by Oliver Cowan.

Spring in the Overberg: A honey bee buzzes lazily over a field of yellow Canola while in the adjacent Renosterveld a butterfly flits gracefully through the warm air searching for a mate. A closer inspection of a daisy flowerhead reveals a monkey beetle gorging himself – face down, oblivious to the ecologist about to prod him with a pencil to better ascertain the patterns on his back.

Above: Aspalthus barbigera pollinators.

The penultimate chapter of my PhD on the functional ecology of Overberg Renosterveld focuses on pollination. Over 80% of the world’s plant species rely on animals to pollinate them. This quest for survival, for without successful pollination a plant has little hope of passing on its genes, has resulted in the evolution of the varied and wonderful flowers we see today. Some plants form exclusive clubs with a specific type of insect – a process known as specialization (Eg. the long-tongued fly and certain Iridaceae). Others are more welcoming, with many daisies providing food for a variety of visitors who, in return, transfer their pollen to neighbouring plants.

Above: Bee Fly.

Of course, the destruction and fragmentation of natural veld has severely impacted the survival of many plant and animal species. The impact this has had on pollinator-plant interactions is largely untested in the Overberg. My research aims to provide baseline data across 3 study sites in an attempt to gain insight into plant-pollinator interaction. By working in pristine, moderately degraded, and severely degraded patches of veld I hope to discover patterns which will further our understanding of the current state of play.

The methodology is fairly simple if somewhat time consuming: Each flowering species in a site is observed in multiple 30 minute time intervals and during this period each and every flower visitor is identified and recorded.  The results of these many hours spent hoping the insects will find the flowers more interesting than myself will be 3 community pollination webs. Pollination webs are diagrams showing all interactions between plants and their pollinators in a community and are extremely useful tools in predicting the consequences of disruptions such as invasion or extinction. Comparing the pollination webs across the degradation gradient will be fascinating and, amongst other things, reveal whether certain interactions disappear as veld integrity is reduced. For instance, do the more diverse pristine sites support a vastly different insect assemblage to the more depleted and uniform degraded sites? And what impact does an increased availability of alien species have on the pollinator community?

Above: Bee fly on Mestoklema tuberosum

I’ve already spent one Spring bathed in suncream, my thoughts accompanied by the constant buzzing of insects and am currently gearing up for my second Spring and, to be honest, I cannot wait!

by Oliver Cowan.

One of the key aims at the heart of the Overberg Renosterveld Conservation Trust has always been the pursuit of greater knowledge about this Critically Endangered, little known and highly misunderstood vegetation type. To this end a growing number of postgraduate students from multiple institutions have built highly successful research collaborations with the ORCT. The research and visitor’s centre at Haarwegskloof Renosterveld Reserve was humming with activity with visiting students during Spring.

Today we bring you an update on the work of one of those students. Abigail Graham is undertaking her Masters Degree in the Department of Environmental and Geographical Sciences at the University of Cape Town, supervised by Dr. Pippin Anderson and Professor Jeremy Midgley. Abigail is undertaking her Masters research investigating the impact of habitat fragmentation upon diversity of small mammals within Eastern Rûens Shale Renosterveld patches of different sizes. This is important research given that although there is a detailed and growing body of literature on rodent diversity and ecology within Fynbos there have still only been a few studies undertaken on rodents and their ecology within Renosterveld vegetation. We also know little of the impact of fragmentation of Renosterveld in the Overberg through transformation for agriculture upon small mammal populations.

To undertake research on small mammals, first you have to catch them. And this requires time, patience and a little bribery and corruption. Rodents are caught using Sherman traps, which are baited with a mixture of peanut butter and rolled oats. Slices of apple are also placed in the traps to ensure that any rodents caught do not get dehydrated. The traps are wrapped in aerothene sheets to insulate them from the cold and cotton wool is placed in each trap for use as nesting material. Trapping is done overnight and then traps are checked early the following morning and after data collection any caught rodents are released back into the veld. Rodents were trapped within small, medium and large patches of Renosterveld to investigate the effect of patch size upon small mammal diversity.

Six different rodent species were trapped during the course of the study. The most commonly caught rodent was the Four Striped Grass Mouse (Rhabdomys pumilio). Rhabdomys have a wide distribution across all of Southern Africa and are highly adaptable to a variety of different habitat types. Next up was the Namaqua Rock Mouse (Aethomys namaquensis), also occurring throughout the subcontinent with tolerance of a broad range of habitats. Four Bush Vlei Rats were also caught as well as eight Southern Multimammate Mice (Mastomys coucha), three Elephant Shrews and three lesser Dwarf Shrews. Preliminary findings show that the majority of rodents were caught in the medium and large patches, suggesting that the smaller patches are less favourable as small mammal habitats. Further data analyses are still to be undertaken but it is hoped that this will reveal further interesting findings to be reported later.

