@article {50064, title = {Pack rats (Neotoma spp.): Keystone ecological engineers?}, journal = {Journal of Arid Environments}, volume = {74}, year = {2010}, note = {//NMSU,USDA//LTER V//entered 07/23/2010; pdf available}, month = {2010}, pages = {1450-1455}, chapter = {1450}, abstract = {

The potential role of two species of pack rats (Neotoma albigula) and Neotoma micropus) as keystone ecological engineers was examined by estimating the species diversity of invertebrates living in the nest middens, and nitrogen mineralization rates in soils associated with the middens. Although pack-rat middens in tarbush (Flourensia cernua) shrublands were smaller than those in creosotebush (Larrea tridentata) shrublands, they housed a higher abundance and diversity of arthropods. The Neotoma spp. middens were an important microhabitat for crickets (Gryllus sp.), wolf spiders (Lycosa spp.), and lycid beetle larvae (Lycidae) in all of the shrub habitats. There were five arthropod taxa that occupied all middens in the creosotebush shrubland, and 12 arthropod taxa that occupied all middens in the tarbush shrubland. Soils associated with pack-rat middens had significantly higher soil organic-matter content than reference soils. Nitrogen mineralization was significantly higher in soils associated with pack-rat middens than in reference soils. Neotoma spp. create habitats with moderate microclimates that are essential for several invertebrates, thus contributing to maintenance of biodiversity. The effects of middens on soil organic matter and nitrogen mineralization create nutrient-rich patches. Neotoma spp. affect biodiversity and critical ecosystem processes, thus supporting the designation of keystone ecological engineers. {\textcopyright} 2010 Published by Elsevier Ltd.

}, keywords = {habitat, mineralization, species diversity, stick nest, woodrat}, doi = {10.1016/j.jaridenv.2010.05.025}, url = {/files/bibliography/10-050.pdf}, author = {Walter G. Whitford and Yosef Steinberger} } @article {50749, title = {Applying species diversity theory to land management}, journal = {Ecological Applications}, volume = {13}, number = {6}, year = {2003}, month = {December 1, 2003}, pages = {1750-1761}, abstract = {

Many theories and hypotheses have been proposed to explain patterns of species diversity and distribution/abundance at particular scales, but they are often unclear on how these ideas relate or how they apply across multiple scales. It has been difficult to use diversity theory to understand patterns at the intermediate scales at which biodiversity is managed. Here, we present a framework for studying diversity based on the ecological processes influencing distribution of organisms at different scales. We use this framework to organize diversity theories into several classes. The framework highlights that processes contributing to diversity patterns depend on the characteristics of the taxa considered, the spatial scales at which organisms respond to environment, and the scales and other characteristics of the particular environments in which investigators hope to explain variation in diversity. At the scales traditionally considered by land managers and conservation biologists, biodiversity is determined b the interactions among habitat occupancy, landscape distribution, and geographic range for a variety of taxa. The framework suggests that, in each case, managers should address the following general questions: 1) which groups of organisms will be considered, 2) how do their domains of scale relate to the land area under consideration, 3) what processes are likely to be important determinants of species distribution at management scales, and 4) how will the proposed management activities interact with these processes? We emphasize the value of considering species diversity theories in a pluralistic and case-specific way, rather than seeking singular explanations or "general laws" explaining diversity variations.

}, keywords = {Chihuahuan Desert, competition, conservation, dispersal, land management, landscape ecology, limitation geographic, macroecology, natural resources management, range habitat, Selection, species diversity}, doi = {10.1890/02-5089}, url = {files/bibliography/JRN00376.pdf}, author = {Brandon T Bestelmeyer and J.R. Miller and J.A. Wiens} } @article {50974, title = {Local and regional-scale responses of ant diversity to a semiarid biome transition}, journal = {Ecography}, volume = {24}, number = {4}, year = {2001}, month = {December 1, 2001}, pages = {381-392}, abstract = {

The locations of biome transitions and ecotones are frequently defined by the rapid shift from one form of dominant vegetation to another. The composition of animal taxa is predicted to shift parallel with that of dominant plants, and species diversity is predicted to be greater in transitional zones than in adjacent areas. We asked whether ant species diversity and composition supported these predictions across a biome transition between shortgrass steppe and Chihuahuan Desert vegetation. Neither species richness nor diversity was highest at the biome transition region as a whole or within habitats in the biome transition. The biome transition region was not intermediate in ant species composition or in the representation of different faunal complexes. The community similarity between matched habitats shared between the biome transition zone and adjacent regions was less than that between distinct habitats occurring within regions. A zoogeographic transition for ants may occur to the nort of the phytogeographic transition and may be coincident with the northern limits of monsoonal precipitation patterns. In contrast, the phytogeographic transition may be related to less extreme climatic variation within the monsoonal region occurring further south.

