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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=764635
• 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”栖息地向非生产性的“接收者”栖息地输送养分、能量和/或有机物时，就会产生食物网补贴。这种物质的移动可以稳定食物网并提高整体生产力，但也可能带来污染物。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。全球有超过 2000 万个小型湿地，其中许多湿地很浅，与周围环境隔离，因此被人类认为无关紧要。水体在冬季完全结冰或干涸，并且缺乏鱼类，因此，它们通常被视为简单的废物汇，导致它们被社会低估，并且经常被排干、填满或退化。将它们视为重要的捐助栖息地，通过大量有翅生物（即半水生（水船昆虫）和新兴（蠓）昆虫）提供重要的食物网补贴。这种补贴可能负责维持渔业。该地区以及世界其他寒冷或干燥地区的河流和湖泊中都有生产，但对其质量知之甚少，包括健康（omega-3 脂肪酸）和有害（汞）化合物。该计划将测试是否通过评估补贴的时间、规模和营养质量，这些湿地对河流、湖泊和田野进行了营养拯救。我的团队将研究北美不同地区（从冰雪覆盖的加拿大北部环境）这些通量的变化。意义重大，夏季由于湿地是已知的汞甲基化热点，因此美国南部的生长季节较短，大多数湿地在夏末完全干燥，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。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类群，这项研究可以揭示昆虫群落组成的新原因。保护加拿大和全球的湿地。