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2003 Prescribed Burn Effect on Chihuahuan Desert Grasses and Shrubs at the Sevilleta National Wildlife Refuge, New Mexico: Grass Recovery Study (2003-2018)

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 every fall of from 2004 until 2012 when vegetation had reached its annual peak biomass. Data were not collected from 2014-2017, but were collected again in 2018.

2003 Prescribed Burn Effect on Chihuahuan Desert Grasses and Shrubs at the Sevilleta National Wildlife Refuge, New Mexico: Species Composition Study (2004-2018)

Disturbance from fire can affect the abundance and distribution of shrubs and grasses in arid ecosystems. In particular, fire may increase grass and forb production while hindering shrub encroachment. Therefore, prescribed fires are a common management tool for maintaining grassland habitats in the southwest. However, Bouteloua eriopoda (black grama), a dominant species in Chihuahuan Desert grassland, is highly susceptible to fire resulting in death followed by slow recovery rates. A prescribed fire on the Sevilleta National Wildlife refuge in central New Mexico in 2003 provided the opportunity to study the effects of infrequent fires on vegetation in this region. This study was conducted along a transition zone where creosote bushes (Larrea tridentata) are encroaching on a black grama grassland. Before and after the fire, above ground plant productivity and composition were monitored from 2003 to present. Following the prescribed fire, there were fewer individual grass clumps and less above ground grass cover in burned areas compared to unburned areas. This decrease in productivity was primarily from a loss of B. eriopoda. Specifically, B. eriopoda density and cover were significantly lower following the fire with a slow recovery rate in the five years following the fire. Other grasses showed no such adverse response to burning. Data were collected from 2004-2013 and 2018. Data were not collected for 2014-2017.

Warming-El Nino-Nitrogen Deposition Experiment (WENNDEx): Soil Temperature Data from the Sevilleta National Wildlife Refuge, New Mexico (1/2006 - 7/2009)

This data set provides soil temperature data in each plot of the warming experiment (see SEV176). Data are collected with automated soil temperature probes at 15-minute intervals at two soil depths under grass and bare patches in each of the 40 plots.

Warming-El Nino-Nitrogen Deposition Experiment (WENNDEx): Soil Moisture Data from the Sevilleta National Wildlife Refuge, New Mexico (1/2006-8/2009)

This data set provides soil moisture data in each plot of the warming experiment (see SEV176). Data are collected with automated soil moisture probes at 30-minute intervals at two soil depths under grass and bare patches in each of the 40 plots.

Pinon Juniper Net Primary Production Quadrat Data from the Sevilleta National Wildlife Refuge, New Mexico: 1999-2001

This three-year study at the Sevilleta LTER was designed to monitor net primary production (NPP) across two distinct ecosystems: pinon/juniper woodland (P) and juniper savannah woodland (J). Net primary production (NPP) is a fundamental ecological variable that measures rates of carbon consumption and fixation. Estimates of NPP are important in understanding energy flow at a community level as well as spatial and temporal responses of the community to a wide range of ecological processes. While measures of both below- and above-ground biomass are important in estimating NPP, this study focused on estimating above-ground biomass production (ANPP).To measure ANPP (i.e., the change in plant biomass, represented by stems, flowers, fruit and foliage, over time), the vegetation variables in this dataset, including species composition and the cover and height of individuals, were sampled twice yearly (spring and fall) at permanent 1m x 1m plots. The data from these plots was used to build regressions correlating biomass and volume via weights of select harvested species obtained in SEV157, "Net Primary Productivity (NPP) Weight Data." In addition, volumetric measurements were obtained from permanent plots to build regressions correlating biomass and volume.Spring measurements were taken in April or May when shrubs and spring annuals reached peak biomass. Fall measurements were taken in either September or October when summer annuals reached peak biomass but prior to killing frosts. Winter measurements were taken in February before the onset of spring growth.

