The Watercress Company has announced that a rare moss beetle has been recorded for the first time in Hampshire during the latest annual ecological survey of the water flowing out of three of their Hampshire farms. The announcement coincides with World Nature Conservation Day which falls on 28 July.
The nationally scarce moss beetle, Ochthebius exsculptus is sometimes known as the sculptured moss beetle. Often described as a water beetle it is in fact amphibious, frequently choosing to live in moss on stones either in the middle of the flow, or on its margins. Normally found in the North of England, this is the first recorded sighting in southern England for some decades and the first ever for Hampshire.
Robert Aquilina, the independent consultant ecologist employed by The Watercress Company to run the annual survey discovered the Sculptured Moss Beetle: “This is a surprising find. These beetles are rare nationally and have never been seen in Hampshire before. What is better still is that the beetle was found at two of the four sites surveyed suggesting it is not just a one-off freak occurrence but that they are happy with the general environment. These beetles are usually found in upland streams in the north of England and Scotland, so these chalk streams with a constant temperature of 10˚c as the water leaves the watercress beds, may represent a refuge for them in the south.”
The Watercress Company is the UK’s biggest grower of watercress with 50 acres of watercress beds split between Dorset and Hampshire, from which they supply most of the country’s major retailers, including Waitrose and Tesco. Watercress grows in flowing spring water that rises up clean and pure through boreholes; the nutrient-rich spring water has been forced up from underground aquifers and in Hampshire has filtered through the chalk of the South Downs. Once it has run through the watercress beds it flows into the River Itchen, world famous for its chalk stream trout and revered by fly fishermen across the globe.
It goes without saying that The Watercress Company therefore takes its stewardship of the water that flows through its beds extremely seriously and in 2016 this resulted in its employing Robert Aquilina to run annual surveys of outflow from four sites: Bishop’s Sutton, above and below Drayton Farm and Manor Farm (all watercress farms around Alresford in Hampshire). The survey measures the biodiversity found at each site and looks at the macroinvertebrates living in the water once it has flowed through the watercress beds and before it enters the Itchen.
Overall, the findings this year were consistent with previous years. The species present were typical of a chalk stream, with good diversity and high water quality scores. An impressive array of macroinvertebrates, highly sensitive to oxygen and pollution levels, were found including mayflies, stoneflies and damselflies, a healthy quantity of Gammarus and also caddisflies. It was interesting that although the water quality from all the sampling points is of the same quality, the surveys gave quite different results in terms of macroinvertebrates present. This is because the three locations are very different environments to each other, with varying levels of shading and water flow. In addition, some locations have gravel bases and others have a silty substrate. It was evident that these environmental characteristics have a huge effect on biodiversity even when water quality is the same resulting in a fascinating patchwork of diversity.
Robert Aquilina concluded: “Clearly water quality is good enough to maintain high biodiversity, other factors being equal. Of course, overlaid on this is the year on year natural variation that weather and management bring.
“Repeated sampling is beginning to show the longer term trend of results cycling around a mean with no significant variation to suggest negative impacts from water quality. However, there is the added excitement this year of the noteworthy discovery of the rare Sculptured Moss Beetle. It is typical of pristine streams where it is found.”
The find has been positively received by the Environment Agency. Tim Sykes, Team Leader, Solent Fisheries, Biodiversity and Geomorphology Team at the Environment Agency said: “The capacity of chalk streams to fascinate us is partly due to their incredible biodiversity. Look closely at your chalk stream and you’ll find lots of wildlife. The Watercress Company did and discovered a species new to Hampshire – the nationally scarce moss beetle, Ochthebius exsculptus – at two sites in the upper Itchen catchment. I’m thrilled that we continue to find new species in our local chalk streams which are special places for people and wildlife.”
Tom Amery, MD of The Watercress Company said: “We have worked hard over the years to ensure that the water leaving our farms is clean; we allow the watercress to remove as much of the free nutrients from the water as possible to assist in reducing nutrification downstream, as reducing phosphate is one of the key objectives of all riparian owners. This is the fifth survey conducted at the outflows of our watercress farms and it confirms we have fantastic water quality, clearly demonstrated by the array of macroinvertebrates living there.
“We have always listened to any challenge over the years and adapted our systems to meet the stringent permits to discharge and the requirements under Special Area of Conservation standards for the Upper Itchen River. Robert’s knowledge and experience is extremely important in demonstrating the fantastic achievements of The Watercress Company and we are always fascinated by his reports, but the presence of this rare moss beetle in the most recent findings is especially exciting as it suggests that we are actively adding to the quality of river life in a far more meaningful way than we would ever have imagined in a farming environment.”
To read the full survey, click here