Download Invasive species in the South Esk Catchment The River South Esk

The River South Esk Catchment
The River South Esk is a Special Area of Conservation (SAC) for Atlantic Salmon and the Freshwater Pearl Mussel. The catchment has a number of designated sites of
international importance due to the range of special species found within the catchment particularly in aquatic environments.
The River South Esk Catchment Partnership aim to highlight the importance of controlling invasive weeds within the catchment in actions outlined in the catchment
management plan (see http://theriversouthesk.org) and by tackling a wide ranging invasive species eradication project.
The problems caused by the invasive weeds on the South Esk include:
l
Loss of biodiversity due to areas of monoculture created leading to
dysfunctional ecosystems.
l
Loss of indigenous species.
l
Reduced access to river banks and riverside pathways.
l
Instability of river banks which leads to increased silt and nutrient input.
The Law and Invasives
l
Section 14 of The Wildlife and Countryside Act (1981) makes it illegal to allow
any animal which is not ordinarily resident in Great Britain, or that is listed on
Schedule 9 to the Act, to escape into the wild, or to release it into the wild.
l
It is also illegal to plant or otherwise cause to grow in the wild any plant
listed on Schedule 9 of the Act (correct May 2011).
Catchment Status
The grey squirrel is abundant and familiar almost everywhere in southern
Scotland and is spreading North. There have been sightings at various
locations within the catchment.
Impacts
Grey squirrels have displaced native red squirrels from much of their
former British range. Worryingly they also carry the squirrel pox virus
which is more often than not fatal to reds if contracted. They damage
trees by gnawing young bark, causing commercial damage to forestry
and nuisance to gardeners. Grey squirrels are also predators of native
birds’ eggs and chicks.
Signal Crayfish Pacifastacus Leniusculus
Invasive species
in the South Esk Catchment
American Mink
Mustela Vison
This small, semi–aquatic carnivore
lives in freshwater and marine
habitats. It is a generalist and
opportunist predator. Mink
habitually follow waterways, lake
edges and coasts, but cross other habitats regularly. They can often spend
time feeding away from water, where conditions allow.
Catchment Status
The American mink has seen target control in areas of North East Scotland
but has been caught recently in various areas of the South Esk Catchment,
particularly in lowland areas.
Impacts
American mink are generalist predators of animals such as domestic ducks
and poultry, gamebirds and fish. They take eggs and chicks in gull and tern
colonies. They are linked to the demise of water vole populations in Britain
and cause damage to fisheries.
Giant Hogweed Heracleum Mantegazzianum
Aptly named ‘giant’, this umbellifer (member of the cow–parsley family) is
native to the Caucasus Region and Central Asia. It may reach 2–3 m high,
bearing umbels of flowers up to 80 cm in diameter. The basal leaves are
often 1 m or more in size. It is especially abundant by lowland streams
and rivers, but also occurs widely on waste
ground and in rough pastures. It grows on
moist fertile soils, achieving its greatest
stature in partial shade. In more open
grassland, flowering may be delayed by
repeated grazing.
Catchment Status
Giant hogweed is widespread through out the
catchment, particularly in mid to lower areas.
Prior to treatment in 2010 larger areas of
Giant Hogweed infestation were estimated to
cover an area of 181,949sq m.
Impacts
The sap can sensitize human skin to ultra–violet light, leading to severe
blisters. Affected skin may remain sensitive for several years. The plant is
also a vigorous competitor, producing almost pure stands which exclude
native vegetation and hinder anglers.
Grey Squirrel Sciurus Carolinensis
Grey squirrels are mainly grey on both body and tail, but some areas of fur
may be more gingery–brown.
The underside of the body is white.
Grey squirrels occur in all
woodland, but are most abundant
in mature deciduous woods;
they also occur in open habitats
(e.g. gardens, farmland) where
trees are present. They readily
cross open areas without trees,
but hesitate to cross open water.
Their small lobster–like appearance makes crayfish easy to recognise
when encountered in a freshwater stream. Compared to native white–
clawed crayfish, the signal crayfish is much larger and its claws are red
underneath with a small turquoise / white blotch on the surface.
Found in most fresh water
habitats. Spreads up and
downstream and may cross land
to colonise adjacent water bodies.
