A study of habitats and ground flora in broadleaved woodlands planted by Moor Trees in the Dartmoor National Park and surrounding area

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1 A study of habitats and ground flora in broadleaved woodlands planted by Moor Trees in the Dartmoor National Park and surrounding area Summary Report Woodland near Scorriton Authors: Bethan Stagg and Dr Maria Donkin With thanks to: Mark Millard and the many volunteers that took part in survey work

2 Contacts Bethan Stagg (OPAL Community Scientist), Moor Trees, The Old School Centre, Totnes Road, South Brent, TQ10 9BP - bethan@moortrees.org, tel , Dr Maria Donkin (Project leader OPAL South West), University of Plymouth, School of Biological and Biomedical Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, - m.donkin@plymouth.ac.uk, tel ,

3 Dr Bea Campbell (Trustee of Moor Trees), Moor Trees, The Old School Centre, Totnes Road, South Brent, TQ10, - bea@moortrees.org, tel Introduction Moor Trees is a woodland restoration and conservation volunteering charity established in Each year the charity works with hundreds of volunteers to plant woodlands in and around the Dartmoor National Park, using trees grown from locally collected seed in the charity s tree nurseries. Moor Trees has now planted sixteen woodlands, with an average size of 2.3 hectares, which the charity hopes will mature into woodland habitats comparable to the adjacent mature woodland (figure 1). In 2008 Moor Trees formed a partnership with the University of Plymouth as part of OPAL, a national initiative engaging people in monitoring their local environment. This summary report presents an overview of a baseline ground flora survey carried out by OPAL in eight of the woodland sites. The aim is to replicate the ground flora survey on a three-yearly basis, to investigate whether these woodlands in time develop a characteristic woodland ground flora. An accompanying instruction manual is provided to enable this and provides an ideal student field project, with practical assistance from Moor Trees.

4 Figure 1. Woodland planted at Wedlake site (left) and ground flora in mature woodland adjacent to sites Scorriton Down The field and the site surveys OPAL selected eight Moor Trees woodland sites that were as comparable as possible in previous land-use (semi-improved pasture), size and tree species composition but diverse in altitude and planting age, from 2002 to 2008 (figure 2). Student volunteers carried out Phase 1 Habitat surveys of the eight sites and surrounding landscapes May - June 2008 (figures 3-4 and see instruction manual) Figure 2 Selected woodland sites

5 Figure 3. Student volunteers carrying out a Phase 1 habitat survey at Courtgate Orchard Figure 4. Phase 1 habitat survey map of Courtgate Orchard (see instruction manual for maps of all sites)

6 Moor Trees volunteers installed ten permanent sampling points in each field site (numbered stakes) and ten temporary points in each neighbouring pasture and mature woodland habitat. Volunteer groups carried out vegetation surveys at all points using 0.25m2 grid quadrats July Sept (figures 5 & 6). Since sites could not be sampled prior to planting, the pasture provided a reference point for origins of the ground flora, whilst the mature woodland provided an aspiration of what the planted woodland might become. In other words the sampling aimed to capture a picture of the past, present and future of the planted woodland. Figure 5. Moor Trees volunteers locating sampling points with GPS and conducting quadrat survey at Wedlake Farm. Figure 6. Map of sampling points in planted woodland and neighbouring pasture and mature woodland at Hillyfield Farm.

7 A variety of volunteer groups carried out vegetation quadrat surveys, including children from two primary schools, excluded young people from regeneration charities Groundwork and BTCV, long-term unemployed, retired and student adults from Moor Trees and employees of a university institute taking part in a teambuilding event. Nearly all volunteers were botanical novices and a variety of methods were used to assist the volunteers with plant identification, including photo ID sheets (see instruction manual), naming games in which the volunteers would develop their own memorable names for unfamiliar species, specimen trays and craft activities that developed botanical skills (figure 7) Figure 7. From top left: Volunteer from Groundwork takes a break during a survey at Scorriton. BTCV participant in Plymouth selecting plant species for extracting plant dyes Devon Wildlife Trust participant at Lydford selecting plant species for hedgerow basketry

