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Desert grasslands, which are very sensitive to external drivers like climate change, are areas affected by rapid land degradation processes. In many regions of the world the common form of land degradation involves the rapid encroachment of woody plants into desert grasslands. This process, thought to be irreversible and sustained by biophysical feedbacks of global desertification, results in the heterogeneous distribution of vegetation and soil resources. Most of these shrub-grass transition systems at the desert margins are prone to disturbances such as fires, which affect the interactions between ecological, hydrological, and land surface processes. Here we investigate the effect of prescribed fires on the landscape...
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This dataset is from a restoration field study conducted at seven sites distributed across the southern Colorado Plateau in northern Arizona as part of the RestoreNet dryland restoration field trial network. The data consist of post-experimental restoration treatment (2018-2019) plant density and height measurements along with site precipitation, temperature, and soils data. Plant data were collected through plot monitoring visits distributed throughout the first year following restoration treatments and seeding.
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These data were compiled for a networked field-trial restoration experiment (RestoreNet) that spans the southwestern US, including 21 distributed field sites. The objective of our study was to understand the environmental factors and restoration practices (including seed mixes and soil manipulation) that increase plant establishment and survival to ultimate improve restoration outcomes in dryland environments. These data represent point-in-time plant density and height measurements at our field sites at the time of monitoring. These data were collected at 21 arid and semi-arid sites, located throughout Arizona, Utah, New Mexico, and California. These data were collected by USGS Restoration Assessment and Monitoring...
Categories: Data; Tags: Arizona, Botany, California, Chihuahuan Desert, Climatology, All tags...
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These data were compiled using a new multivariate matching algorithm that transfers simulated soil moisture conditions (Bradford et al. 2020) from an original 10-km resolution to a 30-arcsec spatial resolution. Also, these data are a supplement to a previously published journal article (Bradford et al., 2020) and USGS data release (Bradford and Schlaepfer, 2020). The objectives of our study were to (1) characterize geographic patterns in ecological drought under historical climate, (2) quantify the direction and magnitude of projected responses in ecological drought under climate change, (3) identify areas and drought metrics with projected changes that are robust across climate models for a representative set of...
In some arid regions, rehabilitation of whole system N-fixation may be strongly facilitated by the recovery of populations of the lichen genus Collema. Identification of the limits to recovery of Collema in apparently suitable habitat should inform selection of rehabilitation techniques. We simultaneously tested the relative importance of three hypothetical limits to Collema recovery: active erosion, resource limitation, and propagule scarcity. We found that in our experimental system, active erosion had no effect on short-term establishment of Collema, whereas propagule addition did enhance recovery and microhabitat (a resource availability gradient) also exerted a strong influence. It is possible that attempts...
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Biological soil crusts are a diverse soil surface community, prevalent in semiarid regions, which function as ecosystem engineers and perform numerous important ecosystem services. Loss of crusts has been implicated as a factor leading to accelerated soil erosion and other forms of land degradation. To support assessment and monitoring efforts aimed at ensuring the sustainability of rangeland ecosystems, managers require spatially explicit information concerning potential cover and composition of biological soil crusts. We sampled low disturbance sites in Grand Staircase?Escalante National Monument (Utah, USA) to determine the feasibility of modeling the potential cover and composition of biological soil crusts...
This interactive workshop was designed to provide background information and stimulate discussion on the effects of climate variability, possible natural and human-related long-term climate change, and land-use change in the rapidly-growing southwestern United States. This information will be used by the U.S. Global Change Research Program as part of a national assessment of Global Change issues. This web conference was open for interactive participation from Monday, July 7 through Friday, July 25, 1997. The articles and comments will remain available indefinitely.
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Biological soil crusts are an integral part of dryland ecosystems. We monitored the cover of lichens and mosses, cyanobacterial biomass, concentrations of UV-protective pigments in both free-living and lichenized cyanobacteria, and quantum yield in the soil lichen species Collema in an undisturbed Mojave Desert shrubland. During our sampling time, the site received historically high and low levels of precipitation, whereas temperatures were close to normal. Lichen cover, dominated by Collema tenax and C. coccophorum, and moss cover, dominated by Syntrichia caninervis, responded to both increases and decreases in precipitation. This finding for Collema spp. at a hot Mojave Desert site is in contrast to a similar...
