hills – Grantham Ecology

Beech Droves and Gnarled Oaks

November 19, 2017November 20, 2017Grantham Ecology1 Comment

I’ve developed a bit of a thing for the Quantock Hills… ever since visiting for the first time last year, I’ve taken every opportunity I can to explore this ancient landscape – usually this means a very early start on a survey in the south-west to factor in some free time when I get there!

One of my favourite places is the Drove Road which is a prehistoric track running across the higher ground, presumed to be an ancient trading route which avoided the wetter lowlands. At one end is the Triscombe Stone accompanied by an information board which has the following to say:

‘[the drove road] is also on a ‘Harepath’ (a Saxon army route) recorded in the 14th century as the “Alferode”. In the year 878 King Alfred may have been familiar with the route during his stay nearby at Athelny, on the Somerset Levels.’

The track is lined with ancient beeches which have been coppiced – their boles much older than their branches – but they encompass the road as though the two have always been together, the arches echoing the holloway which runs beneath.

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If you continue beyond the Drove Road, leaving Crowcombe behind and taking a left along the winding lane towards Nether Stowey, you pass through stunning oak woodland. The gnarled contorted oaks are much older than you might guess from their dwarf stature – the exposed aspect and low nutrients of their habitat slows growth and the result is an eerie, exhilarating woodland – made all the more spectacular by the mist which eddied through the trunks on my last visit.

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This is an ancient landscape, one which is far from intact yet which retains remnants and features which have been lost in much of our modern countryside. The sessile oaks which twist and spiral were coppied for centuries for use for charcoal and in tanning leather. This practise of cutting to the base stimulated fresh growth and allowed the trees to be sustainably harvested by generation after generation – a far cry from the clearfell destruction which you can see at work in the Forestry Commission plantations which have appropriated parts of the nearby Great Wood.

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The ongoing ecological value of these woodlands is incredible – I know from experience that the trees beside the road are packed with bats – and the continuity and history make it culturally important. But you need know little of either to be awed by the impression of entering these spaces. The photograph below is perhaps my favorite – it taps into something primeval which is captured in some of the best literature and still to be appreciated in light and bark and leaf. This is the kind of lane which brings to mind Tolkien’s words:

“It’s a dangerous business, Frodo, going out your door. You step onto the road, and if you don’t keep your feet, there’s no knowing where you might be swept off to.”

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Green hairstreaks at Barnack Hills and Holes

May 12, 2017May 12, 2017Grantham Ecology1 Comment

On the way back from a site survey in Cambridgeshire, I had the opportunity to call by and take my lunch break in Barnack Hills and Holes in the sunshine. Having seen a photograph posted by Nottinghamshire Wildlife Trust the previous day, I knew that green hairstreaks were on the wing so I went off in hunt of these iridescent little jewels!

Green hairstreak (Callophrys rubi) can be hard to track down for a few reasons; firstly, they are wonderfully camouflaged against the leaves – seeing one at a flower can be almost like noticing that one of the leaves is drinking! Secondly, their populations can be small – some colonies are only a few individuals strong and so tracking them down on a large site could be time consuming.

Spot the hairstreak drinking from the hawthorn flower!

Luckily, after a pleasant half an hour wandering through the cowslips and orchids, I came across several on a hawthorn shrub. It was a windy but sunny afternoon and this hawthorn bush was more sheltered than many others. When in flight, the butterflies reveal the brown uppers of their wings making them easy to spot on the wing – but they always rest with their wings held together and blend beautifully into the greenery.

Green hairstreak amongst the hawthorn leaves

I watched two males take up sentry posts, settling on hawthorn buds or leaves, poised to leap into action and defend their territory against intruders. Other males were the most targets likely to be chased, along with other insects and butterflies of other species, but they also use this vantage point to spot females on the wing. When resting and waiting, these males tilted their wings towards or away from the sun, micro-managing their temperature with these movements.

Male green hairstreak poised on a hawthorn bud ready to intercept intruders

Green hairstreaks are widely but locally distributed in the UK – this means there is likely to be a colony somewhere near you but they have particular habitat requirements so you might need to go to just the right place to find them. They occur in a range of habitat types including dry heathlands, grasslands, old railway embankments, woodland and quarries. The key habitat requirement seems to be open grassland with a good scrub component. Adult food plants include trefoils, vetches, hawthorn, gorse and spring flowers such as cowslip and bluebell. The larval food plants are similarly diverse including trefoils, dogwood, vetches, gorse and broom.

Green hairstreak on a hawthorn flower – one of the favoured food sources for the imago (adult butterfly)

These butterflies are on the wing early in the year – often in April and early May through to early-June or perhaps later in the north. Barnack is a great place to spot them but this site can help you find a location near you!

Green hairstreak standing guard over his territory on a hawthorn flower

Above the clouds on the South Downs

January 13, 2017January 13, 2017Grantham Ecology1 Comment

This is not really to do with ecology, and certainly not based in Grantham, so you’ll have to forgive me straying off message!

