A Survey and Assessment of Soil Ph and Nutrient Status on Sites of High Botanical Value, 2014

Home , Calcareous grassland, Long Lye, Rampisham Down, Ripon Parks, Tealham and Tadham Moors, West Sedgemoor

A survey and assessment of soil pH and nutrient status on sites of high botanical value, 2014

Report to Natural England 04 May, 2016

Philip J. Wilson & Belinda R. Wheeler Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

Dr Philip J Wilson MIEEM – lead author. Pennyhayes, Shute, Axminster, Devon. EX13 7QP. 01297 552434 / 07803 126929. [email protected]

Dr Belinda R Wheeler MIEEM Cloudstreet, Brentor Road, Mary Tavy, Tavistock, Devon. PL19 9PY. 01822 810013 / 07801 011150. ecology@belindawheeler.co.uk

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Contents

Acknowledgements ...... 5 Summary ...... 6 1 Introduction ...... 9 2 Methods ...... 12 2.1 Vegetation survey ...... 12 2.2 Soil sampling ...... 12 2.3 Condition assessment ...... 13 2.4 Soil analysis ...... 14 2.5 Analysis of results ...... 16 3 Results ...... 18 3.1 Sample overview ...... 18 3.2 Problems encountered during the project...... 19 3.3 Results from analysis of 2014 results...... 20 3.3.1 Key to results tables ...... 20 3.3.2 Differences in soil variables between BAP priority habitats ...... 20 3.3.3 Differences in soil variables in relation to vegetation condition ...... 22 3.3.4 Differences in soil variables in relation to management ...... 22 3.3.5 Differences in soil variables within each BAP priority habitat in relation to NVC stand type, vegetation condition and management type ...... 24 3.4 Analysis of the combined dataset from 2012 and 2014 ...... 32 3.4.1 Correlations between soil variables ...... 33 3.4.2 Differences in soil variables between BAP priority habitats ...... 36 3.4.3 Differences in soil variables in relation to vegetation condition ...... 37 3.4.4 Differences in soil variables in relation to management type ...... 37 3.4.5 Differences in soil variables within each BAP priority habitat in relation to NVC stand type, vegetation condition and management type ...... 38 3.5 Summary of results of differences in soil properties for individual BAP priority habitats and NVC communities, vegetation condition and management type ...... 47 3.5.1 Lowland calcareous grassland ...... 47 3.5.2 Lowland dry acidic grassland ...... 48 3.5.3 Lowland meadow ...... 48

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

3.5.4 Lowland heath ...... 48 3.5.5 Purple moor-grass and rush-pasture ...... 49 3.5.6 Coastal and floodplain grazing marsh ...... 49 3.5.7 Upland calcareous grassland ...... 49 3.5.8 Upland meadow ...... 50 3.5.9 Habitat condition ...... 50 3.5.10 Management type...... 50 4 Discussion ...... 51 4.1 Differences between the 2012 and 2014 surveys ...... 51 4.2 Soils and UK BAP priority habitats ...... 51 4.3 Soils and NVC communities ...... 53 4.4 Soils and vegetation condition ...... 56 4.5 Soils and site management ...... 59 5 Conclusions ...... 61 6 References ...... 64 Appendices ...... 66 Appendix 1. SSSI units from which soil samples were collected in 2014...... 67 Appendix 2. SSSI units listed for sampling from which soils were not collected...... 79 Appendix 3. Samples lost by courier...... 81 Appendix 4. NVC communities referred to in the text and tables...... 82