Pinon-Juniper Dendrometer, Height, and Crown Area Measurements at Cerro Montosa, Sevilleta National Wildlife Refuge, New Mexico (2006-2009)

Allometry is a standard method of determining biomass and Net Primary Production of many trees. One of the standard variables used in such allometric regressions is bole diameter. On straight trunk trees measurements at breast height (DBH) taken using a DBH tape is adequate for quantifying changes in diameter over time. However, in scrub forests such as the Pinon Juniper PJ woodlands, common on the Sevilleta, both the pinon and particularly the junipers are relatively short and multi-trunked so that measurements must be taken near the ground and the consistency between measurements often lead to erroneous growth analysis. To reduce such discrepancy in readings, dendrometer bands were installed on 20 pinons and 20 junipers in the Cerro Montoso area where understory ANPP has been measured for some time. These dendrometers quantify the expansion (and contraction) of the tree bole through time. The beginning diameter at the time of installation was also measured and recorded. Heights of the 40 trees were also measured. The diameter of the foliage was measured across these trees at the widest point and then again on an axis perpendicular to this first reading. Readings of the dendrometers are repeated on about a monthly basis through the growing season. Heights of the trees are done on an annual basis. Measurements are collected to quantify the increase in bole diameter for a set of Pinons and Junipers in this area over time.

Effect of Long-Term Nitrogen Fertilization on Mycorrhizal Fungi Associated with a Dominant Grass in a Chihuahuan Desert Grassland at the Sevilleta National Wildlife Refuge, New Mexico (2005)

We studied the diversity of arbuscular mycorrhizal fungi (AMF) in a semiarid grassland and the effect of long-term nitrogen (N) fertilization on this fungal community. Root samples of Bouteloua gracilis were collected at the Sevilleta National Wildlife Refuge (New Mexico, USA) from control and N-amended plots that have been fertilized since 1995. Small subunit rDNA was amplified using AMF specific primers NS31 and AM1. The diversity of AMF was low in comparison with other ecosystems, only seven operational taxonomic units (OTU) were found in B. gracilis and all belong to the genus Glomus. The dominant OTU was closely related to the ubiquitous G. intraradices/G. fasciculatum group. N-amended plots showed a reduction in the abundance of the dominant OTU and an increase in AMF diversity. The greater AMF diversity in roots from N-amended plots may have been the result of displacement of the dominant OTU, which facilitated detection of uncommon AMF. The long-term implications of AMF responses to N enrichment for plant carbon allocation and plant community structure remain unclear.

Effects of Kangaroo Rat Mounds on Seed Banks of Grass and Shrublands at the Sevilleta National Wildlife Refuge, New Mexico (2001)

Disturbance is a major factor in determining the spatial structure and temporal dynamics of ecological systems. Many studies have been conducted concerning the plant assemblages around Dipodmys spectabilis mounds compared to the off mound area. These studies have shown that annual plant cover is higher on the kangaroo rat mound compared to off the mound. However, no studies have addressed the effects of these rodents disturbance on the soil seed bank. Soil seed banks are an important component of the plant community particularly in arid environments. Annual plants have been known to create viable seeds that remain dormant in the soil for many years making their seed bank a persistent one. A persistent seed bank allows for future recruitment of plants given favorable conditions that could have a dramatic impact on the overall species diversity of the community. We studied the seed bank of eight forb taxa to ask the following questions: 1) Are there more seeds in the seed bank around kangaroo rat mounds compared to other microhabitats? 2) Does the seed composition differ among the different microhabitats? 3) If the seed composition does differ, do specific physical components of microhabitats predict seed populations?

Ground-Truthing Satellite Imagery with Phenological Observations: Visual Observations from Grasslands at the Sevilleta National Wildlife Refuge, New Mexico

Phenology is the study of recurring natural phenomena. The seasonal "greening-up" and "greening-down" of dominant vegetation can be used as a predictor for a variety of processes and variables at local to global scales. The use of satellites to monitor land surface phenology is important for understanding local and regional ecosystem variability, identifying change over time, and potentially predicting ecosystem response to short and long-term changes in climate. However, the relationship between how phenology is expressed on the ground and how it is interpreted from satellites is poorly understood because phenological stages do not always correspond well to changes in spectral reflectance. In this study, we explored the relationship between greenness as measured by digital camera, the human eye, and ASTER imagery in two perennial grasslands at the Sevilleta National Wildlife Refuge in central New Mexico.

