Honeybird Botanical Survey a Botanical Record of Lucerne & Oak Grove
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Lucerne & Oak Grove Honeybird Botanical Survey A botanical record of Lucerne & Oak Grove History The Lucerne property was purchased by Godfrey and Helene Coetzee in 1997 from Riaan Lourens father. It had originally been farmed along with Stanford Valley by Christian de Kock. In 2002, Lucerne was officially declared a Private Nature Reserve. Its name was registered as Honeybird Valley Private Reserve. The use of term Honeybird was a mistake by the registration authority; the original intention was to be Sugarbird. Topography Lucerne covers an area of about 510ha. Oak Grove is about 81 hectares. The terrain is in general gently undulating hills and valleys. There are no cliff faces but some rock outcrops on the steeper slopes to the south-east of the property. The highest point of the property is on the south-east boundary at ±330m (34° 25.874’S 19° 34.558’E). The lowest point is at the gate on the R326 at ±40m (34° 24.973'S 19° 32.648'E). Drainage is provided by a number of streams, several of which are perennial. There are natural springs in the area around Oak Grove. All the streams feed ultimately into the Klein River to the north of the property. Fig. 1. General topography of Lucerne and Oak Grove with roads and paths. Land use Of the 510ha of Lucerne, 64ha has been used recently for cereal crops. A further 71 ha has at one time been cultivated. This is almost entirely in the shale area below the road. Exceptions to this are 2ha above the road was cleared and fertilized at one point for a vineyard, but this was never used and an area (2 ha) on the north side of the hidden valley was once used as a trial plot for potatoes. The rest of the property has always remained as natural veld with some flower picking. There has also been occasional use of cattle grazing on the natural veld. There is a scrape area (2ha) on the top of the sandstone that was used by the municipality for construction of the road. Of the 81ha of Oak Grove, over 10ha have been severely transformed but further large areas have evidence from past satellite imagery and onground survey of previous disturbance. Land transformed for residential use is found at two sites on Lucerne (10ha and 3ha) and one at Oak Grove (9ha). Currently no farming practices occur on the property other than cattle and horse grazing. The area around Visdam was left fallow from about 1992. Other areas that had been cultivated until 2014, have been left fallow since the new ownership. An area of 147ha has been fenced for introduction of game. Fig. 2. Satellite imagery with past and current landuse overlaid Fig. 3. Agreed use of land for lease pre 2014 at Lucerne (map courtesy of G. Coetzee) Geology Lucerne spans two major geological formations. On the lower slopes to the north and west of the property, the base rock is clayish shales of the Bokkeveld Group. Above the road the formation is almost entirely rock of Table Mountain Group or sands derived from that group. The municipal road traverses a natural division between the two formations. There is a geological fault line along the road to the house from Visdam. In the valley below the road and around the Stone Pines there are large quantities of ferricrete (koffieklip). Across the middle of the Table Mountain Group is a band of Cederberg Formation that forms a shale band from east to west. To the south of this band the hard Peninsula Formation outcrops, whereas to the north the almost as hard Nardouw Formation is found. Fig. 4. Geology of Lucerne and Oak Grove Rainfall Rainfall is typical of the Western Cape with dry summers and wet winters. However, the difference between the two seasons is more moderate than that on the West Coast, due to a greater degree of summer rainfall. There is some influence due to proximity of the sea but the area does not regularly get sea mists and is drier than Hermanus. Rainfall measurements have been taken almost continually on a monthly basis at Lucerne between 1998 and 2015. The average annual rainfall at this point is 597mm, with a range of 425mm (2004) to 727 (2013). Monthly precipitation peaks in August with an average of 80mm. February is the driest month with only an average 23mm falling. The highest monthly rainfall was August 2013 when 243mm fell. Several months have had 5mm or less recorded. A number of dams around the property store water for irrigation and domestic use. Fig. 5. Average rainfall per month in millimetres 1998–2015 90 80 70 60 50 40 30 20 10 0 Fig. 6. Total annual rainfall over the measured period in millimetres 1998–2015 900 800 December 700 November October 600 September 500 August July 400 June 300 May April 200 March 100 February January 0 2000 2011 1999 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2012 