LTREB: Testing tipping points in a model rocky intertidal meta-ecosystem – Climate-change, increasing variances, and response mechanisms

近几十年来，长期以来被认为不受变化影响的海洋生态系统，其结构、多样性和地理范围都受到了破坏，但海洋生物群发生这种变化的实际潜在原因往往不清楚。沿海潮间带(即涨潮和退潮之间的海岸)长期以来一直是重要的生态模式系统，因为它在可获得性和易于观察方面具有优势，可由寿命相对较短的易于研究和操纵的生物占据，并经常暴露在恶劣的环境条件下。这项研究将解决俄勒冈州和加利福尼亚州海岸沿线著名的岩石海岸系统的稳定性问题。之前的长期研究表明，尽管随意观察表明这些系统是稳定的，但实际上，它们可能正处于转换到另一种状态的边缘，失去了贻贝和海星等标志性生物，并开始被海藻主导。这些变化可能相当于从陆地系统中失去了树木和大型捕食者。这项研究将对本科生和研究生进行培训，包括来自代表性不足群体的个人。此外，这项研究将包括对普通公众的推广。研究人员将特别关注日益增加的和更具变数的变暖对社区恢复的影响。例如，近几十年来，气候振荡(如厄尔尼诺现象)、沿海上升流，特别是温度都发生了变化，导致潮间带生物群承受的压力增加。作为明显的反应，沿海生态系统的生产力明显下降，生物体的表现(生长、繁殖)下降，关键的动力过程(物种相互作用)减弱。这项新的研究将通过(1)继续那些导致日益不稳定的洞察力的项目，(2)增加将精确定位生态变化的新项目，以及(3)扩大工作区域，以包括加州的地点，来寻求这些即将到来的“临界点”的强烈暗示。研究将评估海星是否从消耗性疾病中恢复，通过实验测试物种之间的相互作用是否真的在减弱，量化新猎物的年度投入以及潮间带群落的丰度、多样性、稳定性和弹性的变化，并记录物理环境的变化。通过实地观察和实验，这项研究将深入了解环境变化，特别是变暖对沿海生态系统未来的影响，以及更广泛地说，对地球生态系统未来可能的状态的影响。使用这些数据，我们将检验气候变化的直接和间接影响正在推动或可能推动这些系统进入新的替代状态的假设。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

In recent decades, ocean ecosystems, long thought to be immune to change, have undergone disruptions to their structure, diversity, and geographic range, yet the actual underlying reasons for such changes in oceanic biota are often unclear. Coastal intertidal zones (i.e., the shore between high and low tides) have long served as important ecological model systems because of advantages in accessibility and ease of observation, occupancy by easily studied and manipulated organisms of relatively short lifespans, and exposure to often severe environmental conditions. This research will address the stability of a well-known rocky shore system along the Oregon and California coasts. Prior long-term research indicates that, although casual observation suggests these systems are stable, in fact, they may be on the cusp of shifting into another state, losing iconic organisms like mussels and sea stars, and becoming dominated by seaweeds. These changes might be comparable to losing trees and large predators from terrestrial systems. This study would result in the training of undergraduates and graduate students, including individuals from under-represented groups. Additionally, this study would include outreach to the general public.The researchers will focus particularly on impacts of increasing and more variable warming on community recovery. For example, climate oscillations (e.g., El Niño), coastal upwelling, and particularly temperature have all changed in recent decades in ways leading to increased stress on intertidal biota. In apparent response, coastal ecosystems evidently have become less productive, organismal performance (growth, reproduction) has declined, and key dynamical processes (species interactions) have weakened. The new research will pursue these strong hints of an impending “tipping point” by (1) continuing the projects that led to the insights of increasing instability, (2) adding new projects that will pinpoint ecological changes, and (3) expanding the region of work to include locations in California. Research will assess whether or not sea stars recover from wasting disease, experimentally test if species interactions are indeed weakening, quantify the annual inputs of new prey and changes in abundance, diversity, stability, and resilience of intertidal communities, and document changes in the physical environment. Using field observations and experiments, the research will provide insight into impacts of environmental change, particularly warming, on the future of coastal ecosystems, and more generally, into possible future states of Earth’s ecosystems. Using these data, we will test the hypothesis that direct and indirect effects of climate change are driving, or may drive these systems into new, alternative states.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.