Dary Rigueira and myself designed a sample protocol for characterising the vegetation growing on disturbed sites on bauxite. We are hoping that by contrasting sites of different ages and disturbance histories we will be able to identify patterns which point to what determines the assemblages of species growing at a site and help us identify species which may be suitable for the rehabilitation of mined sites. Our 44 study plots are between 3 and 20 years of age since deforestation and in which deforestation had been accompanied by top soil removal or burning and conversion to pasture or simply allowed to recover.
At each site we make a number of observations about the vegetation, leaf litter and the soil. These include the height of the canopy, diameter of the trees composing the canopy, presence or absence of key plants such as bromeliads or mosses, identity of all the plants, compaction of the soil at three depths and many more. In total over twenty observations together with pictures of the understory, leaf-litter and root mat (see below):
As well as visual observation we are using a penetrometer to measure the compaction of the soil at different depths and collecting herbarium samples of any plants that we cannot readily identify in the field. Measuring the compaction of the soil is important as this has a very big impact on soil health and can take a very long-time to recover. I have visited sites compacted by livestock in the 1950’s where you can still see the impact on the soil. It would therefore be safe to assume that this may play an important role in determining what will regenerate at a site. Taking herbarium specimens enables us to identify the material in the Kew Herbarium where we have over 7 million reference collections to compare them to and so ensure a very high quality of identification.