GTRIP 2015 Gobabeb Training and Research Internship Programme – Investigating & Mitigating the Environmental Impacts of Mining
The 2015 GTRIP program aimed to expose students to Namib Desert biodiversity, and to increase their understanding of the role of ecological restoration and awareness of environmental management processes and mitigation of industrial development impacts. This year's programme concentrated on Langer Heinrich Uranium's EMP commitments related to biodiversity, a number of which require baseline surveys or contextual studies that should help define the extent of impacts and their mitigation. The focus was on those commitments which are considered high priority in terms of overall ecological restoration practices, aimed at improving ecological knowledge for future restoration and management practices.
We thank Langer Heinrich Uranium & Gobabeb’s NERMU Project (the Namib Ecological Restoration and Monitoring Unit) who supported the project financially and logistically. In addition, we thank the visiting scientists to Gobabeb who gave lectures to the students while at the station, including: Professor Scott Turner on “Life in the Transients,” Dr Stephan Getzin and Sebastian Hanss on “Namibian Fairy Circles,” Dr Guy Cowlishaw on “Body Conditions in Baboons” and Dr Geraldine Richmond on “Building a Scientific Career”. All of these lecturers provided the GTRIP interns opportunities for international and local networking as well as a perspective on how to develop their futures as young Namibian scientists.
Highlights from the projects
Distribution and abundance of termite mounds in disturbed and undisturbed areas in relation to soil type, vegetation and distance from the sea, in the Central Namib Desert -- Liliana Aushiku
Termites are regarded as important organisms across a variety of ecosystems and they play a fundamental role especially in arid regions. Their spatial distribution contributes to ecological processes such as nutrient concentration and the ability of soils to take up water. Anthropogenic disturbances in the Namib Desert, such as, off-road driving, excavation and blasting are removing top soil and likely threatening these soil engineers. Continued rapid construction of road systems and buildings, soil compaction by heavy trucks and excavation of soil, change the earth's natural soil surface, alter soil textures and, thus, likely lead to unfavourable conditions for termites. This project was initiated to assess the distribution and abundance of termite mounds in disturbed and undisturbed areas. Additionally, this study assessed how other factors, such as distance from the sea, vegetation presence, and soil type,
influence the distribution of termite mounds. The research was conducted in the central Namib Desert and specific study areas included: Langer Heinrich Mine, Hope Mine, and burrow pits along the C14 road. It was found that the abundance of termite mounds was significantly higher in undisturbed areas compared to the disturbed areas. Furthermore, the undisturbed areas had more vegetation coverage and had a higher percentage of clay and silt in the soils. Additionally, more termite mounds were found further from the coast, potentially because of higher vegetation coverage. Overall, there is a relationship between termite activity, soil type and availability of plants. These results therefore indicate that anthropogenic activities may pose negative impacts on termite activities and their role in ecosystem function. As termites are biological indicators of recovery, this information may also be used in ecological restoration projects. Restoration activities should aim to create habitats that are favourable to termites, as their presence is key in ecosystem functioning.
The impacts of off road vehicle track intensities on lichen communities and associated invertebrates in the Central Namib -- Lorentha Haraes
In hyper-arid regions where limited precipitation and nutrients restrict more complex vegetation growth, lichens make up the dominate plant type. Although studied as a single organism, lichens are composed of a unique symbiotic relationship between algae and fungi. Lichens are known to play various ecological roles in the Namib and elsewhere in the world: they provide shelter for insects and reptiles, stabilize soil services, and improve soil fertility through fixing
nitrogen. Despite their tolerance of harsh climates, lichens are extremely vulnerable to mechanical disturbances. Anthropogenic disturbances, such as off road tracks and mining activities, threaten the lichen fields in the central Namib, which have very slow recovery rates. Shifts in lichen communities have been shown to directly impact microfauna or invertebrate communities that rely on them for food and shelter. This study investigated how different track intensities affect lichen coverage and the abundance and diversity of their associated invertebrates. Ten sites of low and high track intensities were chosen within the lichen-dominated gravel plains of the Central Namib. At all ten sites, there was significantly less lichen cover in the tracks compared to the control areas. Further, the high track intensity sites also had less lichen coverage. Undisturbed parent material is likely essential for colonisation and lichen growth in tracks, the high density track areas had limited parent material and, thus, lichen growth was limited. Invertebrate richness did not differ significantly among the sites, though there was a significant relationship between lichen cover and inveterate taxa richness. This study demonstrated that the lichen-dominated fields of the Central Namib are important habitats for invertebrates and that anthropogenic disturbances threaten this ecosystem. More awareness should be raised on the ecological importance of lichens and further studies should continue to monitor the effects on lichens and their associated ecosystem services.
The reproduction of Welwitschia mirabilis in relation to location of catchment and herbivory in the central Namib, Namibia -- Abel Nehemia
Welwitschia is an amazing organism found in the central Namib, often considered as relic from the past due to its ability to live an estimated 1500-2000 years. The plant is ecologically important to its environment, providing microhabitats to various organisms ranging from beetles, snakes, birds and hares. However, in recent years, anthropogenic activities such as mining and browsing by domestic animals have threatened this endemic species. This study investigated the spatial patterns of reproductive output (number of cones produced per individual) and herbivory of Welwitschia in the central Namib. Reproductive output of Welwitschia plants was compared among five different catchments.In order to understand the impacts of browsing by domestic animals on Welwitschia reproductive output, the number of cones on male and female plants was counted from pictures that were taken before and after browsing. Findings revealed that topography and landscape position affect reproductive output of Welwitschia plants. Some catchments had higher
reproductive outputs and, often, more plants occurred in the main drainage channel than elsewhere. The amount of water that flows through the drainage channel could alter the amount of water available to the plants, highlighting the importance of regular water flow through drainage channels. Furthermore, browsing by domestic animals was found to potentially limit the reproductive output of Welwitschia. In order to understand the impact of spatial patterns and herbivory on the reproductive output of Welwitschia, long-term monitoring studies should be conducted. These findings will be used to establish better management plans for Welwitshica and other endemic plants. It is critical to understand the biology of organisms before creating ecological restoration practices aimed at helping mitigate the potential negative impacts of anthropogenic disturbances.
