Over the last half-century, grassland bird populations have declined far more than any other bird group in North America. This is because native grasslands were largely replaced with croplands, and many remaining prairies are degraded. Land managers and conservation organizations are racing to preserve and restore these ecosystems to stem further loss of grassland birds. Given limited resources, bird habitat models are needed to help managers prioritize where conservation efforts will be most effective. In addition to habitat loss and degradation from land use change, altered fire regimes, and woody encroachment, increasing greenhouse gas emissions will likely change temperatures and rainfall patterns across North American grasslands. The effects of these changes in climate are expected to cascade to vegetation communities and the bird species that depend on them. To date, predictions for bird responses to a changing climate have focused on changes in temperature and precipitation, but vegetation productivity (and therefore grassland bird habitat) also depends on factors such as vegetation type and soils. In this project, researchers will study how vegetation influences grassland birds across the western Great Plains and create maps of projected bird distribution given vegetation and land use change under multiple future climate scenarios. Anticipating future bird distribution will help partners understand the regional and climate contexts of site-level projects, including USDA-Agriculture Research Service scientists seeking to target real world solutions for grazing land management that enhance livestock production and bird conservation. These maps will also help Audubon Rockies as they plan expansion of the Conservation Ranching Initiative, which helps ensure livestock grazing operations are “bird friendly” and will provide guidance for conservation actions implemented by Private Lands Biologists with Bird Conservancy of the Rockies. Modules and a web-based application accompanying these maps will increase capacity among Federal, State, Tribal, and private land managers and decision makers in their conservation planning under a changing climate.
Invasions of exotic annual grasses (EAGs like cheatgrass have caused major losses of native shrubs and grasses in western U.S. rangelands. They also decrease the productivity and carbon storage in these ecosystems, which is expected to create dryer soils that may cause further losses in plant productivity. This cycle is the hallmark of desertification – or, fertile lands turning into deserts. Management actions that target EAGs are one of the most widespread land management actions taken in Western U.S. rangelands, but it is unclear which specific actions can simultaneously enhance drought resilience of native plant communities and increase carbon sequestration and storage. This project aims to identify the restoration treatments that are effective in combating EAGs in western rangelands by collecting data to describe the impacts of EAGs on soil carbon and to determine when, where, and how restoration actions such as applying herbicides or planting perennial native plants affect soil carbon and drought resilience. To address a key concern of land managers, the public, and national policy-makers, project researchers will work with a team of land managers across Montana, Wyoming, and Colorado to 1) refine and confirm the suitability of sampling locations, 2) connect with private landowners and land managers to access sampling locations, 3) engage managers in the science discovery process (e.g., interpreting data results) to share ownership of the findings, and 4) co-produce translational guidance for carbon sequestration metrics and for what changes to expect in carbon sequestration and its co-benefits following restoration to prevent or rectify EAG invasions.
In the North Central region, invasive species and climate change are intricately linked to changing fire regimes, and together, these drivers can have pronounced effects on ecosystems. When fires burn too hot or too frequently, they can prevent slow-growing native plants from regrowing. When this happens, the landscape can transform into a new type of ecosystem, such as a forest becoming a grassland. This process is known as “ecosystem transformation”. This project will explore key management priorities including native community resilience and management of invasive species, wildfire, and ecosystem change, in a collaboration of researchers working directly with land managers and other stakeholders through the North Central Regional Invasive Species and Climate Change (NC RISCC) network. The team will identify areas in the North Central region that have experienced ecological transformation due to invasive grasses and their interactions with wildfire or climate change; calculate changes in carbon storage that have accompanied these transformations; and determine areas that are vulnerable to future transformation. Researchers will also identify which management practices enhance carbon storage, a key ecosystem service that agencies want to include in management plans and strategies, yet largely have not yet done so. Through this project, managers and researchers will gain a better understanding of the processes behind ecosystem transformation, as well as the carbon consequences of these changes and the management practices that can address them. This work can be used to adapt management plans for important ecosystem services that may be agency- or organization-specific, including carbon storage, native plant diversity, and ecosystem resilience. This work is critical to addressing the interactions of climate change with both invasive grasses and wildfire, as well as identifying adaptation strategies to restore carbon in forests and shrublands across the North Central region after these disturbances.
