Potential impacts of agricultural development on freshwater biodiversity in the Lake Victoria basin

Abstract

The Lake Victoria basin (LVB) and its tributary rivers are a major biodiversity hot spot, containing at least 234 native fish species, 135 native aquatic plant species, and 50 native freshwater mollusc species. Lake Victoria itself is home to around 500 fish species, most of which are haplochromine cichlids. The LVB is increasingly under threat from unsustainable land conversion and the intensification of agriculture. High population growth is driving the expansion of agriculture, urbanization, and freshwater abstractions, which have a profound impact on freshwater biodiversity. In addition, increased demand for agricultural crops from domestic and international markets are likely to lead to larger agricultural operations, further threatening freshwater biodiversity. This study explores these potential future impacts on the biodiversity found in freshwater rivers in the LVB as a result of projected future changes in land use. A newly developed database of land‐use impacts on freshwater biodiversity is introduced, with a focus on ecological community composition data from freshwater habitats under human pressures. Impacts on freshwater biodiversity are then projected under four different scenarios of land‐use change. Results show that land use has a significant impact on freshwater biodiversity. Freshwater biodiversity is projected to be at most risk in sub‐basins in the Tanzanian, Rwandan, and Burundian part of the LVB, such as the Kagera and Magoga/Isonga sub‐basins. Local species richness levels are particularly affected in the Magoga/Isonga sub‐basin in Tanzania, with an average loss of 10.8% across all scenarios. Model results show the potential to identify broad spatial patterns of likely threats and pressures on freshwater ecosystems under different socio‐economic futures. The analysis of these patterns, where they are consistent and where they differ, can support the production of policy that strives to find the optimal balance between development and conservation in an uncertain future.

Spatial mapping of soil chemical properties using multivariate geostatistics. A study from cropland in eastern Croatia

“…Agriculture activities are one of the main responsible for water quality degradation and biodiversity decrease in rivers and lakes (Van Soesbergen et al, 2019;Withers and Haygarth, 2007). Identifying areas with low and high nutrients will facilitate the management of the farmland and reduce costs (Bongiovanni and Lowenberg-Deboer, 2004;Schimmelpfennig and Ebel, 2006).…”

Theory and practice to conserve freshwater biodiversity in the Anthropocene

“…The 12 articles presented here cover a varied range of geographies and contexts from North America to South America crossing the ocean to Africa and Europe and further west to Asia and Australia. Biodiversity conservation that is linked to livelihoods of local communities is explored in large provinces such as the Andes (Tognelli et al, ), the Amazon (Reis et al, ) and Lake Victoria (van Soesbergen, Sassen, Kimsey & Hill, ). Water planning that includes life‐history needs of specific species is described in the Columbia River Basin of the USA (coho salmon; Flitcroft et al, ) and in discrete systems such as the Hunter Valley in Australia (Linke, Turak, Gulbrandsen Asmyhr, & Hose, ), Greek lakes (Stefanidis, Sarika, & Papastergiadou, ) and Lake Ontario (North America) (Zolderdo et al, ).…”

“…This special issue on freshwater conservation in the Anthropocene includes several examples of model development for improved management of freshwater ecosystems. Van Soesbergen, Sassen, Kimsey, and Hill () have adopted the PREDICTS model (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems; http://www.predicts.org.uk), which is well developed for projecting biodiversity responses to human activity in terrestrial communities, for its first application to freshwater biodiversity. Here, Van Soesbergen et al () compile a large database of land‐use impacts on freshwater biodiversity in the Lake Victoria Basin, a biodiversity hotspot under increasing threat from unsustainable land conversion and intensification of agriculture (Sayer, Máiz‐Tomé, & Darwall, ).…”

“…Van Soesbergen, Sassen, Kimsey, and Hill () have adopted the PREDICTS model (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems; http://www.predicts.org.uk), which is well developed for projecting biodiversity responses to human activity in terrestrial communities, for its first application to freshwater biodiversity. Here, Van Soesbergen et al () compile a large database of land‐use impacts on freshwater biodiversity in the Lake Victoria Basin, a biodiversity hotspot under increasing threat from unsustainable land conversion and intensification of agriculture (Sayer, Máiz‐Tomé, & Darwall, ). Using the PREDICTS framework, Van Soesbergen et al () project anticipated impacts of future development on aquatic biodiversity under different scenarios of land‐use change.…”

“…Here, Van Soesbergen et al () compile a large database of land‐use impacts on freshwater biodiversity in the Lake Victoria Basin, a biodiversity hotspot under increasing threat from unsustainable land conversion and intensification of agriculture (Sayer, Máiz‐Tomé, & Darwall, ). Using the PREDICTS framework, Van Soesbergen et al () project anticipated impacts of future development on aquatic biodiversity under different scenarios of land‐use change. This effort shows that the PREDICTS model can be successfully applied to freshwater ecosystems to identify areas and ecotypes at greatest risk under different socio‐economic futures.…”