Tackling Invasive Plants

 

There are countless examples from around the world of how introductions of non-native wildlife have led to bad consequences for native flora and fauna. Sadly East Lothian is no exception. Species on our hit list include Sea Buckthorn, Giant Hogweed, Pirri-pirri Bur and the very similar Two-spined Acaena, Reed Mace, Himalayan Balsam, Russian vine and Japanese Rose.

We are trying to reduce or remove them all!

This page gives an overview of the plants that countryside volunteers are currently tackling in East Lothian.  Impressive inroads have been made, but it is just the tip of the invasives iceberg. We are hoping to develop an invasives control project in the near future.

For everything you ever wanted to know about invasives, see the official Non-native Species Secretariat website

 

Sea Buckthorn

Sea Buckthorn (Hippophae rhamnoides) is native to parts of UK's East coast, but has been introduced elsewhere. For example, in East Lothian large-scale planting was carried out in Gullane in the 1960s in an effort to help stabilise the dunes.  Historically grazing, in particular by rabbits, would have helped to limit its spread but following myxomatosis outbreaks in the 1950s and 60s this grazing pressure was much reduced and the extent of Sea Buckthorn increased rapidly.

Sea Buckthorn does have benefits to wildlife – the berries are a food for many animals and it offers good nesting habitat and shelter  – but very few other plants can live with it. Its thick, impenetrable growth physically prevents other plants establishing and it also fixes nitrogen in the soil. Higher levels of nitrogen mean that dominating, nutrient-loving plants such as nettles and thistles take over, preventing more delicate plants typical of dune grasslands to grow.  At sites where conservation of dune grassland is a priority (and this is a protected and diminishing habitat nationwide), Sea Buckthorn needs to be controlled.

Clearing Sea Buckthorn scrub is a major winter volunteer task, in particular at Aberlady Bay and Yellowcraig, and over recent years we have had a major impact on its distribution at these sites. At Gullane, Junior Rangers have been helping out as well as external volunteer groups such as the Green Team.  Historically significant removal has also taken place at some sites using contractors with big machines. Not only is this approach is more expensive but also the heavy machinery is much more damaging to to the dunes than volunteers. Following clearance of large areas by machinery, volunteer power is needed to tackle regrowth for example on Spike Island at John Muir Country Park. The removed buckthorn is burnt, often on spectacular bonfires. Great for keeping warm and cooking tatties!

Long-term goals are to  reduce the number of patches and extent of Sea Buckthorn at many of our coastal sites. Some of the larger more mature areas, which are of most benefit to wildlife, will be retained.

Giant Hogweed

Giant Hogweed (Heracleum mantegazzianum) was originally introduced to the UK as an ornamental plant in gardens. It can become an impressive plant, growing up to 6 m tall.  Less impressive is its toxic sap, which causes severe burns and blistering. It is also highly invasive, and has spread throughout the UK.  It can be found anywhere, but is most common along river banks.

In East Lothian the most notable Giant Hogweed growth is found along the Rivers Tyne and Esk and their tributaries and a couple of neighbouring areas of waste ground. Each spring, a group of volunteers don sturdy  gloves and thick clothing to tackle an area of growth along the Tyne close to Hailes Castle. It is also removed from the lower reaches of the Biel each year, the work organised by local farmer and Chair of the Access Forum. Smaller pockets of Giant Hogweed occur in many other places across the county. For example it grows in the dunes at Aberlady Bay and here plants are removed by volunteers when they are small seedlings and the sap poses less of a hazard.

We now have a program to eradicate Giant Hogweed along the river Tyne.

Two-Spined and Four-spined Acaena

Two-spined Acaena and Four-spined Acaena (the latter more commonly known as Pirri-pirri Bur) are similar-looking plants that have the potential to do great harm to dune ecosystems. Pirri-pirri Bur is a problem at Yellowcraig and Barns Ness whereas Two-spined Acaena is the species of concern at Gullane and Aberlady Bay.  They are low-growing plants, which creep their way through the dune grassland and if left unchecked can form dense mats which prevent other plants from growing. It also has a very effective method of seed dispersal: producing burs rather like those of burdock which are very effective at sticking to clothes, boot laces and the fur of dogs and deer (or any other animal passing by).

Two-spined Acaena:

Although the less rampant of the two species, every year volunteers spend time at Aberlady Bay and Gullane Bents moving slowly and methodically through the dunes removing the plants they find.  This seems to be working, with the plant getting harder and harder to find each year!

