Introduction to the Karoo Special Issue: Trajectories of Change in the
Anthropocene§
Joh R Henschel1* , M Timm Hoffman2 and Cherryl Walker3
ABSTRACT
The Karoo is an arid to semi-arid area across the western third of South Africa, comprising the Succulent Karoo and Nama-Karoo biomes. Its environment and people have experienced considerable changes, and now face new challenges as the Anthropocene unfolds. This Karoo Special Issue (KSI) brings together new information in 20 papers, a mixture of reviews, research articles and commentaries, significantly adding to previous syntheses of Karoo knowledge. The KSI comprises several sections focusing on different aspects of change, namely a lead article that provides an overview of social and environmental changes, followed by papers concerning changes
over time from deep history to contemporary conditions (Xhaeruh to Karoo), insights from long-term studies at several sites across the area, different perspectives of ecosystem processes, and ending with a set of reflections and proposals for research priorities. We end this introduction by dedicating the KSI to two outstanding scholars of the Karoo: Dr Suzanne J Milton and Dr W Richard J Dean. These KSI papers, many of which were written by their colleagues, friends and former students, represents a Festschrift that celebrates and honours their research as well as the inspiration and leadership they gave to a generation of scientists.
Keywords: Festschrift, Nama-Karoo, Richard Dean, social-ecological systems, Succulent Karoo, Suzanne Milton
Drivers and trajectories of social and ecological change in the Karoo,
South Africa§
Cherryl Walker1*, Suzanne J Milton2,3 , Tim G O’Connor3, Judy M Maguire4 and W Richard J Dean2,3
ABSTRACT
This review article explores past, present and possible future drivers of change in Karoo social-ecological systems. Biogeographically, the Karoo comprises the arid Succulent Karoo and Nama-Karoo biomes covering significant portions of the Northern Cape, Eastern Cape and Western Cape provinces and a smaller part of the Free State. Despite the Karoo’s specific environment and spatial importance nationally (covering some 30% of South Africa), no government structures address its needs holistically. Today it is a politically and economically marginalised region; perceptions of it as a desert easily morph into perceptions of it as deserted and ripe for exploitation for the benefit of external constituencies, whether in the name of astronomy, shale-gas and uranium mining or renewable energy. To manage the Karoo better for present and future generations, it is clearly desirable for social and natural scientists to work collaboratively, yet there is relatively little interdisciplinary work to date. Against this background this review article provides an overview of social and ecological changes historically and in the present, and offers some cautious reflections concerning climate change, changing land use and governance as key drivers affecting trajectories of change into the future.
Keywords: change, interdisciplinary research, Nama-Karoo, social-ecological systems, Succulent Karoo
Before the Anthropocene: human pasts in Karoo landscapes§
David Morris
ABSTRACT
Karoo landscapes today are replete with evidence of recent human impacts. The Karoo is relatively pristine in the South African imaginary, but it is not untouched. Social and historic change in the last 300 years has been dramatic. The article looks to the evidence of human lifeways and land-use patterns in Karoo landscapes from the deeper past, from before this modern era. In contrast to the ‘fabric heavy’ traces of the colonial period – farmsteads and SKA dishes – those reflecting earlier human inhabitation are generally ‘fabric-light’ and ephemeral, with the odds stacked against their survival in the archaeological record. The Karoo also has a relatively low level of archaeological survey coverage. Yet, where studies have been conducted, research testifies to a remarkable richness in archaeological and rock art heritage, a millennia-long record of non-farming stone-toolusing people. The nineteenth-century Bleek–Lloyd archive of |Xam folklore from the region contains insights into precolonial animist perspectives on living in these landscapes, perspectives which also challenge the distinction conventionally made between ‘the social’ and ‘the ecological’.