The Bureau of Land Management (BLM) manages the largest area of public lands in the United States and manages those lands for diverse and sometimes conflicting resources, uses, and values. As a result, decision-making on BLM lands is complex. Decisions that are informed by the best available science – including climate science – are more likely to allow public land managers to balance different desired uses and values across public landscapes and achieve long-term land management goals. Strengthening the use of science and climate information in federal decision making is a priority for the current administration and for federal agencies, including the BLM. The Climate Adaptation Science Centers are committed to developing climate science that is relevant to decision making. However, conducting a comprehensive review of available science, including climate science, is challenging for BLM land managers due to the volume of science often available and the limited time staff have to compile and synthesize that information. The goal of this project is to develop (and evaluate the utility of) a family of climate-informed short science syntheses and accompanying worked environmental impact analysis examples. Both products will include climate sections to help land managers more quickly understand and assess the influence of changing climate conditions on resources. Both products will also be specifically designed to provide information and analyses required by the National Environmental Policy Act (NEPA). The BLM conducts well over a thousand comprehensive NEPA analyses each year to analyze and disclose to the public the potential environmental impacts of each of their decisions. Thus the products produced in this project, which will focus in the sagebrush biome where many BLM lands occur, has the potential to strengthen science use in hundreds of public lands decisions each year. The project will be conducted in partnership with BLM and US FWS to help ensure that the resulting products are useful and used by managers to strengthen the science, and climate science, foundation for public land management.
Understanding how climate change and variability will impact grassland ecosystems is crucial for successful grassland management in the 21st century. In 2020, the U.S. Geological Survey North Central Climate Adaptation Science Center (USGS NC CASC) began a project to establish a baseline of information to best serve grassland managers (that is, those who develop grassland management plans or implement those plans on the ground) at Federal, State, and Tribal agen-cies and nongovernmental organizations to help meet regional grassland management goals. This project “A Synthesis of Climate Impacts, Stakeholder Needs, and Adaptation in Northern Great Plains Grassland Ecosystems” (hereafter, the Grasslands Synthesis Project), had two primary goals: (1) to synthesize management goals and challenges for grassland managers across the region and (2) to assess the state-of-the-science and identify knowledge gaps for addressing the goals and challenges within the context of climate change. The findings from the Grasslands Syn-thesis Project are described in two volumes. This report serves several purposes, including providing (1) a synthesis of regional grassland management goals and challenges, (2) identification of information needs relevant to grassland management in a changing climate, and (3) summaries of grassland management issues by ecoregion and management organization or agency.
Grasslands in the Great Plains are of ecological, economic, and cultural importance in the United States. In response to a need to understand how climate change and variability will impact grassland ecosystems and their management in the 21st century, the U.S. Geological Survey North Central Climate Adaptation Science Center led a synthesis of peer-reviewed climate and ecology literature relevant to grassland management in the North Central Region (including Montana, Wyoming, Colorado, North Dakota, South Dakota, Nebraska, and Kansas). This synthesis was done to begin to address grassland managers’ information needs and identify research gaps. This open-file report summarizes the impacts of climate change and variability on temperature, water availability, wildfire, vegetation, wildlife, large-bodied ruminants, grazing, and land-use change and the implications for grassland management in the North Central region. This open-file report also identifies areas in which further research is needed. U.S. Geological Survey funded this project.
Increasing fire severity and warmer, drier postfire conditions are making forests in the western United States (West) vulnerable to ecological transformation. Yet, the relative importance of and interactions between these drivers of forest change remain unresolved, particularly over upcoming decades. Here, we assess how the interactive impacts of changing climate and wildfire activity influenced conifer regeneration after 334 wildfires, using a dataset of postfire conifer regeneration from 10,230 field plots. Our findings highlight declining regeneration capacity across the West over the past four decades for the eight dominant conifer species studied. Postfire regeneration is sensitive to high-severity fire, which limits seed availability, and postfire climate, which influences seedling establishment. In the near-term, projected differences in recruitment probability between low- and high-severity fire scenarios were larger than projected climate change impacts for most species, suggesting that reductions in fire severity, and resultant impacts on seed availability, could partially offset expected climate-driven declines in postfire regeneration. Across 40 to 42% of the study area, we project postfire conifer regeneration to be likely following low-severity but not high-severity fire under future climate scenarios (2031 to 2050). However, increasingly warm, dry climate conditions are projected to eventually outweigh the influence of fire severity and seed availability. The percent of the study area considered unlikely to experience conifer regeneration, regardless of fire severity, increased from 5% in 1981 to 2000 to 26 to 31% by mid-century, highlighting a limited time window over which management actions that reduce fire severity may effectively support postfire conifer regeneration.
