Skip to main content
Advanced Search

Filters: Tags: lichens (X)

29 results (78ms)   

View Results as: JSON ATOM CSV
Biological soil crusts, consisting of cyanobacteria, green algae, lichens, and mosses, are important in stabilizing soils in semi-arid and arid lands. Integrity of these crusts is compromised by compressional disturbances such as foot, vehicle, or livestock traffic. Using a portable wind tunnel, we found threshold friction velocities (TFVs) of undisturbed crusts well above wind forces experienced at these sites; consequently, these soils are not vulnerable to wind erosion. However, recently disturbed soils or soils with less well-developed crusts frequently experience wind speeds that exceed the stability thresholds of the crusts. Crustal biomass is concentrated in the top 3 mm of soils. Sandblasting by wind can...
thumbnail
Fifteen fires from the Chronosequence dataset (see Knutson et al. 2014) were visited in 2012 and 2013 and surveyed for cover of lichens and mosses. Fires were selected to cover the range of average precipitation for each of three water years following fire, fire severity, time since fire, season of ignition, total acres burned and grazing intensity. Cattle grazing was characterized by distance from water sources for cattle, cow dung density counts and Animal Unit Months from the Rangeland Administration System of the Bureau of Land Management. Fire was characterized by whether or not a site burned, time since fire, the area burned, and an estimated amount of shrub cover consumed by the fire as compared to seemingly...
thumbnail
Data includes satellite derived pre-fire functional group cover of annual and perennial herbaceous, shrubs, bareground and litter across four rangeland megafires in the Western US, as well as field estimated invasive annual grass measurements from the 2nd to 3rd years post-fire. Additional landscape and restoration treatment covariates hypothesized to influence post-fire invasive annual grass cover are included.
thumbnail
Twenty quadrats within the burn perimeter of a September 2021 wildfire outside of Boise, Idaho were surveyed for the abundance of fire effects, biocrusts and vascular plants immediately post-fire. The fire was too small to be named. Char was measured as a proxy for fire intensity. Biocrusts were surveyed by morphogroup (crustose lichens, cup lichens, fruticose lichens, gelatinous lichens, short moss, tall moss) and vascular plants were surveyed by functional group (annual forbs, perennial grasses). Char was measured ocularly and biocrust/plant abundance was measured via point-vertex intercept at 40 points per quadrat. These data support the following publication: Condon, L.A., Shinneman, D.J., Rosentreter, R. and...
thumbnail
The data reflect surveys from 10-year sampling frames established as part of the Sagebrush Steppe Treatment Evaluation Project. The project tests fuel reduction treatments on the lichen and moss components of biocrusts across the sagebrush steppe.
1. At the heart of the body of research on biodiversity effects on ecosystem function is the debate over whether different species tend to be functionally singular or redundant. When we consider ecosystem multi-function, the provision of multiple ecosystem functions simultaneously, we may find that seemingly redundant species may in fact play unique roles in ecosystems. 2. Over the last few decades, the significance of biological soil crusts (BSCs) as ecological boundaries and ecosystem engineers, and their multi-functional nature, has become increasingly well documented. We compiled ‘functional profiles’ of the organisms in this understudied community, to determine whether functional singularity emerges when...
Seven exclosures that were part of the original 28 Taylor Grazing Act exclosures across northern Nevada were surveyed for cover of biological soil crusts in May 2018. Surveys consisted of 15 quadrats both inside and outside of the exclosures. Quadrats were used to measure biocrust cover via point-intercept at 39 vertices within each quadrat. Cattle grazing outside of the exclosures was characterized by distance from the closest water source as well as permitted, suspended and active Animal Unit Months from the Rangeland Administration System. Abundance of cyanobacteria in the soils was assessed with the moistened soil method.
thumbnail
Sixty-eight monitoring plots within the Browns Park National Wildlife refuge in Northwest Colorado were surveyed in the Summer of 2007 and 2021 for vegetation-community changes after grazing cessation in 1986. Surveys consisted of line-point intercept measurements at 0.5m intervals along three 15-m transects arranged in a spoke around plot center at each plot location.