Keywords: archaeology, land use, Nama-Karoo, Northern Cape, South Africa
An overview of themes in the agrarian and environmental history of the
Karoo since c.1800§
William Beinart
ABSTRACT
This article explores some themes in the agrarian and environmental history of the Karoo since 1800. It argues that environmental change cannot be understood without incorporating social, economic and political history. This is especially so in the case of the Karoo because the landscape and ecology was transformed by intensive commercial livestock production in the nineteenth and twentieth centuries. The scale and economic significance of sheep farming and wool production up to the 1960s is generally underestimated in histories of the Cape and South Africa. The article outlines the patterns of economic growth and also the technologies required, such as fencing and water provision. The environmental impact of intensive livestock farming was recognised from the late eighteenth century and new scientific approaches helped to define understandings of environmental change. Environmental degradation was at its height in the first half of the twentieth century; simultaneously, conservationist ideas were developed and gradually implemented. In the second half of the twentieth century, these approaches, together with socio-economic factors that led to lower levels of stocking, resulted in a stabilisation and even some environmental recovery.
Keywords: conservation, environmental degradation, environmental stabilisation, Karoo agrarian economy
Long-term changes in land use, land cover and vegetation in the Karoo
drylands of South Africa: implications for degradation monitoring§
M Timm Hoffman1* , Andrew Skowno2, Wesley Bell1 and Samukele Mashele1
ABSTRACT
We used several large data sets at a range of temporal and spatial scales to document the land-use/land-cover change (LULCC) dynamics of the semi-arid Succulent Karoo and Nama-Karoo biomes of South Africa. More than 95% of the Karoo is comprised of land classified as Natural, which has been relatively stable since 1990. Over the last 100 years cultivation, as well as the number of domestic livestock, has declined significantly in both biomes. Protected areas have increased since 1980 to comprise nearly 8% of the Succulent Karoo biome, although they only cover 1.6% of the Nama-Karoo biome. There has been a significant recent increase in renewable energy installation applications, which cover 4% of the Karoo drylands. The trend in vegetation productivity (NDVI; 1982–2015) is unchanged over 90% of both biomes, while nearly 10% of the Karoo has shown a significant increase in NDVI trend. An analysis of repeat photographs shows that vegetation cover has either remained unchanged or has increased at most locations. Although the Karoo drylands appear less degraded than they were in the mid-twentieth century, on-going monitoring at different temporal and spatial scales is essential to evaluate the future impact of LULCC on these semi-arid environments.
Keywords: desertification, land cover change, NDVI, remote sensing, repeat photography
Linear structures in the Karoo, South Africa, and their impacts on biota§
W Richard J Dean1,2*, Colleen L Seymour1,3 and Grant S Joseph1,4
ABSTRACT
Linear structures include fences, roads, railways, canalised water ways and power lines, all man-made. Fencing as a way of managing livestock began in the late 1800s, and by the early twentieth century was almost fully implemented throughout the Karoo sensu lato. The advent of these fences, and now in many instances, ‘game proof’ (~2 m high) and electric fences have impacted native flora and fauna in various ways. Roads influence the quality and quantity of vegetation along corridors throughout the Karoo, with impacts on wildlife through increased mortality, but also provide foraging opportunities. Road-side structures, such as transmission poles, offer nest
sites and perches in otherwise treeless landscapes, benefiting certain avifauna. Railway lines create similar corridors, carrying ungrazed vegetation along them. Their associated structures – culverts and (historically) steel frame bridges – provide nest sites for birds and some mammals. Transmission cables and pylons along power lines have mixed benefits to conservation, providing bird nest and perch sites, but can also cause bird mortalities. Unquestionably, these linear structures have had marked effects on the biota of the Karoo, through their effects on wildlife and livestock movement and mortality, plant demography and the spread of native and alien species.
