Reg’s Meadow - February 2006
Winter Patterns – Lichens
Reg’s Meadow is quiet and empty, still in its dormant winter period. Reg’s Meadow is quiet and empty, still in its dormant winter period.
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Melted Frost on Cedar |
As the early morning mist rises, the melting overnight frost hangs from leaves and spiders’ webs as sparkling droplets of water. With very little growing in the meadow we have decided to take a closer look at the variety of lichens found on trees and shrubs around the hedgerows. While most of the foliage is absent these can be seen more clearly than at any other time of the year. We confess that there is a touch of “the blind leading the blind” here, as neither of us has any previous experience of lichen recognition!
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Watery Web |
We have tried to identify the more obvious species and have suggested names for some of the photographs
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Various lichens on |
There are more than 1500 species of lichens in Britain. They are not actually plants but composite organisms, consisting of a fungus and one or more algae that live together in the body of the lichen in a relationship known as symbiotic. The fungal partner provides the body for the relationship and gives protection from extreme heat or drought, while the algal partner provides nutrition by means of photosynthesis.
Lichens can be found all around us, growing on rocks, trees, walls, roofs and pavements, often appearing as roughly circular patches of different colours. They are extremely sensitive to environmental conditions, especially air pollution and are therefore important indicators of the health of a natural environment. Lichens thrived in pre-industrial times but acid rain, resulting from excess sulphur dioxide from industry and coal fires, led to their disappearance from large areas of Britain. With the introduction of clean air acts, many lichens are now coming back to urban areas but in the countryside some are now suffering a different kind of pollution from nitrogen compounds used in intensive farming. It is possible to make quite accurate assessments of air pollution by identifying the lichen species growing in a given area.
In our meadow we appear to have mostly lichens that prefer clean air or only slight pollution but that are also quite tolerant of some level of acid or nitrogen.
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Crustose |
Foliose |
Fruticose |
Lichens grow as three distinct types and we have examples of each type in our meadow, all growing on trees or shrubs.
Crustose lichens grow in a crust-like form close to the bark and could only be removed by cutting the bark. Foliose species are leaf-like, sometimes resembling flattened lettuce or seaweed, and are attached to the branch or twig at various points on their lower surface. Fruticose species are shrub-like and are attached at a single point.
Some Species Found in the Meadow
Crustose
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Lecidella elaeochroma |
Lecanora chlarotera |
Not identified |
Lepraria incana (possible) |
Not identified |
Foliose
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Parmelia perlata (grey-green) |
Not identified |
Xanthoria parietina |
Xanthoria species (possible) |
Fruticose |
Other Lichens Needing Investigation |
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Ramalina |
Not identified |
Not identified |
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The first of the two unidentified species above resembles Crottle, one of the few lichens to be given a common name, but it appears more crustose than foliose, in which case it would be something different. Crottle has been traditionally used as a dye for wool, producing a reddish-brown colour.
The second lichen, growing on a stump, may be fruticose, but it is difficult to tell without examining it further to see if it grows from a single point.
We would be very interested to hear from anyone who has a better
knowledge of lichens than we do – not difficult! If you can
help us, please contact either Monica Johnson or Brigid Campbell at
the Hawk Conservancy (email Monica or Brigid via info@hawkconservancy.org).
Featured species – Grey Heron (Ardea cinerea)
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Adult Grey Heron |
At the end of every day at the Hawk Conservancy Trust, you can go and watch wild birds being fed in the meadow. You will certainly see crows and magpies, snatch-and-grab raids by the resident kestrels, and maybe even a red kite. But the stars of the show are the grey herons – anything up to thirty of them in winter.
The grey heron stands over 3 feet (90cm) tall and its wingspan can be well over 6 feet (180 cm). It’s a huge, majestic bird – only swans and some Canada geese, among our common birds, are bigger. Add long legs, a long neck, and a beak like a dagger, and you have something that is instantly recognisable.
Grey herons have been fed here since the 1960s, when someone brought the founder, Reg Smith, an injured bird, which he put by the pond in the park. Next day another heron joined it, and the numbers grew until over 40 could be found there in the depths of winter.
Reg kept his herons to himself, but after his death in 1995 it was decided to move the feeding site to the meadow and allow visitors to watch from hides. It took a whole winter to persuade the birds to move a few feet at a time, and then to train them to come on schedule using a bell.
About grey herons
Grey herons live in colonies called heronries. They usually lay 4 eggs and the chicks hatch in 4 weeks. They leave the nest at about 9 weeks old and first breed when they reach 2 years. You can tell the age of herons because adults have strongly contrasting black and white patterns on their faces and necks, while young birds have dull shades of grey. They eat practically any form of animal life, including fish, frogs, rats and ducklings.
Herons are found almost all over the world; there are about 65 species worldwide. In Britain we have two other herons – the very rare bittern, and the increasingly common little egret, a dainty white heron that has only colonised Britain in the last 15 years.
Herons are closely related to the storks, ibises (which have long curved bills) and spoonbills, heron-like birds with weird flattened beaks. This means that they are also closely related to another group of birds found in the park, which have been shown by DNA studies to be descended from storks – the American vultures. Strange to think, when you look at the Andean condors in their aviary, that they are much more closely related to our grey heron than to the European, Asian and African vultures on the park!
