Restoration of Withies Croft remnant wall: a trial in natural regeneration.
1. Introduction
In the north-eastern corner of Independent Quarry is an area known as Withies Croft Remnant Wall, named after a feature that has now been removed by quarrying. In May 2005 this area was landscaped by the operators Albion Stone. Landscaping took place on both sides of a quarry haul road running east-west between Independent and Admiralty Quarries. The north-facing slope was not reseeded, but left untreated to test the hypothesis that vegetation would return naturally. In October 2005 the much smaller but environmentally more important south-facing slope had 15 one-year old plants of Horseshoe Vetch Hippocrepis comosa planted along the top margin to encourage rapid colonisation of this important species.
Photos were taken shortly after landscaping in June 2005 and again in October 2005 and April 2006 to record the extent of revegetation. Qualitative surveys of plant species were made in October 2005, April 2006 and September 2006. Further surveys will be made periodically to document the regeneration of flora at this site.
2. Qualitative surveys of plant species
Click here to view the October 2005 plant survey in a new window
Click here to view the April 2006 plant survey in a new window
Click here to view the September 2006 plant survey in a new window
Click here to view the April 2007 plant survey in a new window
Click here to view the October 2007 plant survey in a new window
Click here to view a comparison of the species found in the plant surveys in a new window
3. Conclusion/Summary
In the October 2005 plant survey a total of 45 plant species were found, with 38 species on the much larger north-facing bund and 24 species on the smaller south-facing bund.
Of these a few species were dominant, notably Bristly Ox-tongue, Annual Mercury and Sea Mayweed, with Smooth Sowthistle, Field Poppy, Prickly Lettuce, Weld and Scarlet Pimpernel also very abundant on the north-facing bund. The 7 species that were found only on the south-facing bund were most likely to have spread from the diverse vegetation immediately above the bund. The south-facing bund also had 15 plants of Horseshoe Vetch planted on the same day. In addition to the plants recorded above a large flock (c100) of Linnets Carduelis cannabina were feeding on the north-facing bund.
In the April 2006 survey a total of 30 plant species were found, with 25 on the north-facing bund and 24 on the south-facing bund.
Most changes were likely to be due to seasonal effects, although the arrival of a scarce species, Round-leaved Cranesbill, was noteworthy.
There was no sign of the introduced Horseshoe Vetch plants, suggesting that small-scale planting is not a valid method of encouraging regeneration.
In the September 2006 survey a total of 27 plant species were found, with 22 on the north-facing bund and 20 on the south-facing bund.
Black Mustard appeared for the first time, as did 4 other species.
In the April 2007 survey a total of 38 plant species were found, with 28 on the north-facing bund and 27 on the south-facing bund.
Red Fescue, one of the dominant grass species in calcareous grasland, appeared for the first time, as did Wild Carrot and a number of other species.
In the October 2007 survey a total of 39 plant species were found, with 29 on the north-facing bund and 23 on the south-facing bund.
The most significant arrival was Birdsfoot Trefoil, found at the base of both bunds well away from the area that plants of this species were introduced.
Several other scarce species arrived, including Dwarf Thistle and Annual Beard Grass.
For the first time in 2 years the bunds contained a number of species characteristic of mature limestone grassland.
4. Photos (click to load photos in new page)
June 7th, 2005 (6 images)
October 14th, 2005 (6 images)
April 14th, 2006 (7 images)
October 31st, 2007 (5 images)
Bob Ford, September 2006