Drought

Changing climate conditions can make water management planning and drought preparedness decisions more complicated than ever before.  Federal and State natural resource managers can no longer rely solely on historical trends as a baseline and thus are in need of science that is relevant to their specific needs to inform important planning decisions. Questions remain, however, regarding the most effective and efficient methods for extending scientific knowledge and products into management and decision-making. This project analyzed two unique cases of water management to better understand how science can be translated into resource management actions and decision-making, focusing particularly on how the context of how drought influences ecosystems. In particular, this project sought to understand (1) the characteristics that make science actionable and useful for water resource management and drought preparedness, and (2) the ideal types of scientific knowledge or science products that facilitate the use of science in management and decision making. The first case study focused on beaver mimicry, an emerging nature-based solution that increases the presence of wood and woody debris in rivers and streams to mimic the actions of beavers. This technique has been rapidly adopted by natural resource managers as a way to restore riparian areas, reconnect incised streams with their floodplains, increase groundwater infiltration, and slow surface water flow so that more water is available later in the year during hotter and drier months (Pollock and others 2015). The second case study focused on an established research program, Colorado Dust on Snow, that provides water managers with scientific information explaining how the movement of dust particles from the Colorado Plateau influences hydrology and the timing and intensity of snow melt and water runoff into critical water sources. This program has support from – and is being used by – several water conservation districts in Colorado. Understanding how scientific knowledge translates into action and decision-making in these cases is useful to strengthen knowledge of actionable science for drought management. The project team gathered qualitative data through stakeholder conversations and conducted an extensive literature review. In the case of beaver mimicry, the research identified perceived benefits of and barriers to using beaver mimicry structures and considered how these differ between managers and scientists. The dust on snow case results focused on how and why dust monitoring information is used. Findings from these efforts were also incorporated into a broader Intermountain West Drought Social Science Synthesis effort to determine and assess commonalities and differences among socio-ecological aspects of drought adaptation and planning.

Abstract (from Frontiers in Ecology and Evolution): Tallgrass prairie ecosystems in North America are heavily degraded and require effective restoration strategies if prairie specialist taxa are to be preserved. One common management tool used to restore grassland is the application of a seed-mix of native prairie plant species. While this technique is effective in the short-term, it is critical that species' resilience to changing climate be evaluated when designing these mixes. By utilizing species distribution models (SDMs), species' bioclimatic envelopes–and thus the geographic area suitable for them–can be quantified and predicted under various future climate regimes, and current seed-mixes may be modified to include more climate resilient species or exclude more affected species. We evaluated climate response on plant functional groups to examine the generalizability of climate response among species of particular functional groups. We selected 14 prairie species representing the functional groups of cool-season and warm-season grasses, forbs, and legumes and we modeled their responses under both a moderate and more extreme predicted future. Our functional group “composite maps” show that warm-season grasses, forbs, and legumes responded similarly to other species within their functional group, while cool-season grasses showed less inter-species concordance. The value of functional group as a rough method for evaluating climate-resilience is therefore supported, but candidate cool-season grass species will require more individualized attention. This result suggests that seed-mix designers may be able to use species with more occurrence records to generate functional group-level predictions to assess the climate response of species for which there are prohibitively few occurrence records for modeling.

Drought events have cost the U.S. nearly $245 billion since 1980, with costs ranging from $2 to $44 billion in any given year. However, these socio-economic losses are not the only impacts of drought. Ecosystems, fish, wildlife, and plants also suffer, and these types of drought impacts are becoming more commonplace. Further, ecosystems that recover from drought are now doing so under different climate conditions than they have experienced in the past few centuries. As temperature and precipitation patterns change, “transformational drought”, or drought events that can permanently and irreversibly alter ecosystems – such as forests converting to grasslands – are a growing threat. This type of drought has cascading implications, including the potential to alter the ability of ecosystems to provide important services to human communities.   Managers of our public lands have expressed a need for baseline science to support their decision-making processes about how to best manage the ecological impacts of drought and drought recovery in the 21st century. By synthesizing the state of the science on transformational drought, researchers will provide managers with a better understanding of the potential for and the future impacts of transformational drought across the country. Researchers will also develop a case study that allows managers to explore how targeted science that is specific to ecological transformation can improve the decision-making process.   The team of scientists will work closely with a group of federal land managers, including from the Bureau of Land Management, U.S. Fish and Wildlife Service, National Park Service, and U.S. Forest Service, to ensure that the project products will support federal efforts to navigate ecological transformation on these lands. Ultimately, this project will provide solutions-oriented science to help resource managers prepare for transformational drought.