We went down to stay on a campsite at the base of the South Downs in the campervan just before New Years. We set off in dense fog which, but for a few breaks, persisted all the way down the country. We arrived an hour before sunset, pulled on coats and boots and headed off up the hillside near Ditchling Beacon in the optimistic hope that we could climb up above the pea-souper which had enveloped us all day. Optimistic but not expectant, we were rewarded for our efforts!

Walking up the track was like ascending in an aeroplane on an overcast day, when you break through to find that it’s a sunny day above the clouds. This is effectively the same thing – the clouds in this case are lying over the land due to a temperature difference known as an ‘inversion’ – when there is colder air below and warmer air above meaning that the cloud becomes trapped close to the land. As well as the temperature inversion, you need other conditions such as lack of precipitation and little or no wind to maintain this. This is an excellent blog post to explain more about cloud inversions, and how, when and where to catch them!

The view just as we rose above the fog which filled the valley before us but left our position and the wooded hillside opposite clear. I love how the cloud extends out north across Sussex as far as the eye can see.

The fog passing through the trees at the point where the land lifted clear.

The view from the top looking out towards the coast with Brighton nestled somewhere below. The sheep would often stand and stare out, making it difficult not to imagine that they were appreciating the view as well!

The view out across the downs, with fog swirling up the valleys and flocks of birds dotting the sky on their way home to roost.

A way marker for the South Downs Way against the afterglow of a sunset we never expected to witness after a day spent in the damp darkness of a fog-covered countryside.

What inspired this optimism was another recent experience – just before Christmas we were staying in Freiburg and left the city on a murky foggy day to catch a cablecar to 1000m up. We found an incredible sight awaiting us – not only were we above a thick layer of cloud but there was a further layer of cloud above us meaning that the setting sun lit both layers in one of the most magical experiences I have ever witnessed – a few photographs below to give you an idea!

A November Walk in the Quantocks

November 14, 2016Grantham Ecology2 Comments

Sometimes surveys take me further from home, and a Monday morning survey in Somerset invited an early start to take advantage of the opportunity to explore somewhere new. A chance leaf through the Guardian Travel’s Best Autumn Walks section on Sunday night obliged me with an excellent suggestion – a walk from Adscombe across the Quantock hills to Crowcombe and back.

The drive on the approach to Crowcombe presented this autumnal treat – it’s difficult to get over how beautiful beech trees look in their yellows and golds. The beech is generally considered native only towards the south of Englan, and whilst there are plenty of specimens tp be seen around the Midlands, it’s only really on a trip south that you can really enjoy their autumn exhuberance en masse.

There must be a name for when something inanimate catches your eye and morphs into something alien. When I was on a field site at uni, I remember we watched a hare stock-still in the woods for a good 5 minutes before realising it was an apt arrangement of log and stick. This piece of branch and moss caught through the wire fence at the beginning of the walk put me in mind of a tiny maurauder breaking through the defences, strangely sinister!

The walk took me up through Great Wood, managed by the Forestry Commission. The woodland is varied – from dull conifer plantation to glorious semi-natural oak woodland, all punctuated by beech boundaries where the roots pour over the tops of the banks as the trees cling to their precarious looking anchor points. This smartly-spaced plantation of conifers caught my eye, especially the way the light increases as the beech re-asserts itself on the banks which rise up behind.

There were plenty of mushrooms and fungi to be seen in the woods – this was a particuarly impressive ring around a conifer. I’m not sure on the species but would welcome enlightenment!

The route I took went close to Dead Woman’s Ditch, and passed through this spectacuarly gnarled sessile oak woodland. These trees are of a considerable age, but the poor quality of the soils and the exposure results in them being relativly small and encourages these gnarled, twisted growth forms. These are ancient woodland sites, many of which had uses for charcoal and tanning in the past. These days, they provide excellent roosts for a range of bat species including rare barbastelle and Bechstein bats.

The walk back up from Adescombe took me up Quantock Combe – this is the name given to a steep narrow vally which cuts down the hillsides. The stream running through this combe was gentle and shallow, crossable at almost all points, and overshadowed by ferns and bracken.

Back up to the top once more, I crossed a cow-grazed pasture to reach the Drove Road which took me back towards Crowcombe. This beech-lined trackway has the gnarled roots replacing the rocks in the walls in places, and provides a sheltered passage across the open fields. Sadly, the exposure meant most of the autumn leaves had already been consigned to the wind, but it must be glorious in its peak. This track is probably pre-historic and was once an important trading route. The sunken track bears testimony to centuries of footfalls, which is a truly humbling thought.

Before the descent back into Crowcombe, I walked up to Beacon Hill to take in the view from the trig point. Here, the scenery changes from the lushious woodlands to a blasted heath with gorse, heather and Deschampsia with the flar agricultural plains stretching out below.

Despite being well into the middle of November, there were plenty of flowers to be seen along the route including red campion, bramble, gorse, dandelion, herb robert, wood sage, hedge woundwort and heather.

There are many tracks between Crowcombe and Adscombe, meaning there is no need to retrace your steps on a circular walk between the two. The route I took was a pleasant 8 1/2 miles with some good ascents and descents (certainly compared with my neck of the Midlands!). Allow a few hours to meander and explore, there’s plenty to distract you along the way!