We shall be starting earlier than usual at 6:45pm at the Victoria Hall, Tisbury High Street for mulled wine, mince pies and nibbles before hearing from the world-renowned botanist Dr John Akeroyd.
John always loved plants, even before he was taught at school by the famous botanist Oleg Polunin. He graduated from the Universities of St. Andrews and Cambridge, and held fellowships at the Universities of Trinity College, Dublin and Reading, researching European flora. Lecturer, tour guide, writer and editor, he co-founded Plant Talk, the first global magazine for plant conservation.
He has written or edited seventeen books, including the best-selling Collins Wildguide:Flowers and The Encyclopedia of Wildflowers and many articles on plants, people and places.
As an ambassador for Dark Sky International, Steve Tonkin gave us a comprehensive talk on the importance of doing all we can to reduce nocturnal light pollution. Not only does it cause a disruption to the normal life of a wide range of animals, but it is having a long term effect on species numbers. Bright lights at night cause confusion, leading to death on roads, predation by larger animals and fewer opportunities to mate.
We heard examples about robins who get exhausted, mistaking artificial lights for daylight, as they sing through the night and migrating birds who are disoriented by lights and fly into buildings. There are parts of the world where already crops have to be pollinated by hand; for instance, in parts of Canada for their blueberry crops and in parts of China for their apples because insect colonies have vanished.
Steve warned that we still have a way to go in further decreasing the light pollution across the AONB, otherwise we risk losing our dark skies designation. The light pollution over Tisbury was a particular concern to see when he showed us the satellite imaging of the AONB.
So how can we help? https://darksky.org/ shows the way with guidance on how to assess your own home lighting, particularly in making sure that any outdoor light is appropriately placed with motion sensor activation and downward facing beams in warm not blue tones, to minimise disruption to wildlife. We can also look around our own community to see whether there is unnecessary lighting on public buildings and seek to persuade decision makers to implement changes.
Steve Tonkin, Dark Sky Advisor to the Cranborne Chase AONB, will be talking to us at our next meeting, at 7:30pm in the Victoria Hall, High Street, Tisbury on Thursday 12 Oct 2023 about Why dark skies matter: the importance to wildlife of responsible lighting.
Steve has a life-long passion for astronomy which, of course, has made him aware of the effects of light pollution, and he has been raising the issue with anyone who will listen for the last 30 years.
After a first career as a telecommunications engineer, he took a degree in Environmental Studies, did postgraduate work in technology policy, and went on to teach physics, maths and astronomy before retiring to concentrate on astronomy and outreach activities.
Steve supported the Cranborne Chase bid to become a designated International Dark Sky Reserve and his primary task now, as the AONB’s Dark Skies Advisor, is to continue and consolidate the good work that has already been done, and strengthen the AONB Reserve’s standing.
The bar opens at 7pm. There's no need to book. Members and those under 21 have free entry. Guests £2 on the door or please contact us for our BACs information as we do prefer online payments.
Dave Rumble, CEO of Wessex Rivers Trust (WRT) spoke to one of our largest audiences in recent memory when 56 people came along to the first meeting of the new season to hear about water quality in the River Nadder, why it matters, and what can be done about it.
He explained that the Wessex Rivers Trust works with landowners and others to conserve rivers in a wide area covering the catchments of the Dorset Stour, the Hampshire Avon, the Test and the Itchen, as well as rivers in the New Forest, East Hampshire and the Isle of Wight. These include most of the chalk streams that are one of the UK’s most distinctive ecological habitats and make up 85% of all the chalk streams on the planet. Of these, The Avon, with its tributary the Nadder, is arguably the most important of them all.
What makes chalk streams distinctive are that their source, the underlying chalk aquifer, favours a range of plants, such as the distinctive ranunculus (water crowfoot), the range of invertebrate species such as river flies that feed on these plants and the fish that live there. Dave described the way different invertebrates fulfil different roles, complimenting one another in living off the plant life and help keep the river clean, and made the point that their presence, or absence, are good indicators of a river’s health. And he drew particular attention to the presence in the Avon catchment – in addition to the grayling and trout that chalk streams are commonly known for – of a genetically distinct salmon sub-species that returns from the ocean to spawn here. It is this unique salmon and its vulnerability that makes conserving the Avon, and the Nadder, so particularly important from an ecological perspective. Together these are the reasons why the Nadder and the Avon catchment are considered a Special Area of Conservation.
He described the ‘Trinity of Health’, or ‘three-legged stool’, that a healthy chalk stream and its ecology depend on, as Sufficient Flow or volume of water, Sufficiently Clean, and a Natural Habitat, and he went on to discuss the threats to each of these. The first point he made is that legacy issues take a long time to become apparent; because it may take years or decades for rainwater to percolate through the chalk aquifer, problems may only become apparent long after they were caused. He characterised the principle sources and causes of issues as; pressure from increasing population, climate change, agricultural practices, highways, the underinvestment in sewage treatment infrastructure, and septic tanks. Before talking about each of these and what can be done about them, he described the quality of water in the Nadder along its length.
