Impacts of reed canary grass on the environment:

Current experience on commercial growing of reed canary grass has shown that the crop needs no herbicides at all - even in the establishment year. Weeds grow and survive in the first year, but are shaded out almost completely by the beginning of the second season. Of all the biomass crops grown for energy, reed canary grass needs the least agro-chemical input. Consequently, the risk of environmental pollution by agro-chemicals should be very low.

Reed canary grass covers the ground early on in the season, and as such is an ideal candidate to grow on hill slopes with minimal risk of soil erosion even in the first year of planting. The rhizomes and root mass form a dense matt which aids soil stabilisation.

Reed canary grass is not a very tall crop (a maximum of 2 m in height), and produces a beautiful purple inflorescence around mid June. Therefore, the aesthetic value of the landscape is enhanced by the presence of reed canary grass. Moreover, as a native species there is no concern about the invasiveness of the reed canary grass crop in the surrounding environment. At the end of the life cycle or before, reed canary grass fields could be easily restored to arable land by killing the crop with glyphosate, and the ploughing up the land.

Positive impacts on the ecology:

The DTI funded project on the ecology of perennial grasses in Herefordshire has shown that reed canary grass had a positive effect on wildlife, particularly in the establishment year due to the presence of diverse weed vegetation and low chemical inputs (Semere and Slater, 2005). The authors also found:

Ground flora: In reed canary grass fields, the establishment period is the most floristically diverse. As the season progresses, the field are almost totally weed-free apart from few grass weeds. Weed flora recorded from cropped areas of reed canary grass in the establishment year were very similar to that of miscanthus fields (see previous page). Some of the weed flora species include Chenopodium spp. Stellara media (chickweed), Ranunculus repens (creeping buttercup), Sinapis arvensis (charlock) and Poa annua (annual meadow grass).

Arthropods: The reed canary grass itself supported little insects apart from aphids. Similar to miscanthus, it is the presence of the weed flora and surrounding field margins that support most of the arthropods in the establishment year.

Birds: Reed canary grass covers the ground very early on in the spring season, and therefore did not attract ground nesting birds. In winter, however, the value of the reed canary-grass fields as a foraging area for seed eating birds was very high, with flocks of linnets and individual wrens observed to forage the seed heads.

Small mammals: Six species of small mammals were caught using live trapping in the cropped area of reed canary grass: wood mouse (Apodemus sylvaticus), yellow-necked mouse (Apodemus flavicollis), bank vole (Clethrionomys glareolus), field vole (Microtus agrestis), common shrew (Sorex araneus) and pygmy shrew (Sorex minutus).

Negative impacts on the ecology:

Reed canary grass forms a dense canopy cover early in the season, and as such is not suitable for ground nesting birds. To increase the breeding success of grassland bird species in dense biomass grass crops, some experiments have successfully shown the use of strip harvesting (leaving parts of a field unharvested each year) in switchgrass in North America (Roth et al., 2005), demonstrating the importance of specific management systems in providing habitat.

As a native species, reed canary grass is prone to plant diseases and pest attack. Aphid infestation was reported in two fields out of five in Herefordshire.

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Roth AM, Sample DW, Ribic CA, Paine L, Undersander DJ, Bartelt GA. Grassland bird response to harvesting switchgrass as a biomass energy crop. Biomass and Bioenegry 2005; 28: 490-8.

Semere T, Slater FM. The effects of energy grass plantations on biodiversity. Final report, project number CFP 374/22: London: Department of Trade and Industry; 2005.