Dr. Peter Inness from the Meteorology Department of Reading University opened this fascinating talk, the last in our 2021/22 series of indoor meetings, with two images of the same patch of woodland near his Oxfordshire home taken two years apart to the day. In the first, the forest floor was carpeted with bluebells; in the second merely a green carpet with a few unopened bluebell buds visible. This was one of several illustrations he used to show how short term changes in weather can impact the natural world, as he sought to distinguish this variability from longer term trends.
In her recent PhD thesis a student at Reading had used data collected by volunteers across the British Isles (recorded on the Natures Calendar website managed by the Woodland Trust) to show that across the UK the mean first flower date for bluebells was 1st of May in 2013, but 8th April in 2017, fully three weeks earlier.
Dr Inness was able to explain this difference reflected short term climate impacts, rather than long term trends. Data for bluebell first-flowering dates and temperature records for January to April in successive years show that bluebell flowering dates respond to the weather and temperature conditions during March, February and January, as the plant stems emerge and the flower buds form, rather than during the flowering period itself. And, though invertebrates react rather more rapidly than plants, similar analyses for the first appearance of orange tip butterflies and for blue tits nesting reached similar conclusions.
In 2021, by contrast, hawthorn blossom appeared a whole month later than normal, reflecting an abnormally frosty April.
Looking at longer term trends and the impact of climate change, however, Dr Inness referred to the paper published recently by the Royal Society. This used records on 406 plant species, some dating from as far back as the 18th century, to show a marked shift that took place in the 1980s. Plants are now emerging on average a whole month earlier each year than seventy years ago.
He showed projections prepared by the Meteorological office to indicate that by 2050, in every other year we will experience summer temperatures similar to those we experienced in the very hot year of 2018. And, unless significant reductions in greenhouse gas emissions are achieved globally, these temperatures will be the annual norm by the end of the century. And he also showed projected rainfall maps clearly showing that our winters will be wetter and summers dryer, and warned that individual rainfall events will be 29% stronger. A new UK record for of 316mm rain in a 24 hour period, set as recently as 2009, was surpassed again only six years later in 2015 with a new record of 341mm. All of which suggests that nationally there are considerable tasks and costs ahead to prepare reservoirs and infrastructure to be able to cope.
From a wildlife perspective these climate trends are complex and deeply concerning. Dr Inness gave as examples the likely impact on the relatively shallow root systems of beech trees, less well adapted to cope with summer drought conditions than deeper rooted oaks. And the impact on populations of birds such as swallows whose northerly migrations are triggered by seasonal changes in daylight hours. They may arrive at European destinations too late to feed their young on invertebrates maturing earlier as a result of warmer Spring conditions.
Troubling as these issues are, the talk was hugely valuable and timely, providing us all with deeper insight into the impact weather and climate have on the natural world around us.
by Richard Budden
Dr Peter Inness, a lecturer in the Meteorology Department of Reading University, is coming to give us a talk at the Victoria Hall, Tisbury this coming Thursday at 7:30pm. Please note that we had thought it would be earlier due to travel arrangements, but Pete is able to start at our usual time of 7:30pm.
As the author of "Teach yourself weather" and series editor for a new series of academic textbooks on Weather and Climate Science for Wiley-Blackwell, Pete will have plenty of knowledge to share.
If you haven't already signed up to the talk and want to come, please let us know via the Contact form. We can also send out Zoom links for those who prefer to stay at home. Guests welcome for £2 per ticket.
Slugs and snails have a true champion in Imogen Cavadino, an entomologist who is carrying out research for the RHS. We were treated to a wealth of information with up-close-and-personal photography of these oft-maligned creatures.
Slugs evolved from snails as they simplified their coiled shells and diverged into different families. There’s even such a thing as a semi-slug, one that can’t retract into the shell it carries on top. Some slug species still have a visible pale mantle under the surface, marking their vestigial shell which serves as storage for calcium salts.
The majority of snails have shells which coil to the right, developing asymmetrically via torsion, so that both their respiratory pore and anus end up on the right side of their heads. They are so dependent on moisture that if deprived, they can create an epiphragm to seal themselves in and succumb to a dormant state. Quick to revive if the conditions improve, Imogen told us that a snail was once stuck on a postcard as an exhibit in the British Museum (before they knew about their dormancy behaviour) and stunned everyone by making an escape.
