Ecological drought impacts ecosystems across the U.S. that support a wide array of economic activity and ecosystem services. Managing drought-vulnerable natural resources is a growing challenge for federal, state and Tribal land managers.  Plant communities and animal populations are strongly linked to patterns of drought and soil moisture availability.  As a result, ecosystems may be heavily altered by future changes in precipitation and soil moisture that are driven by climate change.  Although this vulnerability is well recognized, developing accurate information about the potential consequences of climate change for ecological drought is difficult because the soil moisture conditions that plants experience are shaped by complex interactions among weather, atmospheric CO2, plants and soils. There are currently very few ecologically appropriate datasets about future drought with widespread distribution at resolutions suitable for informing natural resource decision making.  This project will meet some of those needs by simulating complex interactions that affect soil moisture availability to plants and generating user-relevant soil moisture projections.  Results will include detailed and synthesized drought information for the 21st century across the entire contiguous U.S. that are delivered via the Climate Toolbox, an established source for long-term climate projections. Data provided by this project will be useful for a wide variety of applications including scenario planning, species distribution models, and ecological drought and habitat vulnerability assessments.  

Project Overview Migratory big game species, like mule deer, are at risk due to human development and more frequent drought events that can limit access to food resources during migration. To address this, researchers supported by this North Central CASC project will collaborate with State, Tribal, and Federal agencies to examine the effectiveness of corridor conservation as a strategy to improve drought resilience for over 40 mule deer herds across Western states. Ultimately, results from this project will benefit ongoing conservation efforts by identifying what levels of development impacts the species’ ability to deal with drought. Project Summary Every year, migratory big game move across landscapes to seek out important food resources and to avoid harsh weather. Yet, the landscapes animals move through are experiencing rapid changes from human development and shifting climatic conditions, which put these ecologically and culturally important migrations at risk. Mule deer, for example, are negatively impacted by drought, which changes when and where key food resources will be available along their migration route. To conserve big game migrations, State, Tribal, and Federal agencies are working together to map and protect migration corridors. Although it is often assumed that corridor conservation should enhance the resilience of migrants to climate change, the idea remains poorly tested. This project will examine the effectiveness of corridor conservation as a drought resiliency strategy for mule deer across the West. As climate change leads to more frequent and longer drought events, it will likely become even more important for deer to freely move and access critical and limited food resources during migrations. At the same time, mule deer movements are altered by human disturbances, which can cause deer to miss out on foraging opportunities. This project will bring together data and partnerships to investigate these two threats on more than 40 mule deer herds across the West, with the aim of understanding the importance of freedom of movement in the survival and resiliency of mule deer in a changing world. Results from this project will identify the amount of human development that constrains the movements of mule deer and the impacts of diminished mobility on drought resiliency. This research links two USGS priorities – conserving big game migrations and enhancing climate resiliency – while filling important knowledge gaps needed to strategically target ongoing conservation efforts.

Dry stream sections are characteristic of most prairie streams. Native fish are highly adapted to variable environments, using refuge habitats (e.g., remaining wet stream fragments) to recolonize areas after seasonal drying. However, dams and other barriers can prevent recolonization of seasonally-dry stream sections habitats known to be critical spawning and rearing areas for many species. This phenomenon will likely become more common as climate change causes increasingly severe droughts, and larger sections of streams become seasonally dry. This could lead to local loss of native prairie fishes, an already at-risk group. Fisheries managers in Wyoming and Montana have limited data on climate impacts to prairie fishes, limiting their ability to prioritize management actions. This is in part because the ecology and possible climate adaptation strategies for many prairie fishes are poorly understood. Managers also have limited time to assess the success of potential restoration actions to increase fish resilience to seasonal drying and ways to increase refuge habitat. This project aims to provide landscape-level maps and resources that will help managers prioritize where and for which species management actions, such as water and habitat conservation and restoration measures, could be most beneficial. A research team will assess which species are most sensitive to drought in addition to expanding a newly created model of streamflow permanence to map drought refuges for vulnerable species. The project will also monitor stream restoration case studies to determine if process-based restoration techniques can be used to increase streamflow permanence and connectivity. Lastly, this work will be leveraged to create a short, species-specific guide to climate adaptation techniques. This guide will help agencies, landowners, conservation districts, and public interest groups determine what can be done to benefit at-risk species in their area of interest.

