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horseshoe crab  (Source: web.rollins.edu)
Sea-level rise and ocean temperatures are affecting horseshoe crab breeding

New research from the U.S. Geological Survey (USGS) reveals that horseshoe crab populations may be declining due to changes in the climate

Horseshoe crabs are arthropods that have lived on the planet for approximately 450 million years. These ancient creatures have declined in population in more recent years, and the main reason is because of overharvesting (for fertilizer and bait) and coastal habitat destruction. But now, climate change may have some part in the dwindling numbers as well.

"Using genetic variation, we determined the trends between past and present population sizes of horseshoe crabs found that a clear decline in the number of horseshoe crabs has occurred that parallels climate change associated with the end of the last Ice Age," said Tim King, lead author of the study and a scientist with the USGS.

According to research by the USGS, accompanying water temperature fluctuations and sea-level rise have contributed to limited horseshoe crab interbreeding and distribution. This leads to a reduction in population, which is what happened when temperatures rose after the last Ice Age.  

Horseshoe crabs are not the only creatures affected by their decline, though. Migrating sea birds like the Red Knot depend on horseshoe crab eggs for food each spring. Red Knots usually eat horseshoe crab eggs at Delaware Bay during migration, but severe population declines in horseshoe crabs have occurred all along the eastern seaboard of the United States. Significant declines have also occurred in the eastern Gulf of Mexico. 

In addition, Atlantic loggerhead turtles have experienced a change in population due to the lack of adult horseshoe crabs in Chesapeake Bay. 

Now, conservation managers are using certain findings, such as the fact that adult male horseshoe crabs travel from bay to bay while females stay in one place, to create both local and regional strategies to help sustain the horseshoe crab populations, and help them to continue reproducing.  

"Consequently, harvest limitations on females in populations with low numbers may be a useful management strategy, as well as relocating females from adjacent bays to help restore certain populations," said King. "Both studies highlight the importance of considering both climatic change and other human-caused factors such as overharvest in understanding the population dynamics of this and other species."

This study was published in Molecular Ecology in August of this year.




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RE: Nature rocks
By Mitch101 on 9/3/2010 9:14:20 AM , Rating: 2
Im sure were having an impact on nature but its also a part of nature for species to become extinct. Apparently a species were familiar with is on the chopping block potentially because of us or part of nature I dont know.

http://wwf.panda.org/about_our_earth/biodiversity/...

Just to illustrate the degree of biodiversity loss we're facing, let’s take you through one scientific analysis...
* The rapid loss of species we are seeing today is estimated by experts to be between 1,000 and 10,000 times higher than the natural extinction rate.*
* These experts calculate that between 0.01 and 0.1% of all species will become extinct each year.
* If the low estimate of the number of species out there is true - i.e. that there are around 2 million different species on our planet** - then that means between 200 and 2,000 extinctions occur every year.
* But if the upper estimate of species numbers is true - that there are 100 million different species co-existing with us on our planet - then between 10,000 and 100,000 species are becoming extinct each year.

Now if you follow Steven Hawkins humans need to get into space travel as humans have all their eggs in one basket which is earth. I believe his estimate was about 110 years left to humanity.


RE: Nature rocks
By Lerianis on 9/5/2010 11:31:34 PM , Rating: 2
Steven was a little...... stupid with that estimate, to be blunt. The fact is that humanity will survive MUCH MUCH MUCH MUCH MUCH longer than 110 years on this planet.


RE: Nature rocks
By Grabo on 9/9/2010 4:20:09 AM , Rating: 2
'The fact is'?
Mankind is volatile, and has always been. Only post-industrialization have we really gotten the tools to really damage ourselves and everything else though. Technology and overpopulation are having a stampede and no one knows where it will end.


RE: Nature rocks
By rcc on 9/23/2010 2:05:55 PM , Rating: 2
I'm sure we are having an impact on nature as well. Mankind has obviously had an impact on many species. But that wasn't the focus of the quote or the comment.

Like it or not,we are the worlds top predator. We will have an impact on the creatures around us. We also, in theory, are sentient and can decide to limit those losses if we want to. So far it's been iffy.

I have confidence in nature though. When an overpopulation of wolves lowers the rabbit population, nature manages to reduce the wolf population. I'm not guessing when humanity will get adjusted, it depends on our ability to adapt and expand, but I'm confident that if we all stay on this little blue ball doing what we are doing, that we will get an adjustment.


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