Presented by Don Spalinger & Nathan WolfThis seminar focuses on our concepts of regulation of nutrient flows through tundra ecosystems and the effect that climate (or weather) has on these processes. Nutrient flow and climate, in turn, should regulate plant phenology and production, and thus caribou behavior and nutrition. We will present some ideas for assessing the landscape patterns of these processes and monitoring their impacts. Finally, we will provide examples of such assessment and monitoring processes from our work in Western Alaska over the past two years.‚Äč
Categories: Data; Tags: ALPINE/TUNDRA, ALPINE/TUNDRA, CARBON, CARBON, CARBON CYCLE/CARBON BUDGET MODELS, All tags...
We evaluated the effects of probabilistic (hereafter DESIGN) and non-probabilistic (PURPOSIVE) sample surveys on resultant classification tree models for predicting the presence of four lichen species in the Pacific Northwest, USA. Models derived from both survey forms were assessed using an independent data set (EVALUATION). Measures of accuracy as gauged by resubstitution rates were similar for each lichen species irrespective of the underlying sample survey form. Cross-validation estimates of prediction accuracies were lower than resubstitution accuracies for all species and both design types, and in all cases were closer to the true prediction accuracies based on the EVALUATION data set. We argue that greater...
thumbnail
Biological soil crusts are a diverse soil surface community, prevalent in semiarid regions, which function as ecosystem engineers and perform numerous important ecosystem services. Loss of crusts has been implicated as a factor leading to accelerated soil erosion and other forms of land degradation. To support assessment and monitoring efforts aimed at ensuring the sustainability of rangeland ecosystems, managers require spatially explicit information concerning potential cover and composition of biological soil crusts. We sampled low disturbance sites in Grand Staircase?Escalante National Monument (Utah, USA) to determine the feasibility of modeling the potential cover and composition of biological soil crusts...
Conclusions:distance from edge and the habitat heterogeneity were the most important variables affecting bryophyte and lichen species richnessThresholds/Learnings:Temperature and light intensity decreased, and humidity increased up to 15m from the edge of fragments in the study.
The tundra biome is the dominant terrestrial ecosystem of the circumpolar north, and its fate in a rapidly changing climate is of high scientific and socioeconomic concern. One of those concerns is that the majority of caribou herds throughout the circumpolar north are declining, perhaps as a result of climate change. The principal objective of this research is to reveal the connections between soil nutrient cycling, forage quality and caribou habitat selection. This framework is underpinned by the concept that tundra ecosystem productivity is ultimately driven by the thermodynamics of the system induced by climate.
Categories: Data, Publication; Types: Citation; Tags: ALPINE/TUNDRA, ALPINE/TUNDRA, CARBON, CARBON, CARBON CYCLE/CARBON BUDGET MODELS, All tags...
Molecular methodologies were used to characterize fungal communities associated with lichen-dominated biological soil crusts (BSCs) at two sites on the Colorado Plateau (USA) in order to investigate their diversity and abundance, in relation to that of bacteria, as well as how these parameters corresponded to overall soil crust cover and the presence of anthropogenic disturbance. Fungal community diversity and composition were assessed with denaturing gradient gel electrophoresis (DGGE) fingerprinting of PCR amplified ribosomal genes and by sequencing. Quantitative PCR, specific for fungi as well as bacteria, was used to evaluate relative microbial densities. Two sites with similar soil characteristics, both of...
thumbnail
The data were collected at Morley Nelson, Birds of Prey National Conservation Area (NCA) where known grazing regimes, including the season of grazing, have been in practice for the last 30 years. Surveyed plots were placed to account for intensity of grazing and to avoid confounding disturbances. Data were collected on the morphogroups of biological soil crusts (biocrusts) found within the NCA, and include measurements on soils related to texture, carbon, nitrogen and the abundance of soil aggregating cyanobacteria in the soil.
Cyanobacterial-lichen soil crusts can be a dominant source of nitrogen for cold-desert ecosystems. Effects of surface disturbance from footprints, bike and vehicle tracks on the nitrogenase activity in these crusts was investigated. Surface disturbances reduced nitrogenase activity by 30?100%. Crusts dominated by the cyanobacterium Microcoleus vaginatus on sandy soils were the most susceptible to disruption; crusts on gypsiferous soils were the least susceptible. Crusts where the soil lichen Collema tenax was present showed less immediate effects; however, nitrogenase activity still declined over time. Levels of nitrogenase activity reduction were affected by the degree of soil disruption and whether sites were...
