This is data for vegetation canopy cover measured from each of the SMES study plots. Vegetation canopy cover was measured from each of the 36 one-meter2 quadrats twice each year. Animal consumers have important roles in ecosystems, determining plant species composition and structure, regulating rates of plant production and nutrient, and altering soil structure and chemistry. The purpose of this study is to determine whether or not the activities of small mammals regulate plant community structure, plant species diversity, and spatial vegetation patterns in Chihuahuan Desert shrublands and grasslands.
The purpose of this study is to determine whether or not the activities of small mammals regulate plant community structure, plant species diversity, and spatial vegetation patterns in Chihuahuan Desert shrublands and grasslands. What role if any do indigenous small mammal consumers have in maintaining desertified landscapes in the Chihuahuan Desert? Additionally, how do the effects of small mammals interact with changing climate to affect vegetation patterns over time? This study will provide long-term experimental tests of the roles of consumers on ecosystem pattern and process across a latitudinal climate gradient. The following questions or hypotheses will be addressed. 1) Do small mammals influence patterns of plant species composition and diversity, vegetation structure, and spatial patterns of vegetation canopy cover and biomass in Chihuahuan Desert shrublands and grasslands? Are small mammals keystone species that determine plant species composition and physiognomy of Chihuahuan Desert communities? Do small mammals have a significant role in maintaining the existence of shrub islands and spatial heterogeneity of creosotebush shrub communities? 2) Do small mammals affect the taxonomic composition and spatial pattern of vegetation similarly or differently in grassland communities as compared to shrub communities? How do patterns compare between grassland and shrubland sites, and how do these relatively small scale patterns relate to overall landscape vegetation patterns? 3) Do small mammals interact with short-term (annual) and long-term (decades) climate change to affect temporal changes in vegetation spatial patterns and species composition? 4) Do small mammals interact with other herbivore and granivore consumers enough to affect the species composition and abundance’s of other consumers such as ants and grasshoppers?
Experimental Design There are 2 study sites, the Five Points grassland site, and the Rio Salado creosotebush site. Each study site is 1 km by 0.5 km in area. Three rodent trapping webs and four replicate experimental blocks of plots are randomly located at each study site to measure vegetation responses to the exclusion of small mammals. Each block of plots is 96 meters on each side. Each block of plots consists of 4 experimental study plots, each occupying 1/4 of each block. The blocks of study plots are all oriented on a site in a X/Y coordinate system, with the top to the north. Treatments within each block include one unfenced control plot (Treatment: C), one plot fenced with hardware cloth and poultry wire to exclude rodents and rabbits (Treatment: R), and one plot fenced only with poultry wire to exclude rabbits (Treatment: L). The three treatments were randomly assigned to each of the four possible plots in each block independently, and their arrangements differ from block to block. Each of the three plots in a replicate block are separated by 20 meters. Each experimental measurement plot measures 36 meters by 36 meters. A grid of 36 sampling points are positioned at 5.8-meter intervals on a systematically located 6 by 6 point grid within each plot. A permanent one-meter by one-meter vegetation measurement quadrat is located at each of the 36 points. A 3-meter wide buffer area is situated between the grid of 36 points and the perimeter of each plot.
Vegetation Quadrat Measurements The foliage canopy area and maximum height of each plant species is measured from each quadrat. All cover values are measured from the vegetation measurement frame, which is 1 meter by 1 meter, and partitioned into a grid of 100, 10 cm by 10 cm squares. Cover is measured by counting the number of 10cm squares that are occupied by the foliage canopy of a particular plant species, or by the soil disturbance, leaf litter etc. Portions down to the 0.1 of a 10cm square are also measured. NOTE: AS OF 2006, ALL PLANT CODES WERE UPDATED TO REFLECT THE USDA PLANTS DATABASE, prior to this plant taxonomic classification followed that of Allred (1996). For dead plant foliage (plant is dead,but still attached to the soil), just cover and not height was recorded.
SMES vegetation quad data from 1995-2008 were compiled and imported into MySQL. Tapes were listened to in order to distinguish between missing data points and quads that had no plants in them. Codes were updated according to the UDSA plants database (http://plants.usda.gov/). Contact data manager for old plant codes.All uknown plants that have since been identified were also updated. Missing data due to human error is represented as -999. Data that is not relevent (ie. height for dea d plants) is represented as -888. If a quad had no plants in it the species code is NONE and the cover and height are 0. For 1995-1998 spring data, all perennial species were removed. If the quad had only perennials in it, the quad was designated as NONE. For dead plant observations, all height observations were recorded -888. 'SEED' is not a Kartez species code, instead it represents unidentifiable seedlings. --Yang Xia January 2009
'SEEDS1 and SEEDS2' are not Kartez species codes, instead they represent unidentifiable seedlings. Changed CHSE to CHSES. Changed EUX4 to EUEX4. Changed CRCR to CRCR3. Changed PLJQ to PLJA. Changed PEBA2 to SPA10. --A. Swann
All data were filtered to identify any duplicates or mistakes in the original excel files. A perl script was then used to verify the consistiency of the parameters.
Additional Information on the personnel associated with the Data Collection / Data Processing
Sevilleta Field Crew Employee History
Megan McClung, April 2013-present, Stephanie Baker, October 2010-Present, John Mulhouse, August 2009-Present, Amaris Swann, August 25, 2008-January 2013, Maya Kapoor, August 9, 2003-January 21, 2005 and April 2010-March 2011, Terri Koontz, February 2000-August 2003 and August 2006-August 2010, Yang Xia, January 31, 2005-April 2009, Karen Wetherill, February 7, 2000-August 2009, Michell Thomey, September 3, 2005-August 2008, Jay McLeod, January 2006-August 2006, Charity Hall, January 31, 2005-January 3, 2006, Tessa Edelen, August 15, 2004-August 15, 2005, Seth Munson, September 9, 2002-June 2004, Caleb Hickman, September 9, 2002-November 15, 2004, Heather Simpson, August 2000-August 2002, Chris Roberts, September 2001-August 2002, Mike Friggens, 1999-September 2001, Shana Penington, February 2000-August 2000.
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