In an effort to better quantify NPP of Creosotebush in the Five-Points region, it was decided to test the Point-Quarter method against the standard 1-m2 quadrat method that has been in use since 1998. Transects were laid out across the 5 mammal trapping webs as well as across burned and unburned plots of the Mixed Shrub site (MS). Repeated measures of the same bushes are performed seasonally. Whole shrubs of various size classes are collected, sorted, and weighed to develop regressions for biomass.
Data was collected initially to determine density and dimensions of creosote bush in the Five points area on core rodent webs and on burned and unburned plots following the 2003 prescribed burn. It was decided to expand the project by continuing measurements through time to quantify the change in shrub size and with simultaneous harvest of shrubs to measure NPP.
Experimental Design The point-quarter technique is used to quantify the density of the shrubs at both the FivePoints Creosote and the Mixed Shrub (MS) sites. At the rodent webs two, 100 m transects are laid out across the diameter of each web. These transects were laid out using the existing trap locating rebar at 10 m intervals. The rebar used are those on the spoke running from 60 to 50 and then from 122 to 132 rebars at 5 m intervals. The stake at the center of the web is not used. This results in 20 points across each web or 80 shrubs per web.
At the mixed shrub site a different arrangement was used. Every other rebar was used along every other line as a measuring point. The rebars were also staggered by 1 rebar from line to line. Ultimately there were 12 rebars used in each plot for a total of 48 shrubs per plot.
Shrub Measurements In the initial sampling the shrub nearest the rebar in each quadrant was identified and the distance from the rebar to the rooting point of that shrub was measured. The height of the shrub was measured as well as the diameter of the crown at its widest point and also a diameter perpendicular to this first diameter. Repeated measures of the same bushes are performed seasonally.
July 2011- All new data were combined and QA/QC. No shrub measurements were taken in February of 2011 due to the fact that there was a shrub die off caused by extremely low temperatures on the refuge (-20F).--A. Swann
February 2009-All new data were combined and QA/QC. On web 4 at the creosote site, shrub 124 was measured twice because it was unknown about if it was one or two bushes and what had been measured in the past. It was identified that sometimes in the past two bushes instead of one was measured. Made note of this to reduce the chance of this happening in the future. At the mixed shrub unburned, shrub 114 and 132 are the same shrub. --A. Swann
January 2009 -All data from 2007 and 2008 were combined. Changed the order of variables on datasets to match metadata variable order. Went through the raw data and changed blank distances or ones with -99.00 to -888.00 to denote missing data. Changed missing data on height and weight due to plant being dead to -888. Changed missing data on height and weight due to human error to -999. -Imported excel raw data into Navicat using the wizard. --A. Swann
Data were scanned by eye to catch mistakes. Data were then filtered in excel to determine if all parameters were met.
Additional Information on the personnel associated with the Data Collection / Data Processing
In January 2011, the Sevilleta NWR experienced an extreme freeze with temperatures reaching below -25 degrees Celcius. These low temperatures negatively impacted the vegetation on the shrubs, resulting in the inablilty to measure the creosote shrubs during that season. Measurements were resumed the following spring of 2011.
Sevilleta Field Crew Employee History
Chandra Tucker, April 2014-present, Megan McClung, April 2013-present, Stephanie Baker, October 2010-Present, John Mulhouse, August 2009-June 2013, 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.