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Field-scale Impacts on Biodiversity from New Crops (extension of the RELU Biomass project) - IF0104

The UK Government is committed to increasing energy security and reducing greenhouse gas emissions. Amongst the sources of renewable energy that have been recognised as important are the contributions that are possible from growing biomass crops. In the UK, the most advanced biomass crops are short-rotation coppice (SRC) willow (Salix spp) and miscanthus grass (Miscanthus x giganteus). Both are fast growing perennials that are able to accumulate large amounts of combustable biomass is relatively short time periods with few chemical inputs. Several recent reviews and policy documents have confirmed the potential of biomass crops as a renewable energy source and a number of practical measures are now in place to support their expansion. Under such policy support, land conversion to biomass crops could expand significantly and this has raised questions concerning the potential impacts of such a land use change.

Compared with arable crops, biomass crops require typically minimal or even no nitrate fertilisers and no fungicides or insecticides. Herbicides are applied but mainly in the establishment of the crop and after cutback. However, biomass crops are much taller than traditional arable crops, they remain in the ground for long periods (up to 25 years), harvesting cycles are long for SRC willow (3-4 years) and harvesting normally takes place in late winter/early spring. These factors have potential implications for the visual appearance and character of the landscape, for farm and tourist income, and for the hydrology and biodiversity of the region.

Some potential impacts of converting land to energy crops, particularly SRC willow, have been researched but there are significant gaps of knowledge and it is also not yet clear how to balance decisions based on climate, soil and water availability, against possible impacts on biodiversity, landscape character, social acceptance and the rural economy. In recognition of this, a project was approved by the Cross-Council Rural Economy and Land Use (RELU) programme, entitled “The social, environmental and ecological implications of increasing rural land use under energy crops” (short title: RELU-Biomass; contract number RES-227-25-0020) which aims to integrate natural and social science studies to develop a scientific framework for Sustainability Appraisal (SA) of the medium and long term conversion of land to biomass crops.

RELU-Biomass provides a comprehensive platform upon which to assess the implications of increasing land use under energy crops. However, it was not possible to cover all aspects under the funding resources available. In particular, biodiversity assessments are very resource-intensive and focus was placed on a comparison of miscanthus and SRC willow with arable and, to a lesser extent, grassland, for established crops at the smaller field scale.

Biodiversity research in the farmscale evaluations (FSE) of genetically modified herbicide tolerant crops has shown that the management systems employed can affect changes in biodiversity, and that these management systems should be optimised to assure the highest biodiversity attainable. For biomass crops, management systems that will affect biodiversity include the scales of growing, within a landscape, and temporal effects including the crop age, time in the cutting cycle and timing of cutting. Presently there is only limited evidence upon which to draw up guidelines on these management systems and, given the rate at which plantings are increasing, it is clear that such data are urgently required.

This project aims to expand the evidence base on biodiversity in energy crops for policy development by determining how the biodiversity of miscanthus and SRC willow is affected by the spatial scale, structuring and management of the plantings. This will be done by sampling for the abundance and diversity of weeds and invertebrates using FSE-standard methods. The suitability of SRC willow and miscanthus crops for birdlife will also depend on the size of a continous planted area and the structure of the crop, and we will investigate the use of both biomass crops by birds in relation to cropping scale.
This project aims to expand the evidence base on biodiversity in energy crops for policy development by determining how the biodiversity of miscanthus and SRC willow is affected by the spatial scale, structuring and management of the plantings. Specific objectives are to:

1. Evaluate, model and test predictions for weed and invertebrate biodiversity changes with the scale of planting (years 1and 2).
2. Measure the dynamics of biodiversity through the succession from previous crops to well established plantations (year 1,2 and 3).
3. Investigate the biodiversity impacts of variation in cutting date (years 2 and 3).
4. Evaluate bird use of miscanthus in relation to planting scale and changes in vegetation structure (year 3).

Such data will build on the large data sets being collected in the recently approved RELU-Biomass project (RES-227-25-0020) and will provide a comprehensive appraisal of biodiversity impacts of energy crops for use in planning and policy decisions on the expansion of these crops.
Project Documents
• FRP - Final Report : 110822 sid5 IF0104 FINAL   (492k)
Time-Scale and Cost
From: 2006

To: 2009

Cost: £374,963
Contractor / Funded Organisations
Rothamsted Research (BBSRC)
Biomass Crops              
Ecosystem Functioning              
Integrated Farming Systems              
Sustainable Farming and Food Science              
Sustainable Farming Systems