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Living in interesting times
Climate change spells an uncertain future for our nationís wild plants, as Francis Rose explains

Over the past decade, climate change has already had a noticeable impact on our flora, most experts now agree. But the situation is complex, and the future difficult to predict. Over the long term, many of our northern or wetland species may find it impossible to cope with novel weather patterns, including summer droughts and sudden storms (see Box). But at the same time, the very mild wet winters in the south of England are introducing a more “Mediterranean” aspect to our climate, which evidently suits a variety of southern species.

Perhaps the most phenomenal example so far has been the reappearance of sea knotgrass Polygonum maritimum, almost extinct for many years except in a few spots on the south coast of Cornwall. It reappeared at Hengistbury near Christchurch in Hampshire. First found here by W. Bomer in 1836 “on the sandy shore towards Mudeford”, it was not seen here again until 1990 when one strong plant appeared. Two years later, there were 49 plants, and in 1993 more than 140 individuals, stretching over some 200 metres of the south end of the Mudeford Spit.

In 1995 Paul Bowman also found 15 plants at the eastern end of the Hampshire coast at Sandy Point, Hayling Island. Five years later this population numbered more than 200 plants. In 1992, it also appeared at Brighton Marina in Sussex, although this colony was subsequently destroyed by a storm in 1996. Over the past six or seven years it has appeared in quantity at West Wittering in Sussex and at Norton Spit in the Isle of Wight, and has increased in south Cornwall.

These records of a truly “Mediterranean” species give hope that another southern plant, the sea cotton-weed Otanthus maritimus, may reappear on south Britain’s coastline, where it was recorded in the 17th and 18th centuries. It is still in south-east Ireland and is abundant on the sandy coast east of Cherbourg in Normandy only about 40 miles south of our south coast. Surely it is only a question of time before it re-colonises the south English coast.

The behaviour of some of our southern orchid species has also been remarkable in recent years. Until the 1980s many botanists believed that such species as the two spider-orchids - Ophrys sphegodes the early spider-orchid, and O. fuciflora the late spider-orchid - were on the way out in Britain. The Kent botanist Eric Philp said to me in about 1985 that he doubted if the latter species would survive into the 21st century. Since then, the early spider orchid has not only increased in many of its known sites, but appeared in completely new ones as at Dungeness Beach and Sandwich Bay dunes. It is now more plentiful in Kent and East Sussex and south-east Dorset, than I have ever seen it in 60 years field work.

In this case, the creation of the artificial undercliff, Samphire Hoe, west of Dover, as a means of disposing of the spoil

MONARCH ventures into “climate space”

How will climate change affect Britain’s species and habitats? A new report investigating this hot topic is entitled Modelling Natural Resource Responses to Climate Change, MONARCH for short. For a range of species, it uses predictions from climate change models to compare current and predicted future “climate space”- that is, the geographical area where a given species could potentially live if climate were the only factor influencing distribution.

Climate change will present threats for some species and opportunities for others. By and large, northerly species will lose suitable climate space, while southerners could potentially expand northwards. According to MONARCH, species most at risk are those currently limited to northern Britain including twinflower Linnaea borealis and globeflower Trollius europaeus. Baltic bog moss Sphagnum balticum is another potential casualty among the Back from the Brink species, since it is more at home in the colder regions of Scandinavia and the Baltic than in Britain.

Worse, there is no guarantee that a species will actually be able to move to new areas, however hospitable their climates may become. Difficulties in dispersal and colonisation could further limit the availability of suitable habitat, with serious implications for our more northern plants.

For more information on the latest research see the website www.ukcip.org.uk


Dr Jenny Duckworth is Plantlife’s Biodiversity Research Manager.

from the excavation of the channel tunnel has created a wonderful new site of chalk mixed with clay. The warm, sheltered, almost frost-free habitat so formed has been colonised by many plants from the cliff above in the past ten years. Ophrys sphegodes now has a population here of more than 1000 plants (2001) on is a site that was under the sea until recent years. Many of the plants are not only very tall and vigorous, but are setting abundant seed.

The late spider orchid has also shown a remarkable expansion in numbers. The White Cliffs Project at Folkestone, funded by the tunnel works, has restored much of the former late spider orchid habitats about Folkestone, by clearing scrub from deteriorating downlands, and provided fencing enabling grazing to take place again after some 40 years in several places. This orchid is now more plentiful than at any other time in the last 60 years, with at least five populations on Folkestone Downs and at least four populations on the Wye Downs NNR. Undoubtedly the “White Cliffs” management work has helped greatly, but I doubt if this would have occurred without the change to mild wet winters of recent years.

All the same, it is quite clear that as time goes by, our more exacting species will only survive in the limited areas of properly managed nature reserves. The future existence of our most interesting plants may well depend on such places, which is why Plantlife's growing network of reserves is so important..

 Reproduced from
Plantlife magazine
with permission

Francis Rose
is a member of Plantlife's Advisory Council