IFES-GCOE グローバルCOEプログラム 「統合フィールド環境科学の教育研究拠点形成」
GCOEの海外研究者招聘事業で招聘しておりますJason Dunham博士 （USGS, Oregon）、および創成研究機構のリーダー育成プロジェクト事業で招聘しておりますTim Beechie博士（NWMFSC, NOAA, Seattle）によるセミナーを以下の要領で開催いたします。
日時: 2010年10月6日（水） 15:00-16:30
講演者: Jason Dunham （USGS, Oregon）
演題: Climate change and fish in the Pacific Northwest US: focus on water temperature
The influence of climate change on water temperatures will lead to profound changes in freshwater species and ecosystems. We understand what many of these basic impacts may be, but as the common saying goes: "a little knowledge can be dangerous." The case of the Pacific Northwest is an excellent example. I provide an overview of some key uncertainties that limit and likely bias our understanding of climate impacts on water temperatures and biota in this region. I focus on examples from bull trout, which is the most cold-adapted native fish in the Pacific Northwest and perhaps most vulnerable to climate change. In the case of bull trout, three issues emerge: 1) our understanding of thermal habitat relationships in the field is limited primarily to summer maximum temperatures, 2) projections of climate impacts are based on projected changes to air, not water temperature, or limited locations within the region, and 3) we understand little about how past temperatures have responded to climate change, or the alternative of other human impacts, such as land and water use. I will address how each of these issues is being addressed in the region and briefly discuss the potential implications for managing bull trout in the face of uncertain climate impacts.
講演者: Tim Beechie（NWMFSC, NOAA, Seattle）
演題: Restoring rivers in a changing climate
Modeled future stream flows and temperatures suggest that riverine habitats will be significantly altered in the next few decades, forcing managers to ask whether and how river restoration plans should be altered to accommodate climate change. To facilitate evaluation of restoration options, we developed a suite of questions that focus analyses on identifying (1) local habitat factors that limit riverine ecosystem recovery, (2) predicted local effects of climate change on stream flow and temperature, (3) the ability of restoration actions to ameliorate climate change effects, and (4) whether restoration actions increase ecosystem resilience. We then mapped predicted stream flow and temperature changes throughout the Pacific Northwest, and reviewed literature on habitat restoration actions to determine the degree to which they either ameliorate a climate change effect or increase habitat diversity and resilience. Recent flow regimes are classified as snowmelt-dominated and transitional across much of the region, but predicted future flow regimes (based on a 2070-2099 climate estimate) are predominantly rainfall-dominated. Summer low flows are predicted to decrease by 35-75% west of the Cascade Mountains, whereas highest monthly averaged flows are predicted to increase by 10-60% across most of the region. Stream temperatures are predicted to increase by an average of 2°C in most rivers by 2030-2069 and ~3.2°C by 2070-2099. Restoring floodplain connectivity and re-aggrading incised channels ameliorate both stream flow and temperature changes and increase habitat diversity, whereas restoring in-stream flows can ameliorate decreases in low flows as well as stream temperature increases. Other restoration actions (e.g., reducing sediment supply, in-stream rehabilitation) are much less likely to ameliorate climate change effects. We offer two decision support processes to illustrate how to use predicted climate change effects and our synthesis of restoration action effectiveness to evaluate (1) whether climate change should alter the types or priority of restoration actions in a salmon habitat restoration plan, or (2) whether a specific restoration project is likely to be ineffective in climate altered future. Actions that restore watershed and ecosystem processes are most likely to sustain salmon populations in a climate altered future because they allow river channels and riverine ecosystems to evolve in response to shifting stream flow and temperature regimes.