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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

Mapping nitrogen loading in freshwater systems: using aquatic biota to trace nutrients

Mapping nitrogen loading in freshwater systems: using aquatic biota to trace nutrients
Motitsoe S.N., Martin P. Hill, Jackie M. Hill
Dept. Zoology & Entomology, Rhodes University

The South African Scoring System (SASS5) is a well-used bio-monitoring tool for the assessment of anthropogenic inputs and ecosystem health in freshwater systems. Increased anthropogenic inputs have numerous effects in aquatic ecosystems, including the facilitation of invasive weeds. There are however a number of ecological challenges associated with SASS5 application, with the primary drawback being that SASS scores only provide “red flags” after ecosystem degradation has taken place. Thus there is a need for new techniques to identify eutrophication before the onset of degradation. Recent work has shown that stable isotope values of the duckweed Spirodela sp. can clearly track different species and concentrations of nitrogen (N) loading in a laboratory setting. This project aims to field test this technique as a bio-monitoring tool in freshwater systems. Previously incubated Spirodela plants with known isotopic values were transplanted in greenhouse cages at ten study sites (with 5 replicates) within the Bushmans-New Year’s and Bloukrans-Kowie river systems,

Eastern Cape.  Using δ15N values of these plants, temporal variation in N loading will be monitored monthly over a 13 month period, along with physicochemical variables. Every three months a comprehensive SASS5 assessment will be done at each site in conjunction with micronutrient water quality analysis. Comparisons of N loading as determined by δ15N values and SASS scores will assess the usefulness of stable isotope techniques for identifying N loading and evaluating ecosystem health.  Successful  field  trials  will  provide  an  early  warning  tool  for  identifying  ecosystem eutrophication with the goal of managing and/or preventing further weed invasions.

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General News Updates

2019 National Symposium on Biological Invasio…

26-02-2019

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

22-01-2019

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

04-09-2018

Who are we? The South African National Alien Grass Working Group was jointly initiated by the South African Biodiversity Institute (SANBI) and the Centre for Excellence in Invasion Biology (C·I·B) in... Read more

Permits for planting indigenous Cynodon?

01-03-2018

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

28-02-2018

Interested in invasive species?  How much do you know about NEMBA invasive species compliance for landowners and organs of state? The South African Green Industries Council (SAGIC) have released... Read more

Communications post for Africa advertised

25-01-2018

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