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Acknowledgements This project was supported by the Rural Development Programme for England, for which Defra is the Managing Authority, part financed by the European Agricultural Fund for Rural Development: Europe investing in rural areas. We are grateful to the landowners for access permission and to the various landowners, agents and graziers for discussing the management of their sites with us. Natural England advisors provided useful information on site ownership and access. Most fieldwork was carried out by the authors but we would also like to acknowledge the help of our additional field surveyors: Dr Clive Bealey, Dominic Price, Gail Quartly-Bishop, Marian Reed, Jude Smith, Michael Gadd and Nick Stewart. We particularly thank Jonathan Bradley (Lead Advisor of the Evidence Programme Team 2 for Natural England) for his management of this project, his colleague Kathryn Oddie for assistance with project management of the soil analysis, and Susan Ward for circulating letters to site owners. Carol Miltenberg assisted with the submission of samples onto the Natural England system. Marian Reed provided comments on this report. Chris Chesterton, Steve Peel, David Martin and Matt Shepherd of Natural England gave helpful comments on the 2012 report and the draft of this report. NRM Ltd carried out all soil pH and nutrient analysis.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Summary 1. Soil chemistry and structure are among the key factors affecting the composition and condition of vegetation. Knowledge of soil conditions is therefore essential when considering the impact of management on vegetation of conservation importance, predicting the outcome of management changes and understanding constraints that might prevent sites achieving favourable condition. Changes in soil properties may under some circumstances be the drivers of change in vegetation condition. 2. In order to better understand the edaphic processes underlying the composition and condition of vegetation of conservation value on statutorily protected sites, and the potential for the restoration to favourable condition of vegetation in unfavourable condition, Natural England commissioned a programme of soil sampling on selected SSSI units during the autumn of 2012. This was intended to complement SSSI condition assessments carried out that year. Results from this survey form the subject of an earlier report. 3. Soils were sampled in four broad habitats: (1) acidic grassland, (2) neutral grassland, (3) calcareous grassland, and (4) fen, marsh and swamp: with samples collected from areas assessed as in favourable and unfavourable condition in some units. The condition of the sampled vegetation was assessed in the field using generic guidelines for the habitat type present. The aims were to enable comparison of soil variables between different broad habitat types and where possible different NVC communities within these broad habitats, to compare soils between vegetation in favourable and unfavourable condition, and where information allowed, between vegetation under different management regimes 4. A second selection of sites was made in 2014. This was intended to be compatible with the 2012 survey so that the results could be analysed both separately and after some transformation of the 2012 data, as an amalgamated dataset. A total of 602 soil samples were collected from 333 SSSI units across 72 SSSIs during 2014. These were located throughout England from West Cornwall to Upper Teesdale. 5. Soil samples were analysed for pH, available phosphorus (Olsen’s method), potassium, magnesium, total nitrogen, organic carbon, total phosphorus, loss on ignition and soil texture. 6. Statistical analysis was carried out using a generalised linear model to determine associations between soil chemical variables and site characteristics. Data from 2014 was first analysed alone and then was amalgamated with the results of the survey carried out in 2012. The combined dataset included 986 samples; 273 lowland meadow samples, 238 lowland calcareous grassland samples, 125 coastal and floodplain grazing marsh (CFGM) samples, 109 purple moor-grass and rush pasture (PMGRP) samples, 101 lowland acidic grassland samples, 74 lowland heathland samples, 25 upland meadow samples and 14 upland calcareous grassland samples. Of these, 445 stands were considered to be in favourable condition while 499 were in unfavourable condition.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler 7. Results demonstrated that: a. Lowland calcareous grassland was defined by high pH, high potassium and low available phosphorus b. Lowland acidic grassland had low pH (but higher than lowland heath), high available phosphorus but low total phosphorus, high potassium, low magnesium and low organic matter. c. Lowland meadow had moderate levels of all variables apart from potassium and magnesium which were high. d. Lowland heath was defined by low pH, low available phosphorus and total phosphorus, low potassium and magnesium, high organic matter but low total nitrogen. e. PMGRP is a diverse habitat and levels of all variables were moderate; f. CFGM was defined by high pH, high available phosphorus, high potassium and high organic matter. g. Upland calcareous grassland had moderate pH, low available phosphorus, low magnesium and low organic matter. h. Upland meadow had low available phosphorus, low potassium and low organic matter. 8. Unfavourable condition was related to high available phosphorus levels. This was significant for the whole dataset, and individually for the priority habitats: lowland calcareous grassland, CFGM and lowland meadow. Potassium levels were higher in vegetation in unfavourable condition for the whole dataset and individually for the priority habitats: calcareous grassland, lowland heathland, lowland meadow and lowland acidic grassland; while magnesium levels were higher in favourable condition calcareous grassland and lowland meadow. 9. These results suggest that low phosphorus availability is essential for favourable condition in calcareous and mesotrophic grasslands, and supports the criteria for high botanical enhancement potential in the FEP guidelines for Higher Level Stewardship. Current Countryside Stewardship guidelines are similar to those for HLS. Soil waterlogging and drought impose other stresses on lowland acidic grasslands, fen meadows and inundation grasslands, and in these habitats, phosphorus availability may not be so important. 10. The results raise the possibility that on some SSSIs, phosphorus status may have increased since they were designated, causing a decline in their condition and a risk to their continued priority habitat status. 11. Associations were found between soil variables and NVC communities. Overall, pH, availability of phosphorus and organic matter content were the most important factors, with high magnesium levels important for some communities such as H5a and MG4. 12. Management type was also associated with soil chemistry, although causality was often obscure. There appeared to be a strong association between low organic matter content and under-management, with mixed grazed and mown sites having the highest

