News from Sarah Anderson for September 2014

  • A galling discovery

    14:30 26 September 2014

    It was whilst saying goodbye to a volunteer group recently that one of the party produced an Oak leaf he’d found, with lots of mysterious round growths on the underside. We had to admit to not knowing what they were, so set out to investigate and found ourselves entering a mysterious and very alien world. The world of Galls.

    No, not France, but the abnormal growths found on many plants usually caused by some sort of attack or penetration into the plant’s growing tissues, making it reorganise it’s cells. Galls can be caused by many different agents such as viruses, fungi, bacteria, insects and mites and there is a huge variety of them. They’re often very distinctive though so the causer can easily be identified by the gall.

    A good example of the possible variety of the growths can be seen in two galls you may well be familiar with – the so called ‘Oak apple’ caused by a small wasp and the ‘Witches Broom’ seen on Birch trees and caused by a fungus.

    Witches Broom - picture from Trees for
    Generally, these growths aren’t just caused for aesthetic reasons, but may provide their inhabitants with food, shelter or protection from predators. It’s often a parasitic relationship, causing harm to the host plant but this isn’t necessarily so. Sometimes it gets very complex too, which is what we found when investigating the aforementioned Oak leaf.

    A load of old Galls - the Oak leaf with it's occupants
     The wasp causing the Oak Apple gall was just one of many different species of ‘Cynipid’ wasp –  all causing different types of gall in Oak trees and our leaf was another one of them. If you must know, the wasp in question this time is Neuroterus quercusbaccurum. I feel confident in saying there’s probably not a common name for the wasp, but the flat disc galls produced this time is a common Spangle gall.

    Alien worlds! a close up on some of the Galls
    However, these flat discs are just part of the story. They contain the developing eggs of the wasp and in autumn will drop to the forest floor where the grubs will develop over winter under the cover of fallen Oak leaves. In Spring an all female generation of ‘agamic’ wasps emerges (meaning they can reproduce without mating) and lays their eggs in oak buds. These in turn produce an entirely different ‘currant’ gall in catkins and leaves, with male and female wasps emerging in June. These mate and fresh eggs are laid on the undersides of leaves, developing into more Spangle galls.

    It goes to show that few things in nature are as simple as they first appear and even a pile of fallen leaves can have a lot more to it than meets the eye ….

    By Rob Clarke, High Wray Basecamp volunteer centre
  • Trolls and creatures from the Black Lagoon

    10:00 12 September 2014

    One of the best things about being an NT ranger is that we get to hidden places around the Lakes.  

    Coldwell Quarry is such a place, hidden in the woods near Outgate its a SSSI important for the exposed geological features in the quarried cliffs. 
    Unfortunately sometime in the past the quarry was not so secret and it had been used to dump waste fencing materials and other rubbish so it was up to us to clear it out, we didn't realise we would encounter a prehistoric creature in the process!

    Volunteer John standing next to the dumped waste
     using a pallat to stop sinking into the sludge.

    And what of the prehistoric monster??  I won't be cheeky about John, (without help from volunteers we would struggle to complete so much work).
    On day 2 of the job we found this Southern Hawker dragonfly newly emerged on our pallat (you can see the shed larval skin called an exuvia next to the insect).  Dragonflies have flown the earth for 300 million years, some fossils have a wingspan of 70cm!
    We were able to watch the dragonfly take it's first flight into the surrounding woodland after about 20mins where it will feed and mature before returning to the quarry to breed. 
     Teneral Southern Hawker

    Removing the rubbish and cutting back overhanging vegetation should improve the habitat, let more light in and make the geology easier to see if you can find the quarry!
    Rubbish removed and cutting back completed.

    Everyone knows that trolls live under bridges but not everyone knows about the old bridge over Blelham beck near the campsite at Low Wray, I didn't until I was asked to clear some trees growing on the bridge.  They had to be removed as their roots were damaging the structure.
    There's a bridge in there somewhere!

    Once again with help from volunteers we were able to clear the trees and ivy and find the old bridge.  The bridge is Grade 2 listed  and dates from the late 19th century when it's thought it was re-modelled as part of changes made to Low Wray farm by the Dawsons who owned Wray castle and it's estate.

    More trees removed.

    The bridge emerging from the woods.
    All bridges have trolls its just a matter of finding them!  After a couple of hours of graft our troll emerged from his leafy hiding place and stands ready to scare anyone who dares to cross his bridge!

     Wray the troll uncovered.

    Richard Tanner
    Woodland Ranger