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These data were compiled for a restoration experiment testing the regenerative and functional response of biocrust inoculum reintroduced to a field setting. Regenerative traits measured included measurements of biocrust cover, chlorophyll content, and the roughness of the soil surface. Functional traits measured included nutrient cycling and soil stability. Additionally, these data were compiled for an experiment testing how much soil is lost from different types of ground cover. The data collected was related to ground cover and the amount of soil lost from plots through time. These data were used to inform the conclusions drawn in the accompanying manuscript.
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These data were compiled to determine whether transient population dynamics substantially alter population growth rates of sagebrush after disturbance, impede resilience and restoration, and in turn drive ecosystem transformation. Data were collected from 2014-2016 on sagebrush population height distributions at 531 sites across the Great Basin that had burned and were subsequently reseeded by the BLM. These data include field data on sagebrush density in 6 size classes and site attributes (seeding year, sampling year, random site designation, elevation, seeding rate). Also included are modeled spring soil moisture data at each site from the year of seeding to sampling. This data release includes associated software...
Biological soil crusts (biocrusts) cover up to 60–70% of the soil surface in grasslands rehabilitated during the “Grain for Green� project implemented in the hilly Loess Plateau region in 1999. As biocrusts fix nitrogen (N), they are an important part of restoring soil fertility. We measured nitrogenase activity (NA) in biocrusts from sites rehabilitated at six different time periods to estimate 1) the effects of moisture content and temperature on NA in biocrusts of different ages and 2) the potential N contribution from biocrusts to soils and plants in this region. Results show that NA in the biocrusts was mostly controlled by the species composition, as the activity of biocrusts dominated by free-living...
Land degradation in drylands is one of the major environmental issues of the 21st century particularly due to its impact on world food security and environmental quality. Climate change, shifts in vegetation composition, accelerated soil erosion processes, and disturbances have rendered these landscapes susceptible to rapid degradation that has important feedbacks on regional climate and desertification. Even though the role of hydrologic?aeolian erosion and vegetation dynamic processes in accelerating land degradation is well recognized, most studies have concentrated only on the role of one or two of these components, and not on the interactions among all three. Drawing on relevant published studies, here we review...
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Drylands cover 40% of the global terrestrial surface and provide important ecosystem services. While drylands as a whole are expected to increase in distribution and aridity in coming decades, temperature and precipitation forecasts vary by latitude and geographic region suggesting different trajectories for tropical, subtropical, and temperate drylands. Uncertainty in the future of tropical and subtropical drylands is well constrained, whereas soil moisture and ecological droughts, which drive vegetation productivity and composition, remain poorly understood in temperate drylands. Here we show that, over the 21st century, temperate drylands may contract by a third, primarily converting to subtropical drylands,...
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Water cycling and availability exert dominant control over ecological processes and the sustainability of ecosystem services in water - limited ecosystems. Consequently, dryland ecosystems have the potential to be dramatically impacted by hydrologic alterations emerging from global change, notably increasing temperature and altered precipitation patterns. In addition, the possibility of directly manipulating global solar radiation by augmenting stratospheric SO2 is receiving increasing attention as CO2 emissions continue to increase - these manipulations are anticipated to decrease precipitation, a change that may be as influential as temperature increases in dryland ecosystems. We propose to integrate a proven...
Studies to understand, measure, and predict changes in physical and ecological landscapes and how these changes influence landscape stability, ecosystem dynamics, and human communities of American drylands.
Soil evaporation, a critical ecohydrological process in drylands, can exhibit substantial spatio-temporal variation. Spatially, ecohydrological controls of soil evaporation may generally depend on a hierarchical structure spanning from the presence or absence of litter, through canopy patches of woody plants and intercanopy patches separating them, up to the overall vegetation mosaic characterized by density of woody plant cover in the landscape, although assessment of these factors in concert is generally lacking. Temporally, ecohydrological controls can be further complicated by not only seasonal climate, but also phenology, particularly in seasonally deciduous drylands. We experimentally assessed the interactive...
