264 research outputs found

    Ecohydrologic Impacts of Rangeland Fire on Runoff and Erosion: A Literature Synthesis

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    Fire can dramatically influence rangeland hydrology and erosion by altering ecohydrologic relationships. This synthesis presents an ecohydrologic perspective on the effects of fire on rangeland runoff and erosion through a review of scientific literature spanning many decades. The objectives are: (1) to introduce rangeland hydrology and erosion concepts necessary for understanding hydrologic impacts of fire; (2) to describe how climate, vegetation, and soils affect rangeland hydrology and erosion; and (3) to use examples from literature to illustrate how fire interacts with key ecohydrologic relationships. The synthesis is intended to provide a useful reference and conceptual framework for understanding and evaluating impacts of fire on rangeland runoff and erosion

    Hydrologic and Erosion Responses to Wildfire Along the Rangeland-Xeric Forest Continuum in the Western US: A Review and Model of Hydrologic Vulnerability

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    The recent increase in wildfire activity across the rangeland–xeric forest continuum in the western United States has landscape-scale consequences in terms of runoff and erosion. Concomitant cheatgrass (Bromus tectorum L.) invasions, plant community transitions and a warming climate in recent decades along grassland–shrubland–woodland–xeric forest transitions have promoted frequent and large wildfires, and continuance of the trend appears likely if warming climate conditions prevail. These changes potentially increase overall hydrologic vulnerability by spatially and temporally increasing soil exposure to runoff and erosion processes. Plot and hillslope-scale studies demonstrate burning may increase event runoff or erosion by factors of 2–40 over small-plot scales and more than 100-fold over large-plot to hillslope scales. Reports of flooding and debris flow events from rangelands and xeric forests following burning show the potential risk to natural resources, property, infrastructure and human life. We present a conceptual model for evaluating post-fire hydrologic vulnerability and risk. We suggest that post-fire risk assessment of potential hydrologic hazards should adopt a probability-based approach that considers varying site susceptibility in conjunction with a range of potential storms and that determines the hydrologic response magnitudes likely to affect values-at-risk. Our review suggests that improved risk assessment requires better understanding in several key areas including quantification of interactions between varying storm intensities and measures of site susceptibility, the varying effects of soil water repellency, and the spatial scaling of post-fire hydrologic response across rangeland–xeric forest plant communities

    Finding sociality in single player games: A case study of tandem play amongst friends and couples

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    Researchers have found that games are sites for rich forms of sociality. However, there has been comparatively less research on sociality facilitated by co-located gameplay focused on single-player games, here termed tandem play. This exploratory case study investigated how known player pairs engaged in turn taking and decision-making behaviors while playing a single-player game together, and also how a narrative-driven video game played over multiple sessions impacted their experience. Initial findings suggest that turn taking was an explicitly negotiated choice, and that decision making power did not necessarily rely on who was holding the controller - player pairs developed their own systems for how they made choices. The narrative and well-known franchise on which the game was based gave pairs a strong base from which to work, building themed playthroughs and systemic approaches for how to treat various characters and situations in game. This research provides further evidence that being social in and around games can be accomplished no matter whether the chosen game is a single or a multiplayer title, and in virtual or physical space

    Enhancing wind erosion monitoring and assessment for U.S. rangelands

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    Wind erosion is a major resource concern for rangeland managers because it can impact soil health, ecosystem structure and function, hydrologic processes, agricultural production, and air quality. Despite its significance, little is known about which landscapes are eroding, by how much, and when. The National Wind Erosion Research Network was established in 2014 to develop tools for monitoring and assessing wind erosion and dust emissions across the United States. The Network, currently consisting of 13 sites, creates opportunities to enhance existing rangeland soil, vegetation, and air quality monitoring programs. Decision-support tools developed by the Network will improve the prediction and management of wind erosion across rangeland ecosystems. © 2017 The Author(s)The Rangelands archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information

    Vegetation, Ground Cover, Soil, Rainfall Simulation, and Overland Flow Experiments Before and After Tree Removal in Woodland-Encroached Sagebrush Steppe: The Hydrology Component of the Sagebrush Steppe Treatment Evaluation Project (SageSTEP)

