This data package contains vegetation cover from plots with various levels of herbivore exclusion on the Jornada Experimental Range (JER) and Chihuahuan Desert Rangeland Research Center (CDRRC) in Dona Ana County, southern New Mexico, USA. Study sites were established in 1995; one in black grama grassland and the other in creosotebush shrubland to compare the impact of herbivores on ecosystem processes between these vegetation types. Parallel studies were established at the Sevilleta LTER site (New Mexico, USA) and Mapimi Biosphere Reserve (Durango, Mexico). Each study site is 1 km by 0.5 km in area. Four replicate experimental blocks were randomly located at the grassland study site to measure vegetation responses using exclusion treatments including a) all mammalian herbivores, including cattle, lagomorphs, and rodents, b) lagomorphs and cattle only, c) cattle only, and d) control accessible to all herbivores. Because grazing cattle are excluded from the entire creosote site, only three replicate experimental blocks were randomly located there including a) all mammalian herbivores, including lagomorphs, and rodents, b) lagomorphs only, and c) control accessible to all herbivores. Thirty-six sampling points were positioned at 5.8-meter intervals on a systematically located 6 by 6 point grid within each plot. A permanent one-meter by one-meter vegetation measurement quadrat is located at each of the 36 points. At each quadrat, percent cover by individual plant species is measured. Other measurements include height (cm) of each species in the quadrat, and plant condition (living or dead). Data were collected in the spring and fall of every year from 1995 to 2005. After 2005, sampling frequency changed to every 5 years in the fall. This study is ongoing.
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Rodent Parasite Data for the Sevilleta National Wildlife Refuge, New Mexico (1990-1998)
The 100,000 ha Sevilleta National Wildlife Refuge (SNWR) in central New Mexico lies in a transition zone that straddles several major biomes of the Southwest, including Great Basin Shrub-Steppe, Mogollon Pinon-Juniper Woodland, Great Plains Grassland and Chihuahuan Desert. During 9 years, (1990-1998), collaborating with the University of New Mexico's Long Term Ecological Research (LTER) program, 3,235 rodents (28 species in 4 families) were collected and identified from permanent collecting sites on the 3 major habitat types (grassland, desert/creosote, woodland) on the SNWR. Hosts were necropsied for endoparasites (protozoa [coccidia], helminths) and some ectoparasites. We identified and analyzed all the parasites found in these hosts. By 1998, we had in place the means to easily identify and moniter the parasites from all mammalian hosts caught on the LTER Phase II grant.This is not just another parasite survey; the data we collected was unique for several reasons: 1) This was the first complete inventory of a natural assemblage of parasites from all mammalian (rodent) hosts in 3 different communities, each from a distinctly defined geographic locality (habitat type) over the period of a decade, and beyond; 2) This study was part of a multidisciplinary approach to address conceptual issues of climate change on ecosystem structure and function at multiple scales (individuals, communities, etc) and correlative data from these related studies will strengthen and contribute to the robustness of this data set; 3) As the only parasite study on any of the LTER projects nationwide, it provided an ideal model, and perhaps incentive for parallel longterm studies of parasite communities to be examined in a variety of other habitat types, and from a variety of different perspectives, and other LTER sites in the network.Upon completing the work, we were able to use these long-term data to try to understand the dynamics of natural host-parasite assemblages. Hypotheses were then erected to test/address at least these questions: How do the different parasite communities colonize, mature, climax and senesce over time (or do they?), Do they vary in response to abiotic (climate change) and/or biotic (dispersal, colonization) factors? What temporal and spatial scales, and among what kinds of organisms, do coevolutionary processes influence the community organization of these parasites? Studies of the dynamics of multiple, coexisting species are confined primarily to microtine rodents and have hinted that multiannual cycles tend to be synchronous (Brown and Heske 1990). Are similar patterns seen for the parasites of our desert rodents? Answers to these questions relating to community structure, as well as to questions concerning parasite biodiversity on the SNWR, can be answered paritially or completely by the information we gathered on the parasite species infecting rodents collected on the SNWR. Initial emphasis of our work was on identifying all the parasites collected, by processing 8 consecutive years of parasite data, and on training the undergraduate and graduate students involved in the art of taxonomy and nomenclature of parasitic protozoans and helminths, to supply some of these answers.
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- Award ID(s):
- 1655499
- NSF-PAR ID:
- 10424407
- Publisher / Repository:
- Environmental Data Initiative
- Date Published:
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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