Tuesday, June 11, 2013

Take the Aluminum, but Please Leave the Eucalypti: A Closer Look at Bauxite Mining in Western Australia

Take the Aluminum, but Please Leave the Eucalypti: A Closer Look at Bauxite Mining in Western Australia
Author: Kacie Shopnitz

(Range of mineral lease, Alcoa.com)
As an undergraduate biology major, it is hard not to be distraught by the never-ending material concerning the rapidly deteriorating health of the natural world around us. Recently I came across a recorded lecture given by Andrew Balmford, who is a conservation biologist at Cambridge University.  Balmford began by bluntly stating the dire states of many of earth’s ecosystems, but goes on to emphasize that perhaps the situation is not as “unremittingly gloomy” as it appears. He provides several success stories for the remainder of the lecture to emphasize the idea that maybe conservationists need to actively highlight the good news too. One success example specifically stuck out to me and I decided to further research Bauxite mining in Western Australia by Alcoa (one of the world's top Bauxite mining and refinery companies). It is not often that a conservation success story centers around a massive industrial corporation. Bauxite mining by Alcoa began in western Australia’s Jarrah forests in 1963. The process of Bauxite mining involves clearing all timber, vegetation, topsoil and caprock followed by large scale excavation of Bauxite ore. This ore is then brought to a refinery in order to be converted into usable Aluminum product. Although restoration incentives largely arose from the desire to save public face, Alcoa’s work to restore mined land not only has been hugely successful, but also provides an intriguing example of preemptive rather than reactionary planning. Restoration efforts began in the late 60s/early 70s before legal regulations for restoration were in place and since have continued to be improved, expanded, and monitored. Alcoa’s current objective is to “establish a self sustaining Jarrah forest ecosystem, planned to enhance or maintain water, timber, recreation, and conservation values”(Norman, 2006). Roughly 550ha of forest are cleared, mined and then rehabilitated each year (Norman). A way in which to approach evaluating the success of restoration efforts is to focus in on how vital ecosystem functions, plant diversity and faunal diversity compare between unmined Jarrah forest and restored sites.

(Rehabilitated Jarrah Forest,

(Jarrah Forest Range, Alcoa.com)

(A look at tree, litter, soil, and understory
mass of a 5.5, 15.5-year restoration
forest and of an unmined forest, Grant 2007)

In terms of ecosystem functions, both litter decomposition and nutrient cycling are key to understanding the health and success of restoration sites. Current evidence suggests that restored sites have similar profiles to unmined sites in regards to litter accumulation, nutrient content and decomposition rates, biomass, and top soil seed stores indicative of plant flowering and the setting of viable seeds. Much of this success arises from introducing healthy topsoil back to the area at the beginning of restoration. Much of the Jarrah forest’s nutrient storage resides in the top layer of soil. Disrupting this during mining greatly disrupts, displaces, and dilutes these nutrients. To counter this, a fertilizer rich in Nitrogen and Phosphate is added to a topsoil layer as well as a dense concentration of legumes. This layer then becomes the understory for the restoration area. The fertilizer helps replenish the soil back to a healthy nutrient level and the legumes act to fix Nitrogen, display fast growth to create a vegetative cover that will reduce erosion, and add organic matter to the soil (Grant, 2007).

 Studies indicate that overall 90-92% of plant diversity is retained in restoration sites (Kocht, 2007). Vertical vegetative structure of the restored forest initially differs from the unmined due to “vigorous growth” at early stages. After this period however, the restoration site becomes increasingly similar to the unmined in structure. One shortcoming in vertical vegetative structure was the lack of old rotting wood that provides habitat and shelter for a number of species. Researchers predict with more time however, this element will appear. Jarrah forests are largely composed of two dominant overstory eucalypt species that include the Jarrah tree and Marri tree. Studies show that restoration Jarrah and Marri trees have just as high a growth rate, productivity rate, and survival rate as trees in unmined areas. Additionally, evidence exists that suggests the Jarrah trees specifically in restored areas are more resistant to disease than those in unmined forest. Although this data is optimistic, it should be pointed out that much of the Jarrah tree restoration is fueled by timber demands. This unfortunately adds an element that is counterintuitive to conservation and restoration efforts in these forests. It provides just another example of how difficult it is to separate restoration from economic demands and perhaps highlights the pressing need to find a balance and coexistence between the two.
(Jarrah Tree, S.D. Hopper & Seale)
(Marri Tree, S.D. Hopper & T. Trapper)

Fauna diversity too, specifically vertebrates, has been researched and monitored in restored versus unmined forest areas. Results concerning mammal re-colonization in restored areas have generated mixed results that are largely dependent on the availability of food and shelter in the area. Additionally, mammal populations in Jarrah forests have greatly plummeted with the introduction of the invasive fox. Such low populations have made it difficult to study diversity trends in restored and unmined forests. Measures have been taken to reduce fox populations and hopefully recover the native mammal populations. To do this, dried meat containing sodium fluoracetate has been distributed throughout the forests. Because this compound is found in naturally occurring native species, native mammals have developed resistance to the compound while the invasive fox species has not. Looking at bird re-colonization into restored areas provides much more promising statistics. Of 70 documented species present in Jarrah forests, 95% appear to re-colonize in restored forest after about 5 years of growth. Reptiles meanwhile have been observed to re-colonize 21 of the 24 species present to restored forest. (Nichols and Grant, 2007).

(Skink, reptile found in Jarrah, Paulr)
(Chuditch, carnivorous mammal found
in Jarrah, Withers)

Recognizing that the financial resources available to Alcoa are not a widespread occurrence and that Alcoa mining restoration will inevitably have flaws and room for improvement, overall it seems they started restoration ahead of the game and are currently in the lead for effective mining restoration. Not only can they be used as a model for other mining restoration initiatives, but also for me they serve as a sort of beacon of hope in a fairly gloomy world outlook. It is refreshing to see an industry taking responsibility for the environmental degradation it has inflicted. Andrew Bramford concludes by suggesting the viewpoint that “nature’s glass is more or less half full still and this gives us time, not a lot but a little to slow down nature’s loss”. We must seek out a way to incorporate economic demands and conservation efforts in a way that significantly slows loss of biodiversity. 

Talk by Andrew Balmford (Alcoa portion at 28 minutes and 52 minutes)

Work Cited
Grant, C & Nichols, O. “Vertebrate Fauna Recolonization of Restored Bauxite Mines-Key Findings from Almost 30 Years of Monitoring and Research”. Restoration Ecology Dec. 2007:116-126.

Grant, C & Ward, S. “Return of Ecosystem Function to Restored Bauxite Mines in Western Australia.” Restoration Ecology Dec. 2007: 94-103

Hobbs, R & Koch, J. “Synthesis: Is Alcoa Successfully Restoring a Jarrah Forest Ecosystem after Bauxite Mining in Western Australia?” Restoration Ecology Dec. 2007: 137-144.

Koch, J & Norman, M. “Vegetation Succession After Bauxite Mining in Western Australia.” Restoration Ecology June 2006: 278-288.

Koch, J & Samsa, G. “Restoring Jarrah Forest Trees after Bauxite Mining in Western Australisa.” Restoration Ecology Dec. 2007:17-25