Habitat fragmentation is one of the greatest ecological challenges facing Renosterveld in the Overberg. It is not known fully to what extent this has impacted upon biodiversity in these Critically Endangered habitat remnants. Preliminary findings from this research also highlights the importance of corridors such as watercourses in the landscape to allow wildlife from insects to rodents to larger mammals to move through the landscape so that patches of veld are not ‘islands’ marooned in a sea of crop monoculture. It is hoped that this work, once complete, will shed a little more light on how well small mammal populations are surviving in the Eastern Rûens. Watch this space for future updates.

The Black Harrier is one of Southern Africa’s most beautiful and charismatic birds of prey. It a graceful, medium sized charcoal-coloured bird with striking white markings, piercing yellow eyes and a long barred tail. The genus name Circus is given in reference to the male’s circling acrobatic display or ‘sky dancing’ flight which is used to impress the female during courtship. The species epithet ‘maurus’ is used to refer to the predominantly dark colouring of the bird. During this flight the males let out a distinctive ‘wheep’ call.

The Black Harrier is a bird of great poignance to the Overberg Lowlands Conservation Trust (OLCT). One may even go so far as to say that the OLCT may not even exist were it not for this beautiful bird. The Trust’s Founder and Director, Dr. Odette Curtis, first became interested in Renosterveld vegetation in the Overberg through studying Black Harriers under the wise supervision of Dr Rob Simmons, Dr Andrew Jenkins and the late Prof Phil Hockey of the Percy Fitzpatrick Institute of African Ornithology. This formed part of the University of Cape Town’s Black Harrier Project, started by Rob, Odette and Andrew at the ‘Fitz’ in 2000. Members of this research group are also designated as the BirdLife Species Guardians of the Black Harrier under the Preventing Extinctions Programme. The main aims of this programme are to assess the biology and monitor the status of this species to inform conservation action.

The findings of Odette’s research formed part of the Black Harrier project and yielded some highly valuable findings of great significance to Renosterveld conservation. Although this project was undertaken some ten years ago its results hold as much significance today as they did when this research was first done. Odette’s work revealed that Black Harriers need a minimum Renosterveld patch size of 100 ha in which to breed. They also use the veld to forage and display. If the Renosterveld becomes fragmented or degraded the Black Harriers will in most cases fail to breed successfully or leave.

The Black Harrier is a bird that needs all the help it can get as its conservation status is fragile owing to loss of habitat due to urbanisation and transformation for agriculture. It is classified as ‘Endangered’ on the latest Red List in South Africa and considered ‘Vulnerable’ at the global scale. There are thought to be no more than 1500 Black Harriers in the world at present with potentially less than 1000 mature individuals remaining. They are endemic to Southern Africa, concentrated predominantly in South Africa’s Western Cape. The range of this species extends across the Eastern Cape, Free State and Northern Cape as well as into Lesotho. There is also a tiny population of less than 50 birds in northern Namibia.

During the 20^th Century the Black Harrier has lost around 50% of its habitat owing to transformation for agriculture. Although they are seen foraging in cereal wheatlands, they struggle to exist and cannot breed here as rodent populations (their primary source of food) are thought to be as little as 33% of that in comparable natural vegetation. In addition, Black Harriers are particularly vulnerable owing to being ground-nesting birds. The main harvest time for wheat is in the middle of the peak breeding season for these birds. Herbicide and pesticide drift is also a significant problem, causing lack of breeding success through low hatching rates. Ingestion of these chemicals is furthermore considered a cause of mortality in adult individuals. Pollution, mismanagement and destruction of vleis, marshes and streams near breeding grounds is considered to be a further threat. In the Overberg only 5% of the former extent of Renosterveld vegetation remains, and loss of this habitat has thought to have brought about a reduction from a total of an estimated 1500 breeding pairs living across the region historically being reduced to a total of only around 60 pairs.

The purchase of the Renosterveld and farmstead at Haarwegskloof Farm in the eastern Overberg by the World Wildlife Fund (WWF) and its latter designation as a nature reserve is of great importance to Black Harrier conservation. The veld at Haarwegskloof is one of the world’s biggest pieces of Renosterveld, therefore making it critical Black Harrier habitat. Protected areas are considered one of the last strongholds for breeding for these birds. This was immediately recognised by Dr Rob Simmons and as a long term friend and supporter of the Trust he was instrumental in fundraising for the conversion of the old derelict farmhouse at Haarwegskloof to a research and visitor’s centre for Renosterveld. A significant donation was made from the Black Harrier Project to support this work. This vital contribution has been recognised through the naming of one of the rooms in the centre at Haarwegskloof ‘the Black Harrier Room’.

