Sea level rise (SLR) imposes increasing salinity and inundation stresses in salt marshes which simultaneously face invasions by exotic plant species. We aimed to improve and apply knowledge on the ecophysiological responses of halophytes to SLR to conservation management of salt marshes. In a mesocosm experiment, we measured and compared phosphoenolpyruvate carboxylase (PEPC) activity and related functional traits of the California-native Spartina foliosa, invasive S. densiflora and their hybrid S. densiflora × foliosa in response to increasing levels of salinity and inundation. S. foliosa was moderately sensitive to salinity, showing a 57% reduction in PEPC specific activity from freshwater to hypersalinity. This native species compensated for the reduction of PEPC activity with increased salinity through 80% higher enzyme activation by phosphorylation. PEPC functional trait responses of S. foliosa were mostly independent of inundation depth. In view of these results, managers should conserve undeveloped lands for accommodation space above current high tide lines to facilitate colonization of stress-tolerant S. foliosa. Our results on functional responses of PEPC traits recorded high sensitivity to salinity for S. densiflora. This was reflected by 65% lower PEPC specific activity together with increasing accumulation of free proline (+96%) and total proteins (+23%) with elevated salinity. These results suggest prioritized eradication of S. densiflora populations in brackish habitats. Measured PEPC responses support the high stress tolerance of the S. densiflora × foliosa hybrid. PEPC traits for the hybrid were mostly independent of salinity and inundation. The hybrid showed higher PEPC-specific activity than S. foliosa (+70%) and S. densiflora (+15%) in freshwater under intermediate inundation. Results suggest that eradication of the hybrid should be the highest management priority. Our study shows that the responses of key functional physiological traits to environmental stresses serve as biological indicators that can guide ecosystem management practices in a scenario of climate change.

中文翻译：

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从生理学到盐沼管理，随着海平面上升而面临的挑战：原生叶天冬草，入侵性链球菌及其杂种的情况。

海平面上升（SLR）在盐沼中增加了盐度和淹没压力，同时面临着外来植物物种的入侵。我们旨在改进盐生植物对SLR的生态生理反应的知识，并将其应用于盐沼的养护管理。在中观实验中，我们测量并比较了响应于盐度和淹没水平的增加，加利福尼亚州原生的Spartina foliosa，侵染性S. densiflora及其杂交S. densiflora×foliosa的磷酸烯醇丙酮酸羧化酶（PEPC）活性和相关功能性状。叶葡萄球菌对盐度中等敏感，显示PEPC比活性从淡水到高盐度降低了57％。这种天然物种通过增加80％的磷酸化酶活化来补偿盐度增加而引起的PEPC活性降低。叶链霉菌的PEPC功能性状反应大多与淹没深度无关。鉴于这些结果，管理人员应保留未开发的土地，以在当前的高潮线以上留出空间，以利于抗逆性链球菌定植。我们关于PEPC性状的功能性反应的结果记录了对盐枝链球菌盐分的高度敏感性。PEPC比活性降低了65％，游离脯氨酸（+ 96％）和总蛋白质（+ 23％）的累积盐分升高，反映了这一点。这些结果表明优先消除微咸生境中的S. densiflora种群。测得的PEPC响应支持S的高应力耐受性。密西兰×叶叶杂种。杂种的PEPC性状主要独立于盐度和淹没。在中间淹没的情况下，该杂种在淡水中显示出比S. foliosa（+ 70％）和S. densiflora（+ 15％）更高的PEPC特异性活性。结果表明，根除杂种应该是最高的管理重点。我们的研究表明，关键功能生理特征对环境压力的响应可以作为生物学指标，在气候变化的情况下指导生态系统管理实践。结果表明，根除杂种应该是最高的管理重点。我们的研究表明，关键功能生理特征对环境压力的响应可以作为生物学指标，在气候变化的情况下指导生态系统管理实践。结果表明，根除杂种应该是最高的管理重点。我们的研究表明，关键功能生理特征对环境压力的反应可以作为生物学指标，在气候变化的情况下指导生态系统管理实践。