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This dataset contains data for soil physical and chemical properties of gypsum and non-gypsum soils in the northern Chihuahuan and eastern Mojave Deserts. Data were obtained from 20 study sites total, 10 located on soils derived from gypsum parent material and 10 located on soils derived from non-gypsum parent materials. Sites were grouped into 10 pairs, in which every gypsum site was partnered with a non-gypsum site located in the same region. Apart from soil type, partnered-site characteristics (topography, climate, elevation, slope, aspect, and presence of biocrusts) were held relatively constant. Site info and characteristics data can be accessed at knb-lter-jrn.210616001. Soil physical properties included: percent gravel, percent < 2mm fraction, soil aggregate stability, and soil compaction. Soil chemical properties were: percent gypsum content, pH, EC, and soil soluble concentrations of calcium, magnesium, potassium, sulfur, and phosphorus. The resulting soil data was used to understand physical and chemical differences between gypsum and non-gypsum soils and to examine how biocrust community types and moss species abundance and composition were associated with the measured soil variables. This study and dataset are complete.
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Cover and frequency of biological soil crust community types, moss species, vascular plants, and abiotic land surface features, on gypsum & non-gypsum soils from the Chihuahuan and Mojave Deserts in 2023
This dataset contains raw and calculated percent cover and frequency data for biological soil crust (hereafter biocrust) functional groups, vascular plant functional groups, and abiotic land surface features on and off gypsum soils in the northern Chihuahuan and eastern Mojave Deserts. Abundance data were obtained from 20 study sites total, 10 located on soils derived from gypsum parent material and 10 located on soils derived from non-gypsum parent materials. Sites were grouped into 10 pairs, in which every gypsum site was partnered with a non-gypsum site located in the same region. Apart from soil type, partnered-site characteristics (topography, climate, elevation, slope, aspect, and presence of biocrusts) were held relatively constant. At each site, cover and frequency assessments were made using the line-point intercept method (LPI) and frequency quadrats (1.0 m^2), respectively. Biocrust functional groups included the following crusts: lichen, moss, incipient algal, light algal, dark algal, unknown photosynthetic crust, and vagrant cyanobacteria. Vascular plant categories included: perennial forbs, perennial graminoids, annual forbs, annual graminoids, subshrub, shrub, Yucca, and cacti. Abiotic land surface features included: woody litter, herbaceous litter, bare soil, rock, bedrock, and animal feces. Moss crusts identified within cover and frequency analyses were sampled, and classified to species level via microscopy. The resulting percent cover and frequency data was used to understand differences in biocrust and moss species abundance and diversity on and off gypsum soils; furthermore, how biocrust and moss species abundance was associated with the measured environmental variables. Soil physical and chemical data from this study can be accessed at knb-lter-jrn.210616002. This study and dataset are complete.
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- Award ID(s):
- 2025166
- PAR ID:
- 10557430
- Publisher / Repository:
- Environmental Data Initiative
- Date Published:
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Introduction In dryland systems, biological soil crusts (biocrusts) can occupy large areas of plant interspaces, where they fix carbon following rain. Although distinct biocrust types contain different dominant photoautotrophs, few studies to date have documented carbon exchange over time from various biocrust types. This is especially true for gypsum soils. Our objective was to assess the carbon exchange of biocrust types established at the world’s largest gypsum dune field at White Sands National Park. Methods We sampled five different biocrust types from a sand sheet location in three different years and seasons (summer 2020, fall 2021, and winter 2022) for carbon exchange measurements in controlled lab conditions. Biocrusts were rehydrated to full saturation and light incubated for 30 min, 2, 6, 12, 24, and 36 h. Samples were then subject to a 12-point light regime with a LI-6400XT photosynthesis system to determine carbon exchange. Results Biocrust carbon exchange values differed by biocrust type, by incubation time since wetting, and by date of field sampling. Lichens and mosses had higher gross and net carbon fixation rates than dark and light cyanobacterial crusts. High respiration rates were found after 0.5 h and 2 h incubation times as communities recovered from desiccation, leveling off after 6 h incubation. Net carbon fixation of all types increased with longer incubation time, primarily as a result of decreasing respiration, which suggests rapid recovery of biocrust photosynthesis across types. However, net carbon fixation rates varied from year to year, likely as a product of time since the last rain event and environmental conditions preceding collection, with moss crusts being most sensitive to environmental stress at our study sites. Discussion Given the complexity of patterns discovered in our study, it is especially important to consider a multitude of factors when comparing biocrust carbon exchange rates across studies. Understanding the dynamics of biocrust carbon fixation in distinct crust types will enable greater precision of carbon cycling models and improved forecasting of impacts of global climate change on dryland carbon cycling and ecosystem functioning.more » « less