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler levels of organic matter. This may have important implications for carbon storage in semi-natural habitats.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler 1 Introduction

Soil chemistry and structure are among the key factors affecting the composition and condition of vegetation (Anon, 2008), and many experiments have demonstrated the decline in botanical diversity of habitats with the addition of inorganic fertilisers containing nitrogen, phosphorus and potassium (Mountford et al., 1994; Willems et al., 1996). A programme of soil sampling in grasslands managed under the Environmentally Sensitive Areas Scheme in England also demonstrated the connections between levels of soil nutrients and botanical species-richness and the frequency of stress tolerant species (Critchley et al., 2001). Knowledge of soil conditions is therefore essential when considering the impact of management on vegetation of conservation importance, predicting the outcome of management changes and understanding constraints that might prevent sites achieving favourable condition. Changes in soil properties may under some circumstances be the drivers of change in vegetation condition.

An understanding of soil properties is not only necessary when endeavouring to understand the processes underlying habitat condition, but is also essential information when undertaking the restoration and recreation of habitats of conservation value (Tytherleigh, 2008). Levels of phosphorus ions available for uptake by plants are thought to be particularly important in determining the outcomes of interspecific competition in plant communities and thus the composition and condition of vegetation (Janssen et al., 1998; Critchley et al., 2001). Threshold levels of available phosphorus have been specified for the potential for botanical enhancement of species-poor grassland within agri-environment schemes (Anon, 2010).

In order to better understand the edaphic processes underlying the composition and condition of vegetation of conservation value on statutorily protected sites, and the potential for the restoration to favourable condition of vegetation in unfavourable condition, Natural England commissioned a programme of soil sampling on selected SSSI units during the autumn of 2012 (Table 1). This was intended to complement SSSI condition assessments carried out that year.

Soil sampling was carried out in specified broad habitat types within SSSI units (http://jncc.defra.gov.uk/page-2433). Sampling was undertaken in four broad habitats: acidic grassland, neutral grassland, calcareous grassland and fen, marsh and swamp, with samples collected from areas assessed as in favourable and unfavourable condition in some units. A subjective condition assessment of the vegetation sampled in each unit was also carried out. The aims were to enable comparison of soil variables between different broad habitat types and where possible different NVC communities within these broad habitats, to compare soils between vegetation in favourable and unfavourable condition, and where information allowed, between vegetation under different management regimes (Wilson, 2014). Results are summarised in Table 2.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Table 1. Numbers of soil samples collected by region in 2012.

Region Number of Number of Total number sites units of samples Bedfordshire, Cambridgeshire and Breckland 28 65 76 Essex and Hertfordshire 6 13 16 Hampshire and Isle of Wight 14 60 71 Oxfordshire and Buckinghamshire 11 17 21 Surrey, Berkshire and London 15 48 65 Herefordshire 3 4 7 Lowland Derbyshire and Nottinghamshire 5 11 22 Northamptonshire, Leicestershire and Rutland 8 13 23 Staffordshire, Birmingham and the Black Country 2 14 24 Warwickshire and Worcestershire 33 36 40 Shropshire 3 11 19 Totals 128 293 384

Table 2. Summary of results from soil sampling carried out in 2012.

Broad Acidic grasslands Low pH, higher available phosphorus than calcareous habitat type grassland, lower total Phosphorus than wetland Calcareous grasslands High pH, lower available phosphorus than all other habitats Wetland Total phosphorus, Loss on ignition, Total nitrogen and Organic matter higher than in all other habitats. Higher available phosphorus than calcareous grasslands and neutral grasslands Neutral grassland Higher magnesium content than all other habitats

Habitat Unfavourable available phosphorus higher in wetland and neutral condition grasslands in unfavourable condition. Favourable Magnesium content higher in favourable condition neutral grassland.

