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Great Basin riparian meadows are highly sensitive to both natural and anthropogenic disturbance. As detailed in earlier chapters, streams in the central Great Basin have a natural tendency to incise due to their geomorphic history (Miller and others 2001, 2004). Anthropogenic disturbances, including overgrazing by livestock, mining activities, and roads in the valley bottoms, have increased both the rate and magnitude of incision (Miller and others 2004; Chambers and Miller 2004). Stream incision within meadow ecosystems alters channel structure and function and causes a decrease in the...

Restoration and management objectives and approaches are most effective when based on an understanding of ecosystem processes and the long- and short-term causes of disturbance (Wohl and others 2005). As detailed in previous chapters, several factors are critical in developing effective management strategies for streams and their associated meadow ecosystems in the central Great Basin. First, many streams and/or valley floors are still responding to a major drought that occurred almost 2000 years BP that stripped the hillslopes of available sediment and resulted in a natural tendency...

Streams and riparian ecosystems are a particularly valuable resource in the arid to semi-arid Great Basin, supplying water for agriculture and domestic uses, forage for livestock, and habitat for diverse aquatic and terrestrial organisms. In upland watersheds of the central Great Basin, many of the streams and riparian ecosystems have been severely degraded (Chambers and Miller 2004b; Chambers and others 2004a). A primary cause of this degradation is ongoing stream incision (downcutting) that occurs during episodic high flow events (Miller and others 2001, 2004). Meadow complexes (areas...

Meadow complexes are located in distinct geomorphic and hydrologic settings that allow groundwater to be at or near the ground surface during at least part of the year. Meadows are manifestations of the subsurface flow system, and their distribution is controlled by factors that cause localized zones of groundwater discharge. Knowledge of the factors that serve as controls on groundwater discharge and formation of meadow complexes is necessary to understand why meadows occur where they do and how anthropogenic activities might affect their persistence and ecological condition. In this...

Three geomorphic processes are of primary concern with respect to the current and future state of wet meadow ecosystems: channel incision, avulsion (the abrupt movement of the channel to a new location on the valley floor), and gully formation. Gully formation often is accompanied by upvalley headcut migration and a phenomenon referred to as "groundwater sapping" that is defined as erosion of bank materials by groundwater flow. In this chapter, we examine the effects of each of these processes on meadow complexes. Although these processes are discussed separately, they are often interconnec...

The hydrologic regime exerts primary control on riparian meadow complexes and is strongly influenced by past and present geomorphic processes; biotic processes; and, in some cases, anthropogenic activities. Thus, it is essential to understand not only the hydrologic processes that operate within meadow complexes but also the interactions of meadow hydrology with other processes that affect these ecosystems. Regional- and watershed-scale analyses have contributed to the understanding and management of meadows. However, investigation of meadow-scale characteristics and processes have shown...

Investigations of geomorphic responses to natural and anthropogenic disturbances have revealed marked differences in the rate, magnitude, and nature by which different watersheds, or components of a given watershed, adjust to perturbations. These differences in response are often characterized using the concept of landform sensitivity. The term sensitivity has been defined by different investigators in different ways. For our purposes, it is defined after Brunsden and Thornes (1979) as “the likelihood that a given change in the controls of the system will produce a sensible, recognizable,...

This report contains the results of a 6-year project conducted by the U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station and U.S. Environmental Protection Agency, Office of Research and Development on stream incision and meadow ecosystem degradation in the central Great Basin. The project included a coarse-scale assessment of 56 different meadows systems coupled with more detailed, fine-scale analyses of six of those meadows. This report presents basic information on the linked geomorphic, hydrologic, and vegetation characteristics of the meadow systems. Then,...

Unsustainable hunting in tropical forests threatens biodiversity and rural livelihoods, yet managing these harvests in remote forests with low scientific capacity and funding is challenging. In response, some conservationists propose managing harvests through spatial management, a system of establishing notake zones where hunting is not allowed. Spatial management was commonly used in customary management and is increasingly used for fisheries management today, but is not yet widely implemented in tropical forests. Through this review, we trace the development of spatial management and...

In the last two decades the exotic plant sickleweed (Falcaria vulgaris Bernh., Apiaceae) has invaded, and come to dominate, large areas of the Fort Pierre National Grassland (FPNG) in central South Dakota, USA. Currently sickleweed is estimated to infest over 3200 ha of FPNG. The purpose of this study was to examine several of the biological and ecological traits that may contribute to the invasiveness of sickleweed in FPNG. Specifically, I researched germination characteristics of sickleweed seed collected from FPNG, the effect of sickleweed on other grassland vegetation in FPNG, and...