Filters: Tags: Soil moisture (X) > Types: Journal Citation (X)
16 results (26ms)
Filters
Date Range
Extensions Types Contacts Categories |
This research investigates the interannual variability of soil moisture as related to large-scale climate variability and also evaluates the spatial and temporal variability of modeled deep layer (40?140 cm) soil moisture in the Upper Colorado River Basin (UCRB). A three layers hydrological model VIC-3L (Variable Infiltration Capacity Model ? 3 layers) was used to generate soil moisture in the UCRB over a 50-year period. By using wavelet analysis, deep layer soil moisture was compared to the Palmer Drought Severity Index (PDSI), precipitation, and streamflow to determine whether deep soil moisture is an indicator of climate extremes. Wavelet and coherency analysis for the UCRB indicated a strong relationship between...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Journal of Hydrology,
Upper Colorado River Basin,
drought,
soil moisture,
wavelet analysis
Forests of the southern Rocky Mountains are punctuated by persistent meadows called parks that are dominated by grasses and forbs. In an attempt to elucidate the maintenance of subalpine parks in the Gunnison Basin, Colorado, soil texture and tree morphology differences along 60-m transects spanning the forest-park ecotone were studied in 6 representative parks. Seedling survivorship, percent seed germination, and soil moisture available to plants were also studied along one of the transects in Willow Park. Soil analyses revealed 40% more silt and significantly less sand and clay in all 6 parks (P < 0.001), which supports the traditional hypotheses that edaphic factors are involved in restricting establishment of...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Colorado,
Gunnison Basin,
Picea engelmannii,
Western North American Naturalist,
forest-meadow ecotones,
Climate change is causing measurable changes in rainfall patterns, and will likely cause increases in extreme rainfall events, with uncertain implications for key processes in ecosystem function and carbon cycling. We examined how variation in rainfall total quantity (Q), the interval between rainfall events (I), and individual event size (SE) affected soil water content (SWC) and three aspects of ecosystem function: leaf photosynthetic carbon gain (inline image), aboveground net primary productivity (ANPP), and soil respiration (inline image). We utilized rainout shelter-covered mesocosms (2.6 m3) containing assemblages of tallgrass prairie grasses and forbs. These were hand watered with 16 I�Q treatment combinations,...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Global Change Biology,
carbon cycle,
climate change,
mesocosm,
photosynthesis,
Soil respiration in semiarid ecosystems responds positively to temperature, but temperature is just one of many factors controlling soil respiration. Soil moisture can have an overriding influence, particularly during the dry/warm portions of the year. The purpose of this project was to evaluate the influence of soil moisture on the relationship between temperature and soil respiration. Soil samples collected from a range of sites arrayed across a climatic gradient were incubated under varying temperature and moisture conditions. Additionally, we evaluated the impact of substrate quality on short-term soil respiration responses by carrying out substrate-induced respiration assessments for each soil at nine different...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Desert scrub,
Litter quality,
Pinyon–juniper,
Ponderosa pine,
Soil Biology and Biochemistry,
Pulses of water availability characterize semiarid and arid ecosystems. Most precipitation events in these ecosystems are small (?10 mm), but can stimulate carbon flux. The large proportion of carbon stored belowground and small carbon inputs create the potential for these small precipitation events to have large effects on carbon cycling. Land-use change can modify these effects through alteration of the biota and soil resources. The goal of our research was to determine how small precipitation events (2, 5, and 10 mm) affected the dynamics of soil carbon flux and water loss in previously cultivated Conservation Reserve Program (CRP) fields and undisturbed shortgrass steppe. Total carbon loss and duration of elevated...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Conservation Reserve Program (CRP),
Cultivation,
Ecological Research,
Land-use change,
Semiarid and arid ecosystems,
