Spiders can help scientists survey plant life by trapping tell-tale pollen in their webs

Spiders can help scientists survey plant life by trapping tell-tale pollen in their webs, says an international team of researchers.

Dr Cheng-Sen Li, of the Chinese Academy of Sciences and the Beijing Museum of Natural History, and colleagues report their findings in the July issue of the journal Review of Palaeobotany and PalynologyCheng and colleagues studied pollen captured in spider webs of southern and central Yunnan, China, and showed that the sticky webs are good at capturing and hanging onto pollen grains from local plants. They say the method may be useful in plant surveys worldwide.

"The [type] of pollen and spores identified from the spider webs can reflect the
vegetation of the sampling site," says Cheng.

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Salvage Logging, Replanting Worse

Contrary to the conventional wisdom, scientists have found that logging big dead trees after a wildfire and planting young ones makes future fires worse, at least for the first 10 or 20 years while the young trees create a volatile new source of fuel.

The findings by scientists from the U.S. Forest Service and Oregon State University raise questions about the long-standing practice of salvage logging on national forests at a time when global warming is expected to increase the size and numbers of wildfires and the annual cost of fighting them is running around $1 billion.

In the first study of its kind, scientists examined satellite images, aerial photographs, and records of logging and replanting to look at areas that burned in the 1987 Silver fire in southwestern Oregon and again in the 2002 Biscuit fire.

"It was the conventional wisdom that salvage logging and planting could reduce the risk of high-severity fires," said Jonathan R. Thompson, a doctoral candidate in forest science at Oregon State, who was lead author of the study appearing this week in Proceedings of the National Academy of Sciences. "Our data suggest otherwise."
They suggested that the large stands of closely packed young trees created by replanting are a much more volatile source of fuel for decades to come than the large dead trees that are cut down and hauled away in salvage logging operations.

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