The Environment Agency analysis (using methodology that dates back to the relevant EU regulation) shows the Headwaters of the Nadder - above Wardour Lake - are Poor in quality. The Upper Nadder, from Wardour down to Tisbury, together with the River Sem, is Moderate, as is the stretch from Tisbury to Wilton. From Lower Wilton to Salisbury the river’s quality improves to Good.
Dave explained that the presence of Phosphates probably arising from septic tanks and agricultural practices, are the most likely largest contributors to the Poor rating in the Headwaters and the Moderate rating in the Upper and Middle stretches. But in addition to the these there are signs of mercury and PBDE (a family of man-made flame retardant compounds used in a wide range of applications) that may come from highways or industrial sources and that are persistent pollutants. Quality improves further down the river, partly at least, as a result of settlement further upstream, and as the river flow increases.
He drew attention to the fact that even treated effluent can cause serious pollution harm, in particular due to the emerging problem that pharmaceutical residues that are toxic to wildlife are not removed during treatment. In this context he also drew attention to the harm that can be caused to invertebrates by traces of insecticides used to treat dogs for fleas, and appealed to dog-owners to be alert to this and not let their pets swim in the river for several days following treatment.
Turning to the issue of effluent treatment, Dave homed in on the issue of storm water overflows of raw sewage into the Nadder at Tisbury, Fovant and Barford St Martin, drawing attention to recently reported data showing that between them the three largest water companies, Thames, Southern and Wessex had spilled raw sewage during dry weather for 3,572 hours in 2022, a problem that will take huge investment to rectify. He went on to discuss the issue of broken or poorly functioning septic tanks, a problem that is largely hidden and that the government has attempted to address with new regulations introduced in 2020 requiring an upgrade, with installation of what is effectively a mini-effluent treatment plant, if you want to sell a house with a septic tank. And he explained the significance of the overturning a day previously in the House of Lords of Government plans to remove a requirement to safeguard river health by ensuring the nutrient neutrality of new developments.
Dave gave examples of Wessex River Trust’s work to address some of the other problems he had mentioned, including changes to drainage to reduce the build-up of silt incorporating tyre residues and other pollutants resulting from run-off from roads. And he showed pictures of work to revive the river Test by reintroducing meanders, and the major project currently underway at Amesbury to revive the Avon’s ecology by reintroducing meanders that had been removed when the river was canalised to permit building of the roundabout at the junction of the A303 with the A345.
And, in comments on the need to reduce fresh water consumption so as to preserve the flow of these valuable natural river systems, Dave emphasised the Trust’s work in education and engagement, involving children in exploring the diverse natural world of chalk streams and explaining to them how important this is.
In a closing summary he stressed that a healthy chalk stream is self-cleaning and suggested anyone interested in pursuing the topic further should read a ‘Guide To River Restoration Techniques’ (on the Wessex Rivers Trust website) and ‘Rivers’ a book describing the natural and man-made changes that have affected British rivers since the last ice written by two river ecologists, Nigel Holmes and Paul Raven.
In response to a question from the audience, Dave remarked that usually the best way to manage a risk of flooding was not to carry out dredging, but to increase the river’s capacity by restoring natural meanders and the flood plain, so as to hold back the flow, and mentioned that DEFRA are about to launch a £35million scheme to support flood management schemes. In response to a question about the impact of watercress, Dave said that, as with other forms of horticulture and agriculture, watercress growers using excess fertilizer could lead to nitrogen and phosphate run-off that would pollute the river. And in response to a question regarding water meadows, like the ones at Harnham above Salisbury Cathedral, he said these are amongst the most abundant wildlife habitats, although entirely artificial, having been created by farmers in the Middle Ages to provide early grazing for sheep.
We look forward to seeing you on Thursday 14 September at the Victoria Hall, Tisbury High Street. Doors open at 7:00pm for the bar and the talk starts at 7:30pm.
Dave Rumble, CEO of Wessex Rivers Trust will give our first talk of the Autumn/Winter series on "Water quality and Biodiversity of the River Nadder and the Avon Basin".
The Wessex Rivers Trust is dedicated to the conservation of chalk streams and rivers throughout the region, looking for ways to improve them and work with partners to make them healthy for both wildlife and people. Dave Rumble has had a love of rivers since his boyhood in Hampshire; before joining the Wessex Rivers Trust three years ago, he had sixteen years’ experience in leading roles with the Hampshire & Isle of Wight Wildlife Trust. In this talk he aims to cover the things that make the Nadder and the Avon catchment special, the threats they face from pollution, and what we should be doing about them.
No need to book. Members and those under 21 have free entry. Guests £2 on the door or please contact us for our BACs information as we do prefer online payments.
On 20th April we had our final evening talk given by Simon Martyn with photos provided by his wife Mandy.
Simon was the European Director of Earthwatch, an International NGO which started out in Boston, USA over 50 years ago but is now worldwide with offices in Australia, UK, India and Japan.
