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German wasp | Vespula germanica

German wasp

Vespula germanica

Coral bush | Ardisia crenata

Coral bush

Ardisia crenata

Purple loosestrife | Lythrum salicaria

Purple loosestrife

Lythrum salicaria

Pom pom weed | Campuloclinium macrocephalum

Pom pom weed

Campuloclinium macrocephalum

Canarybird bush | Crotalaria agatiflora

Canarybird bush

Crotalaria agatiflora

Peanut butter cassia | Senna didymobotrya

Peanut butter cassia

Senna didymobotrya

Rubber vine | Cryptostegia grandiflora

Rubber vine

Cryptostegia grandiflora

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Environmental Programmes

In order to tackle our country’s socio-economic challenges, the government adopted the Outcomes based approach to improve government performance and providing focus on service delivery. find out more

A pilot study of the breeding system of Henry’s St John’s wort, Hypericum pseudohenryi

A pilot study of the breeding system of Henry’s St John’s wort, Hypericum pseudohenryi
Carryn Smith1,2, Ingrid Nänni 2
1University of KwaZulu-Natal; 2Invasive Species Programme, SANBI

Henry’s St John’s Wort (Hypericum pseudohenryi) is an invasive alien plant found in the KwaZulu- Natal Drakensberg and Midlands that has been perceived as a threat. Once established, this species can invade watercourses and undisturbed veld. As it is widely established, it was expected that the plant is able to self-pollinate with a large degree of success. To test whether this is true, pollinator exclusion experiments were conducted at three study sites in the Drakensberg and Midlands. Further pollination tests were done to establish the role of local pollinators. There were three different treatments: emasculated flowers, hand pollinated cross- pollination, and bagged flowers to exclude pollinators and encourage self-pollination. The results show that while plants are able to undergo self- pollination  and  produce  seeds,  the  number  of  seeds  produced  through  self-pollination  was significantly lower than the control samples, which were chosen at random on the plant. However, self-pollinated seed set did not differ significantly from flowers where the anthers were removed. There was no significant difference in seed set between control flowers and hand-pollinated flowers. This shows that while the plant is self-compatible, pollinators are still required to increase seed set through cross pollination. The low number of seeds in the flowers where the anthers were removed is possibly due to pollinators being attracted by pollen as a reward, thus not visiting emasculated flowers. Further testing will be done to determine whether these results are true across the whole flowering season.

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General News Updates

2019 National Symposium on Biological Invasio…


This is your invitation to South Africa's 2019 National Symposium on Biological Invasions. The convention is hosted by the Centre for Invasion Biology (CIB), University of Stellenbosch, and the Biolo... Read more

2019 Invasive Species Training


During the past five years (2014-2018), ISSA invasive species trainers have trained 4 000 in the identification of invasive species and laws pertaining to invasive species across South Africa.  ... Read more

Alien Grass Working Group


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Permits for planting indigenous Cynodon?


On 16 February, 2018, South Africa's Department of Environmental Affairs issued amendments to the regulations and lists relating to the National List of Invasive Species.  Updates to the draft&n... Read more

Invasive species training 2018 dates released


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Communications post for Africa advertised


The Nature Conservancy has advertised a brand new post:  Communications Manager, Africa Region. Knowledge of invasive species and water would be an asset in this post. See details below:    Job Titl... Read more