Desert soil surfaces are generally covered with biological soil crusts, a group of organisms dominated by cyanobacteria, lichens, and mosses. Despite their unassuming appearance, these tiny organisms are surprisingly critical to many processes in past and present desert ecosystems and are vital in creating and maintaining fertility of desert soils. They fix both carbon and nitrogen, much of which is leaked to the soils below. They stabilize soils, capture nutrient-rich dust, and can stimulate plant growth. These organisms must tolerate extreme temperatures, drought, and solar radiation, despite having relatively few wet hours for metabolic activity. Under most circumstances, they are extremely vulnerable to climate...
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These data were compiled to understand the responses of dryland ecosystem properties to long-term simulated atmospheric nitrogen deposition. Objective(s) of our study were to uncover any changes in soil biogeochemistry and ecosystem properties to long-term nitrogen amendments. These data represent ecosystem property data compiled over the nine-year history of a nitrogen deposition simulation experiment. These data were collected from three sites representing a gradient of soil texture in Arches National Park. Data collection began in 2013 and continued through 2019, though metrics were collected at a range of intervals within that timeframe. These data were collected by U.S. Geological Survey field technicians using...
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Data was collected to characterize the conditions under which sagebrush occurs after seeding and wildfire in the Great Basin, and used to parameterize models used to explore adaptive seeding approaches. Data includes plot level field data on sagebrush occurrence, density, weather, and soil moisture conditions in the year that seeding after wildfire occurred. Weather data includes both average annual summaries and average weather at 5-day intervals from day 1-250 of the year of seeding. Also included are summaries of annual temperature and soil moisture conditions from 1979 to 2016 and model predictions of the probability of sagebrush establishment in each of these years.
Desert soil surfaces are generally covered with biological soil crusts, a group of organisms dominated by cyanobacteria, lichens, and mosses. Despite their unassuming appearance, these tiny organisms are surprisingly critical to many processes in past and present desert ecosystems and are vital in creating and maintaining fertility of desert soils. They fix both carbon and nitrogen, much of which is leaked to the soils below. They stabilize soils, capture nutrient-rich dust, and can stimulate plant growth. These organisms must tolerate extreme temperatures, drought, and solar radiation, despite having relatively few wet hours for metabolic activity. Under most circumstances, they are extremely vulnerable to climate...
map background search result map search result map Spatial Modeling of Biological Soil Crusts to Support Rangeland Assessment and Monitoring Dynamics of cover, UV-protective pigments, and quantum yield in biological soil crust communities of an undisturbed Mojave Desert shrubland Environmental conditions, covariate data used in model fitting, and long-term establishment predictions from 1979 to 2016 in the Great Basin, USA Erosion and Rehabilitation Data, Bandelier National Monument, New Mexico, USA Demographic modeling data (including code) at various sites in the Great Basin, USA RestoreNet: seedling treatment and site environmental characteristics data at restoration treatment plots in northern Arizona, USA Ecological property data and experimental lab incubation results from a long-term nitrogen deposition simulation experiment in three semi-arid grasslands, Arches National Park, Utah, USA, 2013-2019 High-resolution maps of historical and 21st century ecological drought metrics using multivariate matching algorithms for drylands of western U.S. and Canada RestoreNet subplot data for 21 sites within major dryland ecoregions throughout the southwestern United States, 2018 - 2021 Erosion and Rehabilitation Data, Bandelier National Monument, New Mexico, USA Dynamics of cover, UV-protective pigments, and quantum yield in biological soil crust communities of an undisturbed Mojave Desert shrubland Spatial Modeling of Biological Soil Crusts to Support Rangeland Assessment and Monitoring RestoreNet: seedling treatment and site environmental characteristics data at restoration treatment plots in northern Arizona, USA Demographic modeling data (including code) at various sites in the Great Basin, USA RestoreNet subplot data for 21 sites within major dryland ecoregions throughout the southwestern United States, 2018 - 2021 Environmental conditions, covariate data used in model fitting, and long-term establishment predictions from 1979 to 2016 in the Great Basin, USA High-resolution maps of historical and 21st century ecological drought metrics using multivariate matching algorithms for drylands of western U.S. and Canada