Several long-term "Biodiversity Observatories" were set up throughout Namibia during 2001 and 2005, ranging from Kavango West in the north, to Karios (near the Fish River Canyon) in the south. (This transect is extended into South Africa through the Richtersveld and Namaqualand as the BIOTA Transect.) A number of approaches are followed: Conceptually, the north-south transect follows a gradient of increasing aridity within Namibia, whilst many observatories are paired to compare a land use difference. The regular resurveying (with a few exceptions, annually) of the observatories is done according to a set scheme, recording plant species and their estimated abundance on 20 ? 50 m plots, and taking fixed-point photos. Since 2016, we are also utilising a drone for surveying, with which we intend to monitor the phanerophytic vegetation. Four long-term biodiversity observatories have been established within the Kalahari Basin in Namibia. This landscape is under severe threat by global climate change, with predictions of dune remobilisation over the next 50 years as far north as central Angola. These observatories stretch over a gradient from roughly 500 mm precipitation per annum in the Kavango West Region (Mile 46 and Mutompo observatories), to 450 mm at Sonop observatory (Otjiozondjupa Region), to 350 mm at Sandveld observatory in the Omaheke Region. The expected changes in composition and structure along this aridity gradient are clearly illustrated. The composition of the woody layer does not readily respond to climatic variations, but fire and anthropogenic influences (e.g. illegal felling of trees, clearing of fields) play a great role in the structure of these woodlands. The herbaceous layer, in particular, the grass sward, shows a stronger reaction to climatic variations in particular in the northern, more mesic environments. Comparing the long-term data, the northern, more mesic vegetation is far less stable than the southern, more arid vegetation. This raises fears of dramatic, near irreversible degradation of these woodlands, to the extent of forming permanent, man-made deserts in these regions. Within the Central Thornbush Savannas, bush encroachment has been reported to be a problem in the extensive grazing systems in the savannas of Namibia since the 1970s. With the aid of aerial photography (both historic aerial photographs used for topographic mapping and present-day drone photography) we can quantify the degree of bush encroachment, or in some cases, bush die-back. Aerial photography gives an impression of the density of the grass sward but provides little information on its composition and condition. This, however, becomes evident by the regular resurveying at the observatories. Again, the condition of the grass sward is highly dependent on both the climatic conditions and the land use system. Over the years, however, a distinct decline in the condition is detectable. This seems to be not only due to straight-forward "overgrazing", but rather a compound effect of transformation of the vegetation structure, erosion of wetland systems and general desiccation of the landscape.

Mier is a rainfall-driven, dryland area in the Savanna Biome of the Northern Cape province. The area is characterised by parallel dunes, pans and hard stony surfaces, typified by certain land-cover units, specific vegetation and different land-use types. Depending on the type of vegetation and prevailing environmental parameters (geology, soil and climate) the local land users resort to an array of different range-management practices. Livestock and game management are the mainland use-types in the region contributing to the financial sustainability and well-being of the local people. One of the most pressing environmental problems land users face, leading to land degradation in the region, is the thickening of woody species such as the black-thorn (Senegalia mellifera) and the three-thorn shrub (Rhigozum trichotomum). This leads to a loss in biodiversity, changes in the structure and composition of the vegetation and a reduction in forage production for livestock. Several restoration activities were implemented to address the causes of land degradation. Dune stabilisation practices were established in the 1990s by the Department of Agriculture, Forestry and Fisheries (DAFF) through the LandCare program. These include brush packing using branches from the encroaching woody species of the inter-dune streets to stabilise dunes and loosening the compacted soil surface on the hard stony areas followed by re-seeding with palatable perennial, climax grasses adapted to the area for increased biomass production. Quantitative vegetation parameters (shrub density, grass species composition and -biomass) were monitored using the step-point walking- and belt-transect, as well as the quadrant method. Results revealed a significant positive effect of bush control of three-thorn shrubs on grazing capacity. In areas where the density of the three-thorn shrub was controlled through restoration practices, the grazing capacity increased dramatically over a five-year period. The perennial grass cover also improved in areas that were well managed and restored. To evaluate land user's perceptions of local environmental change regarding rangeland management and restoration practices, the Integrated Assessment Protocol (IAPro), the photo-voice approach, as well as semi-structured interviews were applied. Documenting indigenous knowledge offered insights into the wealth of site-specific indicators used by the local farming community for the management and restoration of the land. There seems to be an overlap between local- and scientific knowledge regarding the indicators for sustainable rangeland management and restoration. These long-term monitoring outcomes emphasize the participation of all stakeholders (policy, science and land user) in the development of sustainable land management strategies and the application of restoration to combat land degradation. 