Keywords: fencing, high tension pylons, railways, roads, road verges
By their own bootstraps: municipal commonage farmers as an emerging
agrarian class in the Karoo§
Doreen Atkinson* and Mark Ingle
ABSTRACT
Municipal commonage land in South Africa is currently utilised by resource-poor black and coloured farmers. This paper analyses information from two case studies – the Karoo towns of Carnarvon and Williston in the Northern Cape. By comparing data between 2009 and 2018, we show that a significant number of these commonage farmers have increased their livestock holdings. In addition, several have moved their livestock onto ‘new’ commonage farms, purchased by Government, or on land leased from white commercial farmers. We argue that the concept of ‘economic class’ needs to be reintroduced to South African development analysis. The paper compares these proto-commercial farmers with the ‘kulak’ farmers of Russia in the early twentieth century (before the Soviet regime) and the early twenty-first century (after the collapse of communism). We concur with Russian authors that the emergence of new commercial farmers may constitute a new economic class. In South Africa, the situation is of course divergent, given that a strong class of commercial farmers exists. We suggest that the commonage farming phenomenon can make a contribution to current South African land debates.
Keywords: Carnarvon, Karoo, kulaks, municipalities, Williston
Reflections on the Karoo Special Issue: towards an interdisciplinary
research agenda for South Africa’s drylands§
M Timm Hoffman1* , Cherryl Walker2 and Joh R Henschel3
We begin this essay with reflections on major research themes highlighted by the Karoo Special Issue (KSI). These include concerns over land-use change, long-term monitoring, climate change, governance and the need for more interdisciplinary research. We also identify some of the novel contributions of the KSI around these themes and highlight research issues that require further attention. These include greater focus on the social-ecological impact of large-scale infrastructural developments and wildlife ranching, as well as the need for more longitudinal studies related to contemporary social issues. We conclude by outlining a simple framework for thinking about
interdisciplinarity in future research efforts in the Karoo. The first axis relates to the natural science/social science continuum, while the second is concerned with the continuum between basic and applied science. Greater awareness of these two dimensions could not only encourage researchers to reflect more carefully on where their
research fits in relation to the broader research needs of this region but could also promote interdisciplinarity
within the research community. It could also bring researchers closer to the realities and needs of the people who
live in and derive their livelihoods from Karoo environments.
Keywords: applied research, interdisciplinary research, land-use change, social-ecological systems, sustainability
Population change in the Karoo§
Trevor Hill1* and Etienne Nel2,3
ABSTRACT
In common with arid and semi-arid areas worldwide, South Africa’s Karoo has experienced significant population shifts over the last 100 years. These have been caused by a range of considerations related to advances in farming technology and changing labour needs, transport improvements, environmental considerations and contextual economic variables. This paper pays attention to how, in the twentieth century, these factors catalysed net population loss in the Karoo’s rural areas but population gain in all categories of urban settlement, particularly the larger centres. An exception to this was the phenomenon of ‘shrinking towns’, which became discernible in the late twentieth century. In the twenty-first century the process has become more complex, as small towns’ decline has now been reversed and all towns are now attracting rural and inter-regional migrants in the post-apartheid years. We comment on the potential causes, nature and effects of these variations in the Karoo, and discuss the key role of these towns as they reflect the dynamic socio-economic and environmental shifts witnessed in the region.
Keywords: Karoo, population, urban
Spatial, temporal and attitudinal dimensions of conflict between predators
and small-livestock farmers in the Central Karoo§
Marine Drouilly¶*, Marion Tafani¶, Nicoli Nattrass and Justin O’Riain
ABSTRACT
Conflict between predators and small-livestock farmers is a global phenomenon adversely impacting the preservation of wildlife, the well-being of livestock and human livelihoods. Such conflict is pervasive in the Karoo region of South Africa but its contemporary history and various causes remain poorly understood. In this study, we interviewed 77 small-livestock farmers in the Central Karoo between July 2014 and March 2015 to (1) assess the spatio-temporal distribution and severity of the reported predation problems with the main regional predators of livestock (black-backed jackal, caracal and baboon) and (2) describe the perceived reasons for changes in predator
numbers. Farmers reported that serious predation problems have increased since the 1990s for all three predators. Jackal predation appears to have re-emerged, particularly since the 2000s, while baboon predation seems to have escalated rapidly since 2014 for select farmers. Farms with more rugged terrain were more likely to experience serious problems with baboons and caracal but ruggedness did not predict the year of onset of problems. Farmers perceive predator numbers to be increasing and attribute this trend to declining government support for predator management, changes in farming practices and the associated increase in suitable predator habitat, from which they can recolonise commercial farms.