Earthwatch sets up projects both for Wildlife and Archaeology with scientists running the projects, helped by a workforce of volunteers. They carry out research and provide essential statistics to establish conservation schemes for threatened species or habitats as they work alongside local people.
The talk was ‘Glimpses of Wildlife Behaviour’ and was divided into sections.
Firstly, we were shown various habitats and their wildlife such as the much depleted herds of bison in Yellowstone Park, the plains of Africa with the wildebeests and various antelopes, plus the harsh, freezing environment of the Arctic.
Secondly, the emphasis was on territory and, especially during the breeding season. Male lions guarding their prides and fighting off the opposition were illustrated. We saw how Roe and Red deer will also become very aggressive fighting off other bucks and male tigers will kill another male tiger’s cubs in order to mate with the female and pass on his genes. We saw a grisly photo of this. (NB. Badgers also do this, as I can witness).
The effects of climate change were visible in the photos of droughts in Africa, drying up the rivers and water holes, causing many animals to die and causing mayhem at the water points with competing animals.
Thirdly, Simon showed us photos of how many species co-operate with others for the benefit of both. For instance, egrets and finches will hitch rides on buffaloes to eat the ticks and crocodiles will stir up the water and expose the fish for the storks on their backs. In India the Langhur monkeys work as lookouts for the Spotted deer when a tiger is about, shrieking in terror.
Finally, we were treated to humorous photos of various animals and birds in compromising and amusing positions including a harassed mother Brown bear trying to control her three naughty cubs. One was up a tree, another near the river and the third heading up the mountain.
It was an entertaining and illuminating evening with superb photography and a nice change from all things local.
by Debbie Carter
At the last of our indoor events this year, we shall hear from Simon Martyn, a former Europe Director of Earthwatch, that, for anyone unfamiliar with it, is the international NGO founded over 50 years ago to connect people with scientists worldwide, conduct environmental research and empower them with the knowledge they need to help conserve the planet.
In this talk, Simon will share with us, along with pictures taken by his wife, Mandy, some “Glimpses of Wildlife Behaviour” in many different species, gathered from their own travels across many different countries, over many years of living, working and conservation-related travel.
The Victoria Hall, High Street, Tisbury and its bar, will be open as usual from 7:00 p.m (cash & card payments). Members and those under 21 have free entry and we welcome any visitors to join us and pay a guest fee of £2. Please contact us if you'd like a visitor ticket.
Juniper scrub prospers well on rocky screes, exposed to the light, away from heavy grazing activity. Matt Pitts, Meadows Adviser at the Salisbury-based environmental charity Plantlife, showed us striking photographs of sites in Cumbria and the Caledonian forest where juniper growth has persisted since the last Ice Age. Closer to home we heard about Plantlife’s project in the Wylye Valley and the Chilterns where they are regenerating juniper on chalkland downs. Not only will this conserve the habitats for the 50 species of insects and 40 of fungi which solely rely on juniper, but it will also contribute to the biodiversity of species on these sites.
Historical records of land usage show that juniper started to disappear when the downlands were fenced and the shift in grazing patterns caused an impact, with some land also being lost to arable, particularly after the Napoleonic War and World War II. Despite this, Juniper went through a mini regeneration during the myxomatosis period 1960-80 as it no longer had the threat of thousands of rabbits nibbling its young shoots.
We learned a striking fact that the berries have a low fertility with only 1-5% viability, so gathering viable seed is difficult. The Juniper project team is aided by the Millenium Seedbank which stores seed and checks on viability. Plantlife mainly use two methods of cultivation: they grow from seed and store young plants in a nursery for several years until they are strong enough for planting out and they also scatter seed on prepared scrapes of chalkland. Locally they have extensive scrapes on the Fonthill Estate in the Wylye Valley where they are trialling juniper regeneration.
Patience is definitely required because juniper takes a long time to establish. We saw photographs of a scraped chalk fenced area over a ten year period and only by year 3 were tiny shoots in evidence. By year 10 there were 688 clumps of juniper growing well, with a multitude of chalkland orchids, kidney vetch and other flowers naturally seeded.
Matt advised against buying juniper from nurseries because firstly, it might not be a native plant and secondly it could be infected with phytophthora austrocedi, a pathogen which kills our native juniper trees. This fungus-like pathogen is difficult to detect without proper laboratory investigation and it is likely to be carried in the compost, so to preserve the strength and integrity of our native juniper we better leave the juniper regeneration to the specialists.
More information about Plantlife’s juniper project is available on their website.
You can now find the full listing of our Talks and Field Trips for March 2023 to April 2024 on the relevant pages of this website or as a pdf to print out. Members will receive email newsletters with more details closer to each event and Blog posts will follow as reminders. We look forward to your company!
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Photo: Avocets (Izzy Fry)
The headers display photos taken by our members. Do get in touch via the Contact Form if you'd like to submit a photo for selection.