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Ground squirrels act as important members of grassland ecosystems by serving as both ecosystem engineers and as a prey base for carnivores. There is mounting evidence that climate change is driving ground squirrel population declines. We resurveyed 54 historical localities throughout the Wyoming Basin and western Colorado where Wyoming Ground Squirrel (Urocitellus elegans) specimens were collected to investigate if climate change was driving extirpations at these historically occupied sites. We detected extirpations at 12 sites and used binomial generalized linear models in an information-theoretic framework to investigate if climate change was associated with these extirpations. Additionally, we investigated if land cover change was associated with persistence and if land cover ameliorated or exacerbated the effects of climate change. We found that changes in climate, especially increasingly dry summer air and increasing mean summer temperatures, were associated with a reduced probability that U. elegans persisted at a historically occupied site. In addition, we found that current forest cover at a site and increasing rangeland cover at the regional level were associated with reduced probability that U. elegans persisted, although these associations were weaker than the climate associations. The effects of climate change and land cover change did not interact. Our findings build on mounting evidence that montane-associated ground squirrels throughout the Western United States are negatively impacted by climate change. The reduction in ground squirrel abundance or their extirpation due to climate change could lead to changes in ecosystem structure or reductions in trophic complexity. [ABSTRACT FROM AUTHOR]

Headwater forest ecosystems of the western USA generate a large portion of the dissolved organic matter (DOM) transported in streams across North America. Land cover changes that alter forest structure and species composition affect the quantity and composition of DOM transferred to aquatic ecosystems. Clear‐cut harvesting affects ~1% of the forest area of North America annually, leaving most western forests in varying stages of regrowth and the total area of old‐growth forest is decreasing. The consequences of this widespread management practice on watershed carbon cycling remain unknown. We investigated the role of land cover change, because of clear‐cut harvesting, from mixed‐species old‐growth to lodgepole pine‐dominated second‐growth forest on the character and reactivity of hillslope DOM exports. We evaluated inputs of DOM from litter leachates and export of DOM collected at the base of trenched hillslopes during a 3‐year period (2016–2018) at the Fraser Experimental Forest in north‐central Colorado, USA. Dissolved organic carbon and total dissolved nitrogen were higher in lateral subsurface flow draining old‐ versus second‐growth forest. Fluorescence spectroscopy showed that the DOM exported from the old‐growth forest was more heterogeneous and aromatic and that proteinaceous, microbially processed DOM components were more prevalent in the second‐growth forest. Biological oxygen demand assays revealed much lower microbial metabolism of DOM in litter leachate and subsurface exports from the old‐growth forest relative to second growth. Old‐growth and second‐growth forests are co‐mingled in managed ecosystems, and our findings demonstrate that land cover change from a mixture of conifer species to lodgepole pine dominance influences DOM inputs that can increase the reactivity of DOM transferred from terrestrial to aquatic ecosystems. [ABSTRACT FROM AUTHOR]

The article discusses the study that aims to contribute to knowledge of urban ecosystems by quantifying biomass and carbon pools in Colorado's Front Range. It examines the carbon pools of soil and vegetation on landscaped properties in order to characterize vegetation and soils found in urban green spaces. The study also aims to analyze the vegetative carbon storage and the soil carbon storage and compares the suburban ecosystem properties to their counterparts in native grassland and cultivated fields.

New technologies and increasing energy demand have contributed to rapid expansion of unconventional oil and gas development in the U.S. in the past two decades. Quantifying the effects of energy infrastructure on land cover and wildlife habitat is essential for informing land-use policy, developing wildlife conservation strategies, and projecting impacts of future development. The greater sage-grouse (Centrocercus urophasianus ; GrSG) is a species of concern in sagebrush ecosystems of the western U.S. and Canada and the focus of widespread conservation and management efforts. Increasing energy development within GrSG range has prompted the need to quantify and predict impacts of energy infrastructure on their habitat and populations. We mapped the annual distribution, surface type, and activity level of energy and non-energy infrastructure in the Parachute-Piceance-Roan (PPR), a small, peripheral greater sage-grouse population in Colorado with expanding oil and gas development, from 2005 to 2015. During that time, the footprint of energy infrastructure more than doubled to 3,275 ha (+108.6%), including 195 new well pads, 930 ha of new pipelines, and 230 km of new roads. In contrast, non-energy infrastructure decreased to 532 ha (−8.3%). The majority of energy infrastructure present each year (77–84%) was supporting infrastructure (i.e. facilities, roads, pipelines) rather than well pads, with an average of 2.24 ± 0.52 SE ha of supporting infrastructure per ha of well pad. Pipelines comprised 74–80% of reclaimed surface and roads comprised 54–69% of disturbed surface across years. By 2015, anthropogenic infrastructure covered 2.70% of occupied range and 2.93% of GrSG habitat, and energy infrastructure covered 2.50% and 10.79% of two priority habitat management area zones in the PPR. Three land cover classes most affected by energy infrastructure were also those strongly selected by GrSG. Topographic constraints appear to concentrate energy infrastructure in areas with gentler topography that also have the highest GrSG use. Together, these patterns suggest that future energy development will cause substantial additional loss and modification of GrSG habitat in the PPR. Our findings are valuable for assessing surface disturbance caps for land-use management and projections of energy infrastructure effects on wildlife habitat in this and other expanding oil and gas fields. Image 1 • Unconventional oil and gas development has altered greater sage-grouse habitat. • Energy infrastructure in a peripheral population in Colorado doubled from 2005 to 2015. • 77–84% of energy infrastructure was supporting infrastructure rather than well pads. • Total area of energy infrastructure in 2015 exceeded BLM surface disturbance estimates. • Additional habitat loss and modification from energy development is likely. [ABSTRACT FROM AUTHOR]