Soon after the building work was completed and the Centre first came into use we were delighted and overjoyed to discover that no less than three pairs of Black Harriers were breeding in the reserve. This is a wonderful measure of the incredible biodiversity and ecosystem health of this amazing site. Now thanks to WWF, the Overberg Lowlands Conservation Trust and its other supporting partners the conservation of Haarwegskloof Renosterveld Reserve is secured in perpetuity. Long may visitors have the privilege of seeing Black Harriers ‘sky dancing’ over the reserve.

The Watercourse Restoration Project is in full swing with surveys of priority watercourses within the Overberg wheatbelt.

Spectacular renosterveld remnants have been incredibly productive with biodiversity surveys and GIS mapping being conducted over the past few weeks. This means the hardship of fieldwork during the spring and onset of summer has been a ‘burden’ happily borne.

Avifaunal surveys have yielded records of threatened species such as Black Harrier, Denham’s Bustard, Blue Crane, Southern Black Korhaan and Cape Vulture, to name a few. The botanical species have been too numerous to list in detail, but standout species that deserve mention include Polhilia brevicalyx, Moraea debilis, Moraea comptonii and Dronsanthemum flavum. All indicators of the wealth of the renosterveld remnants.

Spring has sprung in the Overberg. The weather is growing warmer, plants are flowering in the Renosterveld and humming with a diversity of insect pollinators. It is a time for us to be busy and a time for new beginnings. It is also time for the launch of the OLCT’s latest conservation initiative.

Watercourses (namely rivers, streams and seepages) form a critical component of biodiversity and ecosystem function. Equally important is the riparian buffer zone adjacent to the watercourse itself, which when ecologically intact regulates water quality and acts as an important habitat, forming corridors of natural vegetation for wildlife, including pollinators, to move through transformed agricultural landscapes.

Sadly many of the watercourses in the Rûens wheat belt of the Overberg are threatened and have been significantly degraded by mismanagement. Numerous rivers, streams and wetlands have been invaded by alien invasive vegetation, suffer problems from soil erosion and water pollution or have destroyed by ploughing.

The OLCT has just received a significant grant from the Nedbank-WWF Green Trust to start a new project focusing on restoration of degraded watercourses within the Overberg Rûens. This initiative shows great promise as watercourses show far greater restoration potential than surrounding Renosterveld vegetation in the area. This will involve a long term experimental research programme to develop capacity and inform best practice on watercourse restoration in the Overberg alongside extension work to raise awareness of the importance of looking after watercourses on their farms and assist landowners with implementing management interventions.

We would like to welcome our new team member Keir Lynch, as the OLCT’s Project Manager on the Watercourse Restoration Project (which currently spans three years, although we hope to make this permanent). He brings to the Trust significant experience and expertise, formerly working with CapeNature as their Stewardship Extension Officer. Keir was involved in implementation of CapeNature’s Protected Area Expansion Strategy, which included assessments of critical biodiversity areas, extension with landowners and proclamation of Nature Reserves. Prior to holding this post he has worked in wildlife management at Sanbona Wildlife and Shamwari Game Reserves. We welcome Keir on board and look forward to working with him on the development and implementation of this exciting new project.

Renosterveld is one of the world’s most species diverse Mediterranean type shrublands. It is also one of the world’s most threatened ecosystems. At the southernmost tip of Africa, the Overberg Lowlands Conservation Trust is working hard to conserve what remains of this Critically Endangered habitat, of which only 5% now remains. Most has been lost due to conversion to agricultural lands, becoming a monoculture of crops such as wheat and canola.

The Millennium Seed Bank (MSB) based at the UK’s Royal Botanic Gardens Kew is one of the world’s largest plant conservation initiatives. Their aim is to bank seeds from 25% of the world’s plants by 2020 in collaboration with a network of local partners from around the world. Seeds are dried and stored at -20°C to facilitate long term preservation.

Staff from MSB have this last week begun collecting in the Renosterveld of the Overberg in order to bank seed from some of the region’s most rare and threatened species. The team have gotten off to a flying start, with numerous new collections made.

The most exciting of these is Polhillia curtisiae. This beautiful shrub from the Pea Family (Fabaceae) was discovered to be new to Science only in 2013. It is Critically Endangered and known only from the Eastern Overberg where just 80 plants remain. To have seed from this species conserved ex-situ provides a little extra assurance of its survival into the future.

