GLADIOLUS ROBERTSONIAE IN THE BALFOUR DISTRICT OF MPUMALANGA AND THE FRANKFORT DISTRICT OF THE FREE STATE.

Text by Charles Craib
Photographs by Connall Oosterbroek.

SUMMARY.
Gladiolus robertsoniae is amongst the rarest South African gladiolus species known from the Ermelo district of west central Mpumalanga across to the vicinity of Frankfort in the north eastern Free State. The plants inhabit areas of short high altitude grassland growing in heavy black clay soil derived from dolerite.

Almost nothing has been published about the autecology of the plants and little exists in the literature to explain the rarity of the species in its restricted distribution range. Some detailed research was conducted during October 2011, to study the plants in the adjacent Balfour and Frankfort districts. This research comprises some of the data for inclusion in a book on the ways in which habitat changes have affected bulbous and caudiciform flora in South Africa and Namibia.

G. robertsoniae is one of the plants that fares poorly with grazing of the grasslands by livestock, particularly cattle. It also declines sharply in degraded grassland particularly those with a proliferation of annual and perennial weeds. A good amount of the habitat, throughout the distribution range of the species, has also been destroyed by crop farming.

This newsletter focuses on the above problems eliciting reasons which explain the plant’s rarity. In addition some simple practical solutions which may help stem the future decline of this beautiful gladiolus species are discussed.

NEWSLETTER.
In their revision of the South African species of Gladiolus the authors, Lewis et al (1972: 181 – 183) refer to G. robertsoniae as occasional across the highveld of the north eastern Free State and the south eastern Transvaal (now north western Mpumalanga). They comment that knowledge of the species was scanty and that it had only been collected four times between 1932 and 1966. Most of the collections were in west central Mpumalanga with only one in the north eastern Free State, near Villiers. Little novel information on the habitats frequented by the plants or aspects of their distinctive autecology were added in a subsequent revision of Gladiolus (Goldblatt and Manning 1988: 209 – 210).

The most interesting and detailed account of the gladiolus in its habitat was given by Fritz (2010: 44 – 46) concerning plants near Devon in Mpumalanga. He noted that in habitat grazed by cattle the G. robertsoniae grew in positions where they were located amongst unpalatable plants such as Hypoxis rigidula. In these situations they were protected from grazing. In the adjacent road reserve, fenced off from the farmland, the gladiolus were not damaged by the grazing cattle.

The account by Georg Fritz gave a good grounding for the baseline of the present research. It indicated that G. robertsoniae may well be largely a road reserve plant in areas where the grasslands were grazed by cattle.

I am writing a book on habitat changes in South Africa and Namibia and how bulbous and caudiciform flora have adapted to these.  It was evident that G. robertsoniae was ideal for inclusion in this book and field research was consequently carried out in October 2011, near the town of Villiers.

The second half of October 2011 fortuitously turned out to be ideally chosen. Good spring rains had fallen in the first half of October and during the second half of that month plants were in peak flower.

THE HABITATS NEAR VILLIERS.
The habitats all consisted of short grassland associated with heavy black clayey soil. The majority of places where the plants were found comprised open level or slightly undulating areas. The G. robertsoniae also occurred but to a lesser extent, on hillocks or gentle rises with dolerite boulders, stones and some gravel overlying the clay soil. These places were also covered in short grassveld.

All localities examined were within a few kilometres of the Vaal River and its tributaries. The gladiolus was not found growing on the more sandy, less clayey soils east of Villiers. This habitat was suitable in every way but lacked the clay content in the soil. A lack of the species was also found in areas with similar soil between Villiers and Frankfort.

All habitats, except for three beside the N3 motorway and one other, were heavily grazed by herds of cattle. The species has, in effect, become a road reserve plant, in the Balfour and Frankfort districts. These reserves appear to have played a significant role in preventing local extinctions of G. robertsoniae.