Pirri-pirri Bur:

A great deal of volunteer effort is spent at Yellowcraig keeping Pirri-pirri Bur under control. This is mostly achieved by removing seed heads and pulling up the plants. Volunteer work days are also spent marking locations of plants with red and white flags, enabling trained staff to follow with careful topical spraying.  Recently large areas of the plant were discovered at Barns Ness. So far there is no evidence that it has made its way into the sensitive dune areas but there is a high risk it could spread here. Teams of volunteers will be out tackling it to hopefully prevent its spread.

Reedmace

Every year Reedmace (Typha latifolia) is removed from a couple of the wetland areas at Aberlady Bay nature reserve and from the bird reserve pools at Levenhall Links. A wet and muddy job which some volunteers love and others are less keen on! However, if left to its own devices, Reedmace spreads quickly, taking over and ultimately causing the water body to dry up.  Whilst they are at it, at Levenhall volunteers also remove Spike Rush and Grey Club Rush to keep these plants under control and maintain plenty of open water areas.

Himalayan Balsam

Himalayan Balsam (Impatiens glandulifera) is widespread along the water courses of East Lothian. It was introduced into the UK in 1839 as a garden plant but has become a big problem in many places. It has the dubious accolade of being the largest annual plant in the UK and can grow from seed to a lofty 2.5 m high in a single season. It spreads rapidly, quickly forming dense stands along river banks and water bodies and preventing other plants from growing. When it dies back in winter the river banks are left bare and prone to erosion. As an annual, it relies on seeds to set to produce next year's growth. If plants are removed every year before the seeds have developed it can be eradicated from an area in a few years.  The problem is that ALL plants need to be removed as seeds from plants in neighbouring areas will soon spread and the plant will return!

In East Lothian much of the control of Himalayan Balsam is carried out by the River Tyne Trust and local angling groups who pull it up from sections of the rivers.  ELCV path wardens also do their bit where it occurs on their patch and the Junior Rangers have tackled it at the bottom of Seton Dean. Plans are afoot to develop a more co-ordinated approach Himalayan Balsam removal and hopefully permanent eradication of this plant can become possible.

This species is listed on Schedule 9 of the Wildlife and Countryside Act in England and Wales therefore, it is also an offence to plant or otherwise cause to grow these species in the wild.

Russian Vine

Russian Vine (Fallopia baldschuanica) is also known as "mile a minute plant" because of its extremely rapid growth and it is for this reason that it is frequently planted by gardeners to provide instant cover.  However, it can very quickly get out of control and due to sheer biomass can cause damage to bushes, shrubs and other structures it climbs over. Every year volunteers spend time on Castle Hill in North Berwick removing Russian Vine. It is notoriously difficult to eradicate and it is likely this will be a never-ending task! But at least we are controlling its spread here.

Japanese Rose

Japanese Rose (Rosa rugosa), sometimes known as Beach Rose or Beach Tomoto is a non-native species that was originally introduced as an ornamental plant. It spreads easily forming dense thickets in sandy coastal areas which prevents growth of other plants and can also cause access problems for people.  It is notoriously difficult to control, with burning, cutting or spraying of aerial parts ineffective as the underground rhizomes remain unharmed.  The plant is important for some wildlife: flowers are visited by insects and the hips are eaten by birds and mammals. The aim in East Lothian is to control its spread, rather than eliminate it completely. So far volunteers have removed some of these prickly plants from the dunes at John Muir Country Park and there are plans for control at Aberlady Bay.

Other plants growing in the wrong place

Volunteers spend time removing (or reducing the amount of) many other species of plant where they are threatening to take over vulnerable habitat.  For example, on the dune grassland at Yellowcraig Sycamore, Scot's Pine and Ash seedlings are removed along with Apple scrub (growing as a result of a throw-away apple core!). These seedlings would quickly become small trees, which become bigger trees... you get the picture... and the valuable dune grassland habitat would eventually be lost. Cotoneaster, Monbretia, Pyracantha have managed to find themselves growing in the dunes at Aberlady Bay and shouldn't be there.  Gorse scrub threatens to take over grassland areas at North Berwick law and large mats of Ivy are taking over parts of the woodland areas at Levenhall Links.  Of course many of these plants have wildlife value, for example as food sources for insects or nesting habitat for birds, so the aim is generally to control rather than eliminate.