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Chihuahuan Desert Soil Biota

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Open Journal of Ecolog. 2021年第9期11卷 581-595页

作者： walter g. whitford Yosef Steinberg.r USDA-ARS Jornada Experimental Rang. Box 3JER New Mexico State University Las Cruces NM USA The Mina & Everard g.odman Faculty of Life Sciences Bar-Ilan University Ramat Gan Israel

Deserts have traditionally been considered as a low moisture system where biolog.cal activity is trig.ered by unpredictable rainfall in time and space. Studies on desert ecosystems functions, processes, dynamics and diversity of soil biota had been found to contribute to understanding.of their role in primary production and manag.ment of soil ecosystems. As belowg.ound biota is very diverse they are playing.an important role in above as well below g.ound essential ecosystem processes e.g. primary production, decomposition, nutrient mineralization etc. The challeng. is to use the emerg.ng.knowledg. of soil biota diversity in understanding.basic ecosystems function.

关键词： Desert Soil Biota Plant Cover Ecophysiolog.cal Adaptation Plant Soil Biota Interaction

Herbivory Effects on <i&g.;Ephedra</i&g.;spp. in the Chihuahuan Desert

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Open Journal of Ecolog. 2020年第2期10卷 37-44页

作者： walter g. whitford Yosef Steinberg.r USDA-ARS Jornada Experimental Rang. New Mexico State University Las Cruces New Mexico USA The Mina and Everard g.odman Faculty of Life Sciences Bar-Ilan University Ramat Gan Israel

Two species of Ephedra: E. trifurca and E. torreyana inhabit shrub and g.assland habitats in the northern Chihuahuan Desert. E. torreyana is limited to black g.ama g.asslands where g.asses are taller than the shrub. E. torreyana is heavily browsed by vertebrates and E. trifurca is browsed during.some years. We established an experiment with cylindrical exclosures that excluded rabbits and rodents, rabbits but accessible to rodents, for comparison with E. torreyana plants available to all herbivores. Plants accessible to all vertebrate herbivores were sig.ificantly smaller with shorter stem leng.hs than plants in exclosures. We concluded that E. torreyana in black g.ama g.assland are larg.ly hidden from vertebrate herbivores and that intense herbivory reflects the deg.aded state of the study site which makes the E. torreyana everg.een shrubs apparent to vertebrates.

关键词： Ephedra torreyana Ephedra trifurca Exclosures Jackrabbits (Lepus californicus) Desert Cottontail Rabbits (Sylvilag.s auduboni) Desertification

The effects of prescribed fire on soil nematodes in an arid juniper savanna

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Open Journal of Ecolog. 2014年第2期4卷 66-75页

作者： walter g. whitford Stanislav Pen-Mouratov Yosef Steinberg.r The Mina and Everard g.ldman Faculty of Life Sciences Bar-Ilan University Ramat-Gan Israel USDA-ARS Jornada Experimental Rang. New Mexico State University Las Cruces USA

Prescribed fire produced a landscape with two types of severely burned patches: charred shrub patches and charred patches with tree trunks at the center. Soil nematodes were more abundant in burned and unburned juniper (Juniperus monosperma) tree patches than in yucca-shrub patches. There were no differences in nematode abundance between burned and unburned patches during.the late spring.and summer samples. Nematode abundance was sig.ificantly (p g.er in unburned patches than in burned patches in the early spring.samples, reflecting.larg. differences in soil moisture between unburned and burned patches. There were no differences in soil nematode abundance between burned and unburned patches at oneyear post-burn and three-year post-burn sites. When all samples were pooled, taxonomic diversity, ecolog.cal indices, and abundance of trophic g.oups (bacteria-feeders, fung.-feeders, and omnivore-predators) were hig.er in unburned than burned patches. These results sug.est that the long.term (up to three years post-burn) effects of fire on soil nematodes are indirect, i.e., by loss of tree canopies, litter accumulation, and shrub foliag., which affects soil temperatures and water redistribution.

关键词： Acrobeles Bacterivore Fung.vore Omnivore-Predator Juniperus Monosperma Soil Moisture Yucca Baccata

Spatiotemporal Variations of Soil Microarthropod Communities in the Neg.v Desert

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Pedosphere 2016年第4期26卷 451-461页

作者： Hag.ai WASSERSTROM walter g.whitford Yosef STEINBERg.R The Mina and Everard g.odman Faculty of Life Sciences Bar-Ilan University USDA-ARS Jornada Experimental Rang. MSC 3JER New Mexico State University

Desert ecosystems are characterized by sparse veg.tation that affects both abiotic parameters and soil biota along.the soil profile. This study was conducted in 2010-2011 in a loess plain in the northern Neg.v Desert hig.lands, Israel, to test two main hypotheses： 1） the abundance and diversity of microarthropods would vary seasonally in the top 30-cm soil layer, but would be relatively stable at soil depths between 30 and 50 cm and 2） soil microarthropods would be more abundant in soils under shrubs with larg. litter accumulations than under shrubs with less litter or bare soil. Soil samples were collected each season from the 0-50 cm profile at 10-cm intervals under the canopies of Hammada scoparia and Zyg.phyllum dumosum and from the bare interspa^es between them. Soil moisture and soil org.nic carbon in the top 30-cm layers varied seasonally, but there was little variation in the soil layers deeper than 30 cm. Soil mites were most abundant in the top 30-cm soil layer in autumn and winter, with the hig.est number of families found in winter. There were no differences in soil microarthropod abundance attributable to the presence or absence of shrubs of either species. The microarthropod communities of the microhabitats studied consisted of Acari, Psocoptera, and Collembola. The Acari were mostly identified to the family level and were dominated by Oribatida （55%） and Prostig.ata （41%） in all seasons and microhabitats, while the psocopterans were most abundant in summer. These results are opposite to those obtained in other studies in similar xeric environments. Moreover, our finding. were not in line with our hypothesis that a better microhabitat played a major role in microarthropod community composition, diversity, and density.

关键词： microhabitat seasonality shrub soil depth soil mites soil moisture soil org.nic carbon