Thursday, 2 March 2017

Report on Bryophyte meeting at Cossington Meadows Nature Reserve

Middle Marsh
The first areas surveyed were rough pasture, hedgerows and trees on 'Middle Marsh' and 'Lower Marsh'. The main species in the grassland is Calliergonella cuspidata, which is abundant where the grass is short. Mixed in are smaller amounts of Cratoneuron filicinum as well as Drepanocladus aduncus, which became more abundant in and around water-filled depressions, where it was growing with long flaccid stems. D. aduncus is a  lowland species of wet places often growing submerged. It is tolerant of eutrophication and has only been recorded from 30 tetrads in Leics. These species benefit from the rough grazing and wet conditions. Brachythecium rivulare was frequent and seemed to replace the otherwise ubiquitous B. rutabulum on the wet ground. Amongst the rush tussocks, it was associated with Oxyrrhinchium hians, which was also the dominant species along the river banks.

Most bryophyte diversity was on trees and scrub. We found many epiphytic species on a recently fallen willow in a ditch along the main track, including Cryphaea heteromalla, Orthotrichum pulchellum and extensive patches of Metzgeria fruticulosa.

Orthotrichum pulchellum
These species belong to the group of species that area spreading due to reduced atmospheric sulphur dioxide concentrations. Willows are a particularly good habitat for epiphytic bryophytes, because of their basic and rough bark, and they usually support a good range of species, particularly in humid conditions.

The tree trunks in the flood zone are a special habitat. We found two species typical of this habitat (Leskea polycarpa and Syntrichia latifolia) in abundance, especially on large trees along ditches and the river, as well as the rarely recorded Scleropodium cespitans (recorded from 11 tetrads in Leics). We also found the rarely recorded, and possibly under-recorded Bryum moravicum (= B. laevifilum) on rotting wood.

The gravel tracks are rich in small acrocarpous mosses, of which we were only able to identify some to species level. The tracks and pool margins, which dry out in summer, would be worth a revisit later in the year.


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