Author: Russell Wynn
In August 2024, I hosted a visit by the Freshwater Habitats Trust CEO (Prof Jeremy Biggs) and Technical Director (Dr Naomi Ewald) to a private site in the northern New Forest where I’ve been conducting ecological surveys over the last couple of years. Naomi was keen to show Jeremy a relatively small pond that was only excavated about five years ago, but that has exceptional freshwater diversity on account of its clean unpolluted water, proximity to ‘source ponds’ on the nearby open forest containing nationally notable species, and the presence of cattle that deliver seasonal conservation grazing and help keep the pond margins open. FHT have surveyed the pond for plants and aquatic invertebrates and have also confirmed the presence of Great Crested Newt using eDNA, while my own surveys have already produced 20 species of dragonfly and damselfly (including Hampshire’s largest colony of Willow Emerald Damselfly).
Image showing the surveyed pond in the northern New Forest (photo: Russell Wynn)
While we were exploring the pond, Naomi casually mentioned that I should keep an eye open for Pondweed Leafhopper Erotettix cyane, as the habitat (including the presence of abundant Broad-leaved Pondweed Potamogeton natans) recalled other sites where she had seen the species. Having never heard of Pondweed Leafhopper before, I did some online research and discovered that it is incredibly rare in the UK, and until recently was known from just a handful of ponds in southern England (e.g. see here and here). In the last five years it has been found at a few more locations in the region and has occasionally ppeared at nocturnal moth traps, but it is still an incredibly rare beast.
Fast forward to 20 Sept 2024, and I was back at the pond looking for Willow Emerald Damselflies, but to no avail thanks to the rather cool and breezy conditions. With Naomi’s comments still fresh in my mind I began dutifully scanning the pondweed with binoculars, and was stunned to see several strikingly blue leafhoppers no bigger than a grain of rice staring back at me! As I continued scanning, I could see there were hundreds spread across the pond, along with good numbers of Pondweed Reed Beetle Donacia versicolorea. I called Naomi and asked for reassurance that Pondweed Leafhopper was indeed the only blue leafhopper in that habitat, which she confirmed, and so I hastily sent across a couple of photos.
A short while later, Naomi replied to say that Dr Alan Stewart at University of Sussex (and UK co-ordinator for leafhopper recording) had confirmed the identification and the apparent status as the first record for Hampshire and the New Forest. Its appearance here is perhaps not too surprising, as there have been recent records a relatively short ‘hop’ away in Dorset, including one at a site bordering the Avon Valley that was erroneously attributed to Hampshire.
I returned to the pond the following day to secure better photos, which was achieved through some rather inelegant wading! A detailed count revealed 110 individuals, including several nymphs, which was a reduction on the previous day due to a further deterioration of the weather. I didn’t return to the site again until 26 Sept, by which time a period of heavy rainfall had ensued and most of the pondweed was submerged, with just a handful of disgruntled leafhoppers on show.
The author going the extra mile to get decent macros shots of the target species! (photo: Christine Sams)
Adult Pondweed Leafhopper on 21 Sept 2024 (photo: Russell Wynn)
Nymph Pondweed Leafhopper on 21 Sept 2024 (photo: Russell Wynn)
So, what next? Encouragingly, preparatory work is already under way for a larger wetland complex to be developed on permanent pasture adjacent to the existing pond, as part of the site owners’ overall plan to increase biodiversity on the site. We are receiving excellent technical support from our FHT colleagues, and hopefully the new wetland complex will expand the available habitat for the species and provide greater resilience if the original pond is negatively impacted (e.g. by non-native invasive species). There is also much to learn about the basic ecology of the Pondweed Leafhopper, including where it overwinters or lays its eggs, so this site also provides an opportunity to conduct research that will aid the future conservation of this remarkable species.
Finally, I'd like to thank Naomi Ewald for her expert input, as without it I probably wouldn't have been carefully scanning pondweed leaves with binoculars! I'm also grateful to the site owners for their continued support of biodiversity monitoring and habitat restoration/creation on the site.
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