Grasslands in the northern Great Plains are important ecosystems that support local economies, tribal communities, livestock grazing, diverse plant and animal communities, and large-scale migrations of big game ungulates, grassland birds, and waterfowl. Climate change and variability impact how people and animals live on and interact with grasslands, and can bring more frequent droughts, fires, or new plant species that make managing these landscapes challenging. Understanding how climate change and variability will impact grassland ecosystems and their management in the 21st century first requires a synthesis of what is known across all of these scales and a gap analysis to identify key areas to focus future research.
Pinyon–juniper (PJ) woodlands are an important component of dryland ecosystems across the US West and are potentially susceptible to ecological transformation. However, predicting woodland futures is complicated by species-specific strategies for persisting and reproducing under drought conditions, uncertainty in future climate, and limitations to inferring demographic rates from forest inventory data. Here, we leverage new demographic models to quantify how climate change is expected to alter population demographics in five PJ tree species in the US West and place our results in the context of a climate adaptation framework to resist, accept, or direct ecological transformation. Two of five study species, Pinus edulis and Juniperus monosperma, are projected to experience population declines, driven by both rising mortality and decreasing recruitment rates. These declines are reasonably consistent across various climate futures, and the magnitude of uncertainty in population growth due to future climate is less than uncertainty due to how demographic rates will respond to changing climate. We assess the effectiveness of management to reduce tree density and mitigate competition, and use the results to classify southwest woodlands into areas where transformation is (a) unlikely and can be passively resisted, (b) likely but may be resisted by active management, and (c) likely unavoidable, requiring managers to accept or direct the trajectory. Population declines are projected to promote ecological transformation in the warmer and drier PJ communities of the southwest, encompassing 37.1%–81.1% of our sites, depending on future climate scenarios. Less than 20% of sites expected to transform away from PJ have potential to retain existing tree composition by density reduction. Our results inform where this adaptation strategy could successfully resist ecological transformation in coming decades and allow for a portfolio design approach across the geographic range of PJ woodlands.
Loss and degradation of sagebrush (Artemisia spp.) rangelands due to an accelerated invasive annual grass-wildfire cycle and other stressors are significant management, conservation, and economic issues in the western U.S. These sagebrush rangelands comprise a unique biome spanning 11 states, support over 350 wildlife species, and provide important ecosystem services that include stabilizing the economies of western communities. Impacts to sagebrush ecosystem processes over large areas due to the annual grass-wildfire cycle necessitated the development of a coordinated, science-based strategy for improving efforts to achieve long-term protection, conservation, and restoration of sagebrush rangelands, which was framed in 2015 under the Integrated Rangeland Fire Management Strategy (IRFMS). Central to this effort was the development of an Actionable Science Plan (Plan) that identified 37 priority science needs (hereinafter, “Needs”) for informing the actions proposed under the five topics (Fire, Invasives, Restoration, Sagebrush and Sage-Grouse (Centrocercus urophasianus), Climate and Weather) that were part of the collective focus of the IRFMS. Notable keys to this effort were identification of the Needs co-produced by managers and researchers, and a focus on resulting science being “actionable.” Substantial investments aimed at fulfilling the Needs identified in the Plan have been made since its release in 2016. While the state of the science has advanced considerably, the extent to which knowledge gaps remain relative to identified Needs is relatively unknown. Moreover, new Needs have likely emerged since the original strategy as results from actionable science reveal new questions and possible (yet untested) solutions. A quantifiable assessment of the progress made on the original science Needs can identify unresolved gaps and new information that can help inform prioritization of future research efforts. This report details a systematic literature review that evaluated how well peer-reviewed journal articles and formal technical reports published between January 1, 2015, and December 31, 2020, addressed four Needs identified under the Climate and Weather topic in the Plan. The topic outlined research Needs broadly focused on understanding the potential effects of climate change on vegetative resilience to inform restoration of sagebrush rangelands. We established the level of progress towards addressing each Need following a standardized set of criteria, and developed summaries detailing how research objectives nested within Needs identified in the Plan (hereinafter, “Next Steps”) were either addressed well, partially addressed or remain outstanding (that is, addressed poorly) in the literature through 2020. Our searches resulted in the inclusion of 92 science products that at least partially addressed a Need identified in the Climate and Weather topic. The Needs that were well and partially addressed included: studies of the complex set of climatic relationships that influence sagebrush rangeland restoration and seeding success; the identification of seed collection areas across the range of environmental variability inhabited by target restoration species; and develop predictive models to assess targeted restoration species’ responses to mid-century climatic conditions. The Need addressed poorly was the identification of native plant species, genotypes and ecotypes, and seed mixes that may be resilient to a changing climate. The information provided in this assessment will assist updating the Plan, and can inform updates of other relevant science planning documents as needed.