USDA conservation program and practice effects on wetland ecosystem services

Abstract. Implementation of the U.S. Department of Agriculture (USDA) Conservation Reserve Program (CRP) and Wetlands Reserve Program (WRP) has resulted in the restoration of .2 million ha of wetland and grassland habitats in the Prairie Pothole Region (PPR). Restoration of habitats through these programs provides diverse ecosystem services to society, but few investigators have evaluated the environmental benefits achieved by these programs. We describe changes in wetland processes, functions, and ecosystem services that occur when wetlands and adjacent uplands on agricultural lands are restored through Farm Bill conservation programs. At the scale of wetland catchments, projects have had positive impacts on water storage, reduction in sedimentation and nutrient loading, plant biodiversity, carbon sequestration, and wildlife habitat. However, lack of information on the geographic location of restored catchments relative to landscape-level factors (e.g., watershed, proximity to rivers and lakes) limits interpretation of ecosystem services that operate at multiple scales such as floodwater retention, water quality improvement, and wildlife habitat suitability. Considerable opportunity exists for the USDA to incorporate important landscape factors to better target conservation practices and programs to optimize diverse ecosystem services. Restoration of hydrologic processes within wetlands (e.g., hydroperiod, water level dynamics) also requires a better understanding of the influence of conservation cover composition and structure, and management practices that occur in uplands surrounding wetlands. Although conservation programs have enhanced delivery of ecosystem services in the PPR, the use of programs to provide long-term critical ecosystem services is uncertain because when contracts (especially CRP) expire, economic incentives may favor conversion of land to crop production, rather than reenrollment. As demands for agricultural products (food, fiber, biofuel) increase, Farm Bill conservation programs will become increasingly important to ensure provisioning of ecosystem services to society, especially in agriculturally dominated landscapes. Thus, continued development and support for conservation programs legislated through the Farm Bill will require a more comprehensive understanding of wetland ecological services to better evaluate program achievements relative to conservation goals

13.4.8. Options for Water-level Control in Developed Wetlands

Wetland habitats in the United States currently are lost at a rate of 260,000 acres /year (105,218 ha/year). Consequently, water birds concentrate in fewer and smaller areas. Such concentrations may deplete food supplies and influence behavior, physiology, and survival. Continued losses increase the importance of sound management of the remaining wetlands because water birds depend on them. Human activities modified the natural hydrology of most remaining wetlands in the conterminous United States, and such hydrologic alterations frequently reduce wetland productivity. The restoration of original wetland functions and productivity often requires the development of water distribution and discharge systems to emulate natural hydrologic regimes. Construction of levees and correct placement of control structures and water-delivery and water-discharge systems are necessary to (1) create soil and water conditions for the germination of desirable plants, (2) control nuisance vegetation, (3) promote the production of invertebrates, and (4) make foods available for wildlife that depends on wetlands (Leaflets 13.2.1 and 13.4.6). This paper provides basic guidelines for the design of wetlands that benefit wildlife. If biological considerations are not incorporated into such designs, the capability of managing wetlands for water birds is reduced and costs often are greater. Although we address the development of palustrine wetlands in migration and wintering areas, many of the discussed principles are applicable to the development of other wetland types and in other locations

The Wetland Continuum: A Conceptual Framework for Interpreting Biological Studies

We describe a conceptual model, the wetland continuum, which allows wetland managers, scientists, and ecologists to consider simultaneously the influence of climate and hydrologic setting on wetland biological communities. Although multidimensional, the wetland continuum is most easily represented as a two-dimensional gradient, with ground water and atmospheric water constituting the horizontal and vertical axes, respectively. By locating the position of a wetland on both axes of the continuum, the potential biological expression of the wetland can be predicted at any point in time. The model provides a framework useful in the organization and interpretation of biological data from wetlands by incorporating the dynamic changes these systems undergo as a result of normal climatic variation rather than placing them into static categories common to many wetland classification systems. While we developed this model from the literature available for depressional wetlands in the prairie pothole region of North America, we believe the concept has application to wetlands in many other geographic locations