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.
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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

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.

​Laura Downer

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.
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​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.
https://www.gov.uk/guidance/public-access-to-military-areas#salisbury-plain

​Organiser: Andrew Graham

​Hambledon Hill ​is the spectacular 192 metre (630 feet) high Site of Special Scientific Interest (SSSI) owned and managed by the National Trust, southwest of Iwerne Minster.  The chalk grassland here is really good for wildflowers and insects, especially butterflies.  The view from the summit provides a real sense of this site’s prehistoric strategic importance and why it’s considered one of the finest Iron Age hillforts in Dorset.

For more on Hambledon Hill itself, go to the National Trust's pages.

This is Andrew's report on the day:

Twelve members spent a pleasant few hours scaling the heights of Hambledon Hill's iron age earthworks to look for butterflies and enjoy the flora.

We saw a total of 17 butterfly species. A small, sheltered quarry on the side of the hill held plenty of butterflies which, because it was not very warm, were not flying much but basking on flowerheads so making them relatively easy to look at and photograph. Several Chalkhill Blues were a highlight as this species is, unfortunately, becoming less common and isn't seen in the Tisbury area. ​

This is known as permaculture, an approach to land management that adopts arrangements observed in flourishing natural ecosystems. The pasture is sown to provide more diversity – the first herbal ley includes chicory with roots that penetrate 8-10 feet down and so help restructure the soil and improve drainage, so is particularly useful for marginal, poorly-draining land. As many as 12-14 different grasses are included, along with clover, sainfoin, horse-shoe vetch and other herbs. Click on the photos to enlarge and see the captions.

​It is in contrast to monoculture farming, which we've been used to until recently, growing only one type of crop at a time on a specific field. ​

​Andrew Graham explains what's going on:

‘In midsummer the hedgerows are thick with vegetation. Much of this is made up of the shrubs which form its structure but mixed in amongst these are a variety of climbers and scramblers. Some, like honeysuckle, old man’s beard (wild clematis), hops and bindweed (convolvulus) twist their way around the stems of other plants as they climb up them. This process is called circumnutation.

'Some plants twist in a clockwise manner, others anticlockwise. When the stem touches some structure or plant, the cells on the outside of the stem grow longer than those in contact with that structure. This causes the stem to curl and wrap around the support. As the weight of the plant below pulls on the stem tips, they tighten their grip around the support.
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'Most often climbers twine around other plants and branches but they will also use man-made objects such as fences or posts. For example, there is splendid hop growing up a telegraph pole and its supporting cable on Hindon Lane near the Beckford -  and hops also grow in the hedges along Tisbury Row. Different growing stems of the same plant will also twist around each other, giving mutual support as they grow upwards.

'Sometimes such twisting cables of stems can add several feet to the top of a hedge. As they age, these twisted cords can become strong and create a web of stems though a hedge or thicket. When we see a cloud of old man’s beard seed heads on a hedge in autumn, very often below there will be some thick old stems congesting the base.

'Two other climbers - black bryony and white bryony – largely die back in the autumn, just leaving skeins of red berries. Despite the similar name, these come from different plant families and climb in different directions. The white bryony has tendrils which look like tiny telephone cords. It sends these out to get entangled about nearby supports. The tendrils can then take up the slack to get support while letting the object to which it is attached to move.

'The dog rose scrambles through many a hedge and thicket. Its vicious backward curving thorns are ideal for hooking onto other vegetation as its shoots climb upwards. Like the honeysuckle, the rose can sometimes climb high into trees where, when it finds a patch of light, it can spread out and flower in profusion.

'What all these climbers and scramblers have in common is that they are using other plants or structures to provide them with support so that they do not have to expend resources on building solid trunks and stems which will hold their weight. This allows them to grow very quickly to reach up to the light and rapidly fill gaps.‘

​A member writes:  I had a wonderful walk from Berwick St John across to Norrington, then up the easterly of the two tracks from there onto the Shaftesbury Way.  The flowers at the top of the track were really beautiful - knapweed, toadflax, scabious, yarrow - attracting some butterflies but maybe disappointingly few.  There's an amazing clump of golden rod on the Shaftesbury Way - legitimately a wild flower (solidago) but this looks so luxuriant it's surely a garden escapee.