Newly described endemic tree for Soutpansberg

Date: 29 January 2016 By: Andries van Zyl

Dr Norbert Hahn, post-doctoral research fellow in the Biodiversity Research Chair at the University of Venda, recently published in the journal Phytotaxa a description of a proposed new Senegalia species (previously Acacia) endemic to the Soutpansberg.

Senegalia montis-salinarum (the specific name meaning “salt-pan mountain”) is only known to be found in two widely separated localities where it grows on rocky scree slopes along the hot, dry northern aspect of the mountain. Hahn, through some 20 years of botanising, has been instrumental in the recognition of the Soutpansberg as a centre of endemism and floristic diversity. This new species brings to 24 the number of endemic plants from the Soutpansberg (57 in the biosphere reserve) and to 594 the number of trees known to occur in the mountain and direct vicinity.

Morphologically most similar to Senegalia burkei, the Black Monkey Thorn or Swartapiesdoring, the new species differs by being multi-stemmed, having smaller flowers that produce a greater number of seeds and soft, almost semi-succulent wood that rapidly decays compared to the relatively hard wood of S. burkei.

Described by Hahn as an “enigmatic tree” known to him since 1992 and which he loosely assigned to the S. burkei complex, the new description came about as part of his post-doctoral work of revising the flora of the Soutpansberg region, the latest study following his PhD on the floristic diversity of the region and his MSc on the endemic flora of the mountains. Noting the morphological differences, as well as the unusual habitat, to determine the identity of this unknown taxon, he studied all S. burkei and related species at the National Herbarium in Pretoria (PRE), the Schweickerdt Herbarium (PRU) at the University of Pretoria and the author’s personal collection (Herbarium Soutpansbergensis, ZPB), as well as fresh material in the field.

Given the size and disjunct nature of the two known populations, estimated to be no more than 250 adult trees, the new species would qualify as endangered under the International Union for Conservation of Nature Red List and this is suggested in the paper. Furthermore, the type locality is situated a mere 450 metres from Coal of Africa’s approved Makhado Colliery project. It is also suggested, therefore, that active monitoring be undertaken to avoid habitat degradation that could further endanger this rare tree through the operations of the mine.

The scientific article, Senegalia montis-salinarum, a new species of Fabaceae: Mimosoideae endemic to the Soutpansberg, South Africa, can be accessed by registered users of the Phytotaxa journal website at http://dx.doi.org/10.11646/phytotaxa.244.2.5. 

To read more about the exciting scientific projects being undertaken by the National Research Foundation's Biodiversity Chair at the University of Venda, visit the website: http://vhembebiosphere.org/sarchi/ (Article by Jabu Linden: Vhembe Biosphere Reserve NPC).

Viewed: 4049

Andries van Zyl

Andries joined the Zoutpansberger and Limpopo Mirror in April 1993 as a darkroom assistant. Within a couple of months he moved over to the production side of the newspaper and eventually doubled as a reporter. In 1995 he left the newspaper group and travelled overseas for a couple of months. In 1996, Andries rejoined the Zoutpansberger as a reporter. In August 2002, he was appointed as News Editor of the Zoutpansberger, a position he holds until today.