Invasive Species and Wildlife Corridors

Oxford Ragwort Senecio squalidus

Recently I have become aware of PlantTracker which has been set up by the Environment Agency, the Nature Locator team at Bristol University and the Centre for Ecology and Hydrology. They are asking for help from the public to track down non-native species that are a threat to our native wildlife. It is well known how species such as Rhododendron ponticum, Fallopia japonica (Japanese Knotweed) and Crassula helmsii (New Zealand Pigmyweed) have become unwelcome aliens in our Country. There is a website and an app for use on smartphones to help locate the plants. The results are already proving to be of help to them and to the BSBI in identifying key risk sites for further invasion problems.

I well remember the excitement back in the 1970s that the late Dr Francis Rose showed when he first found Crassula helmsii in a small pond adjacent to Hatchet Pond in the New Forest. His excitement was caused by the fact that his initial identification of it was Elatine hydropiper, a very rare species that he had never seen before. Further research however put him right, and the truth was that he had had his first encounter with a most unpleasant alien. It did not take long for the whole of the bottom of that pond to be a one species carpet of Crassula helmsii with some important species crowded out completely.

The first occurrence of Crassula helmsii in the New Forest was recorded by the late and very able, deaf botanist Paul Bowman. His notebook showed that having found Crassula helmsii nearby, he then drove to Hatchet Pond. Circumstantial evidence suggests very strongly that a small piece of the plant may well have attached itself to his boot. This shows just what an invasive threat this species must be. The original source of the invasion is thought to have been an aquarist supply shop in Essex.

The story of Oxford Ragwort Senecio squalidus is fascinating. This species is now ubiquitous on the tops of walls and throughout Britain’s railway system. It is now completely taken for granted as part of the British flora. It is called Oxford Ragwort because it was grown in Oxford Botanic Gardens in the late 17th century having been collected from volcanic cinders on the slopes of Mount Etna. It was a small hop from its flower bed in Oxford to the walls of the Botanic Garden from whence it found the walls in the rest of the City and, from 1844, the cinders on the early railway tracks passing through the town. In no time at all, it had established itself throughout Britain on its fast expanding railway network.

Pan Listing – Why looking at all species matters…

Epipogium aphyllum, Buckinghamshire August 1971

It has been a privilege, and a joy, that my professional life has allowed me to indulge fully a fascination with the incredible variety of life forms that live on our planet.

Having taught biology briefly, and developed a passion for Lepidoptera, I was appointed a student assistant at Leicester Museum at the beginning of my career. A biological curator in a regional museum is responsible for looking after study collections in all groups of organism. This gives the opportunity to work on that all important vocabulary that I believe is so necessary in evaluating and understand the ecology of our environment.

Leicester museum concentrated on collections of British specimens. These ranged from stuffed animals to the parasites that live in association with these animals. The museum had an active taxidermy department, and I well remember the disgust of a member of the public who had donated a dead hedgehog to the museum, when, in the museum’s acknowledgement of her presentation, it was described as a ‘fine collection of fleas and other parasites’ which had been added to a large spirit collection of small invertebrates all carefully labelled, preserved in alcohol  and stored in jars. The hedgehog itself was not required for the mammal collection. The specimens had to be identified accurately before they were catalogued. What a fantastic beginning this training was for the dedicated pan lister.

Inspiration through Ecology

Simon Davey studying lichens in Jersey

Life on Earth is a near infinite mix of species with complex inter relationships. It is quite incredible how every group of animals and plants has evolved in a way that also gives the naturalist a perfect avenue of study and development of knowledge. Take birds, for instance. An embryo birder would have little difficulty in distinguishing a robin, a blue tit and a blackbird in the garden. As his experience develops, challenges such as leaf warblers and waders present themselves to give a puzzle equal to any Times crossword.

Lichenologists in a Dutch churchyard

Personally, one of my greatest interests is in lichens. I suppose many would be put off lichens believing them to be far too complicated to get into. However, the ecological value of lichens makes them a challenge that is so worthwhile. Anyone with experience of suburban areas, and with even the slightest observation of the natural world, cannot fail to have noticed the scrambled egg like crusts growing on asbestos garage roofs, walls, or the enriched dog-pee zone at the base of trees in urban parks.

Xanthoria parietina

This is the lichen Xanthoria parietina. With something like 1800 species in Britain, lichens present a challenge that could keep any naturalist inspired and occupied for a lifetime. As with birds, some are easily identified, while the identification procedures to name others require a series of complex processes involving chemicals, high power microscopes and the accurate measurement of structures such as spores.  Lichens are probably the fussiest group about the environment in which they can survive. The presence or absence of many allows an ecologist to make a rapid initial evaluation of the health and ecological importance of a site. It is well known that lichens cannot tolerate acid rain. It was probably lichens that caused environmentalists to take seriously the problems, to us all, of industrial air pollution more than anything else. A few groups of species, and especially lichens, beetles and hoverflies indicate by their presence or absence the ecological continuity and lack of negative disturbance in the places in which they live.