Comparison of bird diversity in areas with high and low density of woody alien invasive species in Swakop and Kuiseb Rivers in the Namib (funded by Tsaobis Baboon Project) -- Cecilia Ndunge
Ephemeral rivers, mainly located in arid areas, flow for a few days or weeks or not at all for some years. These rivers support riparian vegetation and act as seed banks, dispersal corridors, and deposit sites for organic matter and nutrients. One of the major threats for river ecosystems is alien invasive species.
Alien invasive species compete with native species and, thus, can completely alter natural ecosystems. Avian species, a key population in the riparian ecosystem, are very sensitive to changes in habitat, such as loss of native species. Changes in vegetation composition can affect native bird communities through altering or eliminating their habitats and changing food availability. At a larger scale, it is known that alien invasive species negatively affect bird communities, though less is known about how bird communities are affected by invasives at a smaller, more local scale. Birds in the Namib Desert are supported by riparian corridors along ephemeral rivers, such as the Kuiseb and Swakop Rivers. These two ephemeral Rivers flow across the central Namib Desert in Namibia. The most dominant alien invasive species in the Kuiseb River is Nicotiana glauca while Prosopis species are the dominant alien invasive species in the Swakop River. This study was conducted in cooperation with the Tsaobis Baboon Project and Gobabeb Research and Training Centre to determine how bird diversity and behaviour between areas with high density and low density of woody alien invasive species in two riparian zones. In both rivers, more bird species were observed in the areas with a lower density of alien invasive species. However, in the Swakop River, more individuals were spotted in the high density areas while there was no significant difference between the two areas in the Kuiseb River. Natural vegetation seems to provide more niches for the avifauna. The most common birds in the Swakop River were the African Red-eyed Bulbul - Pycnonotus nigricans (low density) and the Grey Go-away Bird - Corythaixoides concolor (high intensity). The Cape Sparrow (Passer melanurus) was the most common bird for both areas in the Kuiseb. More behavorial patterns were observed in the low density areas of the Swakop River while no difference could be found in the Kuiseb. Prosopis is a much larger invasive alien species compared to Nicotiana glauca, and its presence has a greater impact on the native trees and the habitat structure. The bright flowers of the latter attract more nectivorous bird species. The results might suggest that alien invasive species reduce bird species richness and may alter bird behaviours. However, further studies are essential to understand if other factors such as a different season of sampling, climatic stability, and habitat structure affect native bird diversity.
Refining techniques through measures of photosynthesis efficiency to monitor vegetation health in the Namib’s ephemeral river systems -- Elizabeth Ndjomba
In the Namib Desert, scarce and unpredictable rainfall, sudden floods, high temperature fluctuations, and salinity along ephemeral rivers threaten riverine vegetation. The riverine forests are mainly supported by underground water, which is recharged during flood events when heavy rainfalls occur in the river catchment areas. An unsustainable extraction by stakeholders around rivers (mines, towns, farms) would cause the ground water table to drop and plants to experience water stress. Riverine forests provide critical ecosystem services, such as animal corridors and habitats and a loss of these vegetation would affect many other organisms. Two ephemeral rivers in the Central Namib, Swakop and Kuiseb Rivers, are potentially threatened by water stress from nearby mines and towns. The two dominant species in the Kuiseb and Swakop Rivers, Acacia erioloba and Faidherbia albida, are nitrogen fixers and play an important ecological role for the river vegetation. In response to potential threats, the Swakop and Kuiseb Riparian Forest Monitoring Programme (SwaKuRiFoMo) was launched in 2013 by NERMU and Gobabeb Research and Training Centre in cooperation with other stakeholders around the ephemeral rivers. In two different time periods, an indicator of vegetative health, chlorophyll fluorescence, was measured for each of the two species using Handy Photosynthetic efficiency Analyser (PEA). Due to high variation and uncertainty in the SwaKuRiFoMo’s first results, this study aimed to investigate the possible sources of variations in order to improve the SwaKuRiFoMo programme for the future. Measurements of leaves taken during morning and evening gave higher photosynthetic efficiency results in comparison to midday for both species. During midday, the temperature is the highest and plants likely close their stomata in order to reduce water loss by evapotranspiration. Sampling leaves from different directions on the trees did not significantly affect
measurements. Other vegetation measurements, such as height, diameter, and proportion death/alive did not correlate with photosynthetic efficiency measurements, suggesting that these observations alone cannot be used to assess vegetation health. Keeping leaf samples for different time spans (collecting in the morning or afternoon, measuring in the evening) resulted in a dramatically decrease in photosynthetic efficiency. During all measurements, variation in photosynthetic efficiency was higher in F. albida than A. erioloba; long roots of A. erioloba enable to more easily tolerate droughts and water stress. Based on the results of this study, future monitoring approaches for riverine vegetation cannot rely on macro-indicators alone and the measurement of physiological indicators is crucial.The study was conducted to improve the vegetation health monitoring techniques for the SwaKuRiFoMo programme. It is in place to monitor the influence of water extraction by mines and coastal towns along the two rivers and assist the stakeholders to ensure sustainable water extraction.