Summary Detail 3

The dominant plant species on the project site were grasses. Initially, Bents (Agrostis spp.) were dominant, but Yorkshire Fog (Holcus lanatus) had overtaken them to become the most dominant species on the site in 1998.

This seemed to be related to brushcutting. The relationship was indicated by the fact that the only areas where Yorkshire Fog was not dominant, were those which were not cut.

Brushcutting is non-selective and reduces all vegetation to ground level at regular intervals. This eliminates competition from species which would grow taller than the grass given time (Gorse, Heather, tree seedlings). If these are allowed to grow up, they outcompete the Yorkshire Fog and Bents and prevent them from becoming dominant. (However, they would also in time shade out the underlying developing heath vegetation.)

ii) Tree seedlings

The most common tree seedlings on the site were Silver Birch (Betula pendula) and Cherry (Prunus sp.). Brushcutting apparently controls their height, but not their distribution on the site. These two species appeared to be in direct competition. Silver Birch was much more abundant, but Cherry grew more rapidly after cutting.

Tree species were becoming dominant in the control section and in time will shade out the shorter vegetation. The only other area of the site where they are likely to be a problem is section 9 which is uncut. The management regime in this section is hand-weeding, so they will be controlled in this way when resources allow.

iii) Indirect effects

b) Timing

Timing of the brush cut showed a significant effect only on bluebells growing on the project site as a woodland remnant. The Bluebells appeared to declining sections 2 and 4 which are cut in the spring. The distribution of most other species on the site showed little relationship to the timing of brush cutting.

For an ecological sampling exercise, based on Bluebell distribution in strips 1 - 4 seven years after management on the Heathland Restoration site began, click here

c) Frequency

Cutting, whenever it takes place, will have the effect of reducing competition for light and space for a time. This may allow species to establish which would not otherwise be able to compete with the dominant plants. The more frequent the cutting, the more this effect is likely to be exaggerated. This is illustrated by the fact that Section 6, which is cut three times a year, had the highest species diversity on the project site. It was also the only area where annual plants became established.

As a consequence of the frequent cutting in section 6, Heather plants growing in this section had a quite different growth form. They formed very low dense clumps, excluding other species because of the density of their canopy. As a result, Heather may come to dominate in this section in time, because it is likely to outcompete other species through its sheer density.

18. Grass Control

The initial application of Kerb Granules to section 7 for specific grass control prevented grasses from becoming dominant in this section in 1996 and 1997. However, the initial effects were wearing off by 1998 and grasses were increasingly dominant.

Common Bent (Agrostis capillaris) rather than Yorkshire Fog (Holcus lanatus) was now the dominant grass in this section. Sedges had a relatively high % cover in section 7. This may be related to the decrease in competition with grasses for space.