For a researcher, the slime colour can be useful for identifying the species. Slugs produce two types of mucus for defence and movement. We heard that the netted field slug (deroceras reticulatum - above on the left) is the most harmful to our agricultural activities, making a feast of root vegetables in the autumn, but the cellar slugs (Limacus sp. - on the right) feed on rotting material, fungi, lichens and algae and are therefore blameless.
The Royal Horticultural Society (RHS) has been campaigning, with Imogen heavily involved with their media activity, to dispel the myths that all slugs are enemies of the gardener. The last big slug survey was done in the 1940s and the RHS’ recent research has been aided by a formal survey conducted by 60 chosen participants around the country, who performed scheduled slug counts, with the glorious total of 21,000 slugs collected and identified in one year.
They discovered that non-native species were becoming more dominant, no doubt hitching rides on plants from other countries. New varieties are also being discovered, like the ghost slug (Selenochlamys ysbryda - above centre) with no eyes, first identified in Wales in 2014.
Finally, that all important question – how do you euthanise a slug? Obviously, only the types which are eating your veg – please identify them first! The most ethical way is to put them in a sealed container and place in the freezer. Or if you are wanting to maintain their colours for identification purposes, you can drown them in carbonated spring water.
On a more positive note, the RHS welcomes recordings from anyone who wants to get involved. You will find information from Imogen on our Wildlife Recording page, about helping to record slug and snail activity.
At 7:30 pm this coming Thursday in the Victoria Hall, Imogen Cavadino is coming to share her knowledge about slugs and snails.
Imogen is an entomologist currently carrying out research funded by the Royal Horticultural Society (RHS) to help in identifying their species, and to discover which ones are responsible for damaging plants, whether in gardens, on farmland or in the wild.
She aims to inform pest management strategies so that only those slugs and snails that are actually damaging plants are targeted, reducing control costs as well as potential harm to other wildlife.
Mark Elliott of the Devon Wildlife Trust gave a fascinating talk to the Society’s February meeting on the reintroduction of beavers into the UK, based on his experience as leader of the Trust’s project on the River Otter in south Devon.
As he explained, beavers are a species native to Britain that were hunted to extinction roughly 400 years ago. As they are no longer regarded as ‘ordinarily resident’ they can only be released into the countryside with a licence; but things are changing now, as a result of the success of the Devon trials. Last August DEFRA confirmed that the River Otters trial had been sufficiently successful for the beavers to stay indefinitely, and support will now be provided for similar managed projects elsewhere.
This outcome could not have been foreseen at the start of the Devon programme back in 2015. Mark showed us how these semi-aquatic rodents had interacted with the environment on the Otter, showing how the population had grown and migrated along the river catchment over the period since then. From two founding family groups the number had grown to around 13 territories in 2019.
At the outset Mark dispelled the popular misconception beavers eat fish; they are strict vegetarians. And he showed the results of work carried out by the Universities of Exeter and Southampton to measure the beaver’s impacts on fish and other wildlife. The increased variety of habitats that result from the beavers’ dams (that periodically get washed away and then rebuilt) have led to enhanced fish populations of all types and sizes, and the wetlands that result are ideal breeding and feeding grounds for frogs and for wildfowl.
The water storage capacity of the river catchment has increased, and water quality downstream has improved, with lower levels of sediment, nitrogen and phosphorus downstream of the beavers than in the upstream input, and an increase in the concentration of dissolved carbon.
He didn’t disguise occasional problems that have resulted from damage to crops of sweetcorn and flooding of adjacent grazing land, but showed how these can be managed effectively.
Overall the experience in Devon is that the beavers are popular and, if the initial introduction is managed wisely, can exist alongside the human population to provide benefits to our environment.
You can read more about the Devon beaver population and Mark Elliott’s ongoing work by visiting: www.devonwildlifetrust.org/what-we-do/our-projects/river-otter-beaver-trial
Our 40th Annual General Meeting starts at 7:00pm in the Victoria Hall, Tisbury. All are welcome to attend.
The talk starts at 7:30pm. If you haven't already signed up to the talk and want to come, please let us know via the Contact form. We can also send out Zoom links for those who prefer to stay at home. Guests welcome for £2 per ticket.
Our speaker, Mark Elliott heads the project being carried on by Devon Wildlife Trust on the River Otter that has led beaver conservation in the UK for more than ten years.
