Ecological Restoration Alliance of Botanic Gardens

Eden Project, The

Ecological Restoration of a china clay quarry

Posted on 15 September 2016

It is implicit in any restoration project that some process of environmental change or degradation must have happened to lead to a loss of functioning habitat. This degradation needs to be corrected or habitat loss will continue to occur and restoration will be a wasted effort.

Eden Project’s research and practice extends beyond the question of species propagation and re-introduction to focus on the question of the environmental conditions that exist, and the barriers that have to be overcome for successful habitat recovery to take place.

Very different scenarios can be encountered depending on the history of impacts on any particular location. So for example the Eden Project’s own site is set within an extensive landscape of china clay extraction. This mining process has left behind spoil heaps that lack structure, organic matter and functioning biological and nutrient cycles. They are skeletal substrates that have much in common with exposed glacial moraines and a slow natural ecosystem process would take many years. To make it possible to restore vegetation cover different techniques are used for soil creation ranging from the acceleration of natural processes of nutrient and organic matter accumulation, using nitrogen-fixing species, through to the manufacture of starter substrates using a range of composted and recycled organic wastes.

In contrast there are often situations where ecosystems have become degraded because of excessive nutrient pollution. This is an increasingly common problem in areas which have been temporarily used for farming or where there has been a history of certain forms of pollution. With high fertility the rarer and more complex plant and animal communities are outcompeted by aggressive species.

Different methods have been tried to reduce the nutrient load on such sites including ‘cropping off’, trying to deplete the soil by sowing and harvesting a series of agricultural crops. However nutrient budgets show that this is often an exercise of marginal impact – there can be an appearance of nutrient depletion for a few years but the underlying base load is unchanged and gradually the available nutrient supply returns to high levels.

To help develop more effective solutions we have been working in partnership with Landlife, based at the National Wildflower Centre, who have been looking at the potential for deep ploughing and soil inversion as a way of redistributing nutrient load in the soil profile and in particular creating a surface soil layer that is less likely to allow aggressive species to establish.

Results have been extremely positive with ongoing monitoring demonstrating substantial improvements in both plant and animal biodiversity following the treatment.

More details can be obtained from:


Eden setting   


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