A physically based hydrology model is used to produce time series for the period 1916–2003 of evapotranspiration (ET), runoff, and soil moisture (SM) over the western United States from which long-term trends are evaluated. The results show that trends in ET in spring and summer are determined primarily by trends in precipitation and snowmelt that determine water availability. From April to June, ET trends are mostly positive due primarily to earlier snowmelt and earlier emergence of snow-free ground, and secondarily to increasing trends in spring precipitation. From July to September trends in ET are more strongly influenced by precipitation trends, with the exception of areas (most notably California) that receive...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Evapotranspiration,
Journal of Climate,
North America,
Runoff,
Soil moisture,
SUMMARY: *Simulation models indicate that the nitrogen (N) cycle plays a key role in how other ecosystem processes such as plant productivity and carbon (C) sequestration respond to elevated CO(2) and warming. However, combined effects of elevated CO(2) and warming on N cycling have rarely been tested in the field. *Here, we studied N cycling under ambient and elevated CO(2) concentrations (600 micromol mol(-1)), and ambient and elevated temperature (1.5 : 3.0 degrees C warmer day:night) in a full factorial semiarid grassland field experiment in Wyoming, USA. We measured soil inorganic N, plant and microbial N pool sizes and NO(3)(-) uptake (using a (15)N tracer). *Soil inorganic N significantly decreased under...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: 15N tracer,
New Phytologist,
elevated CO2,
free-air CO2 enrichment (FACE),
heating,
We used overhead infrared radiators to add a constant increment of approximate to 15 W/m(2), over 2 yr, to the downward heat flux on five 30-m(2) montane meadow plots in Gunnison County, Colorado, USA. Heating advanced snowmelt by approximate to 1 wk, increased summer soil temperatures by up to 3 degrees C, and reduced summer soil moisture levels by up to 25% compared to control plots. Soil microclimate response to heating varied with season, time of day, weather conditions, and location along the microclimate and vegetation gradient within each plot, with the largest temperature increase observed in daytime and in the drier, more sparsely vegetated zone of each plot. Day-to-day variation in the daily-averaged temperature...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Ecological Applications,
Ecological Society of America,
Rocky Mountains,
climate,
ecosystem manipulation,
Global climate change is predicted to alter growing season rainfall patterns, potentially reducing total amounts of growing season precipitation and redistributing rainfall into fewer but larger individual events. Such changes may affect numerous soil, plant, and ecosystem properties in grasslands and ultimately impact their productivity and biological diversity. Rainout shelters are useful tools for experimental manipulations of rainfall patterns, and permanent fixed-location shelters were established in 1997 to conduct the Rainfall Manipulation Plot study in a mesic tallgrass prairie ecosystem in northeastern Kansas. Twelve 9 x 14–m fixed-location rainfall manipulation shelters were constructed to impose factorial...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Ecosystems,
Konza Prairie,
Springer New York,
climate change,
floristic diversity,
Most major rivers in the southwestern United States have been hydrologically altered to meet human needs. Altered hydrological regimes have been associated with declines in native riparian forests. Today, many riparian areas have little or no regeneration of native riparian species and are now dominated by exotic Saltcedar (Tamarix chinensis Lour.). Success of riparian restoration efforts at least partially depends on the number of seedlings surviving the first growing season. Seedling survival is influenced by many abiotic and biotic factors including competition from other plants and available soil moisture, which is partially dependent on soil texture. In this study, we evaluated the relative importance of four...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Cottonwood seedling,
Middle Rio Grande Valley,
Populus deltoides,
Restoration Ecology,
riparian restoration,
Some single-factor experiments suggest that elevated CO2 concentrations can increase soil carbon, but few experiments have examined the effects of interacting environmental factors on soil carbon dynamics. We undertook studies of soil carbon and nitrogen in a multi-factor (CO2 × temperature × soil moisture) climate change experiment on a constructed old-field ecosystem. After four growing seasons, elevated CO2 had no measurable effect on carbon and nitrogen concentrations in whole soil, particulate organic matter (POM), and mineral-associated organic matter (MOM). Analysis of stable carbon isotopes, under elevated CO2, indicated between 14 and 19% new soil carbon under two different watering treatments with as...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Climate change,