8 Results of ground flora survey Species diversity comparisons Plant species diversity is a measure of the number of plant species in a sample and how rare or common those species are in the sample. The plant species diversity measures in this report do not include grass species because these proved too difficult for the volunteers to identify in grazed pastures. A statistical model called a General Linear Model was applied to the data in the computer application SPSS (version 17) to investigate the influence of planting site age, size, altitude, aspect, slope, proximity of mature woodland and plant species diversity of neighbouring woodland and pasture on the plant species diversity of planted woodland. Altitude, slope and aspect data were derived from ArcGIS. There were no significant relationships identified between any of these above predictor variables and species diversity (Shannon Weiner measure) of planted woodland sites in the subsequent ANOVA statistical test (R2 = 0.589, degrees of freedom = 7, p = 0.108). In other words, we can say fairly confidently that none of the above factors have much influence on the species diversity of the planted woodlands at this point in time. Plant community analysis A plant community is simply the collection of different plant species growing together in a habitat. The computer application PRIMER (version 6) allows us to compare the plant communities in different habitats, to see the extent to which they overlap in the species they contain. Figure 8 depicts the plant communities in the planted woodland, mature woodland and pasture habitats. The figure suggests that the three plant communities are distinctly different; a statistical analysis confirms that these three communities are indeed significantly different from each other.

9 Ancient Woodland Indicators Ancient woodland indicators were identified in the vegetation data using the Wildflower Key by Rose (2006). Figure 9 indicates that all one of the vegetation samples that featured ancient woodland indicators were located in mature woodland. The phase 1 plant species lists reveal that ancient woodland indicators were occasionally present in the other habitats but clearly the sampling was not at sufficiently frequent intervals to capture this information.

10 Discussion of survey techniques and results The results from the first year of the study have not provided much new information but this is not surprising as the main purpose of the study is to monitor vegetation changes over time. This study s main achievements so far are to pilot and explore the use of novice volunteers for botanical surveying and establish a study protocol that will both inform the woodland restoration work of Moor Trees and provide a resource for vocational student undergraduate and postgraduate field projects. It is very encouraging that the plant communities of mature woodland, planted woodland and pasture are already distinctly different. This will make it easier to monitor the anticipated transition of newly and recently planted woodland sites to a mature woodland community. The prevalence of ancient woodland indicators in the mature woodland plant community provides the opportunity to monitor whether these species are able to establish in planted woodlands. Distance of planted woodland from mature woodland is an important factor since such species are typically poor colonisers (Brunet, 2007). It is also important to identify ancient woodland indicator species in other neighbouring habitats, as these were sometimes present in hedgerows (Hillyfield) and in some cases were already present in the planting site (Dean Burn). A study of ancient woodland indicators should be carried out in spring as many of these species are geophytes (bulbous plants) and there may be no visible above-ground growth by mid summer. It is disappointing that the species data does not include grasses as this means the study will be unable to monitor how species diversity is affected by the conversion of the habitat from grassland to woodland. The vegetation survey originally aimed to focus on a number of easily identifiable grassland and woodland indicator species but there was no time to carry out the preparatory work required for this prior to the survey season and group bookings. In 2009 OPAL trialled an indicator species approach in a series of grassland assessments carried out in partnership with Plymouth City Council and this method proved very effective. Due to limited capacity and heavy rain OPAL was unable to carry out light canopy readings or tree composition and density within a defined radius of sampling points.