The landscapes of South Africa’s Overberg region are characterised by rolling hills (known as the Ruggens or Rûens) comprising a mix of both commercial agricultural farmland and fragments of the original Renosterveld vegetation, often in areas where the ground it too steep or rocky to plough. The agricultural lands of the region are farmed with a mix of crops such as wheat, barley and canola on a rotation with fodder crops for grazing by domestic livestock such as sheep and cattle.

At present farmers rely largely on introduced species such as Lucerne and Medicks as fodder crops for their livestock. The quality and successful growth of these fodder crops are of prime importance to farmers as this determines livestock health and productivity. However, with changing climates this region is forecast to become much drier with increasing temperatures forecast in future. This has therefore raised the concern that the existing introduced fodder crops, which are dependent on good winter rains, may not grow successfully in the Overberg in future or the crop may fail more often, thus requiring costly re-sowing and a loss of productivity due to drought stress from these forage crops once they are established.

The main aim of this research is to investigate the palatability of plants which are native to the Renosterveld vegetation of the Overberg in order to look at their potential for use as pasture crops for livestock grazing instead of introduced non-native species. It is likely that plant species native to the region are likely to be far more drought tolerant than the current legume species used, such as Lucerne (Medicago sativa) and will grow with less need for chemical fertilisers, thus saving money and being better for the environment.  Use of native legume pasture crops also may in future create potential for more permanent artificial pastures which are not ploughed up after 8-10 years as is the case with current pasture crops used.

This study, which will be conducted on 9 farms in the Overberg region, aims to understand the chemical components of selected native palatable vegetation (legume and non-legume species) to determine their palatability and nutritional value to livestock. It is hoped that these palatable native plant species which are well adapted to withstand the associated climate conditions will ultimately be used as livestock fodder to supplement the introduced non-native pasture crops currently used.

The study objectives for the project are: (1) To evaluate the nutritive value of selected native palatable legumes and non-legume species in the Overberg lowlands. (2) To determine the seasonal variation (autumn and spring) of the nutritional quality of these native palatable species. (3) To determine the soil chemistry and its effects on the nutritional quality of the native palatable species. (5) To inform the policy makers (Western Cape Department of Agriculture) and farmers, so that improved decision-making processes may be implemented with regards to the increasing the productivity and grazing potential in the previously-farmed Overberg lowlands.

For this research various native plant species were selected to analyse their nutritional quality. These species were then categorised into two groups: Legumes (nitrogen-fixing species that belong to the pea family) and non-legumes (such as grasses and daisies). To determine the nutritional quality of my selected native plant species a suite of different chemical parameters will be analysed.

Thus far I have completed two successful field seasons while staying at the new research centre at Haarwegskloof Renosterveld Reserve. Fieldwork involved visiting various farms across the Overberg and collecting samples of the plants selected for use in the study as well as soil samples for later analysis. I am currently working on grinding samples in the lab pending further analysis. I would like to thank the Trust for their collaboration and research support as well as NRF for project funding, Dr Samson Chimphango and Dr Igshaan Samuels for supervising this research as well as Jannie Groenewald and Zoë Poulsen for assistance and advice during data collection. I hope to report on results within the next year.

Education, ecology and endemism: Unravelling the mysteries of the Overberg’s Quartz Fields

South Africa’s renosterveld is one of the country’s most under-researched vegetation types. There are still many secrets yet to be revealed about its flora, fauna and ecology. Renosterveld was originally thought to be a relatively homogenous vegetation type but more recent research has revealed that this assumption couldn’t be further than the truth. Renosterveld is now recognised as one of the world’s most species-diverse Mediterranean-type shrublands and is considered a priority for research to better understand its ecology and to inform management practice.

This need has brought about the formation of an exciting new international research collaboration for the Overberg Lowlands Conservation Trust, led by Associate Professor Muthama Muasya from the Department of Biological Sciences at the University of Cape Town (UCT). Other team members will include Dr Samson Chimphango (UCT), Professor Charlie Stirton (Special Advisor to the Board of Trustees), Dr Odette Curtis (Trust Director and Founder) and Dr Ute Schmiedel from the University of Hamburg in Germany. Jannie Groenewald will be undertaking his PhD as a key component of the project.

Jannie finished his MSc at Stellenbosch University in 2014 looking at the biodiversity and ecology of Rûens Silcrete Renosterveld and shortly afterwards joined the Overberg Lowland Conservation Trust as Manager of the new Haarwegskloof Renosterveld Reserve. His research will be focussing on deepening our current knowledge of the floristic composition and ecology of quartz patches in Overberg Renosterveld.