Hakskeenpan has become a synonym for land speed racing in South Africa. This 15,000 ha pan is the largest ephemeral wetland in the semi-arid Kalahari Desert region of the Northern Cape province. Since 2010 a British team has been preparing its surface to attempt a new land speed record. The pan was favoured for this event due to its vast, hard, flat surface. However, surficial stones could be detrimental for the race as small stones scattered across the pan's surface could slash the supersonic car's tires. For this reason, over 16,000 tonnes of stones have been removed to smoothen the 22 million m2 track on Hakskeenpan in preparation for the race. This task contributed significantly in uplifting the local Mier community and the race itself is believed to greatly benefit the economy of the province. However, no attempt has been made to understand the impact this event might have had on the biodiversity and ecosystem functioning of the Hakskeenpan wetland itself. Ephemeral pans are subjected to complete desiccation during the dry season, which can last for decades. Consequently, these pans are often regarded as degraded or dead systems by land users. However, when it rains enough for the pans to hold water, dormant aquatic organisms respond and wetlands are resurrected to produce stepping-stone biodiversity corridors in an arid landscape. The variable scale of wetness over space and time and the unpredictable rainfall regime in the Northern Cape, however, challenges consistent sampling protocols during wet spells. Therefore, the pans in the province have been shamefully neglected. The current study investigates the biodiversity of Hakskeenpan, specifically focussing on the Branchiopod crustaceans, which are the flagship species of these arid waterbodies. Dip net measured sweeps were performed in late January and mid-March 2017 after Hakskeenpan received sufficient rain for some sections of the pan to hold water over a three month period. The results reveal the unique herbivores that dominate the pan and illuminate its importance for biodiversity and ecosystem functioning.

Vachellia erioloba is a keystone species in the southern Kalahari because it provides food, shelter, perches, nests and roost sites to many types of animals and harbours a distinct assemblage of plant species below its canopy. There is growing concern that mortality rates in V. erioloba are increasing as a result of threats such as increasing fire frequency, groundwater abstraction, competition from alien invasive species, diseases, harvesting, and the effect of aboricides. The study tracks two populations in different landscapes (interior sandy dune veld versus clayey Nossob riverbed) of a large conservation area and offers valuable data on this species under natural soil moisture conditions and with limited anthropogenic influences. Two plots were surveyed intermittently over nearly four decades in the northern section of the Kalahari Gemsbok National Park. In 1978, eighteen trees were permanently marked in a 1 ha plot in the interior duneveld (Dankbaar site), and in 1979 all trees in a 1 ha plot were surveyed in the Nossob riverbed (Grootkolk site). Tree height and stem circumference were measured at both sites in order to investigate growth rates and population structure. Of the 18 marked trees at Dankbaar, six died and three showed coppice regrowth following substantial die-back after a fire but, no fire-related deaths were reported. Stem diameters increased at a mean rate of 2.50 mm/year (range 0.91–4.86 mm/year) over the monitored period. This mean annual diameter increase is less than the 3.6 mm/year established in a previous study and substantially lower than the 12–14 mm/year previously reported for Acacia species growing in arid and semi-arid environments. Variability in the growth rates of other tree species has been reported and the suggested underlying causes for this phenomenon include microsite conditions and/or genetic potential of individual trees. At this study site in the duneveld, the V. erioloba population was self-sustaining, with recruitment occurring and large individuals presumably dying of old age. At the Grootkolk site in the Nossob riverbed, surveys started in a stand of predominantly young trees, although the size class distribution at that stage already showed a lack of recruitment. Over the study period, few seedlings were recorded and few individuals appeared to be recruiting into the population illustrating that this population was gradually changing from a young and growing to a mature-to-old population. Vachellia erioloba trees in this stand will likely disappear; however, new young stands are appearing at other sites in the Nossob riverbed. In this national park, under negligible anthropogenic influences, it appears that some V. erioloba populations are increasing in size while others are decreasing, but that overall the species will persist. The continued monitoring of these populations is recommended. However, monitoring sites should also be established at additional sites outside of the park to incorporate sites in which various threats to this species can be investigated. Rainfall stations should be erected at all sites to enable the investigation of the influence of significant rainfall events and drought on seed germination, seedling survival and adult mortality.

A handful of very long-term datasets have shown how the timing of growth and reproduction in plants can change in response to climate change. However, long-term plant phenology datasets are rare and are mostly focused on crops. The South African Environmental Observation Network and Sol Plaatje University recognised the value of such long term datasets and set out to collect data on species that are widespread in the arid savanna of South Africa. Not only would such a dataset enable us to model seasonal availability of resources in the face of climate change, but also to model population trends in plant species. The cover of different stages of flowering, fruiting, leaf growth and shoot growth were estimated by a team of observers monthly from October 2017. Climate data were recorded during the same period. Observations based on initial data, which does not yet allow for statistical analyses, are presented here. Among the woody species (Ehretia alba, Searsia lancea, Senegalia mellifera, Vachellia erioloba, Vachellia tortilis and Ziziphus mucronata), there seem to be several different strategies for flowering, fruiting, and leaf and shoot development. From the initial data, it seems that cues for flowering and fruiting are either related to day length or temperature, while growth also occurs within a window period, but requires the availability of moisture. The two grass species (Schmidtia pappophoroides and Stipagrostis uniplumis) both seem to react to rainfall in its reproductive and vegetative growth phases. Several peaks in phenological events were missed due to the intervals in observations being too far apart, especially in the grasses that have very short reproductive phases. The observed patterns and strategies need to be confirmed by long term records. Below average rainfall during the study period resulted in low magnitudes of some phenological events, which might skew the observed patterns. The necessity for more frequent observations was confirmed. There is a lot of potential for additional research to complement the current study which can expand our understanding of species responses to climate change on an individual and population level.