|IPA Factsheet - Brown Moss|
Site Description Brown Moss is an area of former heathland, now largely colonised by woodland, with a series of 13 shallow pools. It is a lowland area of acidic soil, clay, peat and sand. The surface consists of drift deposits made up largely of gravely sands with impermeable clay deposits in the depressions (Edwards, 2007). No buildings exist on the site, though privately owned residential buildings are present on the periphery (Edwards, 2007). The site contains one of the few remaining quaking bogs in Shropshire. The semi-natural broadleaved woodland component of the site consists largely of trees which have grown up since the cessation of grazing in the 1950/60s. There are some older and much larger oaks and birch and a few rowan scattered around the site. A number of Pinus sylvestris and Abies procera were planted in 1967 adjacent to pool 4 by the area of acid grassland (Edwards, 2007). Scrubland within this site consists mainly of willow (Edwards, 2007). Brown Moss is thought to exhibit below average growing season length for the region, as frosts and ice have been observed throughout most of the day when in adjacent areas there is no occurrence after late morning, (Jones 1987, in Edwards, 2007). Brown Moss differs from the other North Shropshire Mosses by consisting of a series of pools set in an area of heathland and woodland, rather than an expanse of peat. It has been suggested that the site may once have been peat covered, but that peat removal in the past has led to the present site conditions (Natural England, n.d.).
Botanical Significance The nationally scarce, European endemic, L. natans has been known to occur at Brown Moss for several years. This species is rare/threatened within a European and global context (Edwards, 2007). This site has been recognised for its importance in swamp and fen plant communities, which include species such as bottle sedge (Carex rostrata) and bladder sedge (C. vesicaria) The site once contained the nationally threatened Pilularia globulifera, which was last seen in 1976 (Edwards, 2007). Oenanthe fistulosa was last seen on this site in 2006, and is classified in the Red Data book as Near Threatened (NT). The nationally rare liverwort Riccia canaliculata is also present on this site. It was recorded 1977, 1978, 1981 and 2003, when it was found in the draw down zone round pool 6 (N.B. same pool as C.helmsii). This is a Red Data Book species (classified as vulnerable), and is listed in the Shropshire BAP (Edwards, 2007). Noted for vascular plant interest.
General Habitat Description Inland Surface water, Woodland and forest, Inland water bodies (standing water, running water) (30%)Broad-leaved deciduous woodland (28%)Fens (20%)Phygrana (10%)Steppes (10%)Other land (including towns, villages, roads, waste places, mines, industrial sites) (2%)Other unquantified habitat: heath, scrub, maquis and garrigue, bogs, marshes (JNCC, 2006; JNCC, n.d.a).However, Edwards, 2007 (see above link) states: Semi-natural broadleaved woodland (67 %)Wetland communities, including areas of open water, (25%)Heathland and acid grassland (5%), Tracks, paths and car parks (2.9%)Schwingmoor (0.1%)
Conservation Issues Introduction of grazing is recommended to halt succession of heath to scrub/woodland. Cattle grazing, which crops vegetation at variable heights, is recommended. Cattle poaching can provide valuable bare ground for seeding establishment of L. natans, as well as aiding suppression of competitive woody species such as birch and willow (Edwards, 2007). Horse grazing has also been suggested (Thorne & Lancaster, 2007). This could be introduced via Commoners’ rights. However, livestock grazing entails the risk of C. helmsii transportation between pools (Edwards, 2007). The presence of non-native Crassula helmsii on this site is a threat to L. natans and other natives (Edwards, 2007). C. helmsii was recorded by Ian Trueman in 1990 in and around pool 6. It may be a garden escapee/present due to domestic pond clearance (Edwards, 2007). C. helmsii, introduced to the UK in 1911, can form dense carpets, particularly where there is organically rich substrate (Edwards, 2007). It may out-compete natives and can cause severe oxygen depletion (Centre for Ecology and Hydrology, 2004). However, there is mixed opinion over the extent of long term damage C. helmsii causes (Edwards, 2007). Management undertaken thus far to control C. helmsii is described in ‘Management’ section of this form. The non-native Azolla filiculoides (introduced from America) was recorded on Pool 3b in 1990s and 2006. It has since disappeared, thus it is hoped that any future re-appearance will be equally short lived (Edwards, 2007).Successional colonisation of this site by trees (especially birch, Betula spp) and bracken (Pteridium aquilinium) is being addressed, but continues to be of concern due to such species’ invasive nature, and their shading, hydrological effects and potential to alter nutrient status in open water and heathland via allochthonous input (Edwards, 2007; JNCC, 2006-above link). These potential invasives require further monitoring (Edwards, 2007).