Keywords: black-backed jackal, caracal, chacma baboon, questionnaire, rangelands
Interactions of grazing and rainfall on vegetation at Grootfontein in the eastern Karoo§
Justin CO du Toit1* , Tshililo Ramaswiela2, Marco J Pauw2 and Tim G O’Connor3
ABSTRACT
Rainfall and grazing are primary drivers of vegetation composition in the Nama-Karoo. Increased rainfall increases grassiness, to where Nama-Karoo transitions to grassland. Severe grazing treatments (e.g. continuous or summeronly) increase abundance of grazing-tolerant dwarf shrubs and annual grasses, and decrease perennial grasses. Grootfontein, which is ecotonal between the Nama-Karoo and Grassland Biomes, houses long-term grazing trials. The area has experienced higher-than-average rainfall in recent decades. Plant basal cover data from the 1960s and 2010s allow several hypotheses to be addressed: (1) historical severe grazing (until 1985) will limit subsequent grassiness (grazing legacy effect); (2) severe grazing will preclude increases in grassiness, independent of rainfall (herbivore trap effect); and (3) historically leniently-grazed sites will transition to grassland with increased rainfall (biome shift effect). Rainfall was lower from 1957–1966 (350 mm) than from 2003–2012 (490 mm). The grazing legacy effect was supported based on the abundance of Aristida diffusa, despite all sites becoming much grassier. The herbivore trap effect was not supported. The biome shift effect was supported in that shifts to grassland sometimes occurred. Results suggest that increasing rainfall has prompted a shift to much increased grassiness and decreased abundance of dwarf shrubs, and that grazing had a smaller secondary effect.
Keywords: biome shift, grassy dwarf shrubland, grazing legacy, herbivore trap, Nama-Karoo
Long-term impacts of livestock grazing and browsing in the Succulent Karoo:
a 20-year study of vegetation change under different grazing regimes in
Namaqualand§
Elelwani Nenzhelele1,2*, Simon W Todd3 and M Timm Hoffman4
ABSTRACT
This study used a fence-line contrast approach to investigate the long-term impact of high grazing pressure on the vegetation at a site in Namaqualand, South Africa. Forty pairs of permanently marked plots were surveyed in 1996, 2006 and 2016. The main objective was to investigate changes in the vegetation structure and species composition between the near-continuously grazed communal rangelands and the relatively lightly grazed commercial rangelands over the 20-year period. The results showed a decline in total vegetation cover in both commercial and communal rangelands in 2016 relative to the two earlier sampling periods. This can be attributed to the low rainfall in 2016 and was due largely to a reduction in annual plant cover, especially on the communal rangeland. Perennial shrub species provide a fodder bank that can be utilised by livestock in times of drought and can buffer short-term deficits in forage supply. However, the annuals that dominate the vegetation of the communal rangeland do not form such fodder banks and consequently do not have the same multi-year buffering capacity as perennial shrubs. This provides the mechanism whereby long-term continuous grazing decreases resilience to rainfall fluctuations and increases livestock variability, thereby promoting non-equilibrium-type dynamics in the system.
