www.ecoinvestor.com.au November 2015


More Trees Help Birds Survive Droughts

Increasing tree cover, particularly on the sides of streams and on floodplains, can help birds to survive during long and severe droughts, says Charles Sturt University ecologist, Dr Dale Nimmo. In a clear message to rural property owners and governments, he says his team's research is timely as climate scientists have observed El Nino is now strengthening to levels not seen since the 1997-1998 event that was the precursor to the Millennium Drought.

Dr Nimmo and his team monitored bird communities through south eastern Australia's 'Millennium Drought' from 2001-2009, including bird species in different agricultural landscapes near the beginning, during and after the drought broke.

Although it was one of the most severe droughts on record, the bird communities remained more stable in landscapes where there was more tree cover on stream sides and floodplains, called riparian vegetation.

"Our previous research showed that The Millennium Drought led bird communities across Victoria's dry woodlands to 'collapse' with bird numbers falling to approximately half that of pre-drought levels," he said. "But this study has shown that landscapes with more riparian tree cover retained a higher proportion of their species.

"The loss of trees from riparian areas occurs because those areas often have very fertile soils and so are of greater value to agriculture. However, this has deprived biodiversity of a key mechanism for coping with long droughts."

Dr Nimmo urges conservationists, land owners and land managers to focus on protecting and restoring native riparian woodlands to help birds cope with future droughts. "Our findings suggest that we can create drought refuges for bird communities by protecting, revegetating and restoring cleared stream sides and former floodplains," he said.

The research is now published in the Journal of Applied Ecology. Dr Nimmo is lecturer in ecology at CSU's School of Environmental Sciences in Albury-Wodonga and a member of the Institute of Land Water and Society.

Dr Nimmo's work investigating if landscape structure can enhance the resilience of biodiversity to climatic extremes has been awarded a grant from the Hermon Slade Foundation.







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