THE FLOWERING SEASON OF G. ROBERTSONIAE AND CATTLE GRAZING IN THE SPRING GRASSVELD.
G. robertsoniae has the misfortune of flowering in October when the first spring rains fall and fresh grasses spring up, particularly in veld that has been burnt the previous winter. The flowers are palatable to cattle and their slender leaves and stems readily trampled in places where they are put out to graze. Large herds of cattle grazing in the spring grasslands were evident on all the farms where land had not been put under the plough for crop production. No gladiolus were observed in any of the localities where cattle were grazed. The plants may well be locally extinct on many of these farms but further data still needs to be gathered. In this respect pastures have to be examined after the first summer rains, before cattle are put out to graze. This type of quality data may prove difficult to collect, since it would depend on co-operation of local farmers at a time when cattle farmers are in need of good quality grazing after the winter drought.

THE CRITICAL ROLE OF ROAD RESERVES FOR PRESERVING G. ROBERTSONIAE.
Road reserves in the grassland areas of eastern South Africa play a pivotal role in preserving much of the local flora. They are, or rather have been until recently, free of grazing livestock but subject to winter grass fires essential for the life cycle of grassland plants. In the instance of the gladiolus, grassland burnt the previous winter allows the corms to flower at their optimum. It also permits pollinators to easily reach the flowers in prominent exposed positions, above the short newly emerged grass blades.

In recent times there have been many problems associated with road reserves. Some of the fences have been dismantled by local people who make use of the wire and fencing stakes. As a consequence the road reserves now feel the full impact of grazing livestock. In the Balfour and Frankfort districts the reserves along major roads, such as the N3 and R26, have intact fences. The same applies, at present, to small public farm roads to the north west, north and north east of Windfield.

Road reserves provide a conserved cross section of G. robertsoniae habitat free from grazing livestock. The gladiolus in these places provide in some cases good indications of adjacent farms where G. robertsoniae once used to occur. The road reserves are, unfortunately, very variable in the extent to which they are capable of preserving the gladiolus. Many of them have a proliferation of annual and perennial weeds as well as plants from agricultural crops in a semi-naturalised state, from neighbouring farmlands such as sunflowers. Many of the weeds, particularly the invasive Kikuyu grass Pennisetum clandestinum have transformed sections of several road reserves.

Some of the road reserves are also scraped during road resurfacing, such as the recent resurfacing of the R26. The grading of the reserve, on this occasion, did not eliminate the gladiolus as the blades of the mechanized scraping machines were set high. The G. robertsoniae corms are usually deep-seated in the soil. A deeper scrape could however have eliminated many of the road reserve populations.

Road reserves as conserving agents of local flora are entirely related to the width of grassland they preserve. National highways, such as the N3, keep intact broad stretches of grassland over many hundreds of kilometres. The reserves adjacent to smaller roads, like the R26, are not nearly as broad and consequently preserve much less habitat. The least amount of habitat is kept intact beside minor farm roads and these are rarely more than a few metres wide. Colonies of G. robertsoniae occur beside the N3, scattered groups of occasional plants beside the R26 and a near absence of plants beside nearly all the minor gravel surfaced farm roads.

The N3 near Villiers is inadvertently responsible for the conservation of three very large scattered colonies of the gladiolus. It may well prove that these colonies are amongst the largest in the overall distribution of the species. This awaits further research to the east in west central Mpumalanga near Bethal, Morgenzon and Standerton.

THE GLADIOLUS IN GRASSVELD WHICH EXCLUDES GRAZING CATTLE.
One of the aims in the preliminary survey was to attempt to locate G. robertsoniae in grassland where there were no grazing cattle. This data was needed to compare and contrast with that gathered from road reserve populations.

Two colonies were found from which grazing cattle had fortuitously been excluded. One of them, north east of Windfield is situated adjacent to a national road. The grassland alongside had two fences, one beside the main road and the other about 500 metres away. Cattle were not grazed in this strip of grassland which extends for about a kilometre.

