THIS FEATURE IS FROM VELD & FLORA MARCH ISSUE 109 (1), PAGES 30-31

#PROTECT

Plant spotters to the rescue

Faced with burgeoning numbers of problem alien plants, SANBI’s scientists are launching a pilot project to recruit community plant spotters to help fight the conservation battle

Apr 17, 2023 | WRITTEN BY THEMBELIHLE J. MBELE, LOYD R. VUKEYA & THABISO M. MOKOTJOMELA. PHOTOGRAPHS BY ZANDILE MYEZA

Above: An infestation of Hudson pear takes over a site in Lindley in the Free State.

WHEN YOU ASK A QUESTION, the answer can open up an unexpected view . . .

Our team from SANBI’s Directorate for Biodiversity Evidence (DBE) was surveying the Bethulie area to check that clearing teams had eliminated Hudson pear (Cylindropuntia pallida) locally.

We were astounded when a community member directed us to more Hudson pear populations in the area that were not recorded in our data. From that day he was registered as one of our spotters undertaking to report any Hudson pear population he encounters.

Local spotters are a new force that we are recruiting to lend us their eyes and ears in tracking down problem plants. They will complement the citizen scientists who have already been giving us great data for some time, helping pinpoint new populations of alien and invasive plants.

TACKLING PROBLEMS

More than 2 000 introduced species have now established themselves beyond the gardens, homes and farms of South Africa. Only about a quarter of these are regulated in one of the four priority categories.

We are concerned about both the 383 invasive alien plant species that are regulated under the National Environmental Management: Biodiversity Act and about the emerging risks of as yet unregulated species. Alien species also continue to be intentionally, accidentally or illegally introduced.

Newer invasive species compound our existing problems – to the detriment of our country’s environment, human livelihoods and the economy.

At the DBE, one of our priority mandates is to detect and eradicate populations of emerging alien species, classified as category 1a in the national regulations, which we monitor at high-risk sites. Populations of these species are smaller but can expand and transform the environment. According to national regulations, their trade is strictly prohibited.

Above: Pinecone cactus roots (Tephrocactus articulatus)

WATCH AND ACT

Our team recorded more than 5 000 instances of alien plant species across the Free State and Northern Cape provinces. These records were dominated by woody alien plant species, which are the most problematic form of alien plant life in South Africa because they are large so they take up more space and use more natural resources such as water than indigenous species –
and then usually outcompete them.

Field records on the extent of invasive alien plant populations guide us when we assess the risk of various species’ impacts on the environment, society and economy. This data helped us reassess Hudson pear as an emerging category 1a species that is no longer an eradication target in South Africa, for example.

ON THE RECORD

But records always need updating. When we assessed purple pampas grass (Cortaderia jubata), the species distribution map in the Southern African Plant Information Atlas (SAPIA) showed records only in Mpumalanga. But citizen-science records and the DBE’s own regional detection had found it much more widely – in the Free State, Northern Cape, Gauteng and KwaZulu-Natal.

Similarly, silverleaf poplar (Populus alba) is found almost everywhere in South Africa but SAPIA records show it occurring only in the north. Our regional team attempted to eradicate pinecone cactus (Tephrocactus articulatus) at 10 sites across the Free State and Northern Cape but this cactus made a strong recovery at these cleared sites. This underlines the urgent need to detect alien and invasive species early and to upscale ocurrence data and update national databases regularly.

This is where our mission really benefits from citizen-science databases providing valuable information. Australian acacias were mostly detected through iNaturalist in the Western Cape, for example. Reports and records of the notorious Hudson pear and pinecone cactus in the Northern Cape were picked up via Facebook.

Above: Pinecone cactus scrambles over arid, rocky earth at Marydale in the Northern Cape.

SEEKING SOLUTIONS

Now we hope to throw the information net wider by developing a spotter pilot project in the Free State and Northern Cape towns to boost detection and recording of emerging alien species that must be cleared. Including as wide a range of people as possible in reporting and controlling invasive alien species can help us manage biological invasions better in the long term.

Our main focus will be tapping into indigenous knowledge systems. We also aim to break the science communication barrier between academics and rural communities through regular awareness campaigns, providing reference material and, we hope, offering occasional training.

All spotters will share pictures and locations of suspicious species on WhatsApp with a DBE pilot team contact and can also join various Facebook groups where citizen scientists share information with others. The DBE team will then go to that location to verify the species before uploading the information to the national database.