2003 Prescribed Burn Effect on Chihuahuan Desert Grasses and Shrubs at the Sevilleta National Wildlife Refuge, New Mexico: Fuel Load Study

The U.S. Fish and Wildlife's plan to apply a prescribed burn to a large portion of Mckenzie Flats was deemed an opportunity to study the effects of fire on the vegetation at the boundary between shrubland and grassland. This study actually was undertaken on an area that had prescribed fire applied to 8 of 16 (300 m x 300 m) plots 10 years before in 1993. This previous study had also examined the effects of fencing to exclude the indigenous prong-horn antelope. In the 2003 study the prescribed fire was applied to the northeastern half of the 16 plots while the southwestern plots were intentionally protected. Sampling prior to the prescribed burn included quantification of fuel load (ie. the standing biomass of all grasses and forbs in the area to be burned). These measurements were made using Daubenmire quadrat frames that are 5 cm x 20 cm and delineate a 0.1 square meter area. Four samples were taken adjacent to the six 3 m x 4 m quadrats in each of the eight plots that were to be burned. Quadrat frames were laid down over the vegetation and all vegetation rooted within the frame was clipped at ground level. This material was bagged, oven-dried and weighed. Following the prescribed burn, re-measurements were made in the fall of 2004 and continue to be measured every fall when vegetation has reached its annual peak biomass.

Data Policies This dataset is released to the public and may be freely downloaded. Please keep the designated Contact person informed of any plans to use the dataset. Consultation or collaboration with the original investigators is strongly encouraged. Publications and data products that make use of the dataset must include proper acknowledgement of the Sevilleta LTER. Datasets must be cited as in the example below. Muldavin, E. 2004. Sevilleta LTER Fertilizer NPP Study Dataset. Albuquerque, NM: Sevilleta Long Term Ecological Research Site Database: SEV155. (Date of download) A copy of any publications using these data must be supplied to the Sevilleta LTER Information Manager.

Sampling:Within each 300 m x 300 m plot, 3 m x 4 m quadrats were marked off with rebar for use in a previous burn experiment. Each of these quadrats also had a rebar on the southern edge of the quadrat with a numbered tag. Six of these quadrats were randomly selected in each plot. Measurements were made using a Daubenmire quadrat frame. These frames are PVC squares that are 5 cm x 20 cm that gives an enclosed area of 0.1 m2. From each corner of the 3 m x 4 m quadrat, a distance of 2.5 m was taped off and the Daubenmire frame was placed on the ground over vegetation. All vegetation rooted within the frame was clipped at ground level and placed in a paper sack. This included all live and dead standing material. Exceptions were made where the frame was located within the canopy of bushes or yuccas. The designation for the four niners in each quadrat was A through D, with A in the SW corner moving clockwise to D in the SE corner.Laboratory techniques:All samples were dried at 60 degrees C for 48 hours and then weighed.Specific location:Data were collected from 16 (300 m x 300 m) plots designated as the "Burn Antelope Exclosure" plots. These plots are located on the southern end of Mckenzie Flats. The plots are laid out in a 4 by 4 square with 300 m buffer between each plot. The plots are enclosed within a 440 ha box.The bounding coordinates of this large box are: Latitude LongitudeNW corner 34.3138 106.6926 NE corner 34.3202 106.6711 SE corner 34.3024 106.6634 SW corner 34.2960 106.2960This large expanse has a variable mix of grass species. The 2 dominant species are black grama (Bouteloua eriopoda) and blue grama (Bouteloua gracilis). There are also sizeable patches of mule grass (Scleropogon brevifolius). A mixture of the drop seed species are present as well. These include Sporobolus cryptandrus, Sporobolus contractus, Sporobolus flexuosus and Sporobolus airoides. Galleta grass (Pleuraphis jamesii) and a couple of Muhlenbergia species are also present. Within this grass matrix are also several shrubs and subshrubs. The most noticeable shrub is creosote bush (Larrea tridentata). Other common non-grasses are Yucca glauca, Ephedra torreyana and Gutierrezia sarothrae.