Scientists Find Essentially Zero Tree Growth For 3-4 Years At Amazon Gold Mine Sites Once Abandoned
The remote Guiana Shield of the Northern Amazon holds some of the largest tracts of unfragmented forest on the planet, but the rapid growth of gold mining in the region threatens to leave a patchwork of devastation for many years to come, a new study has found. The research, published in the Journal of Applied Ecology, found that forest recovery at abandoned Amazon artisanal goldmines remains barren, with virtually no tree growth, three to four years after the miners packed up their equipment and left for other Amazon prospects.
The Guiana Shield covers 270 million hectares (over 1 million square miles), encompassing Guyana, Suriname, French Guiana, parts of Venezuela, Colombia and northern Brazil. The region offers spectacular ecological services: it stores 18% of the world’s tropical forest carbon and 20% of the world’s fresh water. It also sits atop a massive, widespread gold deposit that has sparked the interest of local and international profit-seekers.
The paper’s lead author Dr. Michelle Kalamandeen, a former postgraduate researcher at the School of Geography at Leeds, and a current postdoctoral researcher at Cambridge University, has studied small-scale mining in the Amazon for several years. She explained that while previous studies have looked at forest recovery from agricultural activities, there has not been a field-based assessment of forest recovery from artisanal gold mining. The new study was based on field research at 18 plots spread across two well-known gold mining areas — Mahdia and Puruni — in central Guyana. “There was very little recovery three to four years after a mine pit and tailings pond had been abandoned,” Kalamandeen said. “The overburden site where the discarded topsoil was piled up had a similar rate of recovery to agriculture plots in South and Central America.”
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The study suggested specifically that depleted nitrogen levels were responsible for the restricted growth, as opposed to contamination from heavy metals such as mercury. The research, which sampled for mercury contamination, found levels dropped 250 times lower in abandoned sites compared to active mining areas. Rather than this being a positive finding, Kalamandeen suggested that the toxic element — which doesn’t break down — was likely leaching out into the wider ecosystem, causing problems particularly for nearby indigenous communities who depend on fish as a primary source of food. The study did not explore that possibility within its scope.
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https://news.mongabay.com/2020/08/amazon-gold-mining-wipes-out-rainforest-regeneration-for-years-study/
