DHBlog035 · Baseline Surveys on the Carey Estate
Major landowners and managers in Purbeck, Dorset have recently come together to plan significant changes in rural business practices and nature conservation. They have formed the Wareham Arc and bid successfully for funding from Landscape Recovery, an ambitious land management scheme administered by HM Government's Department for Environment, Food & Rural Affairs. The aim is to expand and reconnect priority habitats within the Purbeck Heaths National Nature Reserve and the Lulworth Army Range, continuing on through Forestry England’s Wareham Forest to RSPB Lytchett Fields on the north shore of Poole Harbour. In doing so, the project will help restore these habitats to a more balanced and resilient state while enhancing public access and protecting threatened species such as Marsh Clubmoss (Lycopodiella inundata), Woodlark (Lullula arborea) and the Speckled Footman moth (Coscinia cribraria).
Major aims of the Wareham Arc include improvements in biodiversity and species abundance, for which ecological baseline and follow-up surveys are required. With this in mind, Robin Walls offered the services of the Dorset Flora Group and an opening assignment was received in the form of an invitation to the Carey Estate on the River Piddle near Wareham. This private estate will be used as an exemplar during the project's development phase and it's hoped that the results from here will encourage the engagement of other private landowners.
On 21st May, five of us arrived to take on the baseline surveys at two sites on the estate. Paul Morton from Birds of Poole Harbour and Chloe Coker, Project Officer based at the RSPB were there to meet us and kindly pointed us in the right direction. This involved giving a wide berth to the nesting Ospreys, for which we were later rewarded with fine views of an adult Osprey in flight and the atmospheric sight of a Barn Owl hunting for prey.
We began with the Lower Orchard water meadows which had dried out considerably in the preceding weeks (having been under water for months) and we overcame some footwear shortcomings to record 58 plant species in just over two hours.
The most abundant species here were Hairy Sedge (Carex hirta) and Floating Sweet-grass (Glyceria fluitans) but a surprise came with the discovery of Tasteless Water-pepper (Persicaria mitis) – a first sighting for all of us. For reasons that are not entirely clear, P. mitis is far scarcer than its familiar and hot-tasting cousin, Water-pepper (P. hydropiper). It typically grows on wet, nutrient-rich mud exposed by drawdown in late summer and is now classed as Vulnerable on the Red List for Great Britain, largely due to changes in the management of wet fields, ponds and ditches.
Differences between P. mitis and P. hydropiper are subtle and at this early point in the season, we had no flowers to guide us. Instead, we made our identification by reference to the long fringing hairs on the fused stipules (ochrea) that encircle the stem and, as the name suggests, the lack of flavour in the leaves. When flowers are present, examination of the pericarp can assist further: in P. hydropiper, there is a dense covering of glands which become pitted during storage while in P. mitis, these glands are absent or at best, sparse. In addition, the long ochrea fringes of P. mitis continue into the inflorescence.
The range of species that we observed on the meadows was modest, mirroring previous findings from other sections of the Piddle and Frome floodplains (Robin Walls, pers. comm.). Considering that the main channels of these rivers are largely unmodified with no significant industry thereon, and also that these meadows are down to permanent grassland and not intensively managed for the most part, this has always been something of a mystery. The aquatic vegetation does not suggest a problem with excessive nutrient accumulation on the Carey Estate, leaving a curious picture that it is worthy of further research. Our species list for the Lower Orchard water meadows can be viewed here:
After a picnic lunch, we made our way into Drive Plantation, an area of mixed woodland with an understorey of locally abundant Rhododendron (Rhododendron ponticum). This is an invasive species with the ability to form dense thickets in woodlands on acid soils, suppressing all vegetation below and decimating the woodland flora. To the estate's credit, significant areas of Rhododendron had been mechanically cleared, and early signs of heathland regeneration were evident with Heather (Calluna vulgaris) emerging in several places.
At the time of survey, the flora was rather sparse but despite this we found 44 species, listed here:
There are plans to clear more Rhododendron to promote the establishment of a native ground flora and shrub layer, and it will be interesting to see how the site develops.
Thanks go to the Carey Estate for their kind permission to visit these private sites.
This article contains contributions from Tom & Jean Smith and Daniel Holloway, and was edited by Daniel Holloway.