Researchers say predicting response in marine ecosystems may be easier
By Summit Voice
SUMMIT COUNTY — Forecasting how marine species will move as the oceans warm may be easier than doing the same for land animals, said a group of scientists who systematically compared the responses of marine and terrestrial species.
To reach their conclusions, the researchers used previously published data on the the physiological temperature limits – tolerance to heating and cooling levels – on 169 cold-blooded marine and terrestrial species, then compared the data with the regions the species inhabit.
Fish and other ocean-dwelling species closely matched up with habitat that met their requirements, while terrestrial animals able to tolerate conditions more outside the range of what their internal thermometers suggest they can live in — in other words, warm temperatures aren’t limiting them from living in closer to the equator.
That means marine species are likely to shift their ranges en suite, while a changing climate could lead to a chaotic jumble of species interactions on land, the study concluded.
“Finding that marine and terrestrial species are limited by their cold tolerance suggest(s) that warming will allow expansions of animals towards the poles to take advantage of newly opened up habitats,” said lead author Jennifer Sunday, a biologist from Simon Fraser University, Canada.
“However because land animals are not limited by heat to the same extent as marine animals, patterns of retreat in the hottest regions of species’ ranges may differ between land and sea,” Sunday said.
The research team found that, while both the cold and warm boundaries of marine species are marching towards the poles, terrestrial species have been less responsive at their warm versus their cold range boundaries.
“We think a combination of things is going on,” said Amanda Bates, co-author from the University of Tasmania’s Institute of Marine and Antarctic Studies. “A species niche isn’t just set by temperature. On land where water is key, species may be hindered more by dryness rather than being too hot at this range boundary.
“Second, it could be that rare heat waves are actually setting boundaries on where species can live. Finally, as Charles Darwin pointed out over 150 years ago, there may be more species and much more ecological competition toward the tropics, which may be enough to exclude species from living in the warmer end of their potential real estate.”
The authors call for research to better understand how climate change will affect animals, especially those on land where predicting responses to warming may be particularly difficult.
“Terrestrial species ranges may stretch towards the poles – expanding their cold range boundaries but responding erratically at their warm boundaries,” says Nicholas Dulvy, a marine biologist at SFU.
“These individuals will be overrun by the ‘pole-wards’ march as other species enter their territories. So we will see all sorts of new ecology as species come into contact and interact as never before.”
The study, published this week in Nature Climate Change, provides insights into why and how species are moving around the globe in response to global warming.
Filed under: biodiversity, climate and weather, Environment, global warming Tagged: | biodiversity, climate, climate change, Environment, global warming, Simon Fraser University, University of Tasmania