Global warming may 'flatten' rainforests
Climate change may push canopy-dwelling plants and animals out of the tree-tops due to rising temperatures and drier conditions, argues a new study published in Proceedings of the Royal Society B. The development may be akin to "flattening" the tiered vegetation structure that characterizes the rainforest ecosystem.
The conclusion is based on surveys of frogs and other canopy-dwelling animals in Singapore and the mountains of the Philippines. Brett Scheffers of James Cook University and colleagues found that the "rainforest's vertical strata provide climatic gradients much steeper than those offered by elevation and latitude, and biodiversity of arboreal species is organized along this gradient." So a tree frog that dwells in the canopy at one location may be found at mid-levels or the understory in a higher elevation area. In a world of changing climate, this means that sensitive species may move toward the ground as temperatures raise and humidity levels fall.
The authors suggest that the effects could be quite significant in some forests.
"The initial downward shift in arboreal species will inflate ground densities by 80% thus compromising normal ecosystem functions," Scheffers told mongabay.com. "These processes will 'flatten' tropical rainforests."
Combined with expected migration of lowland species to higher elevations — and the potential extinction of high elevation tropical species than run out of mountains to climb seeking suitable habitat — the implications for tropical biodiversity could be substantial.
“The Earth’s rainforests are certainly not flat but if citizens and governments do not take the necessary actions to prevent strong changes in climate... they could be," said Scheffers in a statement.
To better understand the impact of climate change on tropical ecology, the researchers conclude by recommending monitoring tropical forests for such downward movement of canopy-dwelling species.
"This could be an early warning that rainforests are under stress," said Scheffers.
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Rainforest canopy image via Shutterstock.