Forest Service, Climate Change and Vulnerability

Symposium

Organizers: Dixie Porter, Brian Logan, Anne Marsh, Patty Klein, Tracy Grazia, Brice Hanberry, and Mary Rowland

Supported by: USDA Forest Service,

In 2011, the U.S. Forest Service (USFS) implemented the first “Climate Change Performance Scorecard” (Scorecard) for all national forests and grasslands across the nation encompassing 193 million acres and the Scorecard was expanded in 2020. Climate change, including increased temperatures, variable precipitation, and extreme events, is expected to disrupt the composition of plant and animal communities and destabilize existing ecosystems. Climate change will affect resources, such as water, food, cover, and breeding habitat, resulting in reduced survival, growth, and reproduction of wildlife. Over longer time periods, vegetation shifts may disorder current assemblages as species respond uniquely in distribution and abundance. Species may respond to habitat changes by adapting within their current range, shifting to new distributions, or by decreasing population sizes in isolated and increasingly contracting refugia. Wildlife will face climate-related challenges through habitat loss or degradation, fragmentation and connectivity issues, phenological changes, extreme weather and related disturbance events, physiological stress and increased vulnerability to disease, and disordered interspecific relationships. Interactions will likely result in a cascade of stressors because poorly nourished animals are less resistant to drought, temperature fluctuations, fire, land use pressure, insecticides, and disease. Climate change may favor generalist and non-native species, possibly resulting in lower biodiversity. Consideration of the myriad of climate change effects on wildlife, resources, and ecosystems when developing wildlife management plans will benefit wildlife and the ecosystems that support wildlife. These four sessions will highlight national and regional approaches using the Climate Scorecard and collaborations with the USDA Climate Hubs and provide examples of work the Forest Service is doing to identify climate change vulnerabilities, develop adaptive management strategies, and address challenges in aquatic systems. We will provide information on how the Forest Service is tracking progress on climate change using its Scorecard and supporting land managers through the USDA Climate Hubs.

 
Climate change connectivity within the global protected area network
Lisa Holsinger, Solomon Dobrowski, Charles Besancon, Joshua Lawler, Caitlin Littlefield, John Abatzoglou, Sean Parks, Katherine Zeller
Climate change connectivity, the ability of a landscape to promote or hinder climate-induced species range shifts, is contingent on the resistance organisms will experience as they track suitable climate over time. Multiple factors can influence climate change connectivity, including the overall distance traveled (i.e. climate velocity) and the prevalence of inhospitable land uses and unsuitable climate conditions that organisms will experience along potential movement routes. Here, we quantify several metrics encompassing climate change connectivity with a specific focus on the global protected area network. In this presentation, we will highlight protected areas with contrasting degrees of climate change connectivity. We also mapped potential climate-induced movement routes among protected areas. When considered cumulatively, these ‘climate corridors’ highlight regions that are particularly important for species range shifts. Overall, our findings could help prioritize spatial planning efforts aimed at achieving global conservation initiatives intended to increase the footprint of protected areas (e.g. 30X30). When identifying new areas for protection, for example, explicit attention to climate change connectivity as a criterion can better facilitate climate-induced range shifts and, more broadly, reduce climate-induced impacts to biodiversity.
 
Climate change and pollinators in the United States
Brice Hanberry
Pollinators are declining, and climate change is an additional stressor. Warming temperatures, increased precipitation variation resulting in droughts and floods, and late frosts may impact growth, survival, and reproduction of pollinators. Changes in insect pollinator traits, such as body size and behavior, may occur. Varying temperature and precipitation may reduce quantity or quality of floral resources for pollinators or decouple timing between flowering and pollination. In addition to considering implications of climate change on wildlife and pollinators, I identified butterfly species likely to shift out of the United States based on climate and classifiers of random forests and extreme gradient boosting. Best management practices, restoration, and citizen participation can reduce effects of stressors and provide floral and nesting resources for pollinators. Despite relatively little information available about pollinators, incorporation of pollinator resources into management plans is critical now to reduce future pollinator declines.
 
Assessing climate vulnerabilities of late seral dependent species to inform adaptation planning on California National Forests
Jessi Kershner, Laura Hilberg, Sarah Sawyer
Old forest dependent species have been at the center of forest management decision-making in the Western US for decades. While historically key threats to the species revolved around timber harvest and resulting habitat loss, today these species face existential threats from climate change, exacerbating the legacies of past land management, as well as other related stressors, like invasive species. Old forest dependent species are sensitive to a variety of climatic changes and disturbance regimes. As habitat specialists and predators, they are indirectly vulnerable to climate changes and disturbance regimes that alter late-seral habitat availability, quality, connectivity, or prey availability. Shifts in air temperature, precipitation, drought, storms, and wildfire regimes may impact habitat structure and the landscape distribution of key forest types, potentially impacting species distributions. Recovery potential for these species is limited by reliance on late-seral stand conditions, which can take centuries to develop, as well as by low reproductive rates. However, old forest species do exhibit some behavioral plasticity (e.g., thermoregulatory behaviors, use of non-traditional habitats) that may facilitate adaptation to changing conditions. We conducted a vulnerability assessment and, based on that assessment, developed adaptation strategies for old forest dependent species in California. Due to their dependence on late-seral habitats, adaptation strategies primarily focus on protecting and enhancing habitat, although some species-specific strategies were also identified. Adaptation strategies can be incorporated into planning on National Forests at multiple scales – from the project scale to the plan scale to the bioregional scale. The US Forest Service is currently undergoing, or preparing to undergo, Forest Plan revision for multiple National Forests in California. Addressing identified vulnerabilities in this planning process is an important step to the long-term conservation of old forest dependent species in the West. 
 