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This dataset contains photosynthetic light response data from biological soil crusts collected from a gypsum sand sheet at White Sands National Park, NM, USA in three different seasons. This study aims to 1) assess the carbon fixation capacity of biocrust types; 2) assess biocrust carbon fixation response under varying incubation times; 3) and understand variability in carbon fixation response in different seasons. Sample collection occurred in July 2020 (summer), September 2021 (fall), and March 2022 (winter). The biocrust types of interest were light cyanobacterial, dark cyanobacterial, Peltula lichen, Clavascidium lichen, and moss crusts. Samples were collected with the intention of taking carbon fixation measurements after different incubation periods (30 min, 2 hr, 6 hr, 12hr, or 24 hr in 2020, and 30 min, 2 hr, 6 hr, 12hr, 24 hr, or 36 hr in 2021 and 2022). For each condition (biocrust type and incubation time) there were five replicates in 2020 (total n=125) and ten replicates in 2021 and 2022 (total n=300). After collection, the intact samples were re-wetted and subjected to their respective incubation period and measured for photosynthetic response. The resulting light response curves and photosynthetic information was be used for comparing biocrust type, incubation time response differences, and seasonal variation to understand variability of biocrust carbon flux response at a single site. This data set includes the light response curve values and photosynthetic data calculated from these curves and raw LICOR output files compiled into 3 spreadsheet files. The included 2020 data is also associated with the White Sands National Park data from Jornada Study 549. This dataset accompanies the in-press article by Hoellrich et al. (2023) cited below, and the study is now complete. Hoellrich, Mikaela R., Darren K. James, David Bustos, Anthony Darrouzet-Nardi, Louis S. Santiago, and Nicole Pietrasiak. "Biocrust carbon exchange varies with crust type and time on Chihuahuan Desert gypsum soils." Frontiers in Microbiology 14:1128631.more » « less
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Biological soil crusts (biocrusts) are living soil surface aggregates housing communities of microbes. They cover an estimated 12% of the Earth’s surface and provide ecosystem services including soil stability, nutrient cycling, and carbon sequestration. However, the ecological dynamics of biocrust have not been comprehensively described across hot desert ecosystems. Our objective was to investigate how biocrust cover and composition varies within a diverse Chihuahuan Desert landscape using an ecological site and state framework and how this variability translates to ecosystem services. We quantified vegetation characteristics, biocrust cover and composition, ecosystem structure, soil chemical and physical characteristics, and soil stability of 63 plots across the Jornada Experimental Range in southern New Mexico. The plots represented clayey, loamy, and sandy ecological sites and each contained 4-5 alternate ecological states. NMDS ordination was used to identify the influence of ecological site and state on biocrust composition and other soil surface categories while environmental fits revealed relationships between the environmental variables and biocrusts. We found that biocrust cover and composition varied by both ecological site and state, for example, clayey and loamy sites had the greatest biocrust functional group richness but also the greatest variability in cover among states. Sandy had the lowest average biocrust cover and diversity. No consistent direction of change in biocrust cover and composition was found as ecological states departed from reference conditions. Specifically, reference and altered states differed greatly between ecological sites in diversity and composition of crust types. For example, crust diversity was very high and complex lichen cover was highest in the most altered, non-vegetated state of clay sites, but not so in the non-vegetated state of loamy sites. Our findings emphasize how biocrust cover and composition are shaped by ecological site and state drivers which differ from state alteration effects on vascular vegetation, and can thus lead to a more holistic understanding of the dryland landscape and provide novel aspects for land management.more » « less
