Landscape Analysis
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The Great Basin is an arid province located in the interior western United States. The region encompasses millions of hectares and quaking aspen forests comprise a minor portion of the total area. However, montane aspen forests play a disproportionately large role in providing ecosystem services in the region, including water retention, biodiversity, wildlife habitat, livestock forage, and recreational uses. With warming temperatures, increasing evaporative demand, and heightened precipitation variability, the future of aspen has become a critical concern. Using dendroecological approaches, we assessed growth patterns of 20 aspen stands across three geographically isolated “sky island” mountain ranges spanning portions of the northcentral Great Basin. We anticipated that the growth of Great Basin aspen would be strongly influenced by regional climatic patterns and largely in synchrony. Results revealed a more complex growth dynamic that varied among mountain ranges and across environmental gradients. In particular, aspen climate-growth relationships in the slightly dryer Ruby Mountains were strongly and positively correlated (r > 0.5) with previous fall to winter moisture availability. The Jarbidge Mountains had a positive but modest relationship with previous fall to winter moisture availability (r > 0.3). Climate-growth response in the Santa Rosa Mountains, the wettest range, showed no significant response to moisture availability during any time period examined but had greater tree-ring growth with warmer May temperatures. Although tree-ring centennial (1910 – 2010) growth trends were positive for all three mountain ranges, only the Santa Rosa Mountains maintained a positive recent growth trend (1970 – 2010). Moreover, distinct temporal shifts in tree growth-climate relationships in each mountain range suggest potentially unique aspen population adaptations to climate variability. For instance, in two of the mountain ranges, there was a shift from positive/neutral to negative growth relationships with temperature starting around the 1963 – 1987 time period, while tree growth also began simultaneously responding more positively to moisture availability. These growth shifts and observed enhanced sensitivities to monthly and seasonal climate variables over time may reflect dynamic tree growth responses caused by ongoing global climate change, but that may be tempered by local or regional factors, such as the relative availability and timing of soil moisture provided by spring snowmelt. A better understanding of biogeographic variation and causality in aspen growth could provide multiple management pathways governed by resilience characteristics in the face of future anthropogenic and climatic threats.
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Explore past and present landscapes from the Great Plains to the Pacific coast. This easy-to-use map uses historic and current aerial imagery to highlight how our landscapes have changed since the mid-20th century and how we can conserve our natural heritage.
Uses of the tool highlighted by Intermountain West Joint Venture.
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Mapped representations of species−habitat relationships often underlie approaches to prioritize area-based conservation strategies to meet conservation goals for biodiversity. Generally a single surrogate species is used to inform conservation design, with the assumption that conservation actions for an appropriately selected species will confer benefits to a broader community of organisms. Emerging conservation frameworks across western North America are now relying on derived measures of intactness from remotely sensed vegetation data, wholly independent from species data. Understanding the efficacy of species-agnostic planning approaches is a critical step to ensuring the robustness of emerging conservation designs. We developed an approach to quantify ‘strength of surrogacy’, by applying prioritization algorithms to previously developed species models, and measuring their coverage provided to a broader wildlife community. We used this inference to test the relative surrogacy among a suite of species models used for conservation targeting in the endangered grasslands of the Northern Sagebrush Steppe, where careful planning can help stem the loss of private grazing lands to cultivation. In this test, we also derived a simpler surrogate of intact rangelands without species data for conservation targeting, along with a measure of combined migration representative of key areas for connectivity. Our measure of intactness vastly outperformed any species model as a surrogate for conservation, followed by that of combined migration, highlighting the efficacy of strategies that target large and intact rangeland cores for wildlife conservation and restoration efforts.
Webinar b.
Presenters will share an overall framework, analysis considerations plus a case study from the Southwest Idaho Wildfire Crisis Landscape. Manager questions and experiences to guide this session are encouraged.
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The 2020 Resources Planning Act (RPA) Assessment summarizes findings about the status, trends, and projected future of the Nation’s forests and rangelands and the renewable resources that they provide. The 2020 RPA Assessment specifically focuses on the effects of both socioeconomic and climatic change on the U.S. land base, disturbance, forests, forest product markets, rangelands, water, biodiversity, and outdoor recreation. Differing assumptions about population and economic growth, land use change, and global climate change from 2020 to 2070 largely influence the outlook for U.S. renewable resources. Many of the key themes from the 2010 RPA Assessment cycle remain relevant, although new data and technologies allow for deeper and wider investigation. Land development will continue to threaten the integrity of forest and rangeland ecosystems. In addition, the combination and interaction of socioeconomic change, climate change, and the associated shifts in disturbances will strain natural resources and lead to increasing management and resource allocation challenges. At the same time, land management and adoption of conservation measures can reduce pressure on natural resources. The RPA Assessment findings and associated data can be useful to resource managers and policymakers as they develop strategies to sustain natural resources.
Symposium website.
Event location: CSU Spur, Hydro Theater; Denver, Colorado
Description: Nature-based solutions are increasingly being recognized as critical tools to making progress towards both climate and biodiversity goals, and countries around the world have committed to both measurable targets and funding to help
reach them. The Symposium will connect the dots across existing efforts across sectors and the continent. Diverse thought leaders from across North America will share innovations and best practices for creating a more nature-positive future. And attendees will learn about high-level challenges and opportunities that we all face in trying to solve the environmental crisis.
*Early-bird pricing ends July 28.
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In fire, fuels weather and topography mean everything. Fuels weather and topography and the timing of these components of the fire triangle must align properly for large fires to occur. Despite uncharacteristically large and continuous fuelbeds in numerous areas, however, it’s been a slow start to the fire season in the coterminous US.
In this webcast, Research Ecologist Dr. Matt Reeves analyzes rangeland fuel conditions across the West with an emphasis on how fire weather and rangeland fuels have not yet converged in 2023. All 2022 recordings are located on the Reading the Tea Leaves page.
Projections are based on Reeves’ Fuelcasting system – a component of the Rangeland Production Monitoring Service that provides projections of expected fuel conditions this grazing season.
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Three species (western meadowlark Sturnella neglecta, loggerhead shrike Lanius ludovicianus, and lark bunting Calamospiza melanocorys) had greater overlap than expected with at least one type of greater sage-grouse habitat, while western kingbirds (Tyrannus verticalis) indicated avoidance of all sage-grouse habitat assessed.
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By comparing connectivity patterns over time, we found that most of the biome experienced moderate change; the amount and type of change varied spatially, indicating that areas differ in the trend direction and magnitude of change. Two different types of designated areas of conservation and management interest had relatively high proportions of stable, high-connectivity patterns over time and stable connectivity trends on average. These results provide ecological information on sagebrush connectivity persistence across spatial and temporal scales that can support targeted actions to address changing structural connectivity and to maintain functioning, connected ecosystems.
Human population growth and accessibility from cities shape rangeland condition in the American West
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Human population growth contributes to the decline of sagebrush-steppe rangelands. More accessible rangelands from population centers have higher quality. Open space preservation provides opportunities for rangeland conservation in cities. Coordinated conservation strategies are necessary to protect rangeland ecosystems.