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的结构、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根本原因往往不清楚。沿海潮间带（即，高潮和低潮之间的海岸）长期以来一直作为重要的生态模型系统，因为其具有可接近性和易于观察的优点，被容易研究和操纵的寿命相对较短的生物体占据，并且暴露于通常恶劣的环境条件。这项研究将解决一个著名的岩石海岸系统沿着俄勒冈州和加州海岸的稳定性。之前的长期研究表明，尽管偶然的观察表明这些系统是稳定的，但事实上，它们可能正处于转变为另一种状态的尖端，失去了贻贝和海星等标志性生物，并成为海藻的主导。这些变化可能与陆地系统失去树木和大型捕食者相当。这项研究将导致对本科生和研究生的培训，包括来自代表性不足群体的个人。 此外，这项研究将包括对公众的宣传。研究人员将特别关注日益增加和更多变化的变暖对社区恢复的影响。例如，气候振荡（例如，近几十年来，厄尔尼诺现象、沿海上升流，特别是温度都发生了变化，导致对潮间带生物群的压力增加。在明显的反应，沿海生态系统显然已成为生产力较低，有机体的性能（生长，繁殖）下降，关键的动力过程（物种相互作用）减弱。新的研究将通过以下方式来追求这些即将到来的“临界点”的强烈暗示：（1）继续导致不稳定性增加的项目，（2）增加新的项目，以确定生态变化，（3）扩大工作区域，包括加州的位置。研究将评估海星是否从消耗性疾病中恢复，实验测试物种之间的相互作用是否确实在减弱，量化新猎物的年度投入以及潮间带群落的丰度、多样性、稳定性和恢复力的变化，并记录物理环境的变化。通过实地观察和实验，该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，了解地球生态系统未来可能的状态。利用这些数据，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。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值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.