NVC stand Calcareous grasslands CG3 samples had higher pH than CG2 and MG6 samples, type CG5 samples had higher potassium content than CG2 samples. Neutral grasslands MG5c samples had the lowest pH. MG11a samples had the highest Olsen’s P, Total P, Total N, Organic matter and Loss on ignition. MG4 samples had higher total P than MG5b samples. MG1 samples had higher pH, K and Mg than MG6.

Management Hay-cut Hay-cut neutral grasslands had lower Olsen’s P but higher Mg than grazed or unmanaged grasslands. Grazed Grazed grasslands had higher organic matter than unmanaged grasslands. Unmanaged Unmanaged neutral grasslands had lower Total N and lower loss on ignition.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

While these results gave a valuable insight into the role of soil chemistry in determining vegetation composition and condition, several shortcomings and gaps were noted. Among these were the lack of sufficient samples from acidic grasslands and heathlands.

A second selection of sites was therefore made in 2014 with the aim of adding more data to the 2012 sample. It was intended that this 2014 survey should be compatible with the 2012 survey so that the results could be analysed both separately and as an amalgamated dataset. The opportunity was taken during the 2014 project to improve the collection of information about vegetation type, condition and management.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler 2 Methods

A spreadsheet of site details was provided by Natural England. This included name of the SSSI to be visited and the individual SSSI units to be sampled, the Natural England advisor name, site owner and contact details. Sites were distributed throughout England from West Cornwall to Durham and Cumbria. Selection was made by Natural England staff to complement the selection made in 2012 and to ensure that particularly for lowland acidic grassland and lowland heathland, sufficient samples were collected to permit meaningful analysis.

All relevant NE advisors were contacted in order to determine whether the owner/manager contact details were correct. NE advisors also provided information about sites, and in some cases this resulted in the selected units being changed. The spreadsheet was amended accordingly where necessary. A letter was circulated to all landowners informing them of the intention to collect soil samples from their land. The owners or managers of all sites were then contacted by telephone or email prior to making any soil sampling visits to arrange access. Where owners were reluctant to allow access or where after repeated attempts the owner could not be contacted the site was withdrawn from the survey. The SSSI unit map for each site was downloaded from the Magic website (http://magic.defra.gov.uk/). All sites surveyed are given in Appendix 1, sites listed but not surveyed in Appendix 2, and those where the samples were lost by the courier in Appendix 3.

A team of eight surveyors was used, all of whom had extensive experience of habitat survey and assessment in England.

2.1 Vegetation survey In each unit the major UK Biodiversity Action Plan (BAP) priority habitats were identified, and further identification to National Vegetation Classification (NVC) sub-community level (after Rodwell, 1991–2000) was made where possible. All NVC communities and sub- communities mentioned in the report are listed in Appendix 4. Species lists and quadrats were not collected, and all vegetation classification relied on the experience of the surveyors.

2.2 Soil sampling Soil sampling followed methods described in Natural England Technical Information Note TIN035 (Tytherleigh, 2008). A standard pot auger with a length of 7.5cm was used for sampling all grasslands and mires. The only regularly cultivated site (Fivehead Arable Fields) was sampled using a cheese corer with a sampling depth of 20cm (approximately standard ploughing depth).

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler A soil sample was taken from each of the major habitats present, with the aims of collecting soil from areas in both favourable and unfavourable condition and collecting soils representative of the whole unit. In practice the maximum number of samples collected from any single unit was five, and in many units only single samples were taken. In some cases where the SSSI unit was very large (some in the New Forest SSSI were more than 1km2), soil samples were collected from a representative part of the unit selected using the experience of the surveyor. A series of at least 25 soil cores was collected from each sampled habitat to a total of between 0.5kg and 1kg and bulked to form a single sample. The SSSI name, the unit number and the number of the sample (relating the sample to the condition assessment and site description) was written on the outside of the bag.

2.3 Condition assessment

Table 3. Attributes recorded in the rapid condition assessment. * Coastal and floodplain grazing marsh priority habitat is an amalgam of other habitat types; those sampled here included lowland meadow and purple moor-grass and rush pasture, and their condition was assessed using the attributes specified for these habitats.

