Competition in a Warming Climate

As climate change continues unchecked, it may not be warming that threatens sensitive plant communities but rather novel competition. A recent study shows that alpine plant communities can handle warming just fine. Competition from novel plants, however, may prove disastrous for these mountain top communities.

Man-made climate change is real. It's happening and we are witnessing its effects all over the globe. For those concerned with the state of the natural world, it is easy to get caught up in the warming aspect. What are the effects of an overall increase in global temperatures? Certainly this is worth fretting over. However, evidence is painting a more subtle picture of exactly how ecosystems are going to respond.

Plants are predicted to track climates. As climate zones shift, plants are "migrating" to keep up. They don't do this by physically moving of course, but rather via seed. As habitats begin to change, new species will inevitably move in. For alpine communities, this means species from farther down the mountain. To simulate this, researchers transplanted alpine plant species down the mountain where their proposed future competitors grow in a climate that is on average 3 degrees warmer.

In the absence of novel competitors, the alpine plants performed just fine. Competition was not significantly different then when they were grown at current temperature regimes among their current competitors. However, when novel competitors from farther down the mountain were present, everything changed. The alpine species fared much worse in this situation. Though warming by itself was not significant, warming coupled with novel competitors spelled disaster for alpine communities. As the authors make sure to point out "changing biotic interactions appear more important than direct physiological effects of warming temperature."

Photo Credits: Wikimedia Commons

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