Plant Removal Study: Recovery of Vegetation Following Disturbance at the Sevilleta National Wildlife Refuge, New Mexico

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.