Deadwood Invertebrate Survey of Styal Woods

SUMMARY

Styal Country Park straddles a wooded gorge section of the River Bollin and contains areas of ancient woodland as well as many veteran trees, in the farmland as well as the woods;

• It lies within the catchment of the River Bollin and is therefore geographically linked to Dunham and Tatton Parks, both of which are known to be of importance for their wood-decay invertebrates.
• Sites with a long history of tree cover and especially open-grown trees have the potential to be notably species-rich in tree associated wildlife, particularly wood-decay (saproxylic) and bark surface (epiphytic) species – fungi and invertebrates in the first category, and lichens, mosses and invertebrates in the latter.

This document reports on an assessment of the assemblages of wood-decay ( saproxylic) invertebrates, based on new field survey carried out across the 2011 and 2012 field seasons, with the objective of assessing their current condition, national importance and whether current management practices are sufficient to conserve the invertebrate fauna.

The survey has demonstrated that Styal Country Park is one of the richest sites in Cheshire and North West England for wood decay beetles in particular. Site condition is overall considered to be favourable at present.

The total number of wood decay beetle species now known from Styal Country Park is 54 and these include 15 species with Nationally Scarce status. The key finds include the hister beetle Plegaderus dissectus and the false darkling beetle Abdera biflexuosa which are both moderate indicators of site quality and are at the northern edge of their British ranges here. Other key species present include the fungus beetles Mycetophagus piceus, Phloiophilus edwardsii, Enicmus rugosus and Euglenes oculatus. Wood decay fly species appear less rich and interesting, but include a good range of deadwood-breeding hoverflies in particular.

The affinities of this fauna are with the northern fringes of the main Temperate broad­leaved old growth fauna of lowland southern Britain – places such as the New Forest, Windsor Forest & Great Park, and Moccas Park. The species totals are only provisional as they may be expected to increase substantially with further study. The Index of Ecological Continuity has already reached 22, a figure of high Regional -North West England – significance and exceeded in the historic county of Cheshire by just three other sites.

The key areas of Styal Country Park for wood-decay invertebrates are:

Oak appears to be the most important tree species, with ash also of particular interest. Although currently dominated by beeches, these are a relatively recent feature of the area, introduced as part of landscape gardening fashions.

Land management implications and recommendations

1. SSSI status:
a. The only other comparable areas of river cliff and dough woodlands in Cheshire is the Lower River Weaver Woods ISR (Invertebrate Site Register) site which partly overlaps with two woodland SSSis.
b. The Country Park has not had its veteran trees mapped but there are estimated to be in excess of 100 examples, which meets one of the three primary criteria for SSSI selection in the JNCC veteran tree guidelines.
c. The National Trust is invited to establish this conservation principle – SSSI site quality – in advance of any designation.
2. Site condition:
a. Styal Country Park appears well-managed for nature conservation and is in favourable condition overall – examples of current good practice were very apparent.
b. A veteran tree survey needs to be carried out, as data is needed both to promote SSSI designation and to plan for future generations of trees. No urgent need for tree planting has become apparent but continuous small-scale planting is recommended- Valley Field is a priority area.
c. An active conservation plan for veteran oak is needed as this is a light­demanding species and the Country Park currently provides very few opportunities for its natural regeneration.
3. Condition monitoring and public engagement:
a. With a site as important as Styal Country Park It IS important to monitor the impacts of land management, etc, on the condition of the habitat and the assemblages it supports. A monitoring plan needs to be developed.
b. It is important that the nature conservation interests and management implications at Styal Country Park are broadly understood by all relevant people: property staff and their advisers, contractors and visitors. This may be achieved through a combination of educational talks, walks, leaflets and posters. For a conservation plan to succeed it needs support from all interest groups. Encouraging and targeting visitor interest may help with site monitoring and discouragement of damage.

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