}, keywords = {ants, Desert insects, grasslands, Habitats, Insect communities, shrublands, species diversity, Steppes, Taxa}, doi = {10.1034/j.1600-0587.2001.d01-194.x}, url = {/files/bibliography/01-015.pdf}, author = {Brandon T Bestelmeyer and J.A. Wiens} } @conference {51089, title = {Effects of small patchy distrubances on plant species diversity at a semiarid grassland ecotone}, booktitle = {85th Annual Meeting, Ecological Society of America}, year = {2000}, month = {August 6-10, 200}, pages = {393}, address = {Snowbird, UT}, abstract = {Our objective was to evaluate the effects of patchy disturbances created by kangaroo rats on species diversity and composition at a semiarid-arid grassland ecotone. Our study was conducted at the Sevilleta LTER in New Mexico, where a grassland dominated by Bouteloua gracilis, a shortgrass steppe species, and a grassland dominated by B. eriopoda, a Chihuahuan Desert species, meet to form patches across the landscape. Four 0.4 ha plots were sampled for vegetation within a 7m x 7m grid in each grassland type. Kangaroo rat mounds were also mapped and sampled in 4 areas of 1.6 ha in each grassland type. The landscape scale abundance of many subordinate species was increased significantly by populations occurring on kangaroo rat mounds in both grassland types. Dominant plants on mounds in the B. eriopoda type were also abundant in off-mound areas whereas dominant plants on mounds in the B. gracilis type were not as abundant off-mound. These results indicate that the presence of mounds in B. gracilis dominated grasslands creates islands of plant communities that are distinct from the rest of the grassland. Therefore, the occurrence of certain plant species in this grassland may be intimately associated with the disturbance regime at this ecotone.}, keywords = {grassland, kangaroo rats, patchy disturbances, semiarid-arid, species diversity}, author = {G. Kroel-Dulay and Hochstrasser, T. and Debra C. Peters} } @conference {51090, title = {The influence of kangaroo rat mounds on species diversity and abundance in two grassland types at a semiarid ecotone}, booktitle = {85th Annual Meeting, Ecological Society of America}, year = {2000}, month = {August 6-10, 200}, pages = {300}, address = {Snowbird, UT}, abstract = {Our objective was to evaluate the effects of kangaroo rat mounds on species diversity and composition at a semiarid-arid grassland ecotone. We expected that source populations of plants occurring on kangaroo rat mounds have important influences on species composition of vegetation at the landscape scale and that these influences differ by grassland type. Our study was conducted at the Sevilleta LTER in New Mexico, where a grassland type dominated by Bouteloua gracilis, a shortgrass steppe species, and a grassland dominated by B. eriopoda, a desert grassland species, meet to form patches across the landscape. Four 0.4 ha plots were sampled for species diversity and composition within a 7m x 7m grid in each grassland type. Kangaroo rat mounds were also mapped and sampled for vegetation measures in 4 areas of 1.6 ha in each type. The landscape scale abundance of many subordinate species was increased significantly by populations occurring on kangaroo rat mounds in both grassland types. However, the are affected by the burrowing activity of kangaroo rats was twice as large in the B. eriopoda dominated grassland type. Furthermore, dominant plants on mounds in the B. eriopoda type were also abundant in off-mound areas whereas dominant plants on mounds in the B. gracilis type were not as abundant off-mound. These results indicate that the presence of mounds in the B. gracilis dominated type is creating islands of plant communities that are distinct from the rest of the grassland. Therefore, the occurrence of certain plant species in this grassland type may be intimately associated with the disturbance regime at this ecotone.}, keywords = {composition, grassland ecotone, kangaroo rat mounds, Sevilleta LTER, species diversity}, author = {G. Kroel-Dulay and Hochstrasser, T. and Debra C. Peters} } @conference {51422, title = {Responses of plant assemblages to disturbance gradients in the northern Chihuahuan Desert}, booktitle = {Winter Meeting of the British Ecological Society}, year = {1995}, month = {December 19-21, }, pages = {71}, address = {University of Sheffield, GB}, abstract = {At three locations in the Chihuahuan Desert, domestic livestock-induced disturbance gradients extend outward from watering points. Soil is more compacted but less stable near the watering points. Plant species richness changes little along the gradient, but species diversity and plant biomass does increase dramaatically with distance from the watering point.}, keywords = {Chihuahuan Desert, disturbance gradients, plant assemblages, species diversity}, author = {A.G. de Soyza and Justin Van Zee and Walter G. Whitford and Jeffrey E. Herrick} } @article {51681, title = {Effects of nitrogen amendment on annual plants in the Chihuahuan Desert}, journal = {Plant and Soil}, volume = {120}, year = {1989}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1989}, pages = {225-231}, abstract = {

Effects of nitrogen amendments on spring annual plant distribution, primary production, and species diversity in a semi-arid environment were studied. The ecological responses of spring annual plant species to nitrogen differed between species, and between sites. The distribution of each species in a control transect was wider than in a nitrogen-treated transect. Annual plant species diversity at each station in the control transect was higher than that of the nitrogen-treated transect. The lower site of the Lower Basin Slope areas had the highest species diversity (0.94 for the control and 0.84 for the nitrogen-treated), and the Upper Basin Slope area, shrub vegetation zone, had the lowest species diversity (0.27 for the control and 0.05 for the nitrogen-treated) in both transects. Inorganic nitrogen in the nitrogen-treated transect soils was consistently higher than that in the control transect soils; however, the former showed more fluctuation from station to station in the latter. Above-ground biomass of spring annual plants in the nitrogen-treated transect was consistently higher than that in the control at each station. The maximum above-ground biomass in the control and nitrogen-treated transect was 24.4+-4.4 g m-2 and 61.2+-10.6 g m-2, respectively. Variations in above-ground biomass along the transect did not parallel with the variation in inorganic nitrogen in soils and species diversity.ty.

}, keywords = {annual plants,nitrogen amendment, article, articles, dominance-diversity curve, ecosystem dynamics, annual plants, fertilization, nitrogen, journal, journals, nitrogen amendment, plants, annual distribution, plants, primary production, plants, response to nitrogen, plants, species diversity, primary production, annual plants, species diversity, transect,annual plants}, url = {files/bibliography/JRN00094.pdf}, author = {Hyeong-Tae Mun and Walter G. Whitford} }