Graham Olivia J, Harvell Drew, Christiaen Bart, Gaeckle Jeff, Aoki Lillian R, Ratliff Baylen, Vinton Audrey, Rappazzo Brendan H, Whitman Tina
Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA.
Washington State Department of Natural Resources, Olympia, WA 47027, USA.
Integr Comp Biol. 2024 Sep 27;64(3):816-826. doi: 10.1093/icb/icae120.
Foundational habitats such as seagrasses and coral reefs are at severe risk globally from climate warming. Infectious disease associated with warming events is both a cause of decline and an indicator of stress in both habitats. Since new approaches are needed to detect refugia and design climate-smart networks of marine protected areas, we test the hypothesis that the health of eelgrass (Zostera marina) in temperate ecosystems can serve as a proxy indicative of higher resilience and help pinpoint refugia. Eelgrass meadows worldwide are at risk from environmental stressors, including climate warming and disease. Disease outbreaks of Labyrinthula zosterae are associated with recent, widespread declines in eelgrass meadows throughout the San Juan Islands, Washington, USA. Machine language learning, drone surveys, and molecular diagnostics reveal climate impacts on seagrass wasting disease prevalence (proportion of infected individuals) and severity (proportion of infected leaf area) from San Diego, California, to Alaska. Given that warmer temperatures favor many pathogens such as L. zosterae, we hypothesize that absent or low disease severity in meadows could indicate eelgrass resilience to climate and pathogenic stressors. Regional surveys showed the San Juan Islands as a hotspot for both high disease prevalence and severity, and surveys throughout the Northeast Pacific indicated higher prevalence and severity in intertidal, rather than subtidal, meadows. Further, among sites with eelgrass declines, losses were more pronounced at sites with shallower eelgrass meadows. We suggest that deeper meadows with the lowest disease severity will be refuges from future warming and pathogenic stressors in the Northeast Pacific. Disease monitoring may be a useful conservation approach for marine foundation species, as low or absent disease severity can pinpoint resilient refugia that should be prioritized for future conservation efforts. Even in declining or at-risk habitats, disease surveys can help identify meadows that may contain especially resilient individuals for future restoration efforts. Our approach of using disease as a pulse point for eelgrass resilience to multiple stressors could be applied to other habitats such as coral reefs to inform conservation and management decisions.
海草床和珊瑚礁等基础栖息地在全球范围内因气候变暖而面临严峻风险。与变暖事件相关的传染病既是这两种栖息地衰退的原因，也是其面临压力的指标。由于需要新的方法来检测避难所并设计适应气候的海洋保护区网络，我们检验了这样一个假设：温带生态系统中鳗草（大叶藻）的健康状况可作为更高恢复力的指标，并有助于确定避难所的位置。全球范围内的鳗草草甸都受到包括气候变暖和疾病在内的环境压力源的威胁。在美国华盛顿州圣胡安群岛，最近鳗草草甸大面积衰退与海草致病疫霉病的爆发有关。机器学习、无人机调查和分子诊断揭示了从加利福尼亚州圣地亚哥到阿拉斯加，气候对海草衰退病患病率（受感染个体的比例）和严重程度（受感染叶面积的比例）的影响。鉴于较高的温度有利于许多病原体，如海草致病疫霉，我们推测草甸中疾病严重程度低或不存在可能表明鳗草对气候和致病压力源具有恢复力。区域调查显示，圣胡安群岛是疾病高患病率和高严重程度的热点地区，整个东北太平洋的调查表明，潮间带草甸而非潮下带草甸的患病率和严重程度更高。此外，在鳗草数量减少的地点中，鳗草草甸较浅的地点损失更为明显。我们认为，疾病严重程度最低的较深草甸将成为东北太平洋未来应对变暖和致病压力源的避难所。疾病监测可能是保护海洋基础物种的一种有用方法，因为疾病严重程度低或不存在可以确定具有恢复力的避难所，这些避难所应成为未来保护工作的重点。即使在衰退或面临风险的栖息地，疾病调查也有助于识别可能包含特别具有恢复力个体的草甸，以便未来进行恢复工作。我们将疾病作为鳗草对多种压力源恢复力的一个脉冲点的方法，可应用于其他栖息地，如珊瑚礁，以指导保护和管理决策。
