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National Symposium on Biological Invasions

17 May 2019

National Symposium on Biological Invasions

The National Symposium on Biological Invasions took place between 15–17 May, 2019, at Waterval Country Lodge, Tulbagh. It was an interesting meeting jointly hosted by the CIB and SANBI. 

We had three very interesting plenary lectures from Peter Lukey, Jasper Slingsby and Andrew Robinson.

Several talks came from the MeaseyLab (see below).

Here are some memorable moments of the Symposium.

MeaseyLab talks and abstracts:

Jubase, N., Measey, J. and Shackleton, R. (2019) A review of invasive species reporting by citizens using different platforms.

Several data management systems exist to share information and data on invasive species, but these databases operate independently and are sometimes oriented toward particular taxonomic groups or regions. Some of these databases are for professional use such as SAPIA, some are online citizen science platforms such as iNaturalist and others are social media platforms such as City of Cape Town Facebook Page and Twitter. In this study we present the preliminary findings of invasive species (listed as category 1a on NEMBA and occur in the Western Cape) reported by citizens across different databases.

Stephens, K., Measey, J., Reynolds, C. and Le Roux, J.J. (2019) Impacts of invasive birds: assessing hybridisation between invasive Mallard Ducks (Anas platyrhynchos) and native Yellow-billed Ducks (Anas undulata) in South Africa

Invasive Mallard Ducks hybridise with the Yellow-billed Duck in South Africa and threaten the genetic integrity of this native duck. We used genomic data to assess hybridisation and determine whether introgression was occurring. We found evidence of hybridisation but a low level of introgression of Mallard Duck genes into the Yellow-billed Duck population. Consequently, the Yellow-billed Duck population is largely unaffected by introgression, but introgression could become more extensive in the future. Therefore, if Mallard Duck control is conducted at a national level, there is still a good chance of protecting the genetic integrity of the Yellow-billed Duck.

Peta, S.T.P., Engelbrecht, G.D. and Measey, J.  (2019) Reptile and bird diversity along a gradient of invasive alien plants in the threatened Woodbush Granite Grassland (Limpopo Province, South Africa)

Invasive alien plants (IAP) pose a threat to biodiversity, with their impact on fauna diversity is poorly understood. The study aimed to compare reptile and bird assemblages in three habitat types: grassland, invaded areas and plantations. Reptiles and birds were surveyed using Y-trap array and point counts respectively. Variation in habitat structure was clearly indicated. Five IAP species were identified. Reptiles (23 individuals from 5 species) were recorded, with the highest abundance and diversity in the grassland. Birds (2 113 individuals from 67 species) showed the greatest abundance, diversity and richness in the invaded habitat.

Wilson, J.R., Measey, J., Richardson, D.M., Van Wilgen, B.W. and Zengeya, T.A. (2019) Biological invasions in South Africa: potential futures

The recent national status report provides a broad-brush picture of biological invasions in South Africa (or at least what monitoring or reporting is needed to improve management and policy decisions). But what of the future? In this talk, we develop scenarios of what the situation might look like a millennium from now, and follow these back through time to evaluate the long-term outcomes of current trajectories. Can such long-term visions provide insights into how we should respond to horizon scanning exercises, estimates of invasion debt, right down to decisions over management planning horizons?

Bell, J. and Measey, J. (2019) Exploring time, effort and efficacy of Guttural Toad (Sclerophrys gutturalis) extirpation efforts in Constantia, Western Cape, South Africa

Extirpations of invasive species in urban settings rely on access to many private properties, therefore requiring owner buy-in. Here we explore the relationship between owner buy-in and effort and efficacy of toad removal in a high-income low-density peri-urban setting. Early attempts to extirpate the expanding population were stymied by owners refusing access to key properties. From 2010, an emphasis was placed on building understanding with owners. To date, ~R0.8 million has removed 5 240 toads since 2011 from ~120 properties. We show an increase in access to private properties results in an increase in removals over a 9-year period.

Davies, S.J., Impson, D., Jurk-Mabin, C., Meyer, M., Rhoda, C., Stafford, L. , Stephens, K., Tafeni, M., Turner, A.A., Van Wilgen, N.J., Wilson, J.R., Wood, J.  and Measey, J. (2019) Co-ordinating alien animal control in the Cape Floristic Region

Animal invasions often go unnoticed next to those by plants, especially in the Cape Floristic Region. However, the CAPE-IAA has now been running for over 10 years, with oversight of six animal control projects, and discussion on a further 15. The group has regular and ongoing support from implementers, academics, conservation, managers and animal welfare role-players. A key forum function is the dissemination of ongoing research, and subsequent rapid implementation thereof. This also requires important and appropriate stakeholder engagement, without which many animal control projects would flounder. The success of the CAPE-IAA may be transferable to other regions.

