Plant Density at Permanent Quad Locations on the Jornada Experimental Range, 1915-ongoing
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,This ongoing data set contains counts of perennial forbs and subshrubs in 122 1m x 1m quadrats on the Jornada Experimental Range in the northern extent of the Chihuahuan Desert of New Mexico, USA. These quadrats were established to investigate livestock grazing effects on plant community dynamics as well as responses to variable climatic conditions over time. Vegetation monitoring is carried out by charting the locations of forbs and subshrubs within each quadrat. Quadrats were established at different times, with start dates from 1915 to 1935. Specific quadrat locations were selected for a variety of reasons, but the overall intent was to represent varying plant community conditions across the Jornada Experimental Range. From 1915 to 1924 charting was done by dividing the quadrat frame into a decimeter grid using straps and reproducing locations of plants on grid paper. From 1925 to 2016 charting was done using a pantograph. With few exceptions, quadrats were charted until 1947, and a portion of the quadrats were charted intermittently between 1947 and 1979. Sampling resumed again in 1995 and continues every 5-6 years. Charts are digitally scanned, georeferenced, and chart features are digitally reproduced by hand. This data set is not yet complete; charts are actively being processed by Jornada Experimental Range staff and will be updated to this data package as they become available. A companion data package of basal cover of perennial grasses and canopy cover of shrubs is also available for this project (data package knb-lter-jrn.210351001).,,
Quadrat-based monitoring of desert grassland vegetation at the Jornada Experimental Range, New Mexico, 1915-2016
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The data set covers a 101-year period (1915-2016) of quadrat-based plant sampling at the Jornada Experimental Range in southern New Mexico. At each sampling event, a pantograph was used to record the location and perimeter of living plants within permanent quadrats. Basal area was recorded for perennial grass species, canopy cover area was recorded for shrub species, and all other perennial species were recorded as point data. The data set includes 122 1m by 1m permanent quadrats, although not all quadrats were sampled in each year of the study and there is a gap in monitoring from 1980-1995. These data provide a unique opportunity to investigate changes in the plant community over 100 years of variation in precipitation and other environmental conditions. We provide the following data and data formats: (1) the digitized maps in shapefile format; (2) data table containing coordinates (x,y) of perennial species within quadrats, including cover area for grasses and shrubs; (3) data table of counts of annual plant individuals per quadrat; (4) species list indicating growth form and habit of recorded species; (5) table of dates when each quadrat was sampled; (6) table of the pasture each quadrat was located within (note that pasture boundaries have changed over time). Additional data to help characterize plant-scale factors related to vegetation dynamics at the quadrat locations are: (7) data table of depth to caliche layer; (8) data table of soil particle size analysis and sand fractionation; and (9) data table of local and patch topography. This data package was created to support a specific data paper. Data are also available in data packages knb-lter-jrn.210351001, knb-lter-jrn.210351002, and knb-lter-jrn.210351003. Pantograph sampling is currently conducted at 5 year intervals by USDA-ARS staff, and new data will be added to those data packages periodically.
NPP Grassland: Central Plains Experimental Range (SGS), USA, 1939-1990, R1
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This data set records the productivity of a semiarid shortgrass prairie steppe located in the Central Plains Experimental Reserve (CPER)/Pawnee National Grassland in north-central Colorado. There are nine data files (.txt). Four files contain measurements of monthly dynamics of harvested above-ground plant biomass, one file each for untreated, irrigated, fertilized, and irrigated + fertilized plots for the period 1970 to 1975. The fifth file contains annual above-ground NPP estimates for the untreated plot for the period 1970-1974. The sixth file contains long-term ANPP estimated from field harvest measurements made between 1970 and 1990 and by correlation with forage production measurements made between 1939 and 1990. Two additional files provide estimates of above- and below-ground NPP based on peak growing season harvests; one record covers 1970-1972 from the Pawnee site and the other covers 1985-1988 from CPER. The ninth file contains climate data for 1912-1990 from a weather station located at CPER.Revision Notes: This data set has been revised to correct the study site elevation, extend the temporal coverage, and add four data files containing estimates of NPP. Please see the Data Set Revisions section of this document for detailed information.
