benefits including improved water quality, reduced erosion, the creation of habitats for wildlife species including pollinators and grassland birds. Less information is available quantifying the benefits of individual practices such as contour strips and converting smaller, more sensitive portions of fields -- as supported by through continuous CRP. This information is needed to examine whether similar benefits can be provided at a lower cost over the long term.
Under continuous CRP, filter strips and contour strips can be placed to intercept water flow, reduce erosion and trap sediment and nutrients before they reach rivers, streams and lakes. Typically, these conservation features are planted to a monoculture of non-native grasses, such as smooth brome, because they are easy to establish, good at covering and protecting the soil, and grow quickly so they are able to keep out weeds. Instead using native grasses and forbs (i.e., wild flowers) in these locations -- such as with prairie strips -- has the potential to offer greater levels of benefits, but thus far there are no field-level comparisons of monocultural grasses and diverse native plantings in the Midwest. Adding prairie back to the Midwestern landscape is of particular interest because of the sharp decline observed in pollinator and grassland bird populations over recent decades.
FSA support is supplementing STRIPS monitoring efforts to quantify how filter and contour buffer strips implemented with different levels of plant diversity impact erosion, nutrients leaving a field, pollinator populations, and bird populations, including evaluation of bird nest success. New commercial farm implementations of prairie strips are compared to existing CRP filter and contour buffer strips. For more information on the status of this effort listen to an FSA hosted webinar on using prairie strips for Blurring the Lines between Working and Conservation Lands featuring investigators Matt Helmers, Mary Harris, and Lisa Schulte Moore, presented in May 2017. A summary of this work can be found here. You can also download and review our most recent progress reports for more information:
- Evaluation of Current USDA Contour Buffer and Filter Strip Designs as Resources for Pollinators and for Meeting Water Quality Improvement Goals in Iowa, Contract # AG-3151-C-0041
- Estimating the Effect of the Conservation Reserve Program (CRP) Contour Strips on Grassland Birds, Contract # AG‐3151‐P‐14‐0065. For more information, see this presentation delivered at the Midwest Fish and Wildlife Conference in January, 2018, and this presentation delivered at the American Ornithology Society in April, 2018.
- Evaluation of Water Quality Benefits of Prairie Strips in Iowa, Contract # AG-3151-P-16-0255
Publications from this work have thus far included:
- Moorhouse, A. 2016. Evaluation of CRP contour buffer and filter strips as habitat for native bees and predatory ground beetles. MS Thesis, Iowa State University, Ames, Iowa.
- Schwarze-Martin, A. 2017. Extending removal and distance-removal models for abundance estimation by modeling detections in continuous time. PhD Dissertation, Iowa State University, Ames, Iowa.
- Stephenson, M.D. 2017. Quantifying methods to improve statistical power in grassland and passerine bird nesting studies. MS Thesis, Iowa State University, Ames, Iowa.