A reminder that we'll be showing the award winning RiverBlue documentary on Thursday 23rd November in the Victoria Hall at 6pm. It is free for under 21s and £1 per ticket for everyone else. Please spread the word. It is open to everyone.
River conservationist Mark Angelo infiltrated the fashion industry to reveal the destruction of some of the world's most vital rivers through the dumping of toxic chemical waste, affecting the people and wildlife who rely on these rivers for survival. RiverBlue acts as a demand for change in the textile industry and offers solutions of hope for a sustainable future. The British Trust for Ornithology (BTO) is an environmental charity which aims to increase our knowledge of birds and other wildlife and, using data gathered by volunteers, seeks to inform decisions on government policy, land use and conservation priorities.
To do this, it organises a range of recording schemes through which volunteers gather data about birds’ numbers, distribution, habits, breeding success, and more. One of these schemes is the Wetland Birds Survey (WeBS) which counts the UK’s internationally important non-breeding waterbirds. This includes wildfowl (ducks, geese, and swans) waders, grebes, cormorants, and herons. Since it started in 1947 this scheme has grown and now over 3000 volunteers monitor 2,800 sites. Each volunteer adopts a location to count once a month, with the core counting season between September and March as this is when the numbers of many species peak. The largest aggregations of waterbirds are at our estuaries. But inland lakes and wetland areas are favoured by certain species so cumulatively they also contribute. Locally, Fonthill Lake and Wardour Castle Lake are monitored, but as waterbirds can be very mobile, and one can often see wildfowl flying between these two areas, there is a risk of double counting. So, one Sunday a month is designated as the core count day, so that all counters can visit their sites on the same days. Records over decades for these sites show significant changes in the balance of species seen and their annual peak counts. Unfortunately, most of these changes show a downward trend. Collecting all the information together from all sites across the country allows the BTO to generate indices and trends for each species. As many of the species that overwinter in the UK breed elsewhere, in Europe or the Arctic, changes in abundance relate to conditions across large parts of the world. Monitoring these bird numbers help us to assess how wildlife populations are responding to environmental change. The efforts of all those volunteers contribute to documents such as the recently published State of Nature report which provides a benchmark for the current status of our wildlife. It doesn’t make happy reading, but one can be assured that it is based on the best data available. Andrew Graham 15 members and friends gathered on the car park at Lodmoor on a bright, sunny but slightly chilly morning. Andrew started out by describing how the marshland of Lodmoor had been designated an SSSI in 1952 but had still suffered from being used as the municipal rubbish dump until the 1970’s. Mercifully, only about a quarter was infilled but this is still evidenced by the vents allowing gases from the landfill to escape – into the car park. Nice.
Lodmoor lies on the east side of Weymouth the earlier parts of which lie on slightly higher ground which separates Lodmoor from Radipole Lake to the west. As the area drains south eastward toward the sea, the freshwater marshes become progressively more brakish until, close to the sea wall and the sluices which control the flow of water between the moor and the sea, it becomes saltmarsh. The flat nature of the area means that reeds, rushes, and other vegetation can obstruct clear views, but we walked along the perimeter paths which gave good visibility out over some of the pools. There were plenty of birds to see including numerous Canada Geese, Lapwings, Teal, Mallard, Shoveller and Gadwall as well as a variety of gull species. The highlight was a flock of around 40 Golden Plover which occasionally got up and flew around together in the sunshine, alternately showing their white undersides and speckled golden upper parts as the swooped around in the blue sky. There were also plenty of Grey Herons as well as several Little Egrets and at least three Great White Egrets. Unfortunately, the Spoonbills which often show up at Lodmoor were not present. These, as well as Egrets, were very unusual birds on Lodmoor 30 years ago but are now relatively commonplace as they colonise the south of the country. There were relatively few wader species to be seen. In addition to about a score of Black Tailed Godwits there were a handful each of Dunlin and Snipe. After being a bit irritating by only showing briefly above the reeds a Marsh Harrier eventually made a decent, very visible flight across the moor. This is another bird, once vanishingly rare in Weymouth which is now resident and breeding and which can usually be seen at Lodmoor and Radipole. After lunch we went over to Radipole Lake which, like Lodmoor, is now managed by the RSPB as a nature reserve. Very different to Lodmoor, visibility is much more restricted by the dense reed beds which make up so much of the reserve. In summer these are full of Reed and Sedge Warblers but throughout the year you can hear the distinctive, and very loud, call of the Cetti’s Warbler. We had our ears peeled for the distinctive call of the Bearded Tit or Bearded Reedling as it is now known (because technically it isn’t a Tit) because this beautiful but elusive bird is more often heard than seen. Unfortunately, we were unlucky although we did hear the unmistakable squealing call of the Water Rail, another rarely seen resident of the reed beds. At the top end of the loop path known as Buddleia Walk, we had views out over the open water where we added Pochard and Tufted to our list of ducks. By the time we dispersed from the car park at Radipole we had seen or heard 40 species of birds, which included Swallow, several of which were flying over on their way south throughout the day. Andrew Graham 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. Andrew Graham has organised our last trip of the season to these two RSPB reserves in Weymouth. The focus will be on resident and migrant birds. Bring binoculars if you have them. No dogs.