11 Moor Trees plants the saplings at variable densities across the planting site to mimic the patterns in natural woodland. These densities will affect light intensity, as will the age and vigour of trees around the sampling point. These variables could have a significant influence on ground flora composition and development and should be included in replicates of the ground flora survey. It is also worth noting that an easier way of marking permanent sampling points would have been to tie a coloured plastic ribbon to a tree; that way the quadrat would have been positioned a set distance from a tree, rather than from a wooden stake. In 2009 our volunteers carried out soil nutrient testing (NPK profiles) and OPAL s Soil and Earthworm survey on the study sites but there was insufficient data collected for analysis (see instruction manual). In 2009 and 2010 we aim to carry out the OPAL National Air Survey, which uses lichen species as biomonitors of nitrogen pollution. This study has, so far, carried out very little monitoring of the accuracy of volunteer data collection, through the use of replicate sampling using experienced botanists. Only one sample was replicated using an experienced botanist; the data was not found to be significantly different from the sample collected by volunteers, which is reassuring. Monitoring of this type was carried in the Plymouth grassland assessments mentioned above and should be included when this study is repeated in 2011 (figure 10). It will require a trained botanist to carry out replicates of at least four of the vegetation quadrat surveys, on the same day as the community volunteers carry out their surveys. Figure 10. Groundwork volunteers conducting grassland assessment in Plymouth

12 Background information on woodland Broadleaved woodland has been the natural vegetation for the British Isles since the last ice age but only 2% of its original amount remains, in the form of small isolated fragments (Peterken, 1996). From the early 1990s a number of government schemes have set out to encourage land owners to create native woodland, including the current Woodland Grants Scheme, which has contributed to a number of Moor Trees planting projects (Honnay et al. 2002). The habitat fragmentation typical of most woodland leads to greater vulnerability to environmental stress and loss of species that are dependent on closed canopy (Saunders et al. 1991; Jules & Rathcke 1999). Habitat fragmentation is also likely to restrict the migration of woodland species northwards or to higher altitudes, as a result of climate change. Many of our native woodland species are already close to the Northern edge of their distributions, particularly our two native oak species, which may not be such a familiar sight in our future landscapes (pers. Comm. Crawford). Packham et al. (1992) observed that whilst government schemes increase tree cover they do not always create plant communities characteristic of the woodlands they seek to replace. Davie et al. (1998) identified that this may be due to their isolation from potential seed sources, poor dispersal and colonisation ability typical of woodland ground flora species and competition from vegetation established by previous past land use. The poor dispersal of many ground flora species has led to them being used as ecological indicators of the presence of old growth woodland (Peterken, 1996). Planting new woodlands adjacent to existing woodland may promote colonisation by woodland species, even as distances of more than 200m, although colonisation may only advance up to 3 metres a year (Brunet, 2007). Within mature woodland, light is considered to be the most influential factor on the composition of ground flora and light intensity is affected by seasonality, human influence or natural processes that include tree decay and gap formation (Hooley & Cohn, 2003). Soil fertility is also an important factor and woodland plants may be out-competed by more vigorous weed species in high fertility soils, particularly if the previous land-use is pasture (Endels et al. 2004). Woodland plants will usually start to colonise a new site a few years after trees are established and become more

13 prevalent following canopy closure, which takes about ten years in densely planted woodland (Brunet, 2007). Flinn & Vellend (2005) identified that the number of woodland species in a planted woodland increases with age, with 70- year-old woodlands in Europe and North America having a species composition comparable with that of many ancient woodlands. So as long as the canopy remains relatively closed, shade-tolerant woodland flora will easily colonize plantations with light demanding tree species such as oak. There are a number of methods for speeding up the colonisation by ground flora, including soil seed bank transferral, direct sowing, planting, and large-scale translocation (Davy 2002). Local provenance is an important issue as local genetic strains of species are expected to perform better in those plant communities than imported genetic strains (Forestry Commission, 2008). Contacts Bethan Stagg (OPAL Community Scientist), Moor Trees, The Old School Centre, Totnes Road, South Brent, TQ10 9BP - bethan@moortrees.org, tel , Dr Maria Donkin (Project leader OPAL South West), University of Plymouth, School of Biological and Biomedical Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, - m.donkin@plymouth.ac.uk, tel , Dr Bea Campbell (Trustee of Moor Trees), Moor Trees, The Old School Centre, Totnes Road, South Brent, TQ10, - bea@moortrees.org, tel