Environmental Impact Assessment (EIA) is a mandatory decision-support tool in every country of the world, developed 50 years ago to ensure the consideration of the environmental consequences of development decisions prior to approval decisions being made. Specifically, the aim of developing an EIA system was to make decision-making affecting the environment more accountable, through the use of objective scientific evidence. It remains the project decision-support tool of choice despite considerable research efforts failing to provide convincing evidence that it achieves this aim. Here we explain this apparent paradox by arguing that EIA supports neoliberal agendas by facilitating economic development. We present arguments based on a neo-Gramscian perspective that explains how apparent advances in the practice of EIA are sanctioned because they actually maintain the political nature of the EIA system, which continues to undermine attempts to use evidence objectively. We use a narratives of change approach to support this perspective. We conclude that EIA can only make decision-making more accountable if strategies to depoliticise it are employed, including emphasising substantive outcomes.
Shrub encroachment in semi‐arid savannas is induced by interacting effects of climate, fire suppression, and unsustainable livestock farming; it carries a severe risk of land degradation and strongly influences natural communities that provide key ecosystem functions. However, species‐specific effects of shrub cover on many animal groups that act as indicators of degradation remain largely unknown. We analysed the consequences of shrub encroachment for ground‐dwelling beetles in a semi‐arid Namibian savanna rangeland, where beetles and vegetation were recorded along a shrub cover gradient (<1% to >30%). Focusing on species niche breadths and optima, we identified two crucial shrub cover thresholds (2.9% and 10.0%), corresponding to major changes in the beetle communities with implications for savanna ecosystem functioning.
Niche optima of most species were between the first and second thresholds; beyond the second threshold, saprophagous, coprophagous, and rare predatory beetles declined in numbers and diversity. This is problematic because beetles provide important ecosystem functions, such as decomposition and nutrient cycling. However, we also found that certain species were adapted to high shrub cover, thus providing examples of niche differentiation. Despite the predominantly negative effects of heavy shrub encroachment on beetle communities, shrubs in their early life stages apparently provide essential structures, which enhance habitat quality for ground‐dwelling beetles.
Our results demonstrate that shrub encroachment can have mixed effects on ground‐dwelling beetle communities and hence on savanna ecosystem functioning. We, therefore, conclude that rangeland management and restoration should consider the complex trade‐offs between species‐specific effects and the level of encroachment for sustainable land use.
In semi-arid environments characterized by erratic rainfall and scattered primary production, migratory movements are a key survival strategy of large herbivores to track resources over vast areas. Veterinary Cordon Fences (VCFs), intended to reduce wildlife-livestock disease transmission, fragment large parts of southern Africa and have limited the movements of large wild mammals for over 60 years. Consequently, wildlife-fence interactions are frequent and often result in perforations of the fence, mainly caused by elephants. Yet, we lack knowledge about at which times fences act as barriers, how fences directly alter the energy expenditure of native herbivores, and what the consequences of impermeability are. We studied 2-year ungulate movements in three common antelopes (springbok, kudu, eland) across a perforated part of Namibia's VCF separating a wildlife reserve and Etosha National Park using GPS telemetry, accelerometer measurements, and satellite imagery. We identified 2905 fence interaction events which we used to evaluate critical times of encounters and direct fence effects on energy expenditure. Using vegetation type-specific greenness dynamics, we quantified what animals gained in terms of high quality food resources from crossing the VCF. Our results show that the perforation of the VCF sustains herbivore-vegetation interactions in the savanna with its scattered resources. Fence permeability led to peaks in crossing numbers during the first flush of woody plants before the rain started. Kudu and eland often showed increased energy expenditure when crossing the fence. Energy expenditure was lowered during the frequent interactions of ungulates standing at the fence. We found no alteration of energy expenditure when springbok immediately found and crossed fence breaches. Our results indicate that constantly open gaps did not affect energy expenditure, while gaps with obstacles increased motion. Closing gaps may have confused ungulates and modified their intended movements. While browsing, sedentary kudu's use of space was less affected by the VCF; migratory, mixed-feeding springbok, and eland benefited from gaps by gaining forage quality and quantity after crossing. This highlights the importance of access to vast areas to allow ungulates to track vital vegetation patches.
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Understanding ecosystems within and around airports can help to determine the causes and possible mitigation measures for collisions between aircraft and wildlife. Small mammal communities are an important component of the semi-arid savanna ecosystems of Namibia, its productivity and its ecosystem integrity. They are also a major direct attractant for raptors at airports. The present study compared the abundance and diversity of small mammals between Namibia's 2 main airport properties (Hosea Kutako International Airport and Eros Airport), and among areas of land used for various purposes surrounding the airports. A total of 2150 small mammals (3 orders, 11 species) were captured over 4 trapping seasons. Small mammal abundance was significantly higher at the end of the growing season than during the non-growing season. The grass mowing regimen in current management plans at the airports resulted in a significant reduction of small mammal abundance at Hosea Kutako during the non-growing season only, thus indicating that annual mowing is effective but insufficient to reduce the overall abundance of mammal prey species for raptors. Small mammal numbers were significantly higher at Hosea Kutako Airport compared to the cattle and game farming land surrounding the airport, while no differences in small mammal densities or diversity were found for areas with different land uses at and surrounding Eros. The study suggests that the fence around Hosea Kutako provides a refuge for small mammals, resulting in higher densities. It also indicates that different surrounding land use practices result in altered ecosystem function and productivity, an important consideration when identifying wildlife attractants at airports.
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