{"id":11752,"date":"2017-03-19T08:20:40","date_gmt":"2017-03-19T08:20:40","guid":{"rendered":"http:\/\/revoscience.com\/en\/?p=11752"},"modified":"2017-03-19T08:20:40","modified_gmt":"2017-03-19T08:20:40","slug":"enormous-swarms-midges-teach-interconnected-landscapes","status":"publish","type":"post","link":"https:\/\/www.revoscience.com\/en\/enormous-swarms-midges-teach-interconnected-landscapes\/","title":{"rendered":"Enormous swarms of midges teach about interconnected landscapes"},"content":{"rendered":"
\"\"
David Hoekman, a former postdoctoral researcher at UW\u2013Madison, now an assistant professor at Southern Nazarene University, in a midge swarm in May 2008. PHOTO: CLAUDIO GRATTON<\/figcaption><\/figure>\n

Swarms of midges rise out of a lake in northern Iceland in such enormous numbers every spring and summer that they can impair breathing and darken the sky, giving the lake its name \u2014 Myvatn, or \u201cmidge lake.\u201d<\/span><\/p>\n

Ecologists at the University of Wisconsin\u2013Madison are trying to understand why the midge population can fluctuate by 100,000-fold across a decade, and what impact these massive swarms have on the surrounding landscape. It\u2019s becoming clear that the billions of midges falling on land fertilize and alter the vegetation on the lakeside, but the cause behind such large fluctuations in the insects\u2019 population remains a mystery.<\/span><\/p>\n

The research aims to better understand lake-dominated environments, including those of Wisconsin.<\/span><\/p>\n

Lake Myvatn sits at the edge of the Arctic Circle, where the sun barely sets during summer field work from May to August. The ecosystem is extreme, yet simple \u2014 a relatively small number of species, like the midges, dominate. This bare-bones environment is perfect for exploring complex interactions within ecosystems.<\/span><\/p>\n

In 2005, when Claudio Gratton<\/a>, a UW\u2013Madison professor of entomology, first saw the huge numbers of midges rising out of the lake and dying on land, he thought of them as a living transfer of nutrients from water to shore. Gratton calculated that the midges were the nutritional equivalent of scattering a half-million Big Macs around the edge of the lake, which is about the size of Lake Mendota in Madison. He wondered how the lakeside responded to this nutritional glut.<\/span><\/p>\n

To test how the midges alter the landscape, Gratton\u2019s laboratory set up experimental plots in the vegetation around the lake. In some, they added dead midges; in others, they used netting to exclude them.<\/span><\/p>\n

\"\"
Resembling a blanket of fog, midges swarm near Lake Myvatn in June 2014.<\/figcaption><\/figure>\n

Over the years, Gratton\u2019s team saw that where they added midges, grasses flourished. Normally starved of nutrients in the poor soil and outcompeted by heartier plants, the grasses took off in response to the influx of rotting-midge fertilizer. The research explained why grass grew in some areas and withered in others.<\/span><\/p>\n

\u201cOnly by understanding the linkage between midges and grass can you explain this pattern in nature,\u201d says Gratton. \u201cThe lake is causing that to happen.\u201d<\/span><\/p>\n

Local shepherds have long called the grass in midge-infested areas \u201cmidge grass\u201d \u2014 they harvest the grass and feed it to their flocks. Gratton\u2019s work suggested that the shepherds\u2019 folklore contained a kernel of truth, and that midges might indirectly nourish the sheep by encouraging more grass growth.<\/span><\/p>\n

Gratton was originally introduced to Lake Myvatn by Tony Ives<\/a>, a UW\u2013Madison professor of zoology, who has a lifelong connection to the island.<\/span><\/p>\n

\u201cI\u2019ve been going to Iceland since I was a kid,\u201d says Ives, whose middle name, Ragnar, was given to him in honor of an Icelandic farmer and friend of his father.<\/span><\/p>\n

Ives learned about the unpredictable and large swings in midge population through Arni Einarsson, the director of the Lake Myvatn research station, who has studied the lake since the 1970s.<\/span><\/p>\n

\"\"
Midges on flowers near Lake Myvatn in August 2006. PHOTO: CLAUDIO GRATTON<\/figcaption><\/figure>\n

