New species of plant discovered in Tokai Park

20 Jul 2020 - 11:15

The Hidden Veldrush discovered in Tokai forest   Photo:  Douglas Euston-Brown

A new species of sedge, the Hidden Veldrush (Schoenus inconspicuus) which is listed as critically endangered, has been discovered in Tokai Park. The plant is currently known from fewer than 10 plants on the planet and has only been collected six times at two localities.

The discovered Hidden Veldrush is described in a recent publication by University of Cape Town (UCT) researchers Dr Tammy Elliott and Professor Muthama Muasya and Doug Euston-Brown who first officially noticed the occurrence of the plant in November 2019.

It closely resembles a grass with which it often grows – Tenaxia stricta, the Cape Wire Grass – and telling them apart requires a very careful look at the leaf sheath (which grass aficionados would know as the flange on the leaf blade where it curls around the stem, and sedges have a closed sheath). Unlike its close relatives, which like wetlands or rocky mountains, the Hidden Veldrush prefers deep, dry sands.

Euston-Brown shared: “I found one plant on 12 November during a species survey and took a sample to Tammy. She had previously discussed this possibly new species with Muthama and [they] were trying to come to a resolution, [they] found this specimen interesting. Tammy and I returned the following weekend and collected type material. We only found three individuals after searching around Tokai Park for half an hour.”  

This population was chosen as the type locality for the description of the new species, however, inspection of records from iNaturalist revealed that the population was recorded in June 2019 during the Friends of Tokai Park volunteer vegetation surveys but was identified only to family level at that time.

Until recently, identification and naming in Schoenus was problematic, a challenge eased through sustained research over the last five years, leading to the discovery and description of 20 species new to science, mostly growing in the Fynbos.

“Doug arrived aptly when we were finalising the sixth manuscript on the taxonomy of the Schoenus,”  Elliot added.

Only the one very small population – a handful of plants – has emerged to date at Tokai Park. This, and another known small population suggests that the Hidden Veldrush is perilously close to extinction. It is presumed to have once been relatively widespread and common within the Bergvliet-Tokai area. As more old plantation blocks are restored to Fynbos it is hoped that a few more plants may emerge as the critically endangered Cape Flats Sand Fynbos recovers.

“As with other threatened species, the Hidden Veldrush’s future is complicated. It appears that this species especially needs fire: but we don’t even know if it coppices to survive fire, or – as appears likely – is killed by fire and has to establish from seeds: an unusual trait among Veldrushes. Its rarity may suggest that this is a species that likes open spaces such as grazed areas and might not compete well with coppicing species such as the Cape Wire Grass. However, Veldrushes are often eaten and don’t fare well in heavily grazed areas. But studies on its regeneration ecology will need to wait for the next fire, and [in the] meantime we have to plan for its future,” shared the research team.

SANParks and SANBI-Kirstenbosch are developing a backup plan to propagate plants, should some unforeseen disaster befall this last population within Cape Town.

Note to editors

These surveys are organised annually to document which species have returned to Tokai after the clearance of the alien pine plantations, and to track recovery and map the rare and threatened species at Tokai. Over 10 500 observations by 77 volunteers of 665 plant species at lower Tokai Park, many of these are rare and endangered species, emphasising Tokai Park as one of the hotspots for conserving threatened biodiversity.  From these surveys we have a very good idea of the distribution of the various animal and plant species at Tokai Park.

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