Keywords: communal rangelands, dryland degradation, fence-line contrast, herbivory, species richness
Long-term vegetation change (>20 years) in the plains habitat on the Goegap
Nature Reserve, Succulent Karoo, South Africa§
Margaretha W van Rooyen1,2* , Annelise le Roux3, Helga van der Merwe2 , Noel van Rooyen4 and Conrad
Geldenhuys5
ABSTRACT
Because vegetation change in arid ecosystems is slow, long-term data are essential to gain an understanding of how the vegetation responds to short-term, inter-annual variation in rainfall; long-term cyclic rainfall patterns; and grazing pressure. The point intercept method was conducted annually over a period of more than 20 years at five transects in the plains habitat on the Goegap Nature Reserve in the Northern Cape, South Africa. Vegetation change was assessed in terms of vegetation cover, species composition, species abundance, growth form composition, range condition and plant diversity. Non-metric multidimensional scaling was used to illustrate the trajectories in floristic data and to determine the strength of the correlations with rainfall and grazing variables. The effects of the high grazing pressure on the plains were apparent in the overall decrease in total plant cover and reductions in the cover of grazingsensitive species
over the monitored period. Diversity parameters, of especially the annual component, were strongly related to rainfall. A directional change, which supports the equilibrium concept, was evident in changes in perennial species composition over time. The annual component, however, showed no directional change, but displayed eventdriven, non-equilibrium dynamics by fluctuating in reaction to the timing and quantity of rainfall.
Keywords: diversity, equilibrium/non-equilibrium, rainfall, vegetation dynamics, wildlife
Vegetation responses to seasonal weather conditions and decreasing
grazing pressure in the arid Succulent Karoo of South Africa§
Ute Schmiedel* and Jens Oldeland
ABSTRACT
The Succulent Karoo biome is a renowned centre of biodiversity and endemism in the arid winter rainfall region of South Africa that is threatened by climate change. On 20 permanently marked plots within a biodiversity observatory, species richness and cover were assessed annually from 2002 to 2017 during the growing season. We were interested, firstly, in whether the vegetation showed any trends in response to the strong decrease in grazing pressure, which occurred at the beginning of the monitoring period, and secondly, in the effect of seasonal climate on the vegetation. We analysed the responses of species richness and cover in four life forms to seasonal rainfall
and the standardised precipitation–evapotranspiration index (SPEI) using linear mixed-effect models. Time had a positive effect on richness of annual species and a negative effect on cover of shrubs and annuals, which increased in response to SPEI and less strongly to rainfall during autumn and winter. Habitat did not have any effect and geophytes and perennial herbs did not show any significant response. The importance of SPEI during autumn and winter is discussed in relation to potential germination cues and the projected decrease in rainfall and increase in temperature during these seasons.
Keywords: biodiversity observatory, Namaqualand, rainfall, SPEI, standardised precipitation–evapotranspiration index, vegetation change
Effects of short-term intensive trampling on Karoo vegetation§
Jeannine McManus1,2¶*, Stefan A Goets1,3¶, William J Bond4 , Joh R Henschel3,5 , Bool Smuts1,2 and Suzanne J Milton3
Plant growth forms likely respond differently to disturbances such as trampling. We investigated the trampling
effect of 1 600 sheep encamped at night in temporary enclosures (kraals, corrals or pens), which were relocated
weekly. To examine trampling effects and regeneration rates of the various growth forms we compared vegetation composition, canopy cover and foliar nitrogen inside and outside kraals, between one and 12 months after
the trampling event. We predicted that inside kraals (1) succulent and non-succulent shrubs would be affected
more severely than grasses, (2) perennial plant cover would decrease compared with annual plant cover, (3) foliar
nitrogen concentrations would increase, and (4) vegetation recovery would be affected by time and rainfall since
last use of the kraal. Grasses and shrubs (succulent and non-succulent) responded differently to kraaling. Density
and diversity of succulent and non-succulent shrubs decreased, while annual and perennial grass cover inside and
outside kraaling areas did not differ. Foliar nitrogen was greater inside kraals. Both succulent and non-succulent
shrub cover increased over time after kraaling irrespective of the rainfall. Our study demonstrates that short-term
intensive trampling and dunging creates nutrient-rich, heterogeneous patches that may enhance restoration of
degraded production landscapes.