Abstract (from ScienceDirect): Paleohydrologic records can provide unique, long-term perspectives on streamflow variability and hydroclimate for use in water resource planning. Such long-term records can also play a key role in placing both present day events and projected future conditions into a broader context than that offered by instrumental observations. However, relative to other major river basins across the western United States, a paucity of streamflow reconstructions has to date prevented the full application of such paleohydrologic information in the Upper Missouri River Basin. Here we utilize a set of naturalized streamflow records for the Upper Missouri and an expanded network of tree-ring records to reconstruct streamflow at thirty-one gaging locations across the major headwaters of the basin. The reconstructions explain an average of 68% of the variability in the observed streamflow records and extend available records of streamflow back to 886 CE on average. Basin-wide analyses suggest unprecedented hydroclimatic variability over the region during the Medieval period, similar to that observed in the Upper Colorado River Basin, and show considerable synchrony of persistent wet-dry phasing with the Colorado River over the last 1200 years. Streamflow estimates in individual sub-basins of the Upper Missouri demonstrate increased spatial variability in discharge during the Little Ice Age (∼1400–1850 CE) compared with the Medieval Climate Anomaly (∼800–1400 CE). The network of streamflow reconstructions presented here fills a major geographical void in paleohydrologic understanding and now allows for a long-term assessment of hydrological variability over the majority of the western U.S.

Abstract: (From: https://www.nrs.fs.fed.us/pubs/59158)  Most regions of the United States are projected to experience a higher frequency of severe droughts and longer dry periods as a result of a warming climate. Even if current drought regimes remain unchanged, higher temperatures will interact with drought to exacerbate moisture limitation and water stress. Observations of regional-scale drought impacts and expectations of more frequent and severe droughts prompted a recent state-of-science synthesis (Vose et al. 2016). The current volume builds on that synthesis and provides region-specific management options for increasing resilience to drought for Alaska and Pacific Northwest, California, Hawai‘i and U.S.-Affiliated Pacific Islands, Interior West, Great Plains, Northeast and Midwest, and Southeast.

Abstract from SpringLink: Many western communities are surrounded by public lands that support land-based and local economies. Bureau of Land Management (BLM) decision-making affects the vulnerability of those land-based livelihoods, especially in the context of climate change. We analyzed Colorado BLM planning documents to evaluate how they are considering climate change, sensitive resources, impacts, and land-based livelihoods in their planning processes using both quantitative word counts and qualitative coding. Documents published in recent years (2011–2015) include more mentions of climate change than older documents (1985–1997). However, the review showed that while climate change is discussed within the National Environmental Policy Act (NEPA) planning documents, the final Resource Management Plans contain few mentions of climate change. Further, there is minimal consideration of how climate change may impact land-based livelihoods. These results prompt questions about the planning process, how climate change considerations are integrated into the final documents, and how that impacts on-the-ground management. The review suggests a need for increased consideration of climate change throughout the BLM’s planning process so that landscapes can be managed with more attention and awareness to climate change and the associated impacts to resources and dependent communities.

Abstract (from DigitalCommons@University of Nebraska - Lincoln): Native American peoples of the Northern and Central Plains have long endured harsh climate conditions, such as floods and droughts, and they possess valuable traditional knowledges that have enhanced their resilience to these extreme events. However, in recent times, limited capacity to adapt to a rapidly changing climate combined with a lack of resources have increased tribes’ vulnerability to climate extremes and their associated impacts. In response, a number of projects have been developed to assist tribes with their self-identified climate- and drought-related needs, particularly in the context of on-reservation decision-making. In this case study, we present an engagement strategy that was piloted for the tribes of the Wind River Indian Reservation in Wyoming and replicated for other tribes across the Northern and Central Plains. We found that frequent, face-to-face interactions between tribal and scientific communities builds relationships and trust between these two groups. We also found that climate capacity-building projects that include a diverse team of physical and social scientists, as well as tribal members, provide the greatest benefit to tribes. Finally, we found that these capacity-building projects can help reinforce tribal sovereignty.

Abstract (from PNAS): Recent decades have seen droughts across multiple US river basins that are unprecedented over the last century and potentially longer. Understanding the drivers of drought in a long-term context requires extending instrumental data with paleoclimatic data. Here, a network of new millennial-length streamflow reconstructions and a regional temperature reconstruction from tree rings place 20th and early 21st century drought severity in the Upper Missouri River basin into a long-term context. Across the headwaters of the United States’ largest river basin, we estimated region-wide, decadal-scale drought severity during the “turn-of-the-century drought” ca. 2000 to 2010 was potentially unprecedented over the last millennium. Warming temperatures have likely increasingly influenced streamflow by decreasing runoff efficiency since at least the late 20th century.