He will be able to describe their work, what we have learned as a result about this amazing animal, how they can benefit us and the landscape around us, and how we can manage potential conflicts with land owners and residents.
Photo credit: Eurasian beaver (Castor fiber). Per Harald Olsen, CC BY-SA 3.0 via Wikimedia Commons
Bob Gibbons gave us a marvellous talk last week, illustrated with his own spectacular photographs of some of the fascinating species found in Purbeck. Explaining that a great percentage of the area is subject to national and international designations because of the habitats and wildlife found there, he suggested that it is possibly the most wildlife rich area in the UK if not Europe.
The appellation “Island” is thought to have come from earlier times when the marshes of the Piddle and Frome valleys to the northwest combined with Poole harbour to partially cut the area off.
Of particular value is the way the mosaic of habitats grade into each other over large areas without hard boundaries. Another factor which explains the great diversity of species is the poor quality of the soil – either inherently poor podzols of the heaths or the chalk and limestone soils which have been impoverished by centuries of grazing. These poor soils made agriculture difficult which held back development as did the “Island’s” status as a hunting forest and this allowed wildlife to survive into the present era.
As a result of an unusually complex underlying geology the area holds many habitats within a relatively small area: heaths, bogs, chalk downs, limestone grassland, Poole Harbour and its islands, commons, coastal cliffs, and dunes. The only thing in short supply is natural broad-leafed woodland.
Another crucial reason for Purbeck’s uniqueness is its position in the centre of our south coast where it enjoys lots of sunshine. It is as sunny as areas further east and warms up in spring as quickly as areas further to west. This seems to result in it being in a “sweet spot” which has produced an amazing assemblage of species, including many on the edge of their range. As a result, in Purbeck you may find species more usually seen in Cornwall alongside others more usually seen in Sussex, and it is a stronghold for many species, particularly insects.
I suspect many who enjoyed Bob’s talk and photos will be planning a visit to Purbeck this summer. The Society is planning a trip to Tyneham in July.
For those of you who missed it, Ian Dunn, Chief Executive of Plantlife gave a sobering talk in November on the climate and biodiversity crisis, the importance of plants, the work of Plantlife and how we all have a role to play in turning the tide.
The World Economic Forum recognises that four of the top five global risks are nature and climate relevant. Some parts of the world have already experienced a 7°c increase in temperature since 1981. Tangible water stress is being felt around the world. Some of the vast underground water wells in Central Africa have dropped by 80-100 metres in the last twenty years. Over extraction is a further problem despite rain falling in higher concentrations in more extreme weather in other parts of the world. Leaders around the world are lagging behind their people in wanting to take action for the climate. Global warming if unchecked will lead to a catastrophic future for hundreds of millions of people unless radical change is achieved.
Biodiversity is in crisis with 60% of global biodiversity lost since the 1970s. As the climate warms, species loss will accelerate. The UK is already one of the most nature depleted nations. 70% of the UK is agricultural land with massive post war industrialisation contributing to catastrophic loss in biodiversity. Biodiversity is critical to our future. Yet 80% of our major global crops come from just nine species.
Plants, which make up 90% of biomass on the planet, are vital for maintaining oxygen levels on the planet: 50% comes from plants; 50% from the oceans. Much more than that, plants are vital for food, medicines, climate control, water management, flood mitigation, clothing, art and culture. The UK despite being in a temperate zone is already seeing shifts in plant habitats northwards. Changing weather patterns are disrupting the symbiotic relationship between plants and insects. Change is already more radical in countries in the developing south with impacts such as desertification underscoring our need to address social justice and inequality issues elsewhere.
Plantlife operates at a global level as well as at national UK and local levels. It contributes to the global strategy for plant conservation and has helped to identify 2200 of the highest biodiverse plant areas across the globe. Alongside Planta Europe, it is working to ensure plants are recognised in every global strategic framework as an important part of addressing climate change and biodiversity.
In the UK Plantlife looks after around 18,000 hectares spanning 23 nature reserves, the largest in Scotland. It advocates for change at a policy level working in partnership with other conservation organisations. It offers extensive best practice advice from wildflower meadows, lawns and road verges to grasslands. At a local level, its No Mow May campaign promotes measures to increase pollinators and plant species.
Visit Plantlife’s website to benefit from its online resources and talks. Read their Strategy to 2030 For a World Rich in Plants and Fungi. Join their mailing list and lobby on their campaigns for road verges, grasslands and plantlife. Support Plantlife by joining as a member or making a donation to support their invaluable conservation work which is vital for our future.