The USGS National Climate Adaptation Science Center (NCASC) is currently engaged in an Ecological Drought initiative, focused on understanding the impacts of drought on natural ecosystems across the country. This project supported the Ecological Drought initiative by creating an Intermountain West Drought Social Science Synthesis Working Group. The goal of this working group was to investigate human dimensions of ecological drought across the intermountain west from a comparative, regional perspective. Throughout the Intermountain West, there has been significant investment in understanding how social factors influence manager and citizen experiences of drought in particular locations. Yet there is still a gap in knowledge of how human dimensions of drought impacts, planning, and resilience are similar and different across cases and regions. The working group engaged social scientists from federal agencies and universities to identify common trends in drought management across the Intermountain West to inform more effective drought preparedness and response across the region. Project outputs included two conference sessions, a typology manuscript to be submitted by the end of FY19, and the conceptual framing of a rapid assessment methodology that was subsequently developed into a standalone project.  

The USGS National Climate Change and Wildlife Science Center (NCCWSC) is currently engaged in an Ecological Drought initiative, focused on understanding the impacts of drought on natural ecosystems across the country. This project was designed to support the Ecological Drought initiative by creating a USGS EcoDrought Actionable Science Working Group. The goal of this working group was to identify science needs for drought-related decisions and to provide natural resource managers with practical strategies for adapting to and planning for drought.   The working group engaged social scientists to garner advice on relevant social science research questions and data needs, as well as to identify any regulatory, institutional, or cultural barriers that may impede adaptation efforts by managers. This approach was taken to help ensure that the science being produced on ecological drought is actionable – that is, it addressed critical stakeholder questions, took into account the complex social dynamics of drought adaptation, and was created to be easily used by decision-makers.   The ultimate goal of the working group was to use integrated social-ecological analysis to forecast the potential implications of drought, to provide better access to climate and drought-related data, and to develop tools that enable managers to visualize the potential impacts of management decisions before they are implemented.

One of the most visible signs of climate change is less mountain snow. In the Western U.S., deep snow has historically been a cornerstone of life for many plants and animals. For example, snow can provide denning shelter for certain species like the wolverine, and snowmelt provides dependable water to mountain streams that are home to fish like the bull trout. Yet snow losses driven by warming temperatures are already causing land and water managers to rethink whether certain species can thrive in the future. A recently completed study by this research team helped the U.S. Fish and Wildlife Service investigate whether wolverines will have enough snow to survive in two areas of the Rocky Mountains.   In June 2020, the project team gathered a large group of regional land managers at a “Snow Collider” workshop event to learn about the wide range of needs for future snow information. Managers identified needs focused on how much snow will be around in the future, as well as how that snow will melt to support streams. This input will guide the direction of the future snow modeling in this study. The main goal of this project is to build better models of future snow conditions for the key areas of the Rocky Mountains identified previously.   The team seeks to understand whether changes in future snowpacks will be sufficient for key species to thrive. This research will zoom in to model future snow conditions at much higher resolutions compared to earlier studies, to allow for an improved method to understand how snow will accumulate and melt across landscapes. This project aims to help managers make more informed decisions about future snow dependent species and choose the most effective ways to allocate resources towards recovery plans and monitoring.

Water resources are critical for ecosystems, agriculture, and communities, and potential climate impacts to hydrologic budgets and cycles are arguably the most consequential to society. Apart from precipitation, evapotranspiration makes up the most significant component of the hydrologic budget. Evapotranspiration is a primary metric for identifying Ecological Drought, a deficit in water availability that negatively impacts ecosystems and ecosystem services. Through an agreement between the USGS Earth Resources Observation and Science (EROS) Center Land Cover Monitoring, Assessment and Projection (LCMAP) program and the North Central CASC, Dr. Senay works to integrate and apply remotely sensed data for eco- and agro-hydrologic modeling. He promotes and advances the use of satellite-derived multi-scale evapotranspiration products by the key stakeholders in the irrigation and water resources community for climate adaptation planning.

