@article {JRN55343, title = {Long-term permanent quadrat sampling project at the Jornada Experimental Range, New Mexico}, year = {2022}, publisher = {Bulletin of the Ecological Society of America}, abstract = {The permanent chart quadrat project at the Jornada Experimental Range was established in 1915. Chart quadrat sampling is done using a pantograph, wherein technicians use a stylus attached to an arm to trace the perimeter of plants within the quadrat, and a pencil at the other end of the arm maps the information onto the data sheet. The Jornada quadrat monitoring effort collected yearly data from 1915 to 1979 and resumed at 5- year intervals beginning in 1995. Quadrat data have been used to understand patterns and mechanisms of long- term vegetation change, plant demography, species interactions, and community transitions.}, keywords = {Jornada Experimental Range, Long-term permanent quadrat sampling, New Mexico, project}, doi = {10.1002/bes2.1940 }, url = {files/bibliography/22-001.pdf}, author = {Erica M. Christensen and Connie J. Maxwell and A. L. Slaughter} } @conference {JRN55402, title = {Vegetation dynamics in drylands related to the Pacific Decadal Oscillation in the 20th century}, booktitle = {Ecological Society of America annual conference}, year = {2022}, month = {3/1/2022}, abstract = {Background/questions/methods: Ecosystem transitions resulting from climatic drivers are observed at multiple time scales. In the arid southwest United States, the role of climate variation in the collapse and recovery of grassland communities is poorly understood. Here we use a quality-controlled vegetation monitoring dataset initiated in 1915 to ask what climate components were most closely correlated to perennial grass dynamics in the 20th century. We constructed a suite of models relating grass cover to climate variables known to influence dryland ecosystem behavior at multiple time scales, including annual precipitation, annual drought indices, El Nino Southern Oscillation (ENSO) index, and Pacific Decadal Oscillation (PDO) index. Results/conclusions: We found that dynamics of perennial grass collapse and recovery during the 20th century were most closely correlated to the Pacific Decadal Oscillation (PDO) index. The relationship out-performed models correlating grasses to yearly precipitation and drought indices, suggesting that ecosystem transitions attributed only to local disturbances were instead influenced by climate teleconnections. We also found that an incidence of grass recovery in the 1960s-70s was accompanied by a significant shift from core species (common, abundant species) to transient species (species that are patchy in space or time). Finally, the relationship between PDO and vegetation cover broke down after 1995, indicating that warming or land degradation overwhelmed multi-decadal variation driven by PDO.}, author = {Erica M. Christensen and D. K. James and Robb Randall and Brandon T Bestelmeyer} } @conference {JRN55405, title = {Vegetation dynamics in drylands related to the Pacific Decadal Oscillation in the 20th century}, booktitle = {Ecological Society of America (ESA)}, year = {2022}, month = {03/01/2022}, abstract = {Background/questions/methods: Ecosystem transitions resulting from climatic drivers are observed at multiple time scales. In the arid southwest United States, the role of climate variation in the collapse and recovery of grassland communities is poorly understood. Here we use a quality-controlled vegetation monitoring dataset initiated in 1915 to ask what climate components were most closely correlated to perennial grass dynamics in the 20th century. We constructed a suite of models relating grass cover to climate variables known to influence dryland ecosystem behavior at multiple time scales, including annual precipitation, annual drought indices, El Nino Southern Oscillation (ENSO) index, and Pacific Decadal Oscillation (PDO) index. Results/conclusions: We found that dynamics of perennial grass collapse and recovery during the 20th century were most closely correlated to the Pacific Decadal Oscillation (PDO) index. The relationship out-performed models correlating grasses to yearly precipitation and drought indices, suggesting that ecosystem transitions attributed only to local disturbances were instead influenced by climate teleconnections. We also found that an incidence of grass recovery in the 1960s-70s was accompanied by a significant shift from core species (common, abundant species) to transient species (species that are patchy in space or time). Finally, the relationship between PDO and vegetation cover broke down after 1995, indicating that warming or land degradation overwhelmed multi-decadal variation driven by PDO.}, author = {Erica M. Christensen and D. K. James and Rob Randall and Brandon T Bestelmeyer} } @article {JRN55325, title = {Quadrat-based monitoring of desert grassland vegetation at the Jornada Experimental Range, New Mexico, 1915-2016}, year = {2021}, abstract = {The data set covers a 101-year period (1915{\textendash}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 1 m by 1 m permanent quadrats, although not all quadrats were sampled in each year of the study and there is a gap in monitoring from 1980{\textendash}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); (7) table of depth to petrocalcic layer measurements taken at quadrat locations; (8) table of particle size analysis of soil samples taken at quadrat locations; (9) table of topographic characteristics of quadrat locations (e.g. concave or convex topography). Pantograph sampling is currently conducted at 5 year intervals by USDA-ARS staff, and new data will be added periodically to the EDI Data Portal Repository (see section V.E.2). This information is released under the Creative Commons license - Attribution - CC BY and the consumer of these data is required to cite it appropriately in any publication that results from its use.}, keywords = {arid grasslands, Chihuahuan Desert, long-term research, New Mexico, particle size analysis, plant community, plant populations, quadrat, rangeland, soil texture}, doi = {10.1002/ecy.3530}, url = {files/bibliography/21-041.pdf}, author = {Erica M. Christensen and D. K. James and A. L. Slaughter and Connie J. Maxwell and Peter B. Adler and Kris Havstad and Brandon T Bestelmeyer} } @proceedings {JRN55188, title = {Monitoring plant community change at the Jornada Experimental Range: 100 Years of quadrat sampling}, volume = {$\#$92}, year = {2020}, month = {02/16/2020}, address = {Denver, CO}, abstract = {

The importance of long-term observational data sets as records of ecosystem responses to climatic variation and directional change continues to increase. Ecologists and land managers use such records to ask questions about how ecosystems responded to past climatic variation and perturbations, in order to understand mechanisms behind increase/decline of species of interest, and to inform predictions about future scenarios.

Sampling using chart quadrats was a common method in the early 20th century as a means to track availability of perennial grasses and other species as forage for liveestock.\  At the Jomada Experimental Range in southern New Mexico, chart quadrat sampling began in 1915 and continues through the present, with permanent quadrat locations being resampled approximately every 5 years. Using this detailed record we can not only investigate trends in grass cover, but also track variation in other plant community properties (e.g. species richness, species tumover, abundance distributions) as the system experienced severe droughts, variation in quantity and timing of yearly precipitation, and an overall trend of shrub encroachment\  over the past 100 \ years.

Like many desert rangelands in the southwest, cover of perennial grasses such as black grama (Bouteloua eriopoda) has declined dramatically since the early 1900s. In recent samples, there is some evidence that cover of B. eriopoda has increased slightly on the quadrats where it has remained, likely the result of new recruits rather than existing individuals increasing in size. We also found that while species richness has remained fairly constant during the past 20 years, rates of tumover were also high, with rates of 50\% tumover on average during each 5-year sampling interval. These results contribute to the broader picture of ecosystem dynamics at the Jomada Experimental Range, and demonstrate the value of long-term consistent sampling initiatives.

}, keywords = {community change, Jornada Experimental Range, monitoring, plant, quadrat sampling}, author = {Erica M. Christensen and Brandon T Bestelmeyer and Connie J. Maxwell and A. L. Slaughter and D. K. James and Kirsten B. Romig and Kris Havstad} }