Keywords: corral, dung, high-density grazing, kraal, livestock, pen, vegetation change
Variation in mammal species richness and relative abundance in the Karoo§
Zoë Woodgate1*, Greg Distiller2 and Justin O’Riain1
ABSTRACT
Understanding how climate change and land transformation may impact the distribution and diversity of wildlife species requires landscape-level foundational biodiversity surveys. The Karoo BioGaps Project aims to provide such data and to support the scientific assessment for shale gas development projects in the Karoo basin. In this paper we present the findings of the BioGaps mammal survey, which recorded medium and large mammals across twenty-five 1 km × 1 km sampling sites within the proposed fracking footprint using camera trapping techniques. We use sample rarefaction curves, non-parametric species richness estimators and non-metric multidimensional scaling plots to explore both species richness and community structure. We also used a generalised linear model to
investigate how species diversity varies with both site-specific and landscape-level predictors. A total of 38 species were recorded at the majority of sites. Longitude (z = 4.018, p = 0.0005) emerged as the best predictor of species diversity across the study area, which we suggest is linked to the clear east–west aridity gradient. Together these results reveal the cosmopolitan distribution of the mammal taxa in the Karoo and could be used to inform decisionmaking linked to mining activities in the area.
Keywords: Karoo, mammals, shale gas
Biological soil crusts of the Succulent Karoo: a review§
Bettina Weber1* , Alexandra Tamm1, Stefanie Maier1 and Emilio Rodríguez-Caballero2
ABSTRACT
The Succulent Karoo is characterised by a dense coverage of biological soil crusts (biocrusts) belonging to different types and successional stages. Whereas the Soebatsfontein region hosts cyanobacteria-dominated and minor amounts of lichen- and bryophyte-dominated biocrusts, the Knersvlakte comprises a rich cover of hypolithic crusts growing on the sides and undersides of quartz pebbles. Apart from dominating photosynthesizers used to classify biocrusts, each crust type hosts a rich and specific fungal and bacterial community and also diverse protists. In a remote-sensing mapping approach, soil-inhabiting biocrusts of the Soebatsfontein region covered ~27% of the surface area, whereas in the Knersvlakte soil-inhabiting biocrusts covered ~16% and hypolithic biocrusts ~42% of
the region. Combining these data with biomass contents, results suggested that the Knersvlakte, despite somewhat harsher environmental conditions, harboured about 65% more biocrust biomass per surface area. In physiological measurements we observed that biocrusts emit the reactive nitrogen compounds nitric oxide and nitrous acid, showing water pulse-dependent emission patterns. In addition, CO2 gas fixation showed characteristic type-specific patterns depending on climatic conditions. Long-term microclimate measurements along a gradient revealed that forecasted climate and land-use change may be detrimental for biocrusts with potentially adverse effects on soil
stability and overall fertility of the Succulent Karoo.
Keywords: biodiversity, climate change, CO2 gas exchange, reactive nitrogen compounds, remote sensing
The composition of the soil seedbank and its role in ecosystem dynamics
and rehabilitation potential in the arid Tankwa Karoo Region, South Africa§
Manam WB Saaed1,2* , Shayne M Jacobs2 , Mmoto L Masubelele3 , Igshaan Samuels4,5 , Lesego Khomo6 and
Yacoub M El-Barasi7
ABSTRACT
Very few soil seedbank studies have been conducted in South Africa, especially in arid rangelands. Insight into the soil seedbank could therefore improve assessment of rangeland dynamics and enhance rehabilitation efforts. This study aimed to characterise the soil seedbanks in various vegetation types of the Tankwa Karoo National Park, an arid environment in South Africa. At 43 sites soil was sampled twice at the end of spring and the end of autumn, and the composition and structure of aboveground vegetation were described at the peak growth period in spring. Seeds were isolated from the soil samples by means of flotation in a salt solution, seedbank species
composition was obtained by seedling germination, and the vegetation was investigated using a line-point survey method. Overall seed density was 8 034 seeds m−2 of which 55% was viable, and the common life-forms were therophytes and chamaephytes. Species richness and diversity were lower in the seedbank compared with those of the vegetation, and the two vegetation spheres were 25% similar. While seedbank composition suggested poor veld condition, there was enough seed density and viability for future regeneration and rehabilitation initiatives. However, this may be impeded by the absence of many perennial species in the soil seedbank.