Human transfer, although illegal,
still continues.
Catchment Status
Distribution in Scotland is limited.
There has been only one record
within the catchment but records
occur for other neighbouring
catchments such as the North Esk.
Impacts
Negative impacts include the almost complete loss of the native crayfish
through the spread of disease and direct competition. Also undermines
riverbanks through burrowing and can predate on native fish eggs and
aquatic invertebrates.
Himalayan Balsam Impatiens Glandulifera
A tall, attractive, annual herb with explosive seed heads. Easy to identify
as a mature plant with its pink–purple flowers, fleshy stem and
characteristic leaves. Found mostly on river banks and in damp woodland,
it can grow in other damp habitat. Now a widespread species in the UK,
especially along urban rivers. Spreads solely by seeds, which are small and
easily carried by wind or water.
Catchment Status
Wide spread through out
the catchment particularly
in the middle reaches.
River Watch
The River South Esk’s website has a river watch section where you
can report any sightings of invasive species. This may help in
controlling a potential small problem before it becomes a major one.
Impacts
This species out–
competes native species
in ecologically sensitive
areas, particularly river banks. Where it grows in dense stands along river
banks it can impede flow at times of high rainfall, increasing the
likelihood of flooding. Die back of extensive stands over winter can leave
river banks bare and exposed to erosion.
Japanese Knotweed Fallopia Japonica
This tall herbaceous perennial with
bamboo like stems and often grows
into dense thickets.
Characteristic leaves and stems,
persistence of last year’s dead
canes and distinctive rhizome
(underground root–like stems)
enables year round identification.
For more information please visit
http://theriversouthesk.org/river-watch
http://theriversouthesk.org/our-projects/
http://www.erft.org.uk/
More information
Visit www.nonnativespecies.org/ for further information on established and
emerging invasive species throughout the UK. Plantlife have produced an
informative leaflet ‘Pond Alert’ for guidance on what plants to use or not to
use in garden ponds. Download from www.plantlife.org.uk
The Saving Scotland’s Red Squirrels project is a point of contact for reporting
grey squirrel sightings. Visit http://www.scottishsquirrels.org.uk/
River South Esk Catchment Partnership
Angus Council Economic Development Division
County Buildings
Market Street
Forfar DD8 3WD
T: 01307 473355 • F: 01307 467357 • E: [email protected]
Japanese Knotweed spreads rapidly
in the wild by natural means and as
a result of spread by humans. Spread is solely by vegetative means, either
fragments of rhizome or stem. It does not produce seed in the UK.
It is common in urban areas, particularly on waste land, railways, road
sides and river banks.
l
Prosen junction – Finavon – 4,103 sq m
l
Glen Ogil area (the Bungalow down to Blackspot Bridge) –
21 records totalling 7,578 sq m
Impacts
Negative impacts include out competing native flora, contributing to
river bank erosion and increasing the likelihood of flooding.
In 2009 the “Esk Rivers and Fisheries Trust Biosecurity Plan” was launched. This plan describes the
biosecurity issues of the Esk District area. Its aims are the prevention, early detection, control and
mitigation of the introduction and spread of selected invasive non native species (INNS) and fish
diseases. The ERFT have led on the control of invasive plant species within the catchment.
Fu
ll
RURAL TAYSIDE
Co
ie
s
Braedownie – 26 records totalling 464 sq m
i
l
df
Acharn – 14 records totalling 2,755 sq m
L an
l
nd
Catchment Status
Prior to treatment in 2010 the estimated total area within the catchment
was 14900 sq m. There are few areas of infestation but some are vast.
m muni t
Angus Environmental Trust
“The River South Esk Catchment Partnership aims to protect and improve the quality of the water,
wildlife and local area within the South Esk catchment. At the same time, recognising the
opportunities there are to use the river and the area it is in to improve social and economic wellbeing well into the future. The work carried out by the River South Esk Catchment Partnership
would not be possible if it were not for our steering group members and in particular our funders.
Thank you to you all for your continued support”.
Species outlines used are from the GB non–native species secretariat. Images courtesy of SNH,
John McAvoy, SWT, ERFT
Angus Council Print & Design Unit
Invasive Non Native Species
in the River South Esk Catchment