Responses of a tidal freshwater marsh plant community to chronic and pulsed saline intrusion
Responses of a tidal freshwater marsh plant community to chronic and pulsed saline intrusion
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潮汐淡水沼泽植物群落对慢性和脉冲盐水入侵的响应
DOI：
10.1111/1365-2745.13885
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发表时间：
2022
影响因子：
5.5
通讯作者：
Pennings, Steven C.
中科院分区：
文献类型：
--
作者：
Li, Fan;Angelini, Christine;Byers, James E.;Craft, Christopher;Pennings, Steven C.
气候变化对生态系统造成长期的和脉冲式的环境变化。在河口，由于海平面上升，干旱和风暴潮期间河流流量减少，潮汐淡水沼泽经历了延长和间歇性的盐度升高时期，但大多数研究集中在延长的(压力)扰动上。在4年的时间里，我们在美国佐治亚州的潮汐淡水沼泽的重复地块中添加了稀释的海水，以将孔隙水盐度从淡水提高到低盐度。我们通过测量优势被子植物、底栖微藻和优势大型无脊椎动物(招潮蟹)的反应，评估了盐度压力(连续)和脉冲(每年2 个月)变化对生态系统的影响。我们将典型的寡盐和中盐条件下的被子植物移植到地块中，作为生物指示器(植物温度计)来评估较长时间内植被变化的潜力。在挤压处理中，所有常见植物的盖度都减少了。在第一个生长季节内，月见草几乎消失；水何首乌在第一个生长季几乎消失；在4 年中，水芹和苦枣都出现了变化，但并没有完全消失。四种最主要植物种类的减少减少了地上植物的总生物量，导致透光率增加，底栖硅藻和蓝藻的密度增加。不同处理对蟹洞密度的影响不显著，但与所有重复的地上植物生物量呈正相关。移栽试验表明，在盐度较高的条件下，典型的植物(如Schoenopectussp.)在新闻报道普遍存在的情况下表现良好。在脉冲治疗中，只有L。植被复盖率下降，对群落水平的地上生物量或其他群落变量没有影响。我们的结果表明，潮汐淡水沼泽植物群落和动物群落容易受到长期盐碱化的影响，但对短期盐碱化脉冲具有弹性。虽然盐度脉冲不会损害大多数生态系统功能，但在脉冲处理中，单一物种(羊栖菜)的减少与沼泽沉积减少和海拔没有增加有关--这些因素对湿地在海平面上升时代的生存肯定是积极的。因此，即使在群落结构发生戏剧性变化之前，周期性盐碱化也可能威胁淡水湿地的长期可持续性。
Climate change causes both chronic and pulsed environmental changes to ecosystems. In estuaries, tidal freshwater marshes experience both extended and episodic periods of elevated salinities due to sea level rise, reduced river discharge during drought and storm surge, but most research has focused on extended (press) perturbations.Over a 4‐year period, we added diluted seawater to replicated plots in a tidal freshwater marsh in Georgia, USA to raise porewater salinities from freshwater to oligohaline. We assessed the ecosystem effects of press (continuous) and pulse (2 months per year) changes in salinity by measuring the responses of dominant angiosperms, benthic microalgae and dominant macro‐invertebrates (fiddler crabs). We transplanted angiosperms typical of oligohaline and mesohaline conditions into plots as bioindicators (phytometers) to assess potential for vegetation changes over longer time periods.In the press treatment, the cover of all common plant species decreased.Ludwigia repensalmost disappeared within the first month;Polygonum hydropiperoidesnearly disappeared within the first growing season;Pontederia cordataandZizaniopsis miliaceadeclined over the 4 years but did not completely disappear. The decline in the four most dominant plant species decreased total above‐ground plant biomass, leading to an increase in light penetration and increased densities of benthic diatoms and cyanobacteria. The density of fiddler crab burrows was not significantly affected by the treatments, but was positively related to above‐ground plant biomass across all replicates. Transplant experiments indicated that plants typical of higher salinity conditions (e.g.Schoenoplectussp.) performed well under conditions prevalent in the press plots.In the pulse treatment, onlyL. repensdeclined, and there was no effect on community‐level above‐ground biomass or other community variables.Synthesis. Our results indicate that tidal freshwater marsh plant and animal communities are vulnerable to extended periods of salinization but resilient to short saline pulses. Although saline pulses did not impair most ecosystem functions, the decline in a single species (L. repens) in the pulse treatment was associated with reduced marsh accretion and no elevation gain—factors which must be positive for wetland survival in an era of rising seas. Thus, periodic salinization may threaten the long‐term persistence of freshwater wetlands even before dramatic changes in community structure occurs.
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影响因子：
7.8
作者：
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通讯作者：
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影响因子：
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影响因子：
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作者：
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通讯作者：
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影响因子：
2.7
作者：
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通讯作者：
Fan Li;S. Pennings
影响因子：
6.4
作者：
Jinsong Wang;Dashuan Tian;A. Knapp;Han Y. H. Chen;Yiqi Luo;Zhaolei Li;E. Hou;Xin Huang;
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