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    Rainfall simulation and overland-flow experiments enhance understanding of surface hydrology and erosion processes, quantify runoff and erosion rates, and provide valuable data for developing and testing predictive models. We present a unique dataset (1021 experimental plots) of rainfall simulation (1300 plot runs) and overland flow (838 plot runs) experimental plot data paired with measures of vegetation, ground cover, and surface soil physical properties spanning point to hillslope scales. The experimental data were collected at three sloping sagebrush (Artemisia spp.) sites in the Great Basin, USA, each subjected to woodland-encroachment and with conditions representative of intact wooded-shrublands and 1–9 yr following wildfire, prescribed fire, and/or tree cutting and shredding tree-removal treatments. The methodologies applied in data collection and the cross-scale experimental design uniquely provide scale-dependent, separate measures of interrill (rainsplash and sheetflow processes) and concentrated overland-flow runoff and erosion rates along with collective rates for these same processes combined over the patch scale (tens of meters). The dataset provides a valuable source for developing, assessing, and calibrating/validating runoff and erosion models applicable to diverse plant community dynamics with varying vegetation, ground cover, and surface soil conditions. The experimental data advance understanding and quantification of surface hydrologic and erosion processes for the research domain and potentially for other patchy-vegetated rangeland landscapes elsewhere. Lastly, the unique nature of repeated measures spanning numerous treatments and time scales delivers a valuable dataset for examining long-term landscape vegetation, soil, hydrology, and erosion responses to various management actions, land use, and natural disturbances. The dataset is available from the National Agricultural Library at https://data.nal.usda.gov/search/type/dataset (DOI: https://doi.org/10.15482/USDA.ADC/1504518; Pierson et al., 2019)

    Structural and Functional Connectivity as a Driver of Hillslope Erosion Following Disturbance

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    Hydrologic response to rainfall on fragmented or burnt hillslopes is strongly influenced by the ensuing connectivity of runoff and erosion processes. Yet cross-scale process connectivity is seldom evaluated in field studies owing to scale limitations in experimental design. This study quantified surface susceptibility and hydrologic response across point to hillslope scales at two degraded unburnt and burnt woodland sites using rainfall simulation and hydrologic modelling. High runoff (31–47 mm) and erosion (154–1893 g m–2) measured at the patch scale (13 m2) were associated with accumulation of fine-scale (0.5-m2) splash-sheet runoff and sediment and concentrated flow formation through contiguous bare zones (64–85% bare ground). Burning increased the continuity of runoff and sediment availability and yield. Cumulative runoff was consistent across plot scales whereas erosion increased with increasing plot area due to enhanced sediment detachment and transport. Modelled hillslope-scale runoff and erosion reflected measured patch-scale trends and the connectivity of processes and sediment availability. The cross-scale experiments and model predictions indicate the magnitude of hillslope response is governed by rainfall input and connectivity of surface susceptibility, sediment availability, and runoff and erosion processes. The results demonstrate the importance in considering cross-scale structural and functional connectivity when forecasting hydrologic and erosion responses to disturbances

    Hydrologic and Erosion Responses of Sagebrush Steppe Following Juniper Encroachment, Wildfire, and Tree Cutting

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    Extensive woodland expansion in the Great Basin has generated concern regarding ecological impacts of tree encroachment on sagebrush rangelands and strategies for restoring sagebrush steppe. This study used rainfall (0.5 m2 and 13 m2 scales) and concentrated flow simulations and measures of vegetation, ground cover, and soils to investigate hydrologic and erosion impacts of western juniper (Juniperus occidentalis Hook.) encroachment into sagebrush steppe and to evaluate short-term effects of burning and tree cutting on runoff and erosion responses. The overall effects of tree encroachment were a reduction in understory vegetation and formation of highly erodible, bare intercanopy between trees. Runoff and erosion from high-intensity rainfall (102 mm · h‒1, 13 m2 plots) were generally low from unburned areas underneath tree canopies (13 mm and 48 g · m‒2) and were higher from the unburned intercanopy (43 mm and 272 g · m‒2). Intercanopy erosion increased linearly with runoff and exponentially where bare ground exceeded 60%. Erosion from simulated concentrated flow was 15- to 25-fold greater from the unburned intercanopy than unburned tree canopy areas. Severe burning amplified erosion from tree canopy plots by a factor of 20 but had a favorable effect on concentrated flow erosion from the intercanopy. Two years postfire, erosion remained 20-fold greater on burned than unburned tree plots, but concentrated flow erosion from the intercanopy (76% of study area) was reduced by herbaceous recruitment. The results indicate burning may amplify runoff and erosion immediately postfire. However, we infer burning that sustains residual understory cover and stimulates vegetation productivity may provide long-term reduction of soil loss relative to woodland persistence. Simply placing cut-downed trees into the unburned intercanopy had minimal immediate impact on infiltration and soil loss. Results suggest cut-tree treatments should focus on establishing tree debris contact with the soil surface if treatments are expected to reduce short-term soil loss during the postcut understory recruitment period
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