Diverse microbial communities live in the gut regions of animals. The precise ecological and evolutionary circumstances that govern relationships between hosts and their gut communities is unclear. In this study, we hypothesize that host feeding strategy shapes the microbial communities within the gut systems of insects. We collected five insect species from the Sevilleta National Wildlife Refuge that exhibited herbivorous, detritovorous and carnivorous diets.

Spatial patterns of structures (e.g., nests and burrows) in animal populations can provide insight into underlying ecological processes. Banner-tailed kangaroo rats (Dipodomys spectabilis) and harvester ants (Pogonomyrmex rugosus) are the largest and most dominant granivores found in rodent and ant communities of the northern Chihuahuan Desert. Both species build conspicuous, above-ground structures and are highly territorial.

The Sevilleta LTER is located at the intersection of several aridland ecosystem types. Although it is axiomatic that water is the key limiting resource in aridland ecosystems, most arid land soils are also chronically low in nutrients and organic matter. Resource availability is a function of the frequency and size of precipitation events as well as the time between events. As a consequence, NPP and organic matter decomposition are often decoupled in space and time, and soil nutrient supply rates may limit NPP during periods when soil moisture is sufficient for plant growth.

Background/Questions/Methods

Drought-related tree mortality occurs worldwide, including recent episodes in piñon-juniper woodlands of the American west. Although the physiological mechanisms of mortality are poorly understood, carbon starvation may occur in trees that limit transpiration (E) to avoid hydraulic failure.

The EcoTrends Project began in 2004 as a joint collaboration among the LTER Program, USDA Agricultral Research Service, and the USDA Forest Service with two goals: (1) to create a book illustrating trends in long -term data and showing the value of long-term data across a network of sites in addressing continental-scale questions, and (2) to make long-term biotic and abiotic data easily accessible through a common web interface with a focus on derived or aggregated data to allow cross-site analyses to be made.

Ground-dwelling arthropods, primarily predators and detritivores, form a large part of the energy flow through ecosystems, but there are few long-term studies looking at many taxa. These animals have been monitored at the Sevilleta National Wildlife Refuge in central New Mexico, a Long-Term Ecological Research (LTER) site since 1990. We report on patterns in relative abundance from 2 study sites: desert grassland and creosotebush shrubland. Arthropods were collected in pitfall traps, operated year-round and collected every 2 months.

Disturbance from fire can affect the abundance and distribution of shrubs and grasses in arid ecosystems. Specifically, 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.

Landscapes at the Sevilleta LTER site are dominated or codominated by two perennial grasses from different biomes, Bouteloua eriopoda (black grama) from the Chihuahuan Desert and B. gracilis (blue grama) from the shortgrass steppe, and the Chihuahuan Desert shrub Larrea tridentata (creosotebush). We used a long-term removal study to examine inter-specific interactions between these dominant species, and to determine which species would eventually dominate following the removal of the others.