Helber Stephanie B, Procaccini Gabriele, Belshe E Fay, Santillan-Sarmiento Alex, Cardini Ulisse, Bröhl Stefanie, Schmid Michael, Reuter Hauke, Teichberg Mirta
Leibniz Centre for Tropical Marine Research (ZMT) GmbH, Bremen, Germany.
Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Wilhelmshaven, Germany.
Front Plant Sci. 2021 Jul 5;12:662682. doi: 10.3389/fpls.2021.662682. eCollection 2021.
is a key foundation species in the Mediterranean providing valuable ecosystem services. However, this species is particularly vulnerable towards high coastal nutrient inputs and the rising frequency of intense summer heat waves, but their combined effect has received little attention so far. Here, we investigated the effects of nutrient addition during an unusually warm summer over a 4-month period, comparing different morphological, physiological and biochemical population metrics of seagrass meadows growing in protected areas (Ischia) with meadows already exposed to significant anthropogenic pressure (Baia - Gulf of Pozzuoli). Our study highlights that the effects of warmer than usual summer temperatures on the population level of seagrass meadows can be exacerbated if the plants are already exposed to higher anthropogenic pressures. Morphological and population level indicators mainly changed over time, possibly impacted by season and the warmer temperatures, and displayed more pronounced reductions in seagrasses from impacted sites. The additional nutrient supply had even more deleterious effects, as shown by a decrease in approximately 67% in cover in fertilized plots at high impacted sites and 33% at low impacted sites. Moreover, while rhizome starch concentration showed a seasonal increase in plants from low impacted sites it displayed a trend of a 27% decrease in fertilized plots of the high impacted sites. Epiphyte biomass was approximately four-fold higher on leaves of plants growing in impacted sites and even doubled with the additional nutrient input. Predicting and anticipating stress in is of crucial importance for conservation and management efforts, given the limited colonizing and reproductive ability and extremely slow growth of this ecosystem engineer. Our results suggest that monitoring efforts should focus especially on leaf area index (LAI), carbohydrate concentrations in the rhizomes, and epiphyte cover on leaves as indicators of the onset of stress in , which can be used by decision makers to take appropriate measures before damage to the ecosystem becomes irreversible, minimize future human interference and strengthen the resilience of these important ecosystems.
是地中海地区的关键基础物种，提供重要的生态系统服务。然而，该物种特别容易受到沿海高营养输入和夏季强烈热浪频率上升的影响，但到目前为止，它们的综合影响很少受到关注。在这里，我们调查了在一个异常温暖的夏季为期4个月的营养添加效应，比较了生长在保护区（伊斯基亚岛）的海草草甸与已经受到重大人为压力的草甸（巴亚 - 波佐利湾）不同的形态、生理和生化种群指标。我们的研究强调，如果植物已经受到更高的人为压力，异常温暖的夏季温度对海草草甸种群水平的影响可能会加剧。形态和种群水平指标主要随时间变化，可能受到季节和温暖温度的影响，并且在受影响地点的海草中显示出更明显的减少。额外的养分供应产生了更有害的影响，在高影响地点施肥地块的覆盖率下降了约67%，在低影响地点下降了33%。此外，虽然低影响地点植物的根茎淀粉浓度呈现季节性增加，但在高影响地点的施肥地块中却呈现出27%的下降趋势。在受影响地点生长的植物叶片上的附生生物量大约高出四倍，并且随着额外的养分输入甚至增加了一倍。鉴于这种生态系统工程师的定殖和繁殖能力有限且生长极其缓慢，预测和预期海草的压力对于保护和管理工作至关重要。我们的结果表明，监测工作应特别关注叶面积指数（LAI）、根茎中的碳水化合物浓度以及叶片上的附生植物覆盖率，作为海草压力开始的指标，决策者可以利用这些指标在生态系统受损变得不可逆转之前采取适当措施，尽量减少未来的人为干扰并增强这些重要生态系统的恢复力。
