CLM Spring issue 2018 - Page 36



The increasing importance of monitoring wildlife responses to habitat management
Box 3 Case studies: examples of monitoring wildlife responses to interventions in early
successional habitats on Wildlife Trust reserves
Mendips limestone grassland, Somerset
Draycott Sleights is a 65ha SSSI located on the southern scarp of
the Mendip Hills, and is owned and managed by Somerset Wildlife
Trust. The underlying geology of limestone and windblown
loess, alongside historical management, has created complex
mosaics of CG2, CG3 and MG5 grassland interspersed with
scrub developing into secondary woodland. The site is important
also for invertebrates, particularly butterflies (with 32 breeding
species). Monitoring aims to assess the impacts of management
to (i) restore degraded mesotrophic and scrubbed-over areas
and (ii) maintain the botanical interest of high-quality calcareous
Scrub-grass mosaic at Draycott Sleights,
grassland. Key questions are, first, how best to retain a dynamic
Somerset. Kiff Hancock
habitat mosaic beneficial to the target species and, second, what
the responses of grassland species are to scrub clearance, focusing on recovery times and impact of mulch depth
on recovery. A variety of techniques is used, including point samples in grids or transects to identify changes in
vegetation communities and to monitor recovery of grassland after scrub clearance.
Former arable farmland, Suffolk
This site consists of several formerly arable fields owned by Suffolk
Wildlife Trust at its Arger Fen & Spouse’s Vale reserve. One of the
fields was taken out of production some 10 years ago and an
area adjacent to an ancient wood was rapidly colonised by Ash
Fraxinus excelsior, while mixed scrub is developing in other areas.
The Ash has subsequently suffered heavily from ash dieback. The
other fields were more recently arable and are not yet showing
large-scale scrub development. The fields are being left to natural
succession for the indefinite future. The long-term vision is for
an extensively grazed mosaic of scrub and grassland, rather than
Ash regeneration at Arger Fen
dense woodland. Monitoring aims to assess how plant, bird and
& Spouse’s Vale, Suffolk. Rob Fuller
invertebrate communities gradually change as a result of the
policy of non-intervention and light grazing by deer. An understanding of how wildlife responds to the developing
vegetation mosaics will inform long-term vegetation management at this and other sites. In total, 96 plots (5m
radius) are located throughout the dying Ash and the mixed scrub. Tree, shrub and ground vegetation cover will be
estimated at each of these plots on an annual basis. The plots will also form sample units for plants and selected
invertebrate groups. Birds will be counted at points along line transects running through all the habitat types.
Magnesian limestone grassland, South Yorkshire
The Yorkshire Wildlife Trust’s Sprotbrough Flash reserve contains
small areas of limestone grassland that are rich in plant species.
This grassland type is localised along a thin belt running north–
south between Nottinghamshire and Durham. The site is a former
quarry that was landfill, with the original topsoil restored. Birch
Betula woodland subsequently regenerated over part of the site,
while other areas were kept free of trees by grazing. Over the past
decade, Hebridean sheep have been used to graze within fenced
plots on the open grassland and the woodland has been partially
cleared, resulting in a species-rich diverse sward structure with low
patchy scrub. Grazing may not be sustainable in the future owing
Grassland at Sprotbrough Flash reserve,
to ongoing antisocial problems. The management question is
South Yorkshire. Rob Fuller
whether the interest of the site can be maintained through periodic
scrub management. Specifically, how do the ground flora and sward invertebrates change with increasing scrub
development, and can ‘tipping points’ be identified beyond which scrub growth becomes detrimental to the
conservation interest? Potentially, monitoring of plants and invertebrates following scrub removal could help to
identify the optimal successional stages that provide the maximum conservation benefits and, in turn, these could
inform adaptive management of the site.
182 British Wildlife February 2016
BWM27_3 07 monitoring-v2.indd 182
29/01/2016 13:49

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