Current Research Projects

The varied topography and large elevation gradients that characterize the arid and semi-arid Southwest create a wide range of climatic conditions - and associated biomes - within relatively short distances. This creates an ideal experimental system in which to study the effects of climate on ecosystems. Such studies are critical givien that the Southwestern U.S. has already experienced changes in climate that have altered precipitation patterns (Mote et al. 2005), and stands to experience dramatic climate change in the coming decades (Seager et al. 2007; Ting et al. 2007).

Plant phenology or life-history pattern changes seasonally as plants grow, mature, flower, and produce fruit and seeds. Plant phenology follows seasonal patterns, yet annual variation may occur due to annual differences in the timing of rainfall and ambient temperature shifts. Foliage growth and fruit and seed production are important aspects of plant population dynamics and food resource availability for animals. The purpose of this study is to assess plant phenology patterns across a series of biotic communities that represent an environmental moisture gradient.

The Sevilleta LTER and University of New Mexico have received a five year grant from the National Science Foundation for the project entitled, "Grassland sensitivity to climate change at local to regional scales: assessing the roles of ecosystem attributes versus environmental context." The overarching goal of this research is to determine the consequences of chronic drought on biodiversity and ecosystem services in grasslands across precipitation and temperature gradients.

The Sevilleta’s climate is characterized by an intriguing combination of abundant sunshine, low humidity, and high variability for most meteorological factors. The site exists at the boundary between several major air mass zones that contribute to the dynamics of the local climate.

This study originated with the objective of parameterizing riparian evapotranspiration (ET) in the water budget of the Middle Rio Grande.  We hypothesized that flooding and invasions of non-native species would strongly impact ecosystem water use.  Our objectives were to measure and compare water use of native (Rio Grande cottonwood, Populus deltoides ssp.

Net primary production (NPP) is a fundamental ecological variable describing rates of carbon consumption and fixation.  Estimates of NPP are important in understanding the spatial and temporal responses of communities to a wide range of ecological processes including decomposition, fertility, and producer-consumer dynamics.  Net primary production is influenced by many factors, including temperature, soil nutrient content, soil texture, pollination, herbivory, and granivory.

Increased atmospheric CO2 concentrations caused by fossil fuel consumption are affecting global climate, increasing temperatures and precipitation variability in many regions. Such changes in climate can exceed the physiological tolerances of existing long-lived plant species or, alternatively, make conditions more favorable, increasing species productivity and abundance. One result is likely to be large scale vegetation change as some species die in areas where they can no longer survive while others increase in abundance and expand their distribution.

This study is designed to look at community or population level fluctuations in bees over the season and on a long term basis, over years. Funnel traps are a very low maintenance method of trapping pollinators with zero human bias. The bias of the traps is that the color determines the species and sexes that it attracts. Therefore the traps provide relative abundance that can be compared over the season or year, but individual species cannot be compared within a season.

This project was designed to examine the long-term response of semi-arid vegetation communities to the removal of dominant species.  One dominant species representing each of the three major biomes occurring at the Sevilleta National Wildlife Refuge was selected for removal from the sampled plots.  These species included: Bouteloua gracilis (blue grama), the characteristic dominant grass of shortgrass steppe, Bouteloua eriopoda (black grama), a dominant grass of Chihuahuan Desert grassland, and Larrea tridentata (creosotebush), a dominant shrub of Chihua

The germination rate of creosote (Larrea tridentata) on the Sevilleta appears to be very low. During the early years of the LTER project it was attempted to quantify such germination through the use of seedling plots which were monitored on a bi-annual basis (spring and fall). During the period from 1989 through 1992 there were no creosote seedling that germinated on the monitoring plots. In 1999 a rather sizeable population of small seedlings was observed in one quite localized area in the vicinity of Five Points.

Most research on microbial soil crusts has been concentrated in the cold desert grasslands of the Colorado Plateau and the Basin and Range region of the western United States.  Relatively little is known about the microbial communities of soils of the warm, semi-arid grassland region of the southwestern United States.

The purpose of this study was to monitor the fruit production of three woody tree species that occur on the Sevilleta National Wildlife Refuge (NWR). Two monoecious species, Pinus edulis and Quercus turbinella, were assessed along with a dioecious species, Juniperus monosperma. Every August the production of fruit was estimated for these three species at five sites at the Sevilleta NWR. For each of the three tree species different protocols were used for estimating fruit production: P. edulis estimations were number of cones per mature tree, Q.