Abstract (from IOPScience): Ecological droughts are deficits in soil-water availability that induce threshold-like ecosystem responses, such as causing altered or degraded plant-community conditions, which can be exceedingly difficult to reverse. However, 'ecological drought' can be difficult to define, let alone to quantify, especially at spatial and temporal scales relevant to land managers. This is despite a growing need to integrate drought-related factors into management decisions as climate changes result in precipitation instability in many semi-arid ecosystems. We asked whether success in restoration seedings of the foundational species big sagebrush (Artemisia tridentata) was related to estimated water deficit, using the SoilWat2 model and data from >600 plots located in previously burned areas in the western United States. Water deficit was characterized by: 1) the standardized precipitation-evapotranspiration index (SPEI), a coarse-scale drought index, and 2) the number of days with wet and warm conditions in the near-surface soil, where seeds and seedlings germinate and emerge (i.e. days with 0-5 cm deep soil water potential > -2.5 MPa and temperature above 0 °C). SPEI, a widely used drought index, was not predictive of whether sagebrush had reestablished. In contrast, wet-warm days elicited a critical drought threshold response, with successfully reestablished sites having experienced 7 more wet-warm days than unsuccessful sites during the first March following summer wildfire and restoration. Thus, seemingly small-scale and short-term changes in water availability and temperature can contribute to major ecosystem shifts, as many of these sites remained shrubless two decades later. These findings help clarify the definition of ecological drought for a foundational species and its imperiled semi-arid ecosystem. Drought is well known to affect the occurrence of wildfires, but drought in the year(s) after fire can determine whether fire causes long-lasting, negative impacts on ecosystems.

The climate of the North Central U.S. is driven by a combination of factors, including atmospheric circulation patterns, the region’s complex topography which extends from the High Rockies to the Great Plains, and variations in hydrology. Together, these factors determine the sustainability of the region’s ecosystems and the services that they provide communities.   In order to understand the vulnerability of the region’s ecosystems to change, it is necessary to have reliable projections of future climate conditions. To address this need, researchers first examined past and present variations in climate and assessed the ability of climate models to effectively project future climate conditions for the region. Second, researchers used these climate models to project how the region’s water balance might change. This information was then used to understand potential future changes in ecosystems that are of interest to stakeholders. For example, researchers found that the increased probability of future drought in Iowa would threaten the state’s tallgrass prairies, as 28 plant species could experience a reduction in habitat suitability by 2040.   This research helps clarify the trajectory of past, present, and future changes in the region’s climate; identifies specific climate conditions associated with extreme events such as drought; and combines this knowledge to evaluate future conditions of ecosystems in the region. Together, this information can be used to support climate adaptation efforts in the North Central region.    

This dataset is a shapefile that contains the grid outlines and identifiers for the tiles produced by the TopoWx ("Topographical Weather/Climate") temperature dataset as applied to the USGS North Central Climate Center Domain and the surrounding area of Montana. The TopoWx dataset contains gridded daily temperature and is an interpolated spatio-temporaldataset in the same vein as the well-known PRISM (http://www.prism.oregonstate.edu) and Daymet products (http://daymet.ornl.gov). Daily Tmin and Tmax are provided at a 30-arcsec resolution (~800m) from 1948-2012 along with the latest 30-year monthly normals (1981-2010). The goals of the TopoWx project were to produce a dataset that: (1) incorporates key landscape-scale physiographic and biophysical factors that influence spatial spatial patterns of temperature;(2) provides estimates of uncertainty; (3) is appropriate for analyzing trends; and (4) is open to the research community for further analysis and improvements.