Coyote Scat Surveys in Chihuahuan Desert Grassland and Shrubland Sites, Spring, Summer and Fall at the Sevilleta National Wildlife Refuge, New Mexico (2008-2009)

This data set contains information regarding carnivore scat surveys that were performed at sites in grama grassland and both creosote and mesquite shrubland habitats at the Sevilleta NWR. A total of nine surveys were carried out along road-based transects, each of which is a mile long, during one season in 2008 (June-July) and three seasons in 2009: spring (April-May), summer (July-August), and fall (October-November). There were 10 transects in grassland areas and 10 in shrubland areas in 2008. All 20 transects, as well as two additional transects in grassland areas, were surveyed in 2009. For more information on the structure of the vegetation surrounding these road based transects, see the "Vegetation surveys in grassland and shrubland sites that are associated with coyote scat surveys at the Sevilleta NWR, 2008-2009" data set. Scat samples were identified in the field and collected for genetic and stable carbon isotope analysis. Field recorded variables include: scat freshness, maximum diameter, length, and GPS coordinates, as well as the field-based species identification for the sample. Information on the lab based species and individual identification results are also presented.This data was collected in order to obtain information on the size and feeding ecology of the coyote populations in grassland vs. shrubland habitats in three seasons (spring, summer and fall) and two years (2008 and 2009) at the Sevilleta NWR. A mark recapture analysis can be performed on the data from 2009 since two surveys were carried out for each scat transect in each of the three seasons and coyote scats were run through a genetic analysis to determine individual identity of the coyotes. A rough assessment of coyote habitat use can also be performed using the individual identity and coyote scat location information. Future isotope analysis will indicate whether the base of the food chain is C4 (grass) vs. C3 (shrubs) plants in grassland vs. shrubland habitats in each of the three

Snakeweed Patch Vegetation Quad Data at the Sevilleta National Wildlife Refuge, NM (1984, 1996)

In 1984, a research project was initiated on a relatively small disturbance patch just south of Deep Well. This disturbance was thought to be the result of an old praire dog town, probably dating back to when a nearby ranch was active, and a lot of old mammal mounds remained in the disturbed area. One of the things that made the disturbance patch particularily noticeable was the lush growth of snakeweed (Gutierrezia sarothrae) within the patch. This prompted the designation of the disturbance patch as the "snakeweed patch" or "Gutierrezia patch." In addition, there was an obvious increase in bare ground and a shift in vegetation composition across the patch boundary. The dominant vegetation was not consistent around the boundary, with a marked dominance of black grama on the west side of the plot and a blue/black grama mix on the other three sides. To obtain information on the cause and/or effect of this disturbance, a survey of the soil and vegetation was performed. This database contains information collected during the vegetation monitoring that was done on the plot in 1984, as well as a follow-up measurement done in 1996. By 1996, virtually all of the snakeweed had died due to a dry period.

Mega-Monsoon Experiment (MegaME) Vegetation Sampling Data from the Sevilleta National Wildlife Refuge, New Mexico

Shrub encroachment is a global phenomenon. Both the causes and consequences of shrub encroachment vary regionally and globally. In the southwestern US a common native C3 shrub species, creosotebush, has invaded millions of hectares of arid and semi-arid C4-dominated grassland. At the Sevilleta LTER site, it appears that the grassland-shrubland ecotone is relatively stable, but infill by creosotebush continues to occur. The consequences of shrub encroachment have been and continue to be carefully documented, but the ecological drivers of shrub encroachment in the southwestern US are not well known. One key factor that may promote shrub encroachment is grazing by domestic livestock. However, multiple environmental drivers have changed over the 150 years during which shrub expansion has occurred through the southwestern US. Temperatures are warmer, atmospheric CO2 has increased, drought and rainy cycles have occurred, and grazing pressure has decreased. From our prior research we know that prolonged drought greatly reduces the abundance of native grasses while having limited impact on the abundance of creosotebush in the grass-shrub ecotone. So once established, creosotebush populations are persistent and resistant to climate cycles. We also know that creosotebush seedlings tend to appear primarily when rainfall during the summer monsoon is well above average. However, high rainfall years also stimulate the growth of the dominant grasses creating a competitive environment that may not favor seedling establishment and survival. The purpose of the Mega-Monsoon Experiment (MegaME) is twofold. First, this experiment will determine if high rainfall years coupled with (simulated) grazing promote the establishment and growth of creosotebush seedlings in the grassland-shrubland ecotone at Sevilleta, thus promoting infill and expansion of creosotebush into native grassland. Second, MegaME will determine if a sequence of wet summer monsoons will promote the establishment and gro

