In 1995, a removal study was initiated at the Sevilleta LTER to examine the response of vegetation following the removal of dominant species. Five sites were selected that were dominated by either blue grama (site 1), blue and black grama (site 2), black grama (site 3), black grama and creosote (site 4), or creosote (site 5). A sixth site was later added in the blue grama community along the foothills of the Los Pinos Mountains (site 6). At sites 1, 3, 5, and 6, five 3m x 4m plots had all plants of the dominant species removed; five 3m x 4m plots were controls. At site 2, 5 plots had blue grama removed, 5 plots had black grama removed, and 5 plots were controls. At site 4, 5 plots had black grama removed, 5 plots had creosote removed, and 5 plots were controls. Initial cover prior to removal was estimated by species for each plot. Grass was removed using a shovel to collect above-ground biomass and crowns just below the soil surface. Shrubs were removed using large clippers to collect above-ground biomass to the soil surface. All biomass removed was bagged, dried, and weighed. Plot maintenance or removal of the target dominant species is performed annually or as needed. Rain gauges were installed at each site and the corners of the areas containing each set of plots GPS'd. Plot corners are marked by nails and are flagged periodically to aid identification and minimize foot traffic in the plots. Each northeast nail has a metal tag with site and plot number on it. Erosion bridges (1 m long) were installed in plots 1, 3 and 5 (removals and controls) at sites 1-5. Initial measurements were made in 1996.
Collecting the Data:
Each fall, during peak biomass (late Aug.-early Oct.), species richness and cover are visually observed in each plot. Data are entered onto a palmtop using the pre-formatted spreadsheet for ease of entry and transfer to a PC. The procedure is as follows:
1. Locate the metal tag on the northeastern nail and enter the site and plot code into the palmtop.
2. Depending on the treatment, certain species may need to be removed in and around the plot. The removal codes are as follows: RU-Remove BOGR2, RA-Remove BOER4, and RC-Remove LATR2. Do not remove plants from the control (C) and total removal (TR) plots.
3. Thoroughly search each plot and record every species present. This is ideally done by 1-2 people, but a single observer is sufficient.
4. The percent canopy cover of each species in the plot is estimated visually using the following numerical ranges:
T = < 0.1%
0.1-0.9% by intervals of 0.1%
1-5% by intervals of 0.5%
5-20% by intervals of 1.0%
20-100% by intervals of 5.0%
Cover is estimated for all species as well as litter. Bare ground is calculated by subtracting the total cover of all species from 100%. Cover of less than 0.1% is recorded in the data as "T" (i.e., trace).
It is advisable to re-flag plot corners and perform plot maintenance prior to assessing cover. To maintain the plots, clip any species to be removed from the edges and middle of the plot. Do not re-clip anything from the total removal plots.
Biomass removed from plots is dried, sorted by live and dead material, and weighed.
In some years, dates of data collection were lost. -999 has been entered for "Date" in such instances.
Also, in 1996, data was collected in both the summer and fall. Therefore, the 1996 data represents the maximum cover of a species observed that year, regardless of sampling period.
Data QA/QC'd and uploaded. Metadata completed for 2010. 11/10/10 (JMM) Data QA/QC'd and uploaded. Metadata updated and completed for years 1996-2009. 3/15/10 (JMM) Metadata completed for years 1996-2008. 3/6/09 (TLK)
Other researchers involved with collecting samples/data: Chandra Tucker (CAT; 04/2014-present), Megan McClung (MAM; 01/2013-present), Stephanie Baker (SRB; 10/2010-present), John Mulhouse (JMM; 08/2010-06/2013), Amaris Swann (ALS; 08/2008-01/2013), Maya Kapoor (MLK; 08/2003-01/2005, 05/2010-03/2011), Terri Koontz (TLK; 02/2000-08/2003, 08/2006-08/2010), Yang Xia (YX; 01/2005-03/2010), Karen Wetherill (KRW; 02/2000-08/2009); Michell Thomey (MLT; 09/2005-08/2008), Heather Simpson (HLS; 08/2000-08/2002),Chris Roberts (CR; 09/2001-08/2002), Shana Penington (SBP; 01/2000-08/2000), Seth Munson (SMM; 09/2002-06/2004), Jay McLeod (JRM; 01/2006-08/2006); Caleb Hickman (CRH; 09/2002-11/2004), Charity Hall (CLH; 01/2005-01/2006), Mike Friggens (MTF; 1999-09/2001), Tessa Edelen (MTE, 08/2004-08/2005).
Due to government shutdown in Fall of 2013, this data was not able to be collected.