Attribute Priority habitat Frequency Frequency % cover of % cover % cover % Heather of +ve of –ve non-grass waterlogging B. pinnatum cover age indicators indicators spp indicators B. erectus scrub structure Lowland calcareous * * * * * grassland Coastal and floodplain grazing marsh* Upland calcareous * * * * * grassland Lowland * * * * * meadow Upland * * * * * meadow Acidic * * * grassland Purple moor- grass & rush * * * * pasture Lowland heath * * *

A brief condition assessment and description were made for each feature sampled. This assessment did not use site specific conservation objectives and the favourable condition tables (FCTs) for each SSSI were not consulted, Many units contain multiple interest features often not listed in the FCTs, and in many cases, sampling all interest features present would require a lengthy mapping exercise and programme of soil collection. The approach taken aimed at sampling the major interest features present in a unit and 13

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler gathering sufficient samples from each priority habitat to enable meaningful statistical analysis of the whole dataset. Condition assessment for the sampled interest features were carried out rapidly using the experience of the surveyors according to generic guidelines for the habitat type present (Robertson & Jefferson, 2000; http://jncc.defra.gov.uk/page- 2199)(Table 3). Each condition assessment carried out applied to the area within which the soil was being sampled rather than the whole unit, and in many cases the SSSI unit assessment is likely to differ from the assessments made here. Only two categories of condition, favourable and unfavourable, were used because of the lack of past comparable data.

2.4 Soil analysis Soils were gathered centrally and information about each sample was entered onto Natural England’s soil submission system. All samples were then sent for laboratory analysis1. Analyses included soil pH (water), available phosphorus (Olsen’s P: mg/l), phosphorus index2 (Index P: 0–9), soil potassium (Soil K: mg/l), potassium index (Index K: 0–9), soil magnesium (Soil Mg: mg/l), magnesium index (Index Mg: 0–9), total nitrogen (Total N: %), loss on ignition (%), total phosphorus (Total P: mg/l), organic carbon (%) and soil texture (see Fig. 1.). The relationships between available phosphorus, potassium, magnesium and the indices are shown in Table 4.

Table 4. The relationship between nutrient content in mg/l and the ADAS Soil Index

Index Interpretation available phosphorus Potassium Magnesium 0 Very low 0–9 0–60 0–25 1 Low 10–15 61–120 26–50 2 Low–Medium 16–25 121–240 51–100 3 Medium–High 26–45 241–400 101–175 4 High 46–70 405–600 176–250

Loss on Ignition is a direct measure of the organic matter content of the soil, and methods used by NRM laboratories have been developed in order to avoid bias due to combustion of calcium carbonate (which can lead to higher estimates for chalky soils) or evaporation of water held in clay lattices (NRM, undated).

Soil texture describes the mixture of particle sizes in a sample (Shaw, 2008), classified as clay, silt or sand or combinations thereof (Table 5). Soils with higher proportions of sand particles are more freely draining, while the drainage of those with higher proportions of clay is more impeded (Fig. 1). Loam describes soils with intermediate proportions of these particles. Although only partly quantitative these are useful descriptors of the physical properties of the soils.

1 NRM Laboratories, Cawood Scientific Ltd. 2 ADAS indices (http://yara.co.uk/images/1_YAS_ADAS_Index_Tech_Bulletin_tcm430-99314.pdf) 14

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

Table 5. Soil particle sizes used in descriptions of soil texture.

Particle class Particle size (mm) Clay < 0.002 Silt 0.002–0.06 Sand 0.06–2.0 Fine sand 0.06–0.2 Medium sand 0.2–0.6 Coarse sand 0.6–2.0

Figure 1. Triangular ordination of soil texture categories (From Shaw, 2008).

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler 2.5 Analysis of results Quantitative results from the chemical analysis of soil samples were analysed using the general linear model option of Minitab 13. This performs a univariate analysis of variance (ANOVA) for each response variable in an unbalanced design (i.e. where there are unequal numbers of samples for each level of the independent variables). Following the ANOVA for each variable, a series of pairwise comparisons were made between all pairs of levels of the independent variables using the Tukey test which gives t-values for each pair and allows determination of significance (p-value) of the differences between each pair. As a large number of pairwise comparisons were made, significance at the p < 0.05 level were treated with caution as such differences would be expected to occur by chance at a frequency of one in every 20 tests. Data transformations were found to be unnecessary and none were carried out.

The results of the 2014 survey were first considered in isolation. The 2014 dataset was then amalgamated with the 2012 dataset and a combined analysis was performed.