These quartz patches form ‘islands’ of differing geology within Rûens Shale Renosterveld and Rûens Silcrete Renosterveld. They are characterised by a unique flora with exceptionally high levels of endemism with species which are predominantly absent from the surrounding vegetation. In 2013 Dr Odette Curtis and colleagues published taxonomic descriptions of no less than six new species endemic to these quartz patches, including the prostrate Aspalathus quartzicola and sedge Ficinia overbergensis. In addition, the Critically Endangered Hesperantha kiaratayloriae was also discovered growing in this habitat and to date only one population of this beautiful geophyte is known.

Our understanding of the ecology of these quartz patches is still limited and this will form the focus of Jannie Groenewald’s PhD research. To date the Overberg’s renosterveld quartz patches have not been comprehensively mapped and undertaking this task will form part of the project.  This research will also help in attaining a better understanding of the role of environmental factors such as soils in determining the assemblages of the unique plant communities of these quartz patches. Comparisons will be drawn between quartz patches in the Overberg and others elsewhere in South Africa within Klein Karoo and Succulent Karoo vegetation.

Recently a collaborative fieldtrip for the project was held in the Knersvlakte in Namaqualand, home to some of the largest quartz fields in Southern Africa. The trip offered an excellent forum for exchanging ideas and knowledge between different members of the team and a highly enjoyable time was had by all. We will report regularly and provide feedback on what will be learnt as the project grows and develops. Watch this space…..

Autumn has arrived in the Overberg. The nights are drawing in and becoming cooler and planting season is well underway for the farmers. The renosterveld seems dry and brown at this time of year, awaiting the coming of the winter rain. It seems that there is little to be seen in the veld at this time of year, but a closer inspection reveals some of the beautiful flowering bulbs that are to be found, bringing colour to the dry autumn landscape.

 

First up is Haemanthus sanguineus, more commonly known as the paintbrush lily or April Fool, after its most common flowering time. It flowers most often after fire, producing its bright red flowers first from a bulb the size of a tennis ball before the leaves emerge later during the season. They are found at seasonally moist sites on rocky areas, sandy plains and slopes in a wide variety of habitats.

The genus Haemanthus is endemic to Southern Africa in Namibia, South Africa, Lesotho and Swaziland and comprises a total of 22 species. Haemanthus bulbs were some of the first plants to be collected from the Cape by Dutch colonists and were cultivated in the Netherlands as early as the 17^th Century. However, despite becoming known as the ‘Cape Tulip’ they failed to gain any popularity in cultivation.

Despite the highly toxic nature of the bulb, Haemanthus sanguineus has a variety of different medicinal uses. Early records report its use for treating ulcers and also in the treatment of asthma. An extract from the bulb was also traditionally used as a diuretic.

Another common sight in autumn at seasonally moist sites is Amaryllis belladonna. This species also flowers most profusely after fire. The name means ‘beautiful lady’ but this bulb is also known as the naked lady owing to the growth of the inflorescence at the head of a bare stalk. The flowers are most strongly scented in the evening, attracting moths as pollinators, but during the day they are commonly visited by Carpenter bees.

One of the largest and most spectacular of all the autumn bulbs is Brunsvigia orientalis. The bright red inflorescence which emerges prior to the leaves can reach as much as 40cm in diameter. The genus Brunsvigia was named by Heister in 1753 in honour of the Duke of Brunswick.

This year we have been treated to the sight of Boophone disticha flowering at Haarwegskloof Renosterveld reserve. These large geophytes from the Amaryllidaceae family do not flower annually and can take as long as ten years to flower from seed and so it is a precious sight to treasure. The flowers are pollinated by bees and flies but also are sometimes visited by ants. The bulb is highly poisonous and the name Boophone is derived from the Greek words ‘Bous’ meaning ox and ‘phone’ meaning death. It is known to be poisonous to sheep and cattle.

Boophone disticha has a variety of different medicinal uses. The Khoi San traditionally used the poison from the bulbs for the tips of their arrows. The outer covering of the bulb has been used to treat boils and abscesses. This species has a wide distribution throughout South Africa and as far north as Uganda. However, it is declining in its natural habitat owing to a combination of habitat loss and collection for muthi or traditional medicine. Within South Africa trade is thought to amount to as much as 1.6 tonnes annually.

Also flowering on the reserve is Nerine humilis. This is a relatively common autumn bulb in the Overberg’s renosterveld vegetation but there are several unusual forms. At Haarwegskloof Renosterveld Reserve we have a very special form with a particularly long reproductive parts (stamens and styles). This is thought to be an adaptation to a specific pollinator but more research is needed to find out what insect this may be. For now it remains a mystery……