Climate Change Vulnerability Assessment for Wildlife Habitats and Species in the Intermountain Region
Megan Friggens, Samuel Cushman, Tosha Wixom, Mary Williams, Karen Bagne
As part of the Intermountain Adaptation Partnership, we assessed the vulnerability of 14 species  occurring in National Forests (Region 4) that are of current management concern. Species were chosen to represent a variety of taxonomic groups and a diversity of traits predicting species’ response to climate change effects. We used an index-based vulnerability assessment tool to determine how species may respond to climate change within a time scale of approximately 50 years. The vulnerability index, SAVS (System for Assessing Vulnerability of Species to climate change) scores species based on predicted response to projected climate change for 21 equally weighted factors. Each factor is associated with species’ sensitivity or adaptive capacity in relation to predicted levels of exposure specific to the region of interest. For this assessment, we generated scenarios of exposure (e.g. habitat loss) based on future climate and habitat projections within the region. Given the large area encompassed by Region 4, exposure was quite variable, thus vulnerability could also vary for wide-ranging species. We note these differences within the region and discuss separate analyses for each subspecies of bighorn sheep.  Scores derived from this system provide relative measures of vulnerability, as well as specific information that can inform management actions related to conservation efforts.  Snow dependent species, like Wolverines, and those that depend upon microhabitat features, like Greater Sage-Grouse and Columbia Spotted Frogs, were most vulnerable whereas Utah Prairie Dogs and American Three-toed Woodpeckers were least vulnerable. However, interpretations of scores must consider data availability and realized variation in impacts among the 21 factors. We review the results of this assessment considering species specific issues, data gaps, and the relative importance of criteria for driving expected vulnerability under future climate changes with respect to how these results might influence management targets.
 
Radiocarbon dating as a tool to evaluate climate change impacts on the American Pika
Katherine Heckman
The American pika, Ochontona princeps, makes its home in the talus piles of western alpine regions. The sensitivity of the pika to warming temperatures has made it a case study in climate change driven habitat range constriction and extirpation. The use of physical surveys for indicators of pika occupation are the most reliable method for assessment of recent extirpation. However, pikas occupy extremely remote areas that may present challenges to frequent survey efforts or may not have been surveyed in recent decades. Therefore, sites may be surveyed as currently extirpated but with no knowledge of how recently the event occurred. Radiocarbon dating of relict pika scat and haypiles offers a unique opportunity to estimate the extirpation timing of sites lacking comprehensive survey information. Though not without its challenges, radiocarbon dating has been successfully employed at sites across the Great Basin and Sierra Nevada mountains in California. Results suggest that the expected range restriction and increasing extirpation associated with rising temperatures is highly probable, with populations in fragmented habitat being especially vulnerable.
 
Climate change impacts on northern spotted owls
Damon Lesmeister, Jeremy Rockweit, Raymond Davis
In the Pacific Northwest, USA, climate change caused by increased concentrations of atmospheric carbon dioxide is expected to result in warmer temperatures and changes in precipitation regimes over the next several decades. We synthesized 20 years of published science on northern spotted owl (Strix occidentalis caurina) ecology with focus on threats and prognosis for populations under climate change. We found that climate change will likely affect northern spotted owl populations through changes in weather, forest cover, disturbance processes, prey availability, and other ecological interactions. Summers are expected to be drier with increased frequency and severity of droughts that will likely negatively impact spotted owl prey populations and increase wildfire activity. Further, even small increases in early summer temperatures and precipitation are associated with increased corticosterone levels and decreased survival of juvenile spotted owls. Due to a range of interacting factors, wildfire activity and spatial extent is expected to increase to the detriment of spotted owl habitat and likely cascading effects on populations. Collectively our synthesis suggests that northern spotted owls are likely to face increasing challenges to persistence related to climate change, especially when coupled with uncertainty of how competitive dynamics with the congener barred owl (S. varia) and availability of suitable habitat will affect spotted owls in the future. The USDA Forest Service can contribute to mitigating some negative aspects of climate change on northern spotted owl populations through continued broad-scale monitoring, engagement in land steward partnerships, and integrating adaptation strategies in forest plan revisions.  

Symposium
Location: Virtual Date: November 3, 2021 Time: 3:00 pm - 4:00 pm