Heather McHaffie

Scots pine growing on forested mires in Abernethy Forest, Strathspey, Scotland

Summary A substantial proportion of the Abernethy Forest Reserve has Scots pine (Pinus sylvestris) growing on the surfaces of a variety of mires. The hydrology of the mires has been affected by drainage and peat cutting but this area is unusual in having had a long period of protection from grazing by domestic stock. There are three main types of pine populations found on these mires. Woodland bog comprises predominantly bog vegetation with abundant pine seedlings due to the heavy seed rain from the surrounding woodland. Only a few very small trees survive, which are stunted, heavily diseased and have very low seed production. Wooded bog also comprises predominately bog vegetation but there are scattered mature trees of a moderate height with an open canopy. The trees are fertile and can form uneven aged stands with regeneration. Bog woodland is a predominantly woodland vegetation with tall, dense tree cover on deep peat. The trees are well grown with a dense canopy. A few remnants of bog vegetation remain in the ground flora although most have been replaced by woodland bryophytes and shrubs. Each of these three types is described and their development is discussed.

Experimental Droughting of Woodsia ilvensis (L.) R. Br.

Summary Populations of Woodsia ilvensis Oblong Woodsia have been observed to decline at all the British sites. It has been suggested that drought might have accelerated this decline. In an experiment with cultivated Plants it was found that summer drought had a more severe effect than drought during the spring.

A morphometric analysis of Scottish Athyrium distentifolium: a contribution to the BAP

Summary A morphologically distinct variety of Athyrium distentifolium called A. distentifolium var. flexile has been found only in Scotland. Research was undertaken for aUK Biodiversity Action Plan. To confirm that this taxon has a definitely recognisable morphology, a morphometric analysis was used on the range of characters used to define this variety. It showed that it can be clearly differentiated.

Vegetation and ombrotrophy on the mires of Abernethy Forest, Scotland

Background: Abernethy Forest, an area of native Caledonian Scots pine forest, includes areas of open or sparsely forested peatland, largely ombrotrophic, but locally influenced by water from mineral ground. Aims: To relate vegetation species-composition to the limit of ombrotrophy inferred from water chemistry. Methods: Species composition was listed in 300 sample quadrats; chemical analyses of water samples were available from 200 of these. The vegetation data were classified using TWINSPAN. Relationships between vegetation and chemical results were analysed statistically using contingency tables. Results: Eleven ‘vegetation types’ were recognised, five (189 samples) judged as primarily ombrotrophic-bog vegetation. The others showed evidence of flushing, or transition to forest. A previous analysis of major cations in the 200 water samples indicated that a limiting Ca/Mg ratio of 1.0 divided 61 samples showing telluric influence from 139 essentially ombrotrophic samples. Neither division was sharp. Contingency tables showed that the division based on vegetation types was strongly associated with the division of the water samples based on cation ratios. Conclusions: Large areas of bog south and east of Loch Garten are unequivocally ombrotrophic; the main telluric-influenced sites occupy openings in the forest west of the loch. The limited ‘fen’ flora probably reflects the small size and isolation of the calcium-rich sites and the dominating influence of the ombrotrophic peats.

A reintroduction programme for Woodsia ilvensis (L.) R. Br. in Britain

Summary There has been a decline in the rare fern Woodsia ilvensis Oblong Woodsia in its few remaining British sites, with no regeneration recorded. As part of a UK BAP recovery programme four reintroductions have taken place into areas where this fern is no longer found; two near Moffat and two in Teesdale. The first reintroductions were made in 1999–2000 and they have now been monitored for up to six years. A good proportion of the Plants have established well, although no progeny have yet been produced.

Scottish ferns in a man-made landscape

Summary The habitats available to ferns and their allies in Scotland have been almost totally altered. From the first agricultural incursions on the wildwood to the progressive management of the whole country, ferns have filled any available niches in a characteristically opportunist fashion. More recently, large areas of the landscape have been reconstructed to provide reservoirs, an extensive network of roads with verges and walls and many other man-made installations. While there has undoubtedly been a loss of many types of habitats, especially of wetland, this is a brief review of some areas which would not otherwise have existed and yet offer suitable conditions for a wide variety of species.