Showing posts with label rise in population. Show all posts
Showing posts with label rise in population. Show all posts

Wednesday, 25 April 2012

Arctic marine mammals and fish populations on the rise


Arctic marine mammals and fish populations are on the rise, according to a report released on Monday by the the Arctic Council's biodiversity working group at a Montreal conference.
In fact fish populations have risen dramatically, according to the findings of the Circumpolar Biodiversity Monitoring Program, theZoological Society of London, and the World Wildlife Fund.
The three organizations collaborated on the analysis, looking at 890 populations of 323 species of Arctic vertebrates.
The Arctic wildlife population changes, they said in a statement, are linked to "Arctic climate oscillations and changes in commercial harvest" in neighboring waters.
The report identified that fish living close to the surface of the water as opposed to near the ocean bottom were most susceptible to climate change, including such commercially important species as Pacific herring, ocean perch and Arctic cisco.
Some mammals were found to be recovering from exploitation, but rising populations of gray whales, bowhead whales and Greenlandic walruses have not returned to historical levels.
Sea ice species ringed seal, beluga whale, and thick-billed guillemot, meanwhile, have declined.
As well, marine birds continued a slow and steady decline that started in the late 20th century. The report said this "may be related to changes in climate, sea ice and food availability" and may be the beginning of a longer-term decline.
The effects of Arctic warming also were not restricted to the far north. The Atlantic Ocean is experiencing a decline in vertebrates thought to be driven by Arctic climate shifts, as well as commercial fishing.
In contrast, the Pacific Ocean has experienced a dramatic increase in vertebrates, amid warmer sea temperatures.

Saturday, 21 April 2012

Record spring respite for rare butterflies

UK butterflies 2011 - The good, the bad and the ugly
April 2012. Last year's record-breaking spring helped some of the UK's rarest butterflies recover following years of decline, a scientific study has revealed. The hot, dry weather provided perfect conditions for early spring specialists enabling them to benefit from extended flight periods as they emerged weeks earlier than usual.

Duke of Burgundy
The threatened Duke of Burgundy bucked a trend of recent declines as its population rose by 65% between 2010 and 2011. Other rare spring butterflies prospered - the Grizzled Skipper recorded a rise of 96% and the scarce Pearl-bordered Fritillary saw numbers jump by 103%.
Long-term decline
But despite last year's much-needed respite, many of our most threatened butterflies remain in a state of long-term decline and need further targeted conservation work to turn their fortunes around permanently.
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