Elevated CO2,
Elevated temperature,
Mineral-associated organic matter,
Old-fields,
Climate change and invasions by non-native organisms are two factors of global change likely to alter the structure and function of arid and semi-arid ecosystems. We conducted a large-scale field experiment to determine how changes in amount of summer precipitation and invasions by an African grass (Eragrostis lehmanniana) may interact with soil texture to affect community and ecosystem processes in temperate grasslands and savannas of southern Arizona, USA. In particular, we investigated the response of soil moisture at several soil depths within seventy-two 2.7 m2 plots under six 9 m×18 m rainout shelters to a 3-fold difference in irrigation between February and November 2002, as well as to a single large pulse...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Journal of Arid Environments,
precipitation pulse,
rainfall manipulation,
rainout shelter,
savanna,
Global environmental change is altering temperature, precipitation patterns, and resource availability in aridland ecosystems. In 2006, we established a multifactor global change experiment to determine the interactive effects of nighttime warming, increased atmospheric N deposition, and more frequent occurrence of El Ni�o years on plant community dynamics in a northern Chihuahuan Desert grassland. Here we only report the results of warming and N addition from the first monsoon growing season prior to the imposition of the precipitation treatments. Our passive nighttime warming treatment increased daily minimum temperatures by 1.4?3.0 �C. Fertilization increased NO3N supply, as measured with Root Simulator Probes,...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Journal of Arid Environments,
bouteloua eriopoda,
bouteloua gracilis,
desert grassland,
nighttime warming,
1. Microclimate was measured and photosynthetic responses to a climate warming manipulation were compared for the evergreen shrub Artemisia tridentata and the herbaceous forb Erigeron speciosus in the Rocky Mountains, Colorado, USA. 2. Soil was warmer and drier under infra-red heaters compared with control plots. 3. Midday xylem pressure potential did not differ for A. tridentata on heated vs control plots but was lower for E. speciosus on heated plots compared with controls. Leaf temperatures did not vary for the two species on heated or control plots. 4. There were no significant treatment or species differences in the diurnal patterns of CO2 assimilation or stomatal conductance to water vapour. Also, there were...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Artemisia tridentata,
Erigeron speciosus,
Functional Ecology,
chlorophyll fluorescence,
gas exchange,
Soil moisture distribution emerges as a key link between hydrologic and ecologic processes in semiarid grassland and shrubland, as it influences evapotranspiration, respiration, and assimilation. In support, we present three years of data (2002?2004) collected from a semiarid grassland and shrubland within the Sevilleta National Wildlife Refuge of central New Mexico; the two sites are separated by about 5 km. Instrumentation includes an eddy covariance tower and typical micrometeorological devices at both locations. Additionally, the grassland site features six soil moisture profiles and the shrubland site features four soil moisture profiles, with the maximum depth at 52.5 cm. At both sites, most rain falls during...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: American Geophysical Union,
Water Resources Research,
eco-hydrology.,
eddy covariance,
evapotranspiration,
Ring-shaped growth patterns commonly occur in resource-limited arid and semi-arid environments. The spatial distribution, geometry, and scale of vegetation growth patterns result from interactions between biotic and abiotic processes, and, in turn, affect the spatial patterns of soil moisture, sediment transport, and nutrient dynamics in aridland ecosystems. Even though grass ring patterns are observed worldwide, a comprehensive understanding of the biotic and abiotic processes that lead to the formation, growth and breakup of these rings is still lacking. Our studies on patterns of infiltration and soil properties of blue grama (Bouteloua gracilis) grass rings in the northern Chihuahuan desert indicate that ring...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Aeolian processes,
Arid ecosystems,
Ecohydrology,
Infiltration,
Oecologia,
|
|