Items filtered by date: October 2018
Partnerships are crucial to improving the management of invasive species. Since 2009, the City of Cape Town Invasive Species Unit (ISU) has maintained a superb working partnership with the National Department of Environmental Affairs’ (DEA) Natural Resources Management Programme (NRMP). The aim of the partnership has been to control the invasive Indian house crow (Corvus splendens) population in Cape Town and to prevent the establishment of new roosts.
House crows or Indian house crows are listed in the National Environmental Management: Biodiversity Management Act 10 of 2004 (NEMBA) Alien and Invasive Species (AIS) Regulations as Category 1a invasive species. This means that the law requires the ISU to control and remove the house crow population in the City of Cape Town.
Since the launch of the Cape Town ISU House Crow Control Programme in 2009, the population of house crows in Cape Town has been reduced from over 10 000 birds to less than 300 birds.
As a innovative job creation project for marginalised Capetonians, this invasive species bird removal project owes its success to funding from DEA NRMP.
Since 2015, the City of Cape Town ISU has also been able to track the movements of the invasive Indian house crow between the Cape Town harbour and the city’s Central Business District (CBD).
This is thanks to a successful 2015 partnership between the City’s ISU and the Transnet National Ports Authority (TNPA), whereby the ISU has been allowed access to the Cape Town Harbour.
History of house crow invasion in Cape Town
House crows first arrived in South Africa in the early 1980s. They are regarded as one of the world’s top 100 - most damaging - invasive species.
House crows are “hitchhikers” travelling by ship from their native range of India, Pakistan and Burma to countries where they do not naturally occur, such as Tanzania, Mozambique and South Africa. A recent BBC feature showed the detrimental impact of a house crow invasion on the city of Mombasa, Kenya.
The City of Cape Town has a better chance of winning the battle against house crows, if we are able to prevent them from entering the country.
The ability to monitor the birds from the harbour affords the Indian house crow team a better chance of detecting house crows that may enter or exit the country.
This control programme is a true example of how partnerships are necessary for sustainability best practice.
Why are house crows an invasive problem?
Indian house crows...
- Are aggressive, opportunistic feeders.
- Have a negative impact on indigenous bird and animal populations, agricultural crops and domestic poultry.
- Pose a health hazard to humans as they are carriers of enteric (intestinal) diseases that are transmitted through their beaks or claws.
- Preys on eggs and nestling of native birds, also eat small native animals.
- Mob humans and pets.
- Occasionally destroys vegetable gardens in informal settlements.
- Are a vector for pathogens that cause cholera, typhoid, dysentery and salmonella poisoning.
Download an identification pamphlet on Indian house crows in Cape Town. Click here
- See pdf attachment at the base of this feature).
How can you help?
Residents who want to participate in reporting house crows, can join Cape Town Invasives on Facebook: www.facebook.com/ctinvasives
NOTE: Invasive Indian house crows should not be confused with indigenous Cape crows or pied crows, the latter of which are very common in many suburbs of Cape Town. The indigenous pied crows are the only crows with a white breast, whereas the indigenous Cape crow is black in colour and is larger than the invasive Indian house crow.
The City of Cape Town's Invasive Species Unit is calling on all residents to report sightings of the invasive Australian bluebell creeper (Billardiera heterophylla).
This internationally notorious invasive creeper can be identified by its delicate blue, bell-shaped flowers.
As part of the invasive species Early Detection and Rapid Response programme, the City of Cape Town's Invasive Species Unit, is launching a public campaign to locate known plants so that a management programme can be developed to remove them.
Invasive species are controlled by the National Environmental Management Biodiversity Act (NEMBA) (Act 10 of 2004) – Alien and Invasive Species (AIS) regulations, which were gazetted on 1 August 2014 and became law on 1 October 2014. The National Invasive Species List comprises 559 invasive species in four categories.
What is a Category 1a invader in South Africa?
In South Africa, the bluebell creeper is classified as a Category 1a invader species under the Invasive Species Regulations under NEMBA.
This means that landowners must control, remove and destroy the plant - and any seed - on their property. Any form of trade or planting of this species is strictly prohibited.
Category 1a plants are highly invasive and potentially very damaging to indigenous species.
For this reason, the City makes every effort to control it on municipal land and even offers assistance to private landowners to control it on private properties at no cost to the landowner.
Hout Bay Bluebell Climber Invasion
In 2014, a population of bluebell creeper was discovered on the Klein Leeukoppie estate in Hout Bay, Cape Town.
Consisting of roughly 3 500 plants, the infestation was cleared by the City of Cape Town Invasive Species Unit in 2015.
Access to the site was give to the invasive species removal teams by the land owner.
Over 100kg of bluebell creeper seed pods were removed from the site at – this amounted to over 8.3 million seeds.
How to identify the Australian Bluebell Creeper?
The invasive Australian bluebell creeper is a vigorous climbing plant or shrub with branches that twine around the stems of other plants for support.
The dense foliage of the bluebell creeper smothers native vegetation, preventing natural regeneration and impacting on native fauna by changing the habitat composition denying them of food and shelter.
Botanically, the bluebell creeper can be identified by its dark, hairless green leaves of about 50mm long. The upper surface of the leaves is distinctly glossy with the under surface being lighter in colour with a prominent mid-vein. The bell-shaped flowers are 10mm long and blue-mauve (sometimes pink or white) in colour with five petals occurring in drooping clusters of between 1 to 5 flowers at the tips of the branches.
Flowers are usually seen in from September to April. The cylindrical fruits (seed pods) are 20mm long and are initially green in colour, turning purple-black when ripe. Each fruit contains numerous small, reddish-brown, sticky seeds.
The seeds are mostly dispersed by birds and small mammals that eat the fruit, or in dumped garden refuse.
Dumping may also spread the plant vegetatively. This species rapidly regenerates and spreads after fire, and as it is found in the fire-prone fynbos biome of the Western Cape, it has the potential to become a serious weed.
Conservationists are now worried that its rapid spread will cause enormous ecological damage by smothering and displacing indigenous vegetation.
The plant is also toxic and can cause skin irritations and nausea.
What can the public do?
· Never dispose of the bluebell creeper as part of waste.
· Like us on facebook and learn more about invasive species in Cape Town: www.facebook.com/ctinvasives
The City encourages residents to participate in the forums as this is an opportunity to be empowered with knowledge about invasive species, which threaten our indigenous species. The more we know, the better equipped we can be as residents to make informed choices that will benefit our environment and future generations.
Get involved... Become a Spotter
You can help fight invasive species by joining the Spotter Network