In western North America, quaking aspen (Populus tremuloides) is the most common hardwood in montane landscapes. Fire suppression, grazing and wildlife management practices, and climate patterns of the past century are all potential threats to aspen coverage in this region. If aspen-dependent species are losing habitat, this raises concerns about their long-term viability. Though lichens have a rich history as air pollution indicators, we believe that they may also be useful as a metric of community diversity associated with habitat change. We established 47 plots in the Bear River Range of northern Utah and southern Idaho to evaluate the effects of forest succession on epiphytic macrolichen communities. Plots were...
Nitrogen translocation was measured in Cladonia portentosa during 2 yr growth in Scottish heathland. Translocation was predicted to occur if N is resorbed from senescent basal tissue and recycled within the thallus. (15)N was introduced into either the lower (TU thalli) or upper (TD thalli) 25 mm of 50-mm-long thalli as (15)N-NH(4) (+), (15)N-NO(3) (-) or (15)N-glycine. Labelled thalli were placed within intact lichen cushions, either upright (TU) or inverted (TD). Vertical distribution of label was quantified immediately following labelling and after 1 and 2 yr. Independently of the form of introduced label, (15)N migrated upwards in TU thalli, with new growth being a strong sink. Sink regions for (15)N during...
thumbnail
Desertification is a global problem, costly to national economies and human societies. Restoration of biological soil crusts (BSCs) may have an important role to play in the reversal of desertification due to their ability to decrease erosion and enhance soil fertility. To determine if there is evidence that lower fertility may hinder BSC recolonization, we investigated the hypothesis that BSC abundance is driven by soil nutrient concentrations. At a regional scale (north and central Colorado Plateau, USA), moss and lichen cover and richness are correlated with a complex water?nutrient availability gradient and have approximately six-fold higher cover and approximately two-fold higher species richness on sandy soils...
In the western United States vast acreages of land are exposed to low levels of atmospheric nitrogen (N) deposition, with interspersed hotspots of elevated N deposition downwind of large, expanding metropolitan centers or large agricultural operations. Biological response studies in western North America demonstrate that some aquatic and terrestrial plant and microbial communities are significantly altered by N deposition. Greater plant productivity is counterbalanced by biotic community changes and deleterious effects on sensitive organisms (lichens and phytoplankton) that respond to low inputs of N (3 to 8 kilograms N per hectare per year). Streamwater nitrate concentrations are elevated in high-elevation catchments...


map background search result map search result map Spatial Modeling of Biological Soil Crusts to Support Rangeland Assessment and Monitoring Evidence for micronutrient limitation of biological soil crusts- Importance to arid-lands restoration Disturbance characteristics, vegetation and biocrust cover from the northern Great Basin (USA) 2012-2013 Biological soil crust cover from the Taylor Grazing Act exclosures Ten-year data for biocrust cover after fire management treatments on sagebrush-cheatgrass sites Fire Response Effects, Biocrust, and Vascular Plant Abundance Following Wildfire near Boise, Idaho (October 2021) Vegetation and soil cover data for long-term monitoring plots within Browns Park National Wildlife Refuge, Colorado, USA Morphogroups of Biocrusts Following Seasons of Grazing Near Boise, Idaho Pre-fire satellite derived and field calculated functional cover across Great Basin megafires Vegetation and soil cover data for long-term monitoring plots within Browns Park National Wildlife Refuge, Colorado, USA Morphogroups of Biocrusts Following Seasons of Grazing Near Boise, Idaho Fire Response Effects, Biocrust, and Vascular Plant Abundance Following Wildfire near Boise, Idaho (October 2021) Spatial Modeling of Biological Soil Crusts to Support Rangeland Assessment and Monitoring Pre-fire satellite derived and field calculated functional cover across Great Basin megafires Biological soil crust cover from the Taylor Grazing Act exclosures Evidence for micronutrient limitation of biological soil crusts- Importance to arid-lands restoration Disturbance characteristics, vegetation and biocrust cover from the northern Great Basin (USA) 2012-2013 Ten-year data for biocrust cover after fire management treatments on sagebrush-cheatgrass sites