Ecosystem-Scale Rainfall Manipulation in a Piñon-Juniper Forest at the Sevilleta National Wildlife Refuge, New Mexico: Meteorological Data (2006-2013 )

Climate models predict that water limited regions around the world will become drier and warmer in the near future, including southwestern North America. We developed a large-scale experimental system that allows testing of the ecosystem impacts of precipitation changes. Four treatments were applied to 1600 m2 plots (40 m × 40 m), each with three replicates in a piñon pine (Pinus edulis) and juniper (Juniper monosperma) ecosystem. These species have extensive root systems, requiring large-scale manipulation to effectively alter soil water availability. Treatments consisted of: 1) irrigation plots that receive supplemental water additions, 2) drought plots that receive 55% of ambient rainfall, 3) cover-control plots that receive ambient precipitation, but allow determination of treatment infrastructure artifacts, and 4) ambient control plots. Our drought structures effectively reduced soil water potential and volumetric water content compared to the ambient, cover-control, and water addition plots. Drought and cover control plots experienced an average increase in maximum soil and air temperature at ground level of 1-4° C during the growing season compared to ambient plots, and concurrent short-term diurnal increases in maximum air temperature were also observed directly above and below plastic structures. Our drought and irrigation treatments significantly influenced tree predawn water potential, sap-flow, and net photosynthesis, with drought treatment trees exhibiting significant decreases in physiological function compared to ambient and irrigated trees. Supplemental irrigation resulted in a significant increase in both plant water potential and xylem sap-flow compared to trees in the other treatments. This experimental design effectively allows manipulation of plant water stress at the ecosystem scale, permits a wide range of drought conditions, and provides prolonged drought conditions comparable to historical droughts in the past – drought events for which wide

Ecosystem-Scale Rainfall Manipulation in a Piñon-Juniper Forest at the Sevilleta National Wildlife Refuge, New Mexico: Volumetric Water Content (VWC) at 5 cm Depth Data (2006- )

Biannual Juniper Branch Demography Study at the Sevilleta National Wildlife Refuge, New Mexico (1989-1993)

This project was designed to investigate the response of plant growth and reproduction to short- and long-term variation in biotic and abiotic environmental variables. Several perennial taxa, including tree (Juniperus monsperma and Pinus edulis), shrub (Larrea tridentata) and bunch grasses (Oryzopsis hymenoides (now Achnaterum hymenoides) and Sporobolus contractus) species, were monitored at 1-3 sites differing in elevation and topography as well as edaphic variables and annual precipitation. The sites represented optimal or marginal/transitional zones for particular species. Demographic measurements were made biannually, after the 'wet' (fall) and 'dry' (spring) seasons. For tree and shrub species, estimates of growth and reproduction were based on branch demography, with ten branch tips from 10-20 individuals per species per site repeatedly measured from 1989-1993. For J. monsperma, P. edulis and L. tridentata, vegetative growth (i.e., branch growth) as well as reproduction were monitored. Additional measurements included needle length for P. edulis and leaf production, leaf size and branchlet production for L. tridentata. For grasses, basal diameter, leaf length and reproduction were monitored for 100 individuals per species per site. This project, SEV028, contains only data on juniper branch demography. Data on other variables and species is contained in SEV006, SEV024, SEV025, SEV026, and SEV027.

Ground Arthropod Community Survey in Grassland, Shrubland, and Woodland at the Sevilleta National Wildlife Refuge, New Mexico (1992-2004)

This data set contains records for the numbers of selected groups of ground-dwelling arthropod species and individuals collected from pitfall traps at 4 sites on the Sevilleta NWR, including creotostebush shrubland, both black and blue grama grasslands, and a pinyon/juniper woodland. Data collections begin in May of 1989, and are represented by subsequent sample collections every 2 months. One site (Goat Draw/Cerro Montosa) was discontinued in 2001, and a new site (Blue Grama) was initiated . Only three sites, creosotebush, black grama, and blue grama were continued between 2001-2004.

openCC (other)May 2023View details →

Monsoon Rainfall Manipulation Experiment (MRME) Meteorology Data from a Chihuahuan Desert Grassland at the Sevilleta National Wildlife Refuge, New Mexico