The veld had not been burnt the previous winter and the dry grass cover was fairly dense in most places. The soil was the usual heavy blackish clay free of stones and flat in some places and gently sloping in others. The G. robertsoniae were thinly scattered across the grassland in small groups consisting of some 3 – 10 mature plants and juveniles at the stage where they have one or two leaves. Several flowering size plants in most groups had not flowered and this may have been associated with the dense cover of dry grass. Further data needs to be collected from this locality after a winter veld fire in order to draw the correct conclusions.

The other colony is situated beside the N3 highway in rocky grassland. The veld here too had escaped winter grass fires and the short dry grass was quite thick. The G. robertsoniae were growing in part of a large area, a few hectares in extent between the N3 and the old tarred road to Villiers.  This area had not been grazed by cattle during the flowering season and probably for at least several years beforehand.

The gladiolus were more plentiful than they were at the site near Windfield, but not nearly as numerous as they were in the colonies of the N3 road reserve. It is possible that the plants are commoner in rocky grassland than they are in flatter places with only clayey soil but this requires further research from additional habitats, if this becomes available.

ROAD RESERVE COLONIES OF G. ROBERTSONIAE.
An extensive search was conducted along the road reserves of small gravel surfaced farm roads west of Villiers in the last two weeks of October. The plants were only found at one spot near Helpmekaar in a very narrow road reserve. One plant was in flower with a few young ones at the single leaf stage. This tiny group was in unburnt rocky grassland in a road reserve about three metres wide.

The road reserve of the R26, south west of Villiers, had far more G. robertsoniae than the narrow reserves of farm roads heavily degraded with weeds, in several areas. The groups of plants were widely scattered at three localities, separated from one another by a few kilometres. At the site closest to Villiers, there were a few groups of G. robertsoniae growing in a road reserve that had been mechanically scraped and was temporarily devoid of grasses and herbs. At the same place small groups of gladiolus were in flower amongst short dry grass, which had escaped scraping, about 30 cms before the boundary fence. None were seen in the farmland over the fence which was heavily grazed by cattle.

The most significant road reserve colonies are situated only a few kilometres north of Villiers on the Mpumalanga side of the Vaal River. The two biggest are around the Engen garages, opposite one another, adjacent to the N3. The number of G. robertsoniae here is remarkable and attributable to a combination of several factors. Firstly and most importantly grazing cattle are excluded from the habitat and secondly the veld is burnt during most winters creating ideal conditions for mass flowering and subsequent seeding. Large numbers of plants in flower are very attractive to pollinators resulting in huge amounts of seed being liberated into the environment. These two locations provide a microcosm for in depth autecological studies. Most of the characteristics of habitats excluding grazing by cattle, in existence in the Balfour and Frankfort districts, are encountered here. Amongst these are invasive weeds, particularly Kikuyu grass, disturbed soil with its attendant proliferation of annual and perennial weeds and moderate pollution of the veld with waste cement, bricks and vehicle tyres. The most serious threat at present at both Engen garage sites is slow but progressive transformation of the veld by highly invasive exotic Kikuyu grass. Potential threats to these inadvertently established G. robertsoniae reserves are extensions to the garage complexes such as the establishment of further parking facilities.

The gladiolus, unlike other bulbous flora growing at the same places, avoid disturbed ground with its associated weeds. They only occur in places where the veld is in good condition free from any form of soil disturbance or pollution left over from building activities.

The road reserve colony north of one of the Engen garages extends for about a kilometre and in places contains thousands of gladiolus. These plants probably have a more secure future than in any of the other reserves. Fences have to be kept in good condition beside a national highway and, in consequence, the status and integrity of these places is kept intact.

POLLINATION.
G. robertsoniae is said to be pollinated by moths (Goldblatt and Manning 1998: 30, 210). There are however as yet no direct observations of pollinators at work.

A careful watch was kept for pollinators during daytime visits to all the field sites. Two nocturnal excursions arranged in an attempt to record pollinators at dusk or in the evening were hampered by strong winds and thunderstorms. The moth species, if it is one, responsible for pollination remains an enigma.