2013 2014 2015 1998 Vegetation Two major vegetation types are found on the farms: fynbos and renosterveld. There are also patches of riparian thicket in the stream valleys. There are no forest patches and the few native trees are restricted to rocky outcrops or near streams in the thicket vegetation. The fynbos is subdivided into Overberg Sandstone Fynbos on the sandstone slopes above the road. Within this is a band of Western Coastal Shale Band Vegetation along the Cederberg Shale which has a mixture of fynbos and renosterveld elements. While below the road Elim Ferricrete Fynbos dominates on the Bokkeveld shales. Where the Elim Ferricrete Fynbos has been degraded the vegetation has turned to renosterveld. The transition between the two main vegetation types, Overberg Sandstone Fynbos and Elim Ferricrete Fynbos, is often obscured by an overlying layer of broken and eroded sandstone above the Bokkeveld shale. This is evident in the area above the Visdam, which shows a transitional fynbos. This transitional fynbos has generalist species found across a wide range of vegetation types (e.g. Protea repens, Cliffortia ruscifolia, Leucadendron xanthoconus). Fire History The largest fire that affected the property in recent years started in January 2006 near Beloftebos and burnt most of the natural vegetation on Lucerne. A more recent fire began at Stanford Valley in 2012 and burnt a small area to the north of the property. Satellite imagery around this time and suggest that a small area at Oak Grove, to the north of the property, just below the road, also burnt. In March 2016, a controlled burn was carried out above the Visdam to encourage the flowering of Moraea insolens. Redlist of Plants A number of plants occur in the farms that are listed on the Redlist of South African Plants. Critically Endangered Moraea insolens Endangered Acrodon parvifolius, Aristea teretifolia, Cyrtanthus leucanthus, Echiostachys ecklonianus, Gnidia humilis, Moraea melanops, Moraea tricolor, Pteronia tenuifolia, Xiphotheca reflexa Vulnerable Berkheya angusta, Cliffortia monophylla, Cyrtanthus carneus, Leucadendron linifolium, Leucadendron platyspermum, Leucospermum cordifolium, Moraea cooperi, Protea aspera, Protea longifolia, Skiatophytum tripolium Near Threatened Aulax umbellata, Freesia caryophyllacea, Geissorhiza nana, Gnaphalium declinatum, Hesperantha radiata subsp. caricina, Ixia stricta, Lachnaea filicaulis, Leucadendron teretifolium, Leucospermum pedunculatum, Leucospermum truncatulum, Merciera leptoloba, Pauridia minuta, Protea compacta, Protea scabra, Serruria adscendens, Serruria elongata, Serruria fasciflora, Spatalla curvifolia Rare Sonderothamnus speciosus Declining Lapeirousia corymbosa, Rapanea melanophloeos Species List To date, 559 species have been identified on the two properties. A further 82 are awaiting formal identification. 26 non-native species have also been recorded. The number of members of grass family, Poaceae, sedge family, Cyperaceae, and restio family, Restionaceae are very poorly recorded to date. Further work is also particularly needed on the pea family, Fabaceae, vygie family, Aizoaceae, and the genus Erica. Cryptogams have not been recorded at all. Achariaceae Searsia rosmarinifolia Kiggelaria africana Searsia scytophylla Aizoaceae Searsia tomentosa Acrodon bellidiflorus Apiaceae Acrodon parvifolius Arctopus echinatus Acrosanthes teretifolia Centella macrocarpa Carpobrotus edulis Centella tridentata Erepsia anceps Chamarea gracillima Erepsia inclaudens* Glia prolifera Galenia herniariifolia Itasina filifolia Lampranthus sp.* Lichtensteinia lacera* Lampranthus pink and white* Lichtensteinia trifida Oscularia deltoides Nanobubon capillaceum Psilocaulon parviflorum Apocynaceae Ruschia sp. creeping* Asclepias crispa Ruschia tenella Aspidoglossum heterophyllum Skiatophytum tripolium Gomphocarpus cancellatus Tetragonia fruticosa Gomphocarpus physocarpus Alliaceae Microloma tenuifolium Tulbaghia alliacea Araceae Amaranthaceae Zantedeschia aethiopica Exomis microphylla Asparagaceae Amaryllidaceae Albuca aurea Amaryllis belladonna Albuca flaccida Boophone disticha Albuca fragrans/goswinii* Brunsvigia orientalis Asparagus africanus Crossyne guttata Asparagus capensis var. capensis Cyrtanthus angustifolius Asparagus declinatus Cyrtanthus carneus Asparagus kraussianus Cyrtanthus leucanthus Asparagus lignosus Haemanthus coccineus Asparagus rubicundus Haemanthus sanguineus Drimia elata Strumaria spiralis Drimia filifolia Anacardiaceae Drimia media Searsia angustifolia Drimia minor Searsia cuneifolia Drimia cf. minor few flowers* Searsia glauca* Eucomis regia Searsia laevigata Lachenalia orchioides Searsia lucida Lachenalia perryae Lachenalia rosea Mairia coriacea Ledebouria ovalifolia Metalasia brevifolia Ornithogalum dubium Metalasia densa Ornithogalum graminifolium