The Monsoon Rainfall Manipulation Experiment (MRME) is to understand changes in ecosystem structure and function of a semiarid grassland caused by increased precipitation variability, which alters the pulses of soil moisture that drive primary productivity, community composition, and ecosystem functioning. The overarching hypothesis being tested is that changes in event size and variability will alter grassland productivity, ecosystem processes, and plant community dynamics. In particular, we predict that many small events will increase soil CO2 effluxes by stimulating microbial processes but not plant growth, whereas a small number of large events will increase aboveground NPP and soil respiration by providing sufficient deep soil moisture to sustain plant growth for longer periods of time during the summer monsoon. Â These data were collected at a meteorological station at the Monsoon Site.

Warming-El Nino-Nitrogen Deposition Experiment (WENNDEx): Soil Temperature, Moisture, and Carbon Dioxide Data from the Sevilleta National Wildlife Refuge, New Mexico

Humans are creating significant global environmental change, including shifts in climate, increased nitrogen (N) deposition, and the facilitation of species invasions. A multi-factorial field experiment is being performed in an arid grassland within the Sevilleta National Wildlife Refuge (NWR) to simulate increased nighttime temperature, higher N deposition, and heightened El Nino frequency (which increases winter precipitation by an average of 50%). The purpose of the experiment is to better understand the potential effects of environmental drivers on grassland community composition, aboveground net primary production and soil respiration. The focus is on the response of two dominant grasses (Bouteloua gracilis and B eriopoda), in an ecotone near their range margins and thus these species may be particularly susceptible to global environmental change. It is hypothesized that warmer summer temperatures and increased evaporation will favor growth of black grama (Bouteloua eriopoda), a desert grass, but that increased winter precipitation and/or available nitrogen will favor the growth of blue grama (Bouteloua gracilis), a shortgrass prairie species. Treatment effects on limiting resources (soil moisture, nitrogen availability, species abundance, and net primary production (NPP) are all being measured to determine the interactive effects of key global change drivers on arid grassland plant community dynamics and ecosystem processes. This dataset shows values of soil moisture, soil temperature, and the CO2 flux of the amount of CO2 that has moved from soil to air. On 4 August 2009 lightning ignited a ~3300 ha wildfire that burned through the experiment and its surroundings. Because desert grassland fires are patchy, not all of the replicate plots burned in the wildfire. Therefore, seven days after the wildfire was extinguished, the Sevilleta NWR Fire Crew thoroughly burned the remaining plots allowing us to assess experimentally the effects of interactions among multip

openCC0Jul 2020View details →

Warming-El Nino-Nitrogen Deposition Experiment (WENNDEx): Soil Nitrogen Data from the Sevilleta National Wildlife Refuge, New Mexico (2006 - 2020)

Humans are creating significant global environmental change, including shifts in climate, increased nitrogen (N) deposition, and the facilitation of species invasions. A multi-factorial field experiment is being performed in an arid grassland within the Sevilleta National Wildlife Refuge (NWR) to simulate increased nighttime temperature, higher N deposition, and heightened El NiÃ±o frequency (which increases winter precipitation by an average of 50%). The purpose of the experiment is to better understand the potential effects of environmental drivers on grassland community composition, aboveground net primary production and soil respiration. The focus is on the response of two dominant grasses (Bouteloua gracilis and B eriopoda), in an ecotone near their range margins and thus these species may be particularly susceptible to global environmental change. It is hypothesized that warmer summer temperatures and increased evaporation will favor growth of black grama (Bouteloua eriopoda), a desert grass, but that increased winter precipitation and/or available nitrogen will favor the growth of blue grama (Bouteloua gracilis), a shortgrass prairie species. Treatment effects on limiting resources (soil moisture, nitrogen availability, species abundance, and net primary production (NPP) are all being measured to determine the interactive effects of key global change drivers on arid grassland plant community dynamics and ecosystem processes. On 4 August 2009 lightning ignited a ~3300 ha wildfire that burned through the experiment and its surroundings. Because desert grassland fires are patchy, not all of the replicate plots burned in the wildfire. Therefore, seven days after the wildfire was extinguished, the Sevilleta NWR Fire Crew thoroughly burned the remaining plots allowing us to assess experimentally the effects of interactions among multiple global change presses and a pulse disturbance on post-fire grassland dynamics. This data set provides soil N availability in each