Functional trait responses of aquatic macroinvertebrates to simulated drought in a Neotropical bromeliad ecosystem
Functional trait responses of aquatic macroinvertebrates to simulated drought in a Neotropical bromeliad ecosystem
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DOI：
10.1111/fwb.12621
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发表时间：
2015-09-01
影响因子：
2.7
通讯作者：
Leroy, Celine
中科院分区：
文献类型：
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作者：
Dezerald, Olivier;Cereghino, Regis;Leroy, Celine
亚马孙东南部旱季的持续时间预计将增加。对于潮湿雨林中的淡水集合如何应对干旱，以及在系统崩溃之前它们在多大程度上抵御了降雨的缺乏，人们知之甚少。我们操纵的避雨棚在坦克形成凤梨（即这些植物的联锁叶腋形成收集雨水的威尔斯），以模拟一个非常长的干旱期（49天，相比之下，10年的平均SD年最大值为175.3天，没有降雨在研究地点），然后再润湿期。通过每周采样超过3个月，我们遵循的动态表示的丰度加权性状在无脊椎动物组合在这些处理厂和对照组。功能结构的组合是抗旱，直到凤梨池中的水量下降了90%，当有一个突然的转变，由于大多数人口的损失，除了抗旱culicids的功能性状结构。与生活史，身体大小和偏好的食物相关的性状对干旱表现出显着的反应。有一个收敛的功能性状的物种生存在干燥的植物，加强了这样的想法，即环境过滤，而不是随机性，决定了功能轨迹的水生组合在干旱期间。在干燥期结束时，从干燥的植物中取出可能含有抗旱卵/孢囊（以及最终活幼虫）的碎屑样品，并在实验室中重新润湿，使我们能够通过来自其他地方的成虫随后产卵来区分抗性物种和需要寄生的物种。在该地区持续存在的充满水的凤梨科植物提供了最重要的殖民者池，社区恢复到干扰前的状态在1- 2周的复湿。我们的研究结果表明，凤梨科无脊椎动物组合的功能性状结构可以保持稳定的降水变化的情况下，将在当地规模的三倍，目前的干旱期的持续时间。今后的实验应评估环境因素如何改变抗旱能力与生态系统进程崩溃之间的临界点。
The duration of the dry seasons in south-eastern Amazonia is expected to increase. Little is known of how freshwater assemblages respond to drought in the humid rainforests and of the extent to which they resist the absence of rainfall before the collapse of the system. We manipulated rainshelters over tank-forming bromeliads (i.e. the interlocking leaf axils of these plants form wells that collect rainwater) to simulate an exceptionally long dry period (49days, compared with a 10-year meanSD annual maximum number of 175.3days without rainfall at the study site) and then a rewetting period. By sampling weekly over 3months, we followed the dynamics of the representation of abundance-weighted traits in invertebrate assemblages in these treatment plants and in a control group. The functional structure of assemblages was drought resistant until the water volume in the bromeliad pools dropped by 90%, when there was a sudden shift in the functional trait structure due to the loss of most populations except the drought-resistant culicids. Traits related to life history, body size and preferred food showed significant responses to drought. There was a convergence in the functional traits of species surviving in dry plants, strengthening the idea that environmental filtering, rather than stochasticity, determines the functional trajectory of aquatic assemblages during drought. At the end of the dry period, samples of the detritus potentially containing drought-resistant eggs/cysts (and eventually live larvae) were taken from the dry plants and rewetted in the laboratory, allowing us to distinguish resistant species from those requiring recolonisation via subsequent oviposition by adults from elsewhere. Patches of water-filled bromeliads persisting in the area provided the most important pool of colonists, and communities returned to the pre-disturbance state within 1-2weeks of rewetting. Our results suggest that the functional trait structure of invertebrate assemblages in bromeliads could remain stable under scenarios of precipitation change that would triple the duration of current dry periods at a local scale. Future experiments should evaluate how environmental factors might alter the tipping point between resistance to drought and a collapse in ecosystem processes.