Thursday, March 6, 2014

Adirondack Insects: Extreme Cold And Climate Change

100_1407Weather anomalies impact the lives of most creatures, including humans, and this year’s protracted winter season is slowly taking its toll on people that dislike the snow and cold, as well as on various members of our wildlife community. While all animals native to the Adirondacks have evolved the ability to survive the rigors of a harsh and prolonged winter, some of the recent arrivals to the region may not be faring as well in this unrelenting, sub-arctic weather siege.

Over the past decade or two, the climate in the Adirondacks has slowly warmed enough to allow numerous forms of life to creep northward and expand their geographic range into our lowlands and valleys. For example, several birds, like the tufted titmouse and wild turkey are appearing more, as are some mammals like the gray squirrel and in the very southern realm of the Park, the opossum. However, the greatest influx of new residents probably lie in the vast array of invertebrates that exist in every ecological setting throughout the Park.

Climate Change PredictionsSince these lower forms of life are not as well studied and researched as are many of the larger and more complex creatures, little is known regarding the extent of the gradual migration of these entities into the region. It is relatively safe to say that as the Park’s climate becomes more temperate, various species of bugs, both from more southern locales and from areas outside our continent will slowly be establishing populations in the Park. Currently, foresters are concerned with the spread of the Emerald Ash Borer, Asian Long-Horned Beetle and a few others that could devastate the health and well being of certain species of trees that commonly occur in our vast stretches of forests.

The Emerald Ash Borer is an insect that spends the winter in a fully developed larval stage within a chamber that it excavates in the sapwood of an ash tree. During the autumn, this insect lowers the moisture content of its cells which causes the remaining water molecules to descend into a super cooled state when exposed to temperatures well below 32 degrees. Yet, this protection from freezing to death does not permit the larvae to survive an indefinite period of intense, sub-zero weather. Researchers have discovered that this generally protects the immature insect from temperatures down to about fifteen below for only several months.

Any chemist will explain that a super cooled fluid may remain a liquid below a prescribed value for a brief period of time, or it may solidify above that point, depending on chance. As water molecules move randomly within a cell, they inevitably encounter other water molecules with the passage of time and link to them which starts the process of ice formation. A super cooled substance will freeze given enough time, the issue becomes how long does it take. (It is like playing the scratch-off lottery games. The greater the length of time that you play, the greater the odds become that you eventually will win some, usually trivial, amount of money.) The presence, or absence of condensation nuclei in the cells also influences the likelihood of a super cooled fluid freezing solid.

The longer winter drags on at this intensity, the greater the chances that a higher percentage of super cooled insects, like the larvae of the Emerald Ash Borer, will develop ice crystals in their cells which leading to their demise. Bugs native to the Adirondacks, like various species of mosquitoes, have evolved a super cooled state with a much lower freezing point. These insects are far more tolerant of well below zero conditions for months and are not as likely to be impacted by the cold, lengthy winter that we are experiencing this year.

Some insects, like black fly larvae, spend the winter in flowing water. Occasionally, ice develops on the shores and over the surface of small streams, however, there is always some water flowing near the bottom that black fly larvae migrate to when necessary. Please don’t think that just because some bugs may be seriously impacted by this winter’s cold that all bug will be fewer in number this coming summer. Also, even if one insect population is decimated by the cold this year, it doesn’t mean that its presence will no long impact the area. Insects have an exceptionally high rate of reproduction, and when conditions become favorable again, their numbers can explode.

This year’s winter is having a negative effect on the survival rate of various creatures. However, the warming of the planet is continuing, and subsequent winters will provide conditions favorable for the spread of unwanted forms of life. Our very temporary reprieve from the warming that our region has been experiencing over the past several decades should slow some ecological changes here, but the transition continues.

Photos: Above, ; and below, from DEC’s Conservationist magazine (August 2007).

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Tom Kalinowski is an avid outdoor enthusiast who taught field biology and ecology at Saranac Lake High School for 33 years. He has written numerous articles on natural history for Adirondack Life, The Conservationist, and Adirondack Explorer magazines and a weekly nature column for the Lake Placid News. In addition, Tom’s books, An Adirondack Almanac, and his most recent work entitled Adirondack Nature Notes, focuses on various events that occur among the region’s flora and fauna during very specific times of the calendar year. He also spends time photographing wildlife. Tom’s pictures have appeared in various publications across the New York State.

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