The flowers are strongly and spicily fragrant, particularly in the late afternoon and towards dusk. This seems to suggest the likelihood that pollinators are active at dusk or during the course of the night.

A number of indirect observations about pollination could nevertheless be made. Pollination of the flowers at the large colonies was excellent with all or nearly all the flowers on the stem producing capsules of ripening seeds. This is all the more remarkable as visits to the flowers by pollinators during most days in October were curtailed by strong winds during the day and often also at night. In addition rain showers occurred fairly frequently in the late afternoon or at night for much of October, wetting the pollen in the flowers.

There are initial indications that, where the gladiolus is sparse, such as in some road reserves, few plants are pollinated. Further data, collected over several seasons, is needed to confirm this. This would only add to the general problems the species has with surviving in its modern grassland environment.

PRESERVATION OF THE GLADIOLUS IN THE FUTURE.
The easiest way of conserving the species is to alert farmers to its existence in the grasslands, and how susceptible the plants are to destruction and trampling by grazing cattle. It may be that some farmers can be persuaded to keep cattle out of certain parts of the grassland at the time when the gladiolus is flowering and seeding. An intervention as simple as this could secure the future of the species in the general grassland habitat.

Another approach may be to collect seeds in the few places where the plants are common. This seed could be scattered on farms where the gladiolus still occurs, in declining numbers. This approach is more complicated since not only does it require the commitment of farmers but also the development of policies by under-resourced provincial authorities.

THE BOOK ON HABITAT CHANGES – THE PHOTOGRAPHY AND BOTANICAL ART.

One of the main aims in the books I write on the autecology of Southern African plants is to have them lavishly illustrated with photographs, botanical art and pencil drawings. Photographs, taken so skilfully by Connall Oosterbroek, of the plants in their habitats, as well as the countryside where they grow is nicely complemented by botanical art.

In the instance of this book I am very fortunate to have botanical artists Gerhard Marx and Jenny Hyde-Johnson as participants. These talented people are involved with painting many of the rare, little known plants about which little detailed published information exists.

Jenny is busy at present with the watercolour painting of G. robertsoniae. She is particularly interested in ecological relationships and these are frequently featured in her paintings. Jenny spent some hours at the gladiolus site observing and photographing the plants that grow with it in the grassland. This sensitivity to ecology is one of several skills that she contributes to the project via her art.

Jenny’s web site address is www.jennyhyde-johnson.com  The G. robertsoniae painting will be photographed when completed and displayed on her web site in due course.

FURTHER READING.
Georg Fritz has conducted further original interesting research on G. robertsoniae and also taken many high quality photographs of the plants in their habitats. Further aspects of his research are due to be published in Aloe, the journal of the Succulent Society of South Africa. The paper “Accidental Discoveries of some Interesting Plants in southern Gauteng” is scheduled for publication in Aloe 48: 3: 2011. The expected date of publication is late November 2011. Further particulars about Aloe may be obtained from the Succulent Society web site. The address is www.succulentssociety.co.za

ACKNOWLEDGEMENTS.
I would like to sincerely thank Mr. Georg Fritz of Heidelberg in Gauteng for his help with the research and invaluable discussions about G. robertsoniae in the field. Thanks are also due to Connall Oosterbroek for taking photographs of his usual high standard under testing windy conditions in the field. Jenny Hyde-Johnson is thanked for painting the gladiolus as well as her interesting observations and comments about the plants in the field.

REFERENCES.
P. Goldblatt and J. Manning. Gladiolus in Southern Africa, Fernwood Press, Vlaeberg, Cape Town, 1998.
G. Fritz. Surprise Discoveries of some Mesembs in Gauteng, Aloe 47: 2: 2010.
G.J. Lewis, A.A. Obermeyer and T.T. Barnard. A Revision of the South African Species of Gladiolus. Journal of South African Botany, Supplementary Volume No. 10, Purnell, Cape Town, 1972.