For those of you who missed Ian's talk, he has kindly given us permission to share it with you here.
Robin Walter came to give our last talk of 2021 and we had a mix of people listening in the Victoria Hall and on Zoom. Robin shared photos from his new book “Living with trees” and his experience over the last 30 years of working for organisations dedicated to the conservation of trees and biodiversity.
A striking statistic was that 13% of the UK now has forest cover, compared to 40% average coverage across countries in Europe, with Finland being a stand-out at 70%. Of course, many countries in Europe cover large areas, with differing population densities and we are a small island with an historic industrial growth, but it strikes home how much we differ.
It is estimated that during the Roman period we were at 20% and our lowest point was after the First World War. The Forestry Commission was then set up in 1919 to address the parlous state of our 4.7% forest cover. A particular strategy after WW2 was to put in conifer plantations on old woodland sites so that they could hold both deciduous and spruce. For instance, at Kingsettle Wood near Shaftesbury, the pines can now gradually be removed to let in more light around the ash and the ground cover can expand.
Robin is a member of the Shaftesbury Tree Group which prepared The Town Tree Plan for 2020-25. It is active in educating the community about their glorious trees and created a map so that people can self-navigate or go on arranged walking tours. 60 people turned up for their inaugural walk! The striking Swedish whitebeam opposite the Abbey on Park Walk draws a lot of attention.
The government has set a target to reach 19% UK woodland cover by 2050. As Robin encouraged, it is up to whole communities to get together and talk about what they want and work with local landowners and councils to come to agreement on plans for the future. We were pleased to share the news that this Sunday, Debbie Carter was organising a group of volunteers to plant trees from the Woodland Trust, as part of Tisbury’s contribution to the ‘treebilee’, the Queen’s Green Canopy planting initiative created to mark Her Majesty’s Platinum Jubilee in 2022.
Jemma Batten gave the talk which had been postponed from September. She explained how she was invited to work as a consultant by the Defence Estates Licensees and Tenants Association (DELTA). These tenant farmers of the MoD-owned Salisbury Plain have set up Plain Conservation https://plainconservation.co.uk/ to work together “to enhance habitats, and protect wildlife, historic and landscape features, water and soils.”
Jemma advises on how to deliver the key conservation objectives from the detailed plans drawn up by all the stakeholders. We saw examples on-screen of all the various mapping layers of Salisbury Plain. Areas are graded from low to high priority for land management reasons or the encouragement of native flora and wildlife. We were fascinated to see that there were also Super Plans which drilled down to field level detail where named plants such as horseshoe vetch and bastard toadflax on chalk downland and pheasant’s eye on arable fields were protected by sensitive management and where the wildflower field margins would stretch to 30 metres in places.
Fertilisers are no longer used and wilding practices of leaving mown areas for seed dropping have helped contribute to the increased appearance of Britain’s rarest butterflies like the marsh fritillary, adonis blue and brown hairstreak and the shrill carder bee, Britain’s rarest bumblebee. Birds such as the bittern, hen harrier and stone curlew are also being seen more widely as the marsh and grasslands improve in quality.
We learnt that staying on top of the fast-growing scrub needs to be actioned every two months, either by tractor or by mob grazing cattle. Grazing areas are marked out by erecting temporary electric fences that need moving every 2-3 days. A time-consuming task, so some farmers set up virtual fences and use radio activated collars on the cattle which bleep when they are within feet of a virtual fence and then administer a mild electric shock if they cross over the “line”. The cows soon learn! Being a military zone, not only are there pockets of dangerous or simply inaccessible places on Salisbury Plain, but farmers also have to respond immediately to commands to move their herds, often with zero notice.
We expressed awe in the face of what is obviously a complicated and heavily monitored way of farming on Salisbury Plain. There is no doubt that these chalk grasslands have benefited from the strict measures put in place over the last 20 years to bring a healthier bio-diversity to an area that, though never having had artificial fertilisers or pesticides, has in the past been neglected.
The passion for conservation runs deep with these farmers, so take a look at their DELTA website to learn more about their work https://plainconservation.co.uk/
Please refer to the Gov.UK website for guidance about the public access of Salisbury Plain and always ring 01980 674763 before a visit. An answer phone recording gives up to date information on areas open for public access.
Photo: Barn owl
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