Friday, June 8, 2012

Rains a Mixed Blessing for Chesapeake Bay Waterfowl

The scientists compared waterbird communities in estuaries of the Chesapeake Bay during 2002, a year of severe drought, to 2003, a year of high rainfall. During the drier year, the species of waterbirds present included both those that fed generally on many species of invertebrates and those that only fed on specific ones. However, the waterbird community was made up of most generalists the following year after heavy rain. The high rainfall increased nutrient runoff into the estuaries which reduced the estuaries' populations of small invertebrates. Because the dynamics of the invertebrate populations were affected, so in turn were the dynamics of the waterbird communities that fed on them.
I strenuously object to any study making hard and fast conclusions based on a comparison of two single years in the Chesapeake Bay (or anywhere else for that matter).  There are too many factors that can control the abundance of different waterfowl to be accounted by a single difference in two years in the Bay.  What about conditions in the north, where the birds go in summer to breed?  Could that have been the difference?

And as for the alleged reason for the effect, increased rainfall increases the probability of anoxia in the deep waters of the Bay.  These waters are approximately 5% of the Bay, and are out of reach of waterfowl in any event.  A change in the area of the anoxia would affect less than 5% of the area of the Bay.  Not likely to leave a mark on the waterfowl populations in a single year.
"We're seeing more extreme rainstorms in this region, so our results give a snapshot of what bird communities in urban estuaries might look like in the future," said Colin Studds, lead author and postdoctoral fellow at the Smithsonian Conservation Biology Institute at the time of the research. "As urban development continues, we need new solutions for managing water quality or we stand to lose the Bay's iconic natural treasures."
There is actually no evidence for "more" extreme weather as a result of global warming.  This is simply a way to invoke global warming without actually having to explain that the difference in temprature between years is generally small and inconsistent.  But if you say it will cause "more extreme weather, you can try to scare people regardless.  Hurricanes and tornadoes really are scary

Floods – no increase in frequency, less intense
Extreme weather events – no trend
Global precipitation – no trends
Weird weather – no trends
Forest fires – decreasing frequency

No comments:

Post a Comment