Getting tied up in Knotweed

We have been invaded, but it is almost unnoticed by most of the people it is affecting.
Japanese Knotweed is a bamboo-like plant that can grow to 2-3 metres tall, has broad leaves and spreads, and spreads, ... and spreads. For the record, it is not bamboo and it can be very damaging.

The key problem it poses is that the roots and stalks are very strong, and the large leaves are slow to break down.

Plants push up through pipes, concrete and around flagstones, breaking up the structures on the way and undermining foundations of walls as well as breaking pipes. Above ground, one plant keeps growing and spreading in a way that prevents other native plants from growing by reducing light and creating a layer that stops other seeds from getting established.

Like many other invasive species, such as the Ringnecked Parakeet or the American Bullfrog, it was originally brought it for 'ornamental' reasons, in this case from Japan, without a thought for the potential effect. Now it affects pretty much all parts of the UK.

In Forest Hill, the Japanese Knotweed plant can be found in many places, including in a large mass along the sides of the railway on Stanstead Road. You can also see how invasive it is on the pavements and drives on the corner of Devonshire Rd and Waldram Crescent - where it was potentially responsible for what seemed like a permanent and rather dangerous leak this winter.
This plant spreads vegetatively, in other words it spreads from cuttings of the roots of other plants, and not by seed. It is, in fact, one single female plant that has spread along waterways, railway cuttings and spreading of soil waste.

It takes only the tiniest fragment of root for it to regrow. That makes it very hard to eradicate as it is almost impossible to ensure you remove all root fragments. Treatment with glyphosate on the leaves of young plants has some effect; older plants might require an injection directly into the stem. Nonchemical treatments are being developed, but short of removing, and safely disposing of, many cubic metres of soil from your garden, it is probably not yet possible.

Why should we care? Any invasive species threatens natural habitats and therefore native species. This one also threatens our property. At the moment, the level of our problem here in SE23 is small, but it could potentially get much worse and public awareness is very important.

We must all do our bit to help each other as plants in one garden can easily spread to neighbours' land. We also need to encourage the Council to deal with public areas.

You have been warned!
Read more here: http://bit.ly/japanese_knotweed
Photo from http://www.flickr.com/photos/srcosmo/169318031/

Green Aliens Invade SE23!

The Wildside — A regular look at the non human residents of SE23

They come from a place far, far away but they have found conditions here perfect for colonisation. In fact, Rose-Ringed Parakeets are now one of the most frequently seen birds in gardens and parks in SE23. And with their emerald-green feathers and noisy squawk, they are an exotic addition to our urban landscape.

But how can they survive here in South East London? Although they look like they’re used to tropical summers, they actually originate from the foothills of the Himalayas, so they don’t need soaring temperatures in order to feel comfortable. They are also very good generalists, able to survive in a wide range of habitats, like grey squirrels, cockroaches and rats (only prettier).

They are strongly social birds, constantly communicating, even in flight, which is why that unmistakeable cry is so familiar to anyone living in this area.

Flocks of up to fifty are quite common around Forest Hill and Honor Oak and numbers seem to have been increasing rapidly in recent years, perhaps a result of milder winters. Across London as a whole, the population numbers about 30,000 and the RSPB estimates it will rise to nearly 50,000 by 2010. It’s thought that 90% of the UK parakeet population lives in and around London.

Nobody knows for sure how they got here but there are some exciting myths. Are they descended from parakeets released by Jimi Hendrix as a peace offering? Or perhaps they escaped from the set of “The African Queen?” The far more plausible, but prosaic, explanation is that the population of wild parakeets was started by a series of escaped pets.

Opinion is divided as to whether they are a “bad thing” and the government has ordered a survey to assess their impact on native species. There are concerns that they might compete with other hole-nesting birds such as woodpeckers and starlings but there’s no strong evidence. And whether we like it or not, it looks like they are here to
stay.

* Photo taken by Fraser Elliot on his balcony on Honor Oak Road

Hanging on in Forest Hill

It’s Halloween and Mayow Park is pitch black, save for the ghoulish faces of the pumpkins flickering in the cold night air. The children have morphed into witches, devils and worse. And there’s an overwhelming smell of sticky sweets, which they tricked or treated earlier in the evening. We’re all set for a Bat Walk!

It was late in the year for bat hunting. As the insects they eat disappear, the bats start thinking about hibernating. But they made a special effort for Halloween. We didn’t actually see any but we did pick up a couple on our bat detectors – electronic devices, which convert the bats’ ultrasonic, echolocation calls into audible clicks. These were pipistrelles – small, fluttery bats, which are the ones we’re most likely to encounter in our parks and gardens. They may even roost around our houses in summer without us knowing they’re there. They weigh less than a pound coin but they eat up to three thousand insects a night.

Our guide for the night was Colin Higgins, the new warden of Sydenham Hill Wood who works for the London Wildlife Trust. He says we’ve got at least six bat species in Forest Hill out of seventeen species nationally, which is pretty good seeing as they are in decline due to loss of habitat and the overuse of pesticides which kill off the insects they eat.

At Sydenham Hill Wood we’re lucky enough to have brown long-eared bats - one of the more attractive UK species. They normally prefer rural locations, such as farms, but the wood has a good supply of insects and plenty of places to roost.

There is a Woodland Bat Roost Project, funded by the SITA Trust, with extra help and money from Southwark and Lewisham Councils, which seeks to improve the wood as a habitat for bats. This involves surveying the woods with bat detectors and putting up bat boxes to provide extra roosting spaces. There are also plans to carry out building works on the disused railway tunnel to improve it as a bat hibernation site.

The best way to see and hear bats is to go on a bat walk. These are public events held in many parks and public places generally between May and September, when bats are most visible.

And if you’d like to do your bit for bats, you can contact the Bat Conservation Trust at www.bats.org.uk or 0845-1300-228