Keywords: arid environment, interpatches, life-form spectra, patches, rangeland condition, species composition, Succulent Karoo
Assessing the success of experimental rehabilitation on a coastal mineral
sands mine in Namaqualand, South Africa§
Marco J Pauw1* , Karen J Esler2 and David C Le Maitre3
ABSTRACT
The success of different rehabilitation treatments following surface mining on the arid west coast of South Africa was assessed. Treatments consisting of one or a combination of topsoil addition, plant translocation and seeding were applied to experimental rehabilitation sites in 2001, while the treatment of another site in 2008 combined all three techniques. Vegetation and species cover, species richness, diversity and evenness, and grazing capacity of rehabilitation sites were sampled during winter 2009 and summer 2010, and compared with a reference site. All rehabilitated sites achieved the objective to attain a minimum grazing capacity of 20 ha per small stock unit. Rehabilitation trials were successful in establishing a vegetation cover, but were unable to return species richness and diversity to reference levels and did not resemble the reference site in species composition. Common species in reference sites were absent or only occurred in low numbers. No treatment outperformed the others and further experimentation is needed to determine the most suitable combination. It is recommended that rehabilitation should be done in multiple stages in future to improve seedling survival and to return species that are unable to establish in the adverse conditions present at the onset of rehabilitation.
Keywords: reseeding, strip mining, Succulent Karoo, topsoil, translocation
Response of arthropod communities to plant-community rehabilitation
efforts after strip mining on the semi-arid west coast of South Africa§
Adam Steed1 , Rudi Swart1 , Marco J Pauw2 and Francois Roets1*
ABSTRACT
Strip mining in arid ecosystems causes extreme ecological destruction that may take decades to recover. The present study examined the effect of different plant-community rehabilitation treatments on arthropods after strip mining in the arid Namaqualand region of South Africa. Vegetation cover and plant species richness were significantly lower at all rehabilitated sites compared with those at a reference site. Arthropod species richness did not differ amongst the different treatments and the reference site. Except for the most recently rehabilitated site, arthropod abundance in all guilds was higher at all treatments compared with that of the reference site. Overall
arthropod abundance was positively correlated to plant cover and negatively correlated to plant species richness, but these vegetation characteristics had no effect on arthropod species richness. This may be explained by a high cover of pioneer plants at the rehabilitated sites, which offer ample food for generalist arthropod taxa. Arthropod community composition differed significantly between treatments. We demonstrate that rehabilitation of ecosystem function after mining in arid systems is a lengthy process, even after implementation of intensive rehabilitation protocols. We also show that arthropod communities provide additional insights into the level of ecosystem
recovery otherwise obscured when only considering plant community data.
Keywords: biodiversity conservation, insects, rehabilitation, Succulent Karoo
Reflections on the Karoo Special Issue: towards an interdisciplinary
research agenda for South Africa’s drylands§
M Timm Hoffman1* , Cherryl Walker2 and Joh R Henschel3
ABSTRACT
We begin this essay with reflections on major research themes highlighted by the Karoo Special Issue (KSI). These include concerns over land-use change, long-term monitoring, climate change, governance and the need for more interdisciplinary research. We also identify some of the novel contributions of the KSI around these themes and highlight research issues that require further attention. These include greater focus on the social-ecological impact of large-scale infrastructural developments and wildlife ranching, as well as the need for more longitudinal studies related to contemporary social issues. We conclude by outlining a simple framework for thinking about
interdisciplinarity in future research efforts in the Karoo. The first axis relates to the natural science/social science continuum, while the second is concerned with the continuum between basic and applied science. Greater awareness of these two dimensions could not only encourage researchers to reflect more carefully on where their research fits in relation to the broader research needs of this region but could also promote interdisciplinarity within the research community. It could also bring researchers closer to the realities and needs of the people who live in and derive their livelihoods from Karoo environments.
Keywords: applied research, interdisciplinary research, land-use change, social-ecological systems, sustainability
