Einstein Science Reporting for Kids
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14-May-2009

Contact: Science Press Package
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American Association for the Advancement of Science

Longer seasons for many different reasons



Many complex relationships exist between Earth's seasonal cycles, the global climate, and the lives of individual species in nature. Changes made to one of these things usually means that the other two will change in some way as well. Now, some new research is highlighting just how much we still don't understand about these important and complex relationships.

In a Perspective article this week, Heidi Steltzer and Eric Post discuss how the responses of individual species to climate change have been affecting the annual growing season, making it longer and longer each year. They combine biological data with satellite images that have monitored Earth's growing seasons for many years, and explore how changes in the length of species life histories from birth, through reproduction, and until death directly affect the length of the growing season.

The authors say that when individual species grow old, reproduce, and die off quicker in response to warming climate, the growing season usually becomes longer during the year. Since scientific data indicates that the Earth is warming and seasons are becoming longer, they suspect that it is connected to the overall shortening of species' life histories in nature.

Steltzer and Post say that this phenomenon is altering the structure and function of ecological communities around the world, possibly in negative ways. Even though an extended growing season could lead to increased plant production, it remains very uncertain because if individual species are shortening their life histories, then the whole structure of pollinator activity could change and new species might move in on the plants.

All of these complex relationships indicate that global warming could be changing the way plants and species interact during the year, and there is currently no way we can predict exactly how they will change. With a better understanding of how global warming, individual species, and the length of seasons interact with each other, researchers could design better models in the future to predict the outcomes of these ongoing changes.

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