Perennial grass recovery following livestock overgazing and shrub removal: an experiment at the Jornada Experimental Range (Jornada Basin LTER), 1996-2016
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,The objective of this ongoing study is to determine the effect of cattle grazing and shrub removal on the decline and recovery of perennial grasses in a mesquite-invaded black grama grassland on sandy soils in the northern Chihuahuan Desert. The experiment was implemented as a randomized complete block with 3 levels of grazing (summer, winter, and control) and 2 levels of shrub treatment (shrub removal and control) in each of 3 replicate blocks. The 18 experimental units are 0.5 ha (70 x 70 m) exclosures constructed in a mesquite-invaded black grama grassland in the southwest portion of the Jornada Experimental Range in Dona Ana County, New Mexico, USA. Vegetation sampling was conducted with the line-point intercept method. Initial pre-treatment sampling occurred in 1996. Grazing treatments removed 65-80% of aboveground perennial grass biomass over 24-36 hour periods in each of four years from summer 1996 to winter 2000; shrub removal occurred during this time as well. No livestock grazing or shrub removal have occurred since 2000. Post-treatment sampling occurred in 2002, 2009, and 2016.,,
NPP Grassland: Central Plains Experimental Range (SGS), USA, 1939-1990, R1
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This data set records the productivity of a semiarid shortgrass prairie steppe located in the Central Plains Experimental Reserve (CPER)/Pawnee National Grassland in north-central Colorado. There are nine data files (.txt). Four files contain measurements of monthly dynamics of harvested above-ground plant biomass, one file each for untreated, irrigated, fertilized, and irrigated + fertilized plots for the period 1970 to 1975. The fifth file contains annual above-ground NPP estimates for the untreated plot for the period 1970-1974. The sixth file contains long-term ANPP estimated from field harvest measurements made between 1970 and 1990 and by correlation with forage production measurements made between 1939 and 1990. Two additional files provide estimates of above- and below-ground NPP based on peak growing season harvests; one record covers 1970-1972 from the Pawnee site and the other covers 1985-1988 from CPER. The ninth file contains climate data for 1912-1990 from a weather station located at CPER.Revision Notes: This data set has been revised to correct the study site elevation, extend the temporal coverage, and add four data files containing estimates of NPP. Please see the Data Set Revisions section of this document for detailed information.
State-and-Transition Simulation Models, parameters, input data, and simulation results
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This is a spatially-explicit state-and-transition simulation model (STSM) of sagebrush-steppe vegetation dynamics for greater sage-grouse (Centrocercus urophasianus) Priority Areas for Conservation (PACs) in the Great Basin. The STSM was built using the ST-Sim platform and uses an integrated stock-flow submodel (STSM-SF) to simulate and track continuous vegetation component cover changes caused by annual growth, natural regeneration, and post-fire sagebrush seeding and planting restoration. Spatially explicit models were built for three sage-grouse PACs (Klamath Oregon/California [KLAM], NW Interior Nevada [NWINV], Strawberry Utah [STRAW]) that differed in historic wildfire patterns and the amounts of various component vegetation cover present (sagebrush, annual grass, pinyon-juniper percent cover), and represented a range of possible variation in annual area burned (fire size, frequency), annual grass invasion, conifer encroachment and simulated potential for habitat restoration. Thirteen restoration scenarios representing a combination of three revegetation alternatives (no restoration, seeding, planting) under three effort levels (post-fire treatment area), and two durations (single-year, multi-year) were simulated for each PAC landscape. Seeding and planting effort levels were based on historic treatment area polygon data (median size) for sagebrush seeding (6 km2) and planting (4 km2). Planting scenarios represented the sagebrush cover gains of planting 4 plants/m2 (low-density; LD planting) and 8 plants/m2 (high-density; HD planting). A combination seeding-planting scenario representing single-year gains from seeding and multi-year gains from HD planting was also simulated to compare with single- and multi-year seeding or planting scenarios.
Vegetation cover from line intercept transects in lagomorph exclosure and shrub removal plots at the Jornada Experimental Range, southern New Mexico, USA, 1938-2001
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,This package contains data from a study to quantify vegetation dynamics in response to lagomorph and shrub exclusion on the Jornada Experimental Range from 1938-2001. Data consist of vertical line intercept measures of the perennial grasses, suffretescents and shrubs. Sixteen plots at each of 3 sites (Gravelly Ridges, Dona Ana exclosure, and Parker Tank) were established in 1938-39. Plots were 21.3 x 21.3 m with a 7.6 m buffer zone between each. Plots were divided into east and west halves and 14 randomly located 10.65 m transects were located in each half plot. Vegetation was measured using vertical line intercepts in 1938, 1947, 1956, 1960, 1967, 1989, 1995, and 2001 for the Gravelly Ridges site, and in 1938/9, 1947, 1960, 1967, and 2001 for the Parker Tank and Dona Ana sites. The treatments include lagomorph exclusion (using wire fencing), shrub removal (hand grubbing at the ground surface), furrowing (shallow, hand raked furrows to trap surface water), and seeding (broadcast applications of seeds of native perennials). Seeding and furrowing treatments were only applied in 1939. Lagomorph exclusion has persisted since establishment, and shrub removal treatments have been reapplied immediately following all years of vegetation sampling. The dataset contains information on the site, year of data collection, plot number, line number, vegetation, and number of vegetation present on each line. This study is complete.For more information, refer to:Havstad, K.M., R.P. Gibbens, C.A. Knorr, and L.W. Murray. 1999. Long-term influences of shrub removal and lagomorph exclusion on Chihuahuan Desert vegetation dynamics. Journal of Arid Environments 42: 155-166. https://doi.org/10.1006/jare.1999.0516,,