The Chalk Downlands, Southern England
Southern England is famous for its chalk landscape, epitomised by the white cliffs of Dover. It was formed in the late Cretaceous through the deposition of many millions of tiny marine planktonic algae (coccoliths), responsible for its distinctive white colour.
The chalk aquifer is mildly karstic, with a fine rock matrix that acts like a sponge holding a vast reservoir of freshwater, and a network of well-connected fissures and fractures facilitating rapid groundwater flow.​The aquifer also plays a vital role in delivering baseflow to our globally rare chalk streams, an iconic and ecologically important feature of this landscape.
The Chalk landscape close to one of our monitoring points in Hampshire, southern England.
Groundwater fauna in the Chalk
Although the diversity of groundwater fauna in England is limited, attributed to previous glaciations, most of the stygofauna species known from England can be found in the Chalk.
Recent molecular work has highlighted the existence of several distinctive species groups that differ from related species in continental Europe, and through the establishment of a new national groundwater ecology monitoring network, new locations for many of these species have been recorded.
One such example is the rediscovery of a tiny stygobitic copepod species, last recorded in England in a chalk well in the 1930s.
Balancing environmental and economic interests
The chalk is the most important source of freshwater in southern England, supplying over half the potable supply to the south-east of the country. This area is also one of the most densely populated. The chalk aquifer is therefore under multiple pressures that pose a significant threat to populations of groundwater fauna and their habitats.
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Through our new groundwater ecology monitoring network and development of innovative monitoring tools, including the use of eDNA, we hope to improve our knowledge and understanding of groundwater ecosystems informing their future management and protection.
One of our monitoring boreholes for the GReG project.