Are Ericoid Mycorrhizas a factor in the success of heathland restoration?
Wednesday 16th July 2014
The decline in abundance and contiguity of British lowland heath during the past few centuries has been well documented. One of the most important causes has been land change due to agricultural intensification. The restoration of lowland heath is now a United Kingdom Biodiversity Action Plan priority, and there has been a particular interest in the methods for the restoration of heathland on improved agricultural land. Early work has confirmed that the conversion of heathland to agriculture caused persistent changes in soil chemistry and physical structure and that successful heathland restoration was likely to require some form of amendment to the soils in order to reduce pH and nutrient availability. A number of techniques have been used to attempt to achieve this such as soil stripping and soil acidification techniques including the addition of elemental sulphur.
The restoration of heathland on improved agricultural land often not only involves soil amendment but also the addition of heathland propagules either as translocated cut-turves of heathland or as clippings collected from mown heathland.
The methods used at each site of lowland heath restoration vary depending on edaphic factors and the need for the introduction of ericaceous propagules. This study investigates the effect of some methods on the growth of an important ericaceous species, Heather (Calluna vulgaris). It also explores whether success of growth of C. vulgaris in restoration schemes is affected by its degree of colonisation by Ericoid mycorrhizal fungi (ERM). The success of Heather growth was compared at three sites, a control area of natural heathland and two restoration sites. These were a quarry where soil had been translocated but not chemically manipulated and a site on agricultural land where the top soil had been improved but then either stripped away or acidified prior to attempting heathland restoration. Propagules of C. vulgaris were applied either as turves or as clippings. Results show that clippings produced as dense a cover of C. vulgaris as turves over a period of 13 years and that plants in such swards can exhibit a degree of ERM colonisation comparable to that found in mature plants growing in natural heathland. Young (<2 years of age) plants of C. vulgaris had less extensive mycorrhizal colonisation of their roots, particularly when growing on restored agricultural soils. A relationship was found between lower levels of mycorrhizal colonisation and smaller above ground plant growth. Success of heathland restoration may be improved by finding means to enhance the rate and extent of mycorrhizal colonisation of young C. vulgaris growing in a restoration environment.
Read the full article here.