Meet at the Nadder Centre car park at 09:00am or at the Beach car park at Lodmoor DT4 7SX, just to the west of the entrance to the Lodmoor reserve, at approximately 10:30am. Distance, Difficulty and Footwear : The combined distance at these two separate locations will amount to approximately 5 km/3 miles on flat gravel paths which may be a bit muddy after rain. Good stout shoes should suffice rather than wellingtons. Bring a packed lunch and refreshments. There is no limit to numbers on this visit, but it will help if we know how many people to expect. Either use the Contact form here or send us an email to the address mentioned in the members' newsletter. 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. The day was sunny with that slight September chill in the air and we marvelled at the greenness of the trees in Savernake Forest for this time of year. After a wet May and then regular bouts of rain, the trees were showing fewer signs of stress and had kept their leaves longer. Keith Lea had prepared a fascinating day of study and exploration for us as we went off the main paths and visited different sections of the forest.
One of the first tips he shared was the way to differentiate pedunculate from sessile oaks by inspecting the way the leaves and acorns attached to the twigs. Our alliterative aide memoire of sessile-stalk will hopefully stick with us, where the sessile oak has long stalks to its leaves, whereas the pedunculate oak has the leaves forming from barely visible short stalks. We had lively discussions about fungi, having spotted Shaggy parasol, Chicken in the woods, Beefsteak, Earthball and these tiny translucent white parasols perched up high on branches whose name we didn’t know. There were majestic ancient trees to marvel at and glades where trees formed circles round beaten down leaves and mast, or around grassy pastureland in the more open sections. Shifts in the scents of the forest and temperature surges were noticeable as we moved through the different sections. We had a truly immersive day in the life of the forest and Keith was an excellent leader, sharing his knowledge of the trees and wildlife. The end of summer always brings lots of wasps to interrupt our picnics or irritate us in pub gardens. Another member of the wasp family, the Asian Hornet has been in the news lately because of concern about its potential to colonise the UK. It was accidentally introduced into southern France, probably off a container ship, in 2004, since when it has spread rapidly across Europe and towards the Channel.
The Asian Hornet is a very effective predator of insects, including honeybees and other pollinators. It can cause significant losses to bee colonies, and potentially other native species. As one hornet can consume up to 300 bees a day the species could have a devastating impact on our bees if it becomes established. As a result, much effort has gone into publicising the threat and encouraging people to report any sightings. There is even an “Asian Hornet Watch” app to help you to do this. It provides useful photos of the Asian Hornet and other species with which it could be confused. This includes the continent’s only indigenous species, the European Hornet. You can use the app to report a sighting, ideally with a photo. The way to identify an Asian Hornet in three steps is to ask: 1) does is it look mostly black; 2) has it a wide orange stripe on 4th segment of the abdomen (body or “tail”); and 3) do its legs look as if they have been dipped in yellow paint? Taken together these factors clearly separate it from other candidates. Our European Hornet, which has is quite common in the south of England, is a handsome insect slightly larger than the Asian Hornet and about twice the size of a wasp. It has similar markings to the wasp but is chestnut brown and yellow rather than black and yellow. It is not nearly as aggressive as the wasp and will only sting humans if threatened. Indeed, males do not even have a sting. Like other wasps they make paper nests of chewed up wood or bark, often in hollow trees. We may see them foraging in good weather throughout the autumn before the newly mated queens go into hibernation ready to start a new nest in spring. The rest of the colony, including the old queen, dies by winter. You may see the queens stocking up on nectar from flowers prior to hibernation. Since 2016, nationally there have been 52 confirmed sightings of Asian Hornets and 45 nests destroyed. Most sightings have been in Kent and although there have been a few in Dorset and Hampshire, there have been no sightings in Wiltshire yet. It is certainly important to prevent the spread of the Asian Hornet, but we shouldn’t allow our concern to lead us to unnecessarily persecute our native, and largely harmless hornet species. Andrew Graham 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. Dick Budden There are spaces available for our September Field Trip, organised by Julia Willcock, your editor. Guests are very welcome for £2 per ticket. Members and under 21s are free. If you'd like to join us, please use the Contact form or the new email address which Andrew (controller of the lists) and other members of the committee can access, as requested in the monthly TDNHS newsletters. Unfortunately we can no longer publish that email address in our blogs because we're attracting Spam!
Keith Lea is guiding us around a section of Savernake Forest and we shall be learning about the veteran trees and biodiversity of this Special Site of Scientific Interest (SSSI) which boasts more than a thousand years of history as a forest. Keith has over 30 years' consultancy experience in woodland management, with the overall aim of his work being to improve woodland biodiversity. He is the Vice-Chairman of The Salisbury and District Natural History Society and says "I have been a birdwatcher for over 40 years and have a keen interest in butterflies and native flora. I enjoy leading natural history walks and sharing my knowledge with others." Special instructions: No dogs. Please note that the forest is grazed by cattle which may be near us at times on our outing. Bring binoculars if you have them. Meet at the Nadder Centre car park at 9:00am on Sat 30 Sept or roughly one hour later at the Burbage petrol station, SN8 3AR at the junction of the A338/A346/B3087. There are parking bays at the garage or by the side of the B3087. We shall gather there and Keith will lead us in convoy to the parking area on the Grand Avenue, within the forest. Distance, Difficulty and Footwear - Under 3 miles with plenty of stops before lunch and there will be a short (5 minutes) drive after lunch for the optional afternoon walk of under 2 miles. The terrain is generally flat with gravel or hard tracks. Some minor pathways can be muddy and slippery underfoot. There are a few inclines, but they are relatively short. Hiking boots should be fine, rather than wellies, although it always worth packing them. Bring a packed lunch and refreshments. |
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.
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