Can isolated wetlands come to the trophic rescue of surrounding ecosystems? Investigating new pathways for food web connectivity

孤立的湿地能否对周围生态系统进行营养拯救？

• 批准号: RGPIN-2018-04291
• 负责人: Jardine, Timothy
• 金额: $ 2.4万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=654523
• 关键词: isolated; wetlands; come; trophic; rescue

Food web subsidies occur when a productive “donor” habitat sends nutrients, energy and/or organic matter to an unproductive “recipient” habitat. This movement of materials can stabilize food webs and enable higher overall productivity, but can also deliver contaminants. These fluxes are challenging to study and to manage because they are at odds with conventional notions of ecosystem boundaries. ******There are more than 20 million small wetlands across the globe, and many of these are deemed inconsequential by humans because they are shallow, isolated from surrounding waterbodies, freeze or dry out entirely in the winter, and lack fish. As such, they are regularly viewed as simple sinks for waste, leaving them undervalued by society and often drained, filled or degraded. This research program challenges that notion, and instead examines them as important donor habitats, providing a significant foodweb subsidy via a large flux of winged organisms – namely semi-aquatic (waterboatmen) and emergent (midges) insects. It is possible that this subsidy is responsible for maintaining fisheries production in rivers and lakes both in this region and in other cold or dry regions of the world, but little is known about its quality, including both healthy (omega-3 fatty acids) and harmful (mercury) compounds.******This program will test if these wetlands come to the trophic rescue of rivers, lakes and fields by evaluating the timing, magnitude, and nutritional quality of the subsidy. My team will examine how these fluxes change in different parts of North America, from northern Canadian environments where ice-cover is significant and the summer growing season is short, to arid environments in the southern United States where most wetlands dry completely in late summer. We will also determine if these insects deliver contaminants such as mercury from wetlands to rivers, because wetlands are known hotspots for mercury methylation. Finally, we will evaluate how changes in water quality affect insect community composition and whether wetland degradation from eutrophication and salinization favors migrant or non-migrant taxa. Together, this research could reveal new reasons to conserve wetlands in Canada and across the globe.

当生产性的“捐赠者”栖息地将养分、能量和/或有机物输送到非生产性的“接受者”栖息地时，就会出现食物网补贴。这种材料的移动可以稳定食物网，实现更高的整体生产率，但也可能带来污染物。这些通量的研究和管理具有挑战性，因为它们与生态系统边界的传统概念不一致。*全球有2000多万个小湿地，其中许多被人类认为是无关紧要的，因为它们很浅，与周围的水体隔绝，在冬天完全冻结或干燥，而且缺乏鱼类。因此，它们经常被视为垃圾的简单水槽，导致它们被社会低估，往往被耗尽、填满或退化。这项研究计划挑战这一概念，转而将它们视为重要的捐赠者栖息地，通过大量有翼生物--即半水栖(水生)和新兴(蚊虫)昆虫--提供可观的食物网补贴。这项补贴可能负责维持该地区和世界其他寒冷或干旱地区河流和湖泊的渔业产量，但人们对其质量知之甚少，包括健康的(omega-3脂肪酸)和有害的(汞)化合物。*该计划将通过评估补贴的时机、规模和营养质量来测试这些湿地是否对河流、湖泊和田野起到营养拯救作用。我的团队将研究这些通量在北美不同地区的变化，从加拿大北部冰盖显著且夏季生长季较短的环境，到美国南部的干旱环境，那里的大多数湿地在夏末完全干涸。我们还将确定这些昆虫是否将汞等污染物从湿地输送到河流，因为湿地是汞甲基化的已知热点。最后，我们将评估水质变化如何影响昆虫群落组成，以及富营养化和盐碱化导致的湿地退化是否有利于迁徙或非迁徙的类群。总之，这项研究可能会揭示保护加拿大和全球湿地的新理由。