Senator George J. Mitchell Center for Sustainability Solutions
Morning Session
Session Co-Chairs:
Maine encompasses many types of habitats that could be critical to retaining cold conditions as winters warm and shoulder seasons shift toward later autumn and earlier spring. Climate refugia are places on the landscape that remain relatively buffered from changing climate, allowing species and ecosystems to persist. For example, mountain ecosystems develop and retain snow and lake ice more reliably and for longer durations than lower-elevation counterparts. In addition to elevation gradients, significant climate variability from coastal to northern and inland locations, and the effect of microclimate features, can produce cold climate refugia at different scales. In this session, we invite presentations related to climate refugia, trends and patterns in winter or dormant season processes, scale and connectivity of climate conditions, and novel approaches to maintaining or creating cold refugia. The session will open with an invited presentation regarding how climate change refugia conservation can help Maine’s ecosystems. Talks that cover freshwaters and forest ecosystems will follow.
Additional information for this session will be posted shortly.
Session Overview
Session Presentations
Presenters are indicated in bold.
8:30AM – 9:00AM
How climate change refugia conservation can help Maine’s ecosystems
Toni-Lyn Morelli
Department of Environmental Conservation, University of Massachusetts Amherst
9:00AM – 9:30AM
Maritime climate and the forests of coastal Maine
Jay Wason1, Xinyuan Wei1, Sean Birkel2, Daniel Hayes1, Peter Nelson3, Colby Bosley-Smith1, Shawn Fraver1, Rose Gellman4, Megan Grega1, Emily MacDonald1, Gregory McHale1, Nicole Rogers5, Camilla Seirup6
1. University of Maine School of Forest Resources
2. University of Maine Climate Change Institute and Cooperative Extension
3. Laboratory of Ecological Spectroscopy
4. Smokey House Center
5. Maine Forest Service
6. National Park Service
The Gulf of Maine is one of the fastest warming places in North America, threatening the future of its coastal forest ecosystems. Spruce-fir forests exist further south of their typical range along the coast and depend on historically cool and moist conditions. However, we need to know more about where these climate refugia exist to inform sustainable management and conservation decision making. In this study, we used a spatial analysis of climate and forest data to identify the climate indicators that characterize this coastal region and compared a set of machine-learning clustering models to define new climate zones to inform regional forest management and conservation. We found that a model including seasonal indicators of extreme temperature, vapor pressure deficit (VPD; dryness of the air), and precipitation delimited zones along the coast of the Gulf of Maine that best matched the distribution of spruce and fir trees. These new climate zones can now be used to prioritize conservation and management decisions for this highly vulnerable forest type.
9:30AM – 10:00AM
Integrated riverscape assessment and restoration opportunity identification including focus on thermal refugia to support recovery of native salmonids
Michael Burke, Keith Kantack
Interfluve
Following multiple decades of habitat connectivity barrier identification, inventory, prioritization, and mitigation, significant gains in habitat connectivity have been realized in many Maine riverscapes that critical to the recovery of native salmonids. Although naturalized, the riverine habitats that these fish return to lack diversity, richness, and quality, have impaired water quality regimes (in particular water temperature) during critical survival bottlenecks, and are often unable to overcome their degraded quality under present hydrological and sedimentary regimes. The emerging next phase of recovery in Maine requires increased direct action to improve the quality of riverscape habitats, yet the scale of the endeavor is daunting in the shadow of the magnitude of past impacts and degradation, and the expanse of the affected geography. Hence, strategic identification of the most impactful restoration actions will be critical to achieve measurable gains within limited timeframes and resources, and to effectively apply restoration funding efficiently as it becomes available. This presentation describes methods that result in streamlined assessment of geomorphic and habitat condition, identification of riverscape status and trajectory, synthesis of limiting factors, and identification project-scale restoration opportunities in an integrated process. This technique utilizes streamlined assessment protocols adapted from standard protocols and leverages multiple decades of applied restoration design and implementation experience to result in coupled opportunity identification including those targeting thermal refugia, which is a distinguishing improvement over other assessment protocols. The streamlined methods lead to more efficient identification of prioritized restoration actions when applied at the watershed, sub-watershed, or reach scale.
10:00AM – 10:30AM
Lake phenology across the landscape and climate change refugia
R. Hovel1, J. Daly1, S. Nelson2, S. Dykema3, A. Gavin4
1. University of Maine at Farmington
2. Appalachian Mountain Club
3. Alder Environmental
4. University of Maine
Research on climate change refugia in aquatic systems frequently emphasizes cold-water habitats and resistance to increasing temperature. Higher-elevation locations are often identified as important for preserving conditions suitable for cold-water organisms or communities. However, this concept remains understudied in lentic compared to lotic systems, even as lakes variably experience pronounced climate-related impacts including ice loss and higher temperatures. Lake responses to climate depend on characteristics such as landscape position, but the role of elevation is not well-documented and associated biological responses are unclear. Here, we describe spring ice and thermal dynamics in small remote lakes in Maine, USA, ranging from 76 to 955 m above sea level, and how temperature influences zooplankton phenology and community composition. Ice persisted on average 8 days longer in high-elevation (>500 m) lakes and, after ice breakup, high-elevation lakes warmed faster (0.3˚C/day) than low-elevation lakes (0.2˚C/day), and reached maximum temperatures 45 days earlier on average. Zooplankton phenology was driven by water temperature, but zooplankton taxa varied in response to lake conditions, shaping different zooplankton assemblages in high- and low-elevation sites. This suggests that refugial high-elevation lakes with prolonged ice and cold spring conditions could present an important regional conservation priority.