In a 2008 article<\/a> in the journal Nature, Ives, Einarsson and their collaborators laid out a straightforward mathematical framework that might explain how the midge population spikes and crashes so dramatically and unpredictably. They suggested that small, random environmental changes \u2014 too much wind one year, or a late spring the next \u2014 could send the population crashing. But the true causes of this hair-trigger sensitivity remain elusive.<\/span><\/p>\n

In the nine years since, the team has been searching for clues that can help them understand the population changes better. Each year, they measure water quality, nutrient concentrations, and the amount of lakebed algae among other factors that might affect the insects. Then they wait for the midges.<\/span><\/p>\n

\u201cEvery year around this time I start holding my breath,\u201d wondering how the dynamic midge population will respond in spring, says Ives. \u201cIt\u2019s kind of like slow-motion suspense.\u201d<\/span><\/p>\n

Supported by a 10 year National Science Foundation grant for long-term research, Ives and his collaborators are waiting for the natural experiment to proceed through an entire population boom and bust. This year, the researchers might see the population crash \u2014 but they don\u2019t know.<\/span><\/p>\n

As the ecologists work to better understand the spare Lake Myvatn ecosystem, they are also extending their studies to the lake-filled Wisconsin landscape. Gratton and UW\u2013Madison postdoctoral researcher Mireia Bartrons, now at the University of Vic in Spain, developed a model<\/a> of how insect emergences from Wisconsin lakes affect lakeside ecosystems. With more than 15,000 lakes and 34 percent of the state lying within 200 meters of a lake or stream, the scientists expect aquatic insects to affect a large share of the state.<\/span><\/p>\n

Gratton sees ecosystems, whether in Iceland or the American Midwest, as an interwoven tapestry of interactions rather than isolated patches of land or water.<\/span><\/p>\n

\u201cThe character of the land would change without these lakes,\u201d says Gratton. \u201cOur landscapes are completely interconnected.\u201d<\/span><\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

Swarms of midges rise out of a lake in northern Iceland in such enormous numbers every spring and summer that they can impair breathing and darken the sky, giving the lake its name \u2014 Myvatn, or \u201cmidge lake.\u201d Ecologists at the University of Wisconsin\u2013Madison are trying to understand why the midge population can fluctuate by […]<\/p>\n","protected":false},"author":6,"featured_media":11753,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[15,17],"tags":[],"class_list":["post-11752","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-environment","category-research"],"featured_image_urls":{"full":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Gratton-6-775x581.jpg",775,581,false],"thumbnail":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Gratton-6-775x581-150x150.jpg",150,150,true],"medium":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Gratton-6-775x581-300x225.jpg",300,225,true],"medium_large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Gratton-6-775x581-768x576.jpg",750,563,true],"large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Gratton-6-775x581.jpg",750,562,false],"1536x1536":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Gratton-6-775x581.jpg",775,581,false],"2048x2048":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Gratton-6-775x581.jpg",775,581,false],"ultp_layout_landscape_large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Gratton-6-775x581.jpg",775,581,false],"ultp_layout_landscape":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Gratton-6-775x581.jpg",760,570,false],"ultp_layout_portrait":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Gratton-6-775x581.jpg",600,450,false],"ultp_layout_square":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Gratton-6-775x581.jpg",600,450,false],"newspaper-x-single-post":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Gratton-6-775x581.jpg",654,490,false],"newspaper-x-recent-post-big":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Gratton-6-775x581.jpg",480,360,false],"newspaper-x-recent-post-list-image":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Gratton-6-775x581.jpg",87,65,false],"web-stories-poster-portrait":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Gratton-6-775x581.jpg",640,480,false],"web-stories-publisher-logo":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Gratton-6-775x581.jpg",96,72,false],"web-stories-thumbnail":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2017\/03\/Gratton-6-775x581.jpg",150,112,false]},"author_info":{"info":["Amrita Tuladhar"]},"category_info":"Environment<\/a> Research<\/a>","tag_info":"Research","comment_count":"0","_links":{"self":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts\/11752","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/comments?post=11752"}],"version-history":[{"count":0,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts\/11752\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/media\/11753"}],"wp:attachment":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/media?parent=11752"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/categories?post=11752"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/tags?post=11752"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}