• (2/9/2019) by George Peterken

    Our wild flora has been changing rapidly. All over Britain and much of mainland Europe, the populations of wild plants have been thinning out. Throughout the English lowlands, counties have been losing species at roughly one species every second year, i.e., 50 species going extinct in a century. Many species are now virtually confined to nature reserves and other protected sites.

    Most of these losses can be blamed on the need for agriculture to be far more productive than it once was – we all need to eat – so we had some reason to hope that Brockweir, Hewelsfield and St Briavels had escaped the worst. After all, we still have all the woods we had a century ago, and much of the other land is not intensively cropped. Further, in the Parish Grassland Project, we have an organisation that has, among other things, promoted interest in the environment in general and flowers in the fields in particular. However, we suspected that all was not well, and for the last two years we have, with the help of some other residents, checked on the fate of our flora over the last century and current trends.

    We have based our assessment on the Flora of Chepstow (1920), which was compiled by W A Shoolbred, a physician who lived in Chepstow from 1878 to 1928. In the words of the Flora of Gloucestershire (1948), he was “one of the best systematic botanists … of his day … a careful, critical and enthusiastic collector of all the most difficult genera [who] was always careful in the matter of rare plants.” One imagines him cycling and walking up to 15 miles out into the Chepstow hinterland scouring the district for vascular plants and bryophytes.

    We know from Shoolbred’s Flora the names of 123 species that definitely grew within our parishes a century ago. Most of these were species that were infrequent or interesting enough to locate, such as the rare Annual Mercury, which grew on an old wall in Brockweir. The rest of the parish flora can be compiled from general descriptions, e.g., Dandelion was “very common in grassy places” and must have grown within our parishes. After making judgement calls like this, we compiled a list of 487 species that were certainly or probably present a century ago and a further 94 that might have been.

    In 2017 and 2018, with some help from other residents, we set out to find all the wild-growing species in the parishes, and by mid September 2018 we had found 504 species. A few species were being found for the first time in early September, but by then we were subject to the law of diminishing returns: it was hard to add any, and the season was running into autumn. We have a list of a further 38 species that we expected to find, but did not, but for analysis we have taken the list at face value.

    Botanical surveys are never complete, but in round terms we reckoned that roughly 500 species grew wild in our parishes a century ago, and found 500 doing so now. So, the first response is relief: our wild flora is still as rich as it was. But is it? Comparing the lists in detail reveals a great deal of change.

    To view the draft version of our full report, click here.

    First, the gains. We found 46 neophytes that were not on the 1920 list. These are species that have escaped from cultivation or been introduced in the last 400 years (either deliberately or by chance e.g. seeds on car wheels etc), usually much more recently. Shoolbred had found a few of these, including Gooseberry (“escape, hedges and woods”) and Red Valerian (“locally abundant, old walls”), but we added a mix of welcome species (e.g. Celandine, Saxifrage, Greater Cuckooflower) and now-notorious species, notably Japanese Knotweed, Cherry Laurel, Indian Balsam and Spanish or hybrid Bluebell. We also added nine archaeophytes – species that escaped from cultivation more than 400 years ago, including Swine-cress, Cornflower, Bristly Oxtongue, Chicory and Lesser Periwinkle.

    Gained – Greater Cuckooflower

    The rest are species native to Britain. One, Reflexed Saltmarsh-grass, has spread in response to salt treatment of roads, and is certainly a post-1920 arrival, but the others may have been present, but overlooked in 1920 – there is simply no way to be sure. They include three orchids (Broad-leaved Helleborine, Pyramidal Orchid, Bee Orchid), riverside plants (e.g. Sea Aster, Flowering- rush, Lesser Pond-sedge, Yellow Loosestrife, Water Chickweed), infrequent species of woodland, heath and grassland (Wood Small-reed, Crab Apple, Climbing Corydalis and Lesser Hawkbit), and species associated with water (Pink Water-speedwell, Broad-leaved Pondweed, Greater Duckweed).

    Gained – Bee Orchid

    Now, the losses. Of the 123 species recorded explicitly from within the parishes a century ago, 55 were not found in 2017-8. They include species that were common or fairly common in 1920, Hairy Rock-cress, Almond Willow, Narrow Buckler-fern, Alder Buckthorn and Lemon-scented Fern. Of the other 364 species that were judged to be within the parishes in 1920, 48 were not found, including several that were common or very common in 1920, such as Hairy Tare and Marjoram. They may eventually turn up, but they have certainly declined. In 1920, more species were said to grow in woodland than in any other habitat, which is hardly unexpected in a well-wooded district. Since 1920, the area of woodland has, if anything, increased, so one might have expected the woodland species to have survived but, in fact, 29 species have not been found.

    So, how do woodland species disappear if the woodlands survive? The answer is neglect of management and consequent loss of open spaces within woodland. As a result, our woods have lost Heather, Saw-wort, Adder’s tongue, Lady’s mantle, Harebell and many others. They just can’t withstand the periods of heavy shade.

    One loss – Heather

    Much the same can be said about species of pasture, heathland, wet ground, open water and cultivated ground. Thus, the parishes have lost Heather, Bell Heather, Cross-leaved Heath, Heath Cudweed, Lesser Butterfly-orchid and other species of bogs and heaths, while Trailing St John’s- wort, Common Milkwort, Heath Bedstraw and many others are much reduced. Despite the increase in arable cultivation, we have lost many weeds of cultivation, such as Corn Buttercup and Common Fumitory, while diligent search revealed just one “Common” Poppy plant in 2018, a species that was common in cornfields in 1920.

    Danger list – Giant Bellflower

    We hope to keep searching in 2019, but can we draw any firm conclusions now? Our wild flora has changed substantially, but local extinctions have been approximately balanced by new arrivals. Moreover, several species are heading for local extinction, including Harebell, Tormentil and Giant Bellflower. We still enjoy a colourful spring flora, but our hedges, verges and woodland paths are now mostly stocked with common and widespread species, not the variety of a century ago. Species still come and go: in the last 20 years we have watched Early-purple Orchid, Bird’s-Nest Orchid and Autumn Lady’s-tresses re-appear briefly.

    No doubt our flora has changed constantly. A glimpse of this comes from William Heard Thomas, a Tintern physician, who recorded Lady’s Slipper-orchid Cypripedium calceolus and Mezereon Daphne mezereum amongst a list of more credible species in the steep woods above the wireworks bridge. However, as in so much else, the pace of change has accelerated. Numerous causes, such as loss of niche habitats like bogs, can be identified, but ultimately, the driving force is the change in the way we use the land, which races back to the change from a traditional way of life to a community dominated by commuters, teleworkers and the retired. Does it matter? That’s for PGP members and residents to decide!