  Lab  meetings

Congratulations Jennica!

16 May 2019

Congratulations Jennica!

Jennica Poongavanan just received her marks back from her MSc dissertation, to find that she's passed with a distinction!

You may remember that Jennica was working on the data from Marike's aSCR project. Marike defended her MSc in March last year (see blog post here). But Jennica carried on working to place all of that data into a model that could predict the presence of the Peninsula Moss Frog, Arthroleptella lightfooti

Jennica's thesis was supervised by Res Altwegg, and co-supervised by Ian Durbach and myself.

Poongavanan, J. (2019) Modelling the range-wide density patterns of the Arthroleptella lightfooti using acoustic monitoring data. MSc thesis. University of Cape Town.

  aSCR  Frogs  Lab

Off to France again

03 May 2019

Natasha is back in France

Yes, it's time again for Natasha to move from Summer in the southern hemisphere to summer in France. One of the plus sides to doing a PhD is that you get to travel, and Natasha has certainly done that. 

John sends Natasha off to Paris

It wasn't an easy start to the French season. Natasha was off walking those oh so hard streets of Paris all day Friday hoping that the French admin would provide a password for her to pick up her stipend. Finally the code came through and she was able to pick up her bursary from Campus France - not an easy task on a Friday afternoon and it did take a 20 minute international call to underline the importance of students needing money to survive the weekend.

So what will Natasha be doing in France? 

Apart from the odd visit to a museum (actually the MNHN to spend a week with Anthony Herrel), Natasha will be analysing and writing up all of the data that she's collected over the past 2.5 years. It's a big task, so we're all eagerly waiting to hear what she's managed to find out about Xenopus laevis tadpoles.

Interested in doing a PhD? See some advice on this subject from this YouTuber:

  Lab  Xenopus

Paper on Chinese Xenopus published

03 May 2019

African Clawed Frogs in China

Some of you may remember that I visited China in June last year (if not, see the blog post here). Today the resulting paper with my Chinese collaborator, Supen Wang, was published in BioInvasions Records.

There are a couple of interesting points about this new invasion:

1. It's the first reported for mainland China. Not surprising perhaps as China is the source of most of the pet Xenopus laevis that are pumped around the world at the moment (that was the subject of another paper - see here). 

2. This is the first report of an albino invasive population. All of the others around the globe feature the 'wild-type' African clawed frogs that most of you will be familiar with. However, in the pet trade, it is albinos that dominate.

Here's a piece I wrote for the CIB website


A new population of African clawed frogs (Xenopus laevis) has become established on mainland China, according to a new publication by C·I·B Core Team Member, John Measey. Working with colleagues from the Chinese Academy of Sciences, Measey trapped a site near the city of Kunming, Yunnan Province. The African clawed frogs they found were all albinos, the most common form in the pet trade. Previous work by Measey had shown that the vast majority of African clawed frogs moving around the world in the pet trade originate from China.

Invasive populations of African clawed frogs are known from Europe, North and South America and were previously only known from Japan in Asia. This discovery now places an invasive population on continental Asia with the potential for a much larger invasion in this area. These frogs are known to heavily impact local amphibian and invertebrate populations.

Trade in the African clawed frog started in the 1930s following their use as the first pregnancy test. The species was so easy to keep that it then became the standard laboratory amphibian all over the world, a status it continues to enjoy today. Breeding in laboratories has become so successful that animals are no longer exported from South Africa. Since the 1980s, however, this species has become very popular in the pet trade. Now hundreds of thousands of animals are shipped around the globe destined to become aquarium pets.

The researchers used molecular methods to check whether members of the invasive population carried the fungal chytrid pathogen, known for decimating amphibian populations globally. All frogs caught tested negative. However, the site is known for having a population of American bull frogs, which the team heard calling as they set out the traps. It is unknown how these two globally invasive frogs interact.

The site is on the edge of Lake Kunming, possibly allowing these frogs access to a large are in southern China”, said Measey. “We were surprised to find an established population as this area fell outside the global climate model predicting suitable areas.

Read the full article here:

Wang, S., Hong, Y. and Measey, J. 2019. An established population of African clawed frogs, Xenopus laevis(Daudin, 1802), in mainland China. BioInvasions Records (2019) Volume 8, Issue 2: 457-464. DOI 10.3391/bir.2019.8.2.29.

  Frogs  Lab  Xenopus
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