Climate & Fire & Adaptation
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Climate change is increasing the risk of extreme events, resulting in social and economic challenges. I examined recent past (1971–2000), current and near future (2010-2039), and future (2040-2069) fire and heat hazard combined with population growth by different regions and residential densities (i.e., exurban low and high densities, suburban, and urban low and high densities). Regional values for extreme fire weather days varied greatly. Temperature and number of extreme fire weather days increased over time for all residential density categories, with the greatest increases in the exurban low-density category. The urban high-density category was about 0.8 to 1 °C cooler than the urban low-density category. The areas of the urban and suburban density categories increased relative to the exurban low-density category. Holding climate change constant at 1970-2000 resulted in a temperature increase of 0.4 to 0.8 °C by 2060, indicating future population increases in warmer areas. Overall, U.S. residents will experience greater exposure to fire hazard and heat over time due to climate change, and compound risk emerges because fire weather and heat are coupled and have effects across sectors. Movement to urban centers will help offset exposure to fire but not heat, because urban areas are heat islands; however, urban high-density areas had lower base temperatures, likely due to city locations along coastlines. This analysis provides a timely look at potential trends in fire and heat risk by residential density classes due to the expansion and migration of US populations.
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A new USGS report supported by the Northwest CASC presents a novel decision making framework to help resource managers use climate science and local knowledge to identify adaptation strategies appropriate for their specific situations. This Climate Adaptation Integration Tool (CAIT) consists of four steps:
- Define a focal resource and assess its vulnerability to climate change.
- Answer Critical Questions about the future climactic suitability, value, and current condition of these resources.
- Select appropriate management approaches based on the answers to these questions.
- Select adaptation strategies and actions most likely to address the management approaches identified.
Within the tool, managers can find resources to make decisions at each step, such as information on finding and choosing appropriate downscaled climate models and decision-making matrices to help link decisions across steps.
We observed that juniper canopy dieback was most severe (>60% canopy dieback) at hot, dry, low elevation sites, and was associated with drought-induced hydraulic damage. There was no evidence that biotic agents could be the primary drivers of this dieback, implicating the acute effects of drought as the main causal agent. The speed and scale of this drought-induced juniper dieback seems to be historically unprecedented in the region and foreshadows an uncertain future for piñon-juniper woodlands as the region continues to get warmer and drier.
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Southwest FireCLIME is a multi-year research partnership between scientists and resource managers to synthesize current knowledge of regional climate-fire-ecosystem dynamics. Our project has addressed this goal through science synthesis, an annotated bibliography, modeling, a vulnerability assessment, and Fire-Climate adaptation tools.
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Shifts from longer seasonal snowpacks to shorter, ephemeral snowpacks (snowpacks that persist for <60 days) due to climate change will alter the timing and rates of water availability. Ephemeral snowmelt has less predictable timing and lowers soil water availability during the growing season. The Great Basin, United States is an ideal system to study snow ephemerality across a broad climate gradient. To identify the climatic controls on snow ephemerality, we analysed moderate resolution imaging spectroradiometer (MODIS) snow‐covered products from water years 2001–2015 using an object‐based mapping approach and a random forest model. Winter temperature and precipitation were the most influential variables on the maximum snow duration. We predict that warming the average winter air temperature by 2 and 4°C would reduce the areal extent of seasonal snow by 14.7 and 47.8%, respectively (8.8% of the Great Basin’s areal extent is seasonal in the historical record), with shifts to ephemeral snowpack concentrated in lower elevations and warmer regions. The combination of warming and interannual precipitation variability (i.e., reductions of 25%) had different effects on vegetation types. Vegetation types that have had consistent seasonal snow cover in their historical record are likely to have lower resilience to a new hydrologic regime, with earlier and more intermittent snowmelt causing a longer but drier growing season. Implications of increased snow ephemerality on vegetation productivity and susceptibility to disturbance will depend on local topography, subsurface water storage, and physiological adaptations. Nevertheless, patterns found in this study can help target management intervention to species that are most at risk.
Description: The event will provide leaders intent around the Cohesive Strategy moving forward and context for 2020 implementation to date.
Presenters: Vicki Christiansen, Chief, US Forest Service; Jeff Rupert, Director, Office of Wildland Fire, DOI; George Geissler, State Forester, Washington State DNR. Additional presenters will be announced in the coming weeks based on your suggested topics and questions.
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In coniferous western forests, recent widespread tree mortality provided opportunities to test the long-held theory that forest cover loss increases water yield. We reviewed 78 studies of hydrologic response to standing-replacing (severe wildfire, harvest) or nonstand-replacing (drought, insects, low-severity wildfire) disturbances, and reassessed the question: Does water yield or snowpack increase after forest disturbance? Collective results indicate that postdisturbance streamflow and snowpack may increase, not change, or even decrease, and illuminate factors that may help improve predictability of hydrologic response to disturbance. Contrary to the expectation that tree mortality reduces evapotranspiration, making more water available as runoff, postdisturbance evapotranspiration sometimes increased—particularly following nonstand-replacing disturbance—
because of (a) increased evaporation resulting from higher subcanopy radiation, and (b) increased transpiration resulting from rapid postdisturbance growth. Postdisturbance hydrologic response depends on vegetation structure, climate, and topography, and new hypotheses continue to be formulated and tested in this rapidly evolving discipline.
Conference website.
The Annual SRM meeting will be virtual. The meeting theme is “Rangelands – New Frontiers” and we hope to highlight many new ideas and endeavors occurring on rangelands across the globe. Call for sessions is now open.
Imagine the great opportunities this digital alternative will offer to gather people from everywhere who love rangelands to learn about stewardship of these amazing landscapes. The 2021 Annual Meeting will include the familiar oral presentations, posters, symposia, workshops, and campfire conversations that are a part of traditional SRM meetings. The 2021 Event will also include exceptional plenary sessions, interactive committee meetings, SRM awards and business sessions, plus opportunities to engage with colleagues and fellow SRM members. As we enter this new frontier, start thinking about how to show others what you and your organization are doing on the ground.
Efforts to conserve biodiversity increasingly focus on identifying climate- change refugia – areas relatively buffered from contem-porary climate change over time that enable species persistence. Identification of refugia typically includes modeling the distribu-tion of a species’ current habitat and then extrapolating that distribution given projected changes in temperature and precipita-tion, or by mapping topographic features that buffer species from regional climate extremes. However, the function of those hypothesized refugia must be validated (or challenged) with independent data not used in the initial identification of the refugia. Although doing so would facilitate the incorporation of climate- change refugia into conservation and management decision mak-ing, a synthesis of validation methods is currently lacking. We reviewed the literature and defined four methods to test refugia predictions. We propose that such bottom- up approaches can lead to improved protected- area designations and on- the- ground management actions to reduce influences from non- climate stressors within potential refugia.
Disturbance refugia – locations that experience less severe or frequent disturbances than the surrounding landscape – provide a framework to highlight not only where and why these biological legacies persist as adjacent areas change but also the value of those legacies in sustaining biodiversity. Recent studies of disturbance refugia in forest ecosystems have focused primarily on fire, with a growing recognition of important applications to land management. Given the wide range of disturbance processes in forests, developing a broader understanding of disturbance refugia is important for scientists and land managers, particularly in the con-text of anthropogenic climate change. We illustrate the framework of disturbance refugia through the individual and interactive effects of three prominent forest disturbance agents: fire, drought, and insect outbreaks. We provide examples of disturbance ref-ugia and related applications to natural resource management in western North America, demonstrate methods for characterizing refugia, identify research priorities, and discuss why a more comprehensive definition of disturbance refugia is relevant to conser-vation globally