Himalayan Balsam (short video)

An introduction to the invasive plant Himalayan Balsam (Impatiens glandulifera), found along the River Mole at Gatwick.

 

Roving Records - Land East of the Railway Line: 19/03/2014

Recently I've been really spoiled by warm and sunny weather, so I had to give myself a kick to get outside on this cool, blustery day.

Underside of a Mink: the colour is quite beautiful but the fur is rather oily in texture

On the way to the site, along the A23 was a grim but still an interesting find: a squashed American Mink (Neovison vison), which came off worse after meeting a car. I've seen plenty of tracks and droppings around our streams and rivers, but I've yet to see a live one. American Mink were brought in and farmed in the UK for their fur before it was banned in the '90s. Sadly this practice still goes on in European countries and the US. The descendants of the escapees here are an invasive species and voracious predators, thought to be at least partly responsible for the decline of the UK's Water Voles.
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Scots Pine and Birch trees dominate the entrance of Upper Picketts Wood

Into Upper Picketts Wood and a colony of Jackdaws were making the most of the stiff breeze, leaping off the trees and being buffeted happily about. A group of Goldfinches high up in the Scots Pine were also singing lusitly, a sound which I normally associate with my housing estate.

The woodlands are really alive with bird song at the moment, in particular Wrens, Robins, Goldfinches, Great Tits and Chaffinches. Great-spotted Woodpeckers were drumming and a Green Woodpecker was 'yaffling' in the distance. I regularly hear a Marsh Tit around the entrance to Goat Meadow and have occasionally seen a pair flitting around together. I really like its shrill 'pit-choo' calls, which can feel like a greeting, though in actuality is telling me 'where to go'.

I was sneaking a look under the reptile refugia around the meadow, when something which looked like a massive rubber snake draped over a branch caught my eye...

Refugia at the Grass Snake boulevard

A rubber snake

It was in fact a very real and pretty massive Grass Snake! It's close to a meter long and I've seen this big ol' female in the same spot last year. I was hoping she wouldn't mind our rennovating her brash pile, which was breaking down and getting a bit sparse, but it seems to have gone down nicely.

Grass Snake (Natrix natrix)

On to checking the hedgehog tracking tunnels, kindly lent by one of our Ecology volunteers George. We are hoping to get some indication of Hedgehog activity on our sites...

A Hedgehog tracking tunnel - corrugated plastic with an ink pad and pieces of plain paper at either end

They were baited with spam and tinned sweetcorn, as like some humans, most mammals don't seem to be that fussy! After just one night, all the food was gone and left behind were lots of little inky mammal tracks. Sadly no hedgehog prints yet, although it was probably a bit of a long shot.

These tiny tracks are most likely from Field Voles and Common Shrews

Halfway through checking the tunnels, I spotted two bees hawking over the grass... I had a quick sweep of my net and one got away, but I snagged this cute little fella - a mining bee of the Andrena genus.

Male Andrena spp. As well as two large compound eyes, you can see the three ocelli (simple eyes) on the top of his head which assist with light detection and navigation

I was told it is probably the Small Sallow Mining-bee (Andrena praecox), one of the earlier species to be out and about. Male Andrenas can all look pretty similar so I would need to use an identification key to be sure, but as I am pretty tight for time, I let it go.

He was released on Blackthorn flowers, though it might have preferred a Willow catkin

Finally, under the reptile refugia I am also finding many of these little click beetles...

Elaterida is the Click Beetle family and consists of 73 species in the British Isles

At some point I will have a crack at using some invertebrate identification keys, but right now I am on a steep learning curve in terms of Airport and Aerodrome Ecology, so it is on the back burner!

Gatwick's Alien Invaders

A battle is being fought all around Gatwick Airport... Aliens landed here quite some time ago, but together JS Agriculture and Gatwick Greenspace Partnership have plans for defeating these invasive species!

American Signal Crayfish (Pacifastacus leniusculus)

Signal Crayfish burrows in the bank and Himalayan Balsam growing along

 a section of the River Mole at Povey Cross

An important part of our Biodiversity Action Plan is to monitor the presence of non-native species occurring on Gatwick's land and to come up with plans to tackle them. As they have been established in our countryside for quite some time they are virtually impossible to eliminate, so instead we aim to control them as best as possible, reducing their impact on our native flora and fauna.

Bucket 'o' crays:  They have reached plague proportions in our part of the River Mole.
We humanely euthanise them under instruction from the Environment Agency

Tiny wee Signal Crayfish from the River Mole

The American Signal Crayfish (Pacifastacus leniusculus) was introduced to Britain in the 1970's and escaped from fish farms into our waterways. Having witnessed the size and quantity of their tiny larvae I'm not surprised they did! They are tough little pioneers and easily colonised our waterways; unfortunately they carry a disease which our native White-Clawed Crayfish (Austropotamobius pallipes) is vulnerable to. As a result White-Clawed Crayfish are now pretty rare and highly protected in areas where they still remain.

Our licensed crayfish traps with fish bait. 

Signal Crayfish have a voracious appetite and eat whatever they can get their claws on, be it aquatic plants, fish fry or invertebrates. They also burrow deep into river banks which causes destabilisation, erosion and eventually bank collapse. By trapping them on a section of the river and reducing the number of large, voracious adults I hope to see a positive effect on the aquatic biodiversity.

Gatwick Greenspace volunteers Adrian and James removing Himalayan Balsam; 

waders are not such a bad job on a hot summers day

Another problem alien here is Himalayan Balsam, which was introduced to Britain in 1839 as an attractive ornamental garden plant. It is a rapid coloniser, spreading along our waterways, growing very tall and quickly out competing our native flora. It has impressive pink flowers which are a good nectar source for bees and other pollinators, but perhaps at some cost to our own native wildflowers.

Himalayan balsam (Impatiens glandulifera) in flower

The root of the problem: the fleshy roots die back each winter, meaning the soil is left loose and exposed. This however does mean it is easy to pull up. 

The seed pods are pressurized, popping open at the lightest touch, scattering seeds into waterways which are then carried far and wide. The roots of this plant are weak and die back each winter, resulting in exposed mud which then erodes easily away .

Gatwick Greenspace volunteers are all-weather people with the correct gear, precautions and an ample supply of refreshments (I can testify to their high-standard biscuit selection!) On one of the hottest days of the year, they tackled a good length of the River Mole around Povey Cross, pulling up every individual balsam plant they could find.

Balsam is heaped into piles to rot down before it has flowered and seeded

Volunteer Georgina with a near full-grown Signal Crayfish

Gatwick Greenspace Partnership conservation volunteers at Povey Cross, North West Zone

The JS Agriculture team, balsam-bashing in the southern part of Horleyland Wood,

 Land East of the Railway Line

We are continuing the fight against Gatwick's invaders for the next few weeks. If you interested in volunteering and conservation around Gatwick then check out the website for Gatwick Greenspace Partnership, part of the Sussex Wildlife Trust.