Geology topics

Charles A. Rewa

Publications and source records attributed to Charles A. Rewa.

3 recordsLinked to original sources

USGS2017

Assessing pollinator habitat services to optimize conservation programs

Pollination services have received increased attention over the past several years, and protecting foraging area is beginning to be reflected in conservation policy. This case study considers the prospects for doing so in a more analytically rigorous manner, by quantifying the pollination services for sites being considered for ecological restoration. The specific policy context is the Conservation Reserve Program (CRP), which offers financial and technical assistance to landowners seeking to convert sensitive cropland back to some semblance of the prairie (or, to a lesser extent, forest or wetland) ecosystem that preceded it. Depending on the mix of grasses and wildflowers that are established, CRP enrollments can provide pollinator habitat. Further, depending on their location, they will generate related services, such as biological control of crop pests, recreation, and aesthetics. While offers to enroll in CRP compete based on cost and some anticipated benefits, the eligibility and ranking criteria do not reflect these services to a meaningful degree. Therefore, we develop a conceptual value diagram to identify the sequence of steps and associated models and data necessary to quantify the full range of services, and find that critical data gaps, some of which are artifacts of policy, preclude the application of benefit-relevant indicators (BRIs) or monetization. However, we also find that there is considerable research activity underway to fill these gaps. In addition, a modeling framework has been developed that can estimate field-level effects on services as a function of landscape context. The approach is inherently scalable and not limited in geographic scope, which is essential for a program with a national footprint. The parameters in this framework are sufficiently straightforward that expert judgment could be applied as a stopgap approach until empirically derived estimates are available. While monetization of benefit-relevant indicators of yield changes (crop and honey) and of habitat benefits due to enhanced pollination and pest bio-control services would be relatively straightforward, the merits of proceeding when other services cannot be valued now should be carefully considered.

Report↗

USGS2016

Western Lake Erie Basin: Soft-data-constrained, NHDPlus resolution watershed modeling and exploration of applicable conservation scenarios

Complex watershed simulation models are powerful tools that can help scientists and policy-makers address challenging topics, such as land use management and water security. In the Western Lake Erie Basin (WLEB), complex hydrological models have been applied at various scales to help describe relationships between land use and water, nutrient, and sediment dynamics. This manuscript evaluated the capacity of the current Soil and Water Assessment Tool (SWAT2012) to predict hydrological and water quality processes within WLEB at the finest resolution watershed boundary unit (NHDPlus) along with the current conditions and conservation scenarios. The process based SWAT model was capable of the fine-scale computation and complex routing used in this project, as indicated by measured data at five gaging stations. The level of detail required for fine-scale spatial simulation made the use of both hard and soft data necessary in model calibration, alongside other model adaptations. Limitations to the model's predictive capacity were due to a paucity of data in the region at the NHDPlus scale rather than due to SWAT functionality. Results of treatment scenarios demonstrate variable effects of structural practices and nutrient management on sediment and nutrient loss dynamics. Targeting treatment to acres with critical outstanding conservation needs provides the largest return on investment in terms of nutrient loss reduction per dollar spent, relative to treating acres with lower inherent nutrient loss vulnerabilities. Importantly, this research raises considerations about use of models to guide land management decisions at very fine spatial scales. Decision makers using these results should be aware of data limitations that hinder fine-scale model interpretation.

Lake Erie Basin↗

USGS2011

Changes in historical Iowa land cover as context for assessing the environmental benefits of current and future conservation efforts on agricultural lands

Conservationists and agriculturists face unprecedented challenges trying to minimize tradeoffs between increasing demands for food, fiber, feed, and biofuels and the resulting loss or reduced values of other ecosystem services, such as those derived from wetlands and biodiversity (Millennium Ecosystem Assessment 2005a, 2005c; Maresch et al. 2008). The Food, Conservation, and Energy Act of 2008 (Pub. L. 110-234, Stat. 923, HR 2419, also known as the 2008 Farm Bill) reauthorized the USDA to provide financial incentives for agricultural producers to reduce environmental impacts via multiple conservation programs. Two prominent programs, the Wetlands Reserve Program (WRP) and the Conservation Reserve Program (CRP), provide incentives for producers to retire environmentally sensitive croplands, minimize erosion, improve water quality, restore wetlands, and provide wildlife habitat (USDA FSA 2008a, 2008b; USDA NRCS 2002). Other conservation programs (e.g., Environmental Quality Incentives Program, Conservation Stewardship Program) provide incentives to implement structural and cultural conservation practices to improve the environmental performance of working agricultural lands. Through its Conservation Effects Assessment Project, USDA is supporting evaluation of the environmental benefits obtained from the public investment in conservation programs and practices to inform decisions on where further investments are warranted (Duriancik et al. 2008; Zinn 1997).

Iowa↗