Schoenefeldia transiens ( Poaceae ) : Rare new record from the Limpopo Province , South Africa

http://www.abcjournal.org doi:10.4102/abc.v44i1.325 Background: Schoenefeldia is a genus of C4 grasses, consisting of two species in Africa, Madagascar and India. It is the only representative of the genus found in southern Africa, where it was previously only known from a few collections in the southern part of the Kruger National Park (Mpumalanga Province, South Africa), dating from the early 1980s.


Introduction
Schoenefeldia Kunth (1830:283) is a genus of C 4 grasses, consisting of two species in Africa, Madagascar and India (Watson & Dallwitz 1994).Schoenefeldia transiens (Pilger) Chiovenda (Chiovenda 1916:186;Pilger 1914: 418) is known from Ethiopia, Somalia, Sudan, Kenya, Tanzania, Uganda, Mozambique, Zimbabwe and South Africa (Clayton et al. 2014).It is the only representative of the genus found in southern Africa, where it was previously only known from a few collections in the southern part of the Kruger National Park (Mpumalanga Province, South Africa), dating from the early 1980s (see details under 'Additional specimens examined' below).No other specimens collected between 1982 and the current collection (2014) could be found.
A specimen of S. transiens was collected between Musina and Pontdrift, about 30 km east of Mapungubwe National Park, in the Limpopo Province of South Africa.This is not only a new distribution record for the quarter degree grid (QDS: 2229BA), but the first record of this grass in the Limpopo Province.As the collection reported on here was made in an area that is exploited by coal mines, the conservation of this species in the Limpopo Province is not secure.awns flexuous, curving gracefully, becoming entangled with awns of other spikelets (Cope 1999;Gibbs Russell et al. 1990); anther 0.7 mm -1.0 mm long (Figure 1).Flowering January to February.Reported to be cleistogamous.

Distribution and ecology
Schoenefeldia transiens occurs in southern Africa in the Mpumalanga and Limpopo Provinces of South Africa, and northwards through to East Africa, Ethiopia, Somalia and Sudan (Figure 2).The newly recorded S. transiens population in the Limpopo Province is situated in the Limpopo River The new population of S. transiens occurs in Colophospermum mopane woodland on relatively seasonally flooded flats, in heavy soil, such as shallow loamy sandy soil that is associated with a high percentage of sandstone and quartzite surface rocks and outcrops (Figure 3).The habitat slope is between 5° and 10°, with a predominantly northern aspect.The woody component of the habitat is dominated by trees and shrubs that are mostly between 2.2 m and 0.8 m (average 1.5 m) high.The grass and herbaceous layer is only moderately to poorly developed due mainly to the shallow rocky nature of the substrate.

Conservation status and habitat sensitivity
The frequency of S. transiens in southern Africa is rare.
Although the habitat of the new population itself is not considered to be particularly sensitive, it is under imminent threat of destruction as a result of current open cast coal mining activities in the direct vicinity of the newly recorded   population.A strong suspicion exists that the population has already been fragmented and partially destroyed because of mining activities.Depending on the future planning of mining activities, the whole population is under serious threat of total destruction.It is therefore proposed that this population of S. transiens be considered to be of conservation significance, and it should be made a high priority in the overall environmental management programme of the mining company that owns the land.It is the view of the authors that if this population is lost as a result of carelessness or ignorance by either the relevant conservation authorities or the current landowner (i.e. the mining company), it will be a loss not only to our natural heritage, but also a loss in terms of the gene pool of this species and to the biodiversity of the southern African region.
Valley between Musina and Pontdrift, on the farm Over Vlakte 125 MS.It grows on a north-facing hill slope approximately 1 km south of the Limpopo River.Coordinates of specimens and sub-populations of the larger population of S. transiens on the farm Over Vlakte 125 MS in the Limpopo River Valley are 22°08′58.3′′S, 29°40′ 49.7′ E and 22°09′01.9′′S, 29° 40′39.6′′E.

FIGURE 1 :
FIGURE 1: Schoenefeldia transiens, depicted in, (a) habit (the growth form of the plant) and (b) lemma (the lower of two bracts enclosing the grass flower or floret).

FIGURE 2 :
FIGURE 2: Known distribution range (•) of Schoenefeldia transiens in southern Africa, with the black arrow indicating that further populations can be found to the north.