Jan 9, 2009

Science - Dark buildings, vehicles, roads act as 'ecological traps' for organisms

Washington, Jan 8 (ANI): Insects and other creatures can mistake smooth, dark buildings, vehicles and even roads for water, which act as "ecological traps" that jeopardize animal populations and fragile ecosystems, according to a researcher at Michigan State University.

Bruce Robertson, an ecologist studying at the W.K. Kellogg Biological Station in Hickory Corners, north of Kalamazoo, claimed that the polarized light reflected from asphalt roads, windows, even plastic sheets and oil spills, mimics the surface of the water for some species.

As these organisms use water to breed and feed, the resulting confusion could drastically disrupt mating and feeding routines and lead insects and animals into contact with vehicles and other dangers.

Robertson said that polarized light reflected from man-made structures could overwhelm natural cues to animal behaviour.

For example, Dragonflies, and similar aquatic insects that are at the centre of the food web, can be prompted to lay eggs on roads or parking lots instead of water. And hence, insect population crashes can impact higher levels of the food chain.

"Any kind of shiny, black object -- oil, solar cells, asphalt -- the closer they are to wetlands, the bigger the problem," he said.

In fact, even predators following misdirected insect prey, can also find themselves in danger.

While its known that natural light is vital for creatures' ability to navigate, even visible light pollution from man-made sources can have a negative impact.

For example, newly hatched sea turtles have a tendency to move from their beach nests toward landward light sources instead of following moonlight to the safety of open water.

Robertson said that horizontally polarized light has been found to be a reliable cue for creatures to locate water, and the researchers are trying to discover the effects of light reflected from man-made structures. lthough the research highlights new concerns about human impact on native species and ecological communities, it suggests the importance of building with alternative materials and, when necessary, employing mitigation strategies, which might include adding white curtains to dark windows or adding white hatching marks to asphalt.

Robertson said that its also possible to turn it to an advantage-in locations where trees are being destroyed by insect infestations, for example, "you may be able to create massive polarized light traps to crash bark beetle populations," if such species are found to be responsive to polarized light cues.

The findings were reported in Frontiers in Ecology and the Environment. (ANI)

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