A yellow-bellied marmot pup. Credit: Raquel Monclus
Global warming is proving positive for Colorado’s yellow-bellied marmots, according to research that improves on a previously poor understanding of how climate change is affecting species. Imperial College London’s Arpat Ozgul and his colleagues claim to show that changes in when the seasons happen can simultaneously change the body mass and population size of a species for the first time. “Marmots are awake for only four to five months of the year,” explained lead author Ozgul. “These months are a busy time for them – they have to eat and gain weight, get pregnant, produce offspring and get ready to hibernate again. Since the summers have become longer, marmots have had more time to do all these things and grow before the upcoming winter, so they are more likely to succeed and survive.”
It is difficult to collect enough data to work out exactly how climate change affects plants and creatures’ lives. However, Ozgul and his colleagues from the Universities of Florida, Kansas, California and Sheffield, UK, took advantage of records of Colorado marmots dating back to 1962, focusing on the most complete data set from 1976-2008. Writing in leading scientific journal Nature on Thursday, the team also used a recently-developed method to analyse body masses and survival rates. They saw an abrupt increase in the proportion of adult marmots among the population and in the mass of those older marmots. “Marmots are now born earlier and they have more time to grow until the next hibernation,” the team writes. “This increase in juvenile growth has caused an increase in body mass in all age classes.” Read the rest of this entry »
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