Four independent variables were considered:

1. UKBAP priority habitat. The majority of samples were taken from lowland calcareous grassland, coastal and floodplain grazing marsh (CFGM), lowland heathland, lowland meadow, purple moor-grass and rush-pasture (PMGRP) and lowland dry acidic grassland. Samples were also collected from upland meadow and upland calcareous grassland. The few samples collected from lowland fen, swamp, upland acidic grassland, arable field margins and woodland were not included in the analysis. Where samples were collected from stands of Pteridium aquilinum or from scrub, these were treated as stands of the adjacent habitat but in unfavourable condition in situations where the P. aquilinum or scrub was obviously recently invasive. 2. Habitat condition (favourable or unfavourable). A rapid assessment of condition was made for each interest feature sampled using the experience of the individual surveyors in these habitats within the context of Common Standards Monitoring (http://jncc.defra.gov.uk/page-2217). Interest features were classified as in either “favourable” or “unfavourable” condition. The “unfavourable” category was not divided into the recovering, no change or declining sub-divisions of SSSI unit condition assessments. 3. NVC stand type. Where possible and where surveyor expertise allowed, a rapid determination of NVC type (Rodwell, 1991a &b, 1992, 1995, 2000) was carried out (Table 6): in some cases this was only to community level, although many stands were identified to sub-community. 4. Management. Where possible the most frequent management practice was identified for each sampled vegetation stand. The following categories were present in sufficient numbers to allow use in the analyses: cattle-grazing, sheep-grazing,

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler pony-grazing, mixed-grazing, cut (mown for hay/silage, cut for conservation management, including stands where the aftermath is grazed.), and unmanaged (included sites which were severely under-managed).

Table 6. NVC types sampled in sufficient numbers to allow their use as independent variables in the combined 2012 and 2014 analysis. See Appendix 4 for community names.

BAP Priority Habitat NVC Community Lowland calcareous grassland CG2a, CG2c, CG3a, CG3b, CG3d, CG5a Coastal and floodplain grazing-marsh MG6a,MG7, MG11a Lowland heathland H1, H2, H4, H5a, M16a Lowland meadow MG1e, MG4, MG5a, MG5b, MG5c, MG6a, MG6b, MG9 Purple moor-grass and rush-pasture M22a, M22b, M23a, M23b, M25a, M25c, MG10a Lowland dry acidic grassland U1b, U1d, U4b, U4e, U20 Upland meadow MG2, MG3, MG6b

The 2012 and 2014 datasets were edited to remove samples in priority habitats with few cases (e.g. arable field margins, lowland fen, swamp, woodland, dense bracken in the absence of adjacent priority habitat, unidentified). Upland meadow and upland calcareous grassland samples were only available from the 2014 survey.

Quantitative response variables were: pH, available phosphorus determined using Olsen’s method (mg/l), magnesium (mg/l), potassium (mg/l), total nitrogen (%), total phosphorus (%), loss on ignition (%), organic carbon (%).

Soil texture was examined in the 2012 survey (Wilson, 2014) but as the results demonstrated that it contributed little to the understanding of past or future management, this was not repeated for the 2014 survey.

The soil association for each site was provided for the 2012 samples only but was not used in the analysis due to complexity of the dataset and insufficient replication of the majority of association types.

The whole dataset was analysed initially with respect to priority habitat, condition and management type in order to detect any relationships between these variables and soil characteristics. Following this first analysis, the dataset was divided into sub-sets corresponding to the priority habitats in order to determine any associations between soil characteristics and different NVC communities.

A matrix of Pearson’s correlation coefficients was calculated for all quantitative soil variables in order to determine whether there were any co-linearities. These are variables which effectively explain other variables and therefore add no additional information to the analyses.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler 3 Results

3.1 Sample overview In 2014 soil samples were collected from a total of 333 units at 72 SSSIs. (Table 7, Appendix

1). The total number of samples collected was 626. Subsequently 36 samples from 20 SSSI units were lost by couriers delivering samples to the laboratories; surveyors were able to re- collect 15 of these samples from 11 SSSI units resulting in a final loss of 21 samples from 9 units (Appendix 3).

Table 7. Numbers of soil samples collected by county in 2014

County Number of sites Number of units Number of samples Avon 2 9 23 Berkshire 2 3 6 Buckinghamshire 2 8 14 Cambridgeshire 1 4 10 Cornwall 8 19 50 Cumbria 1 7 11 Derbyshire 1 7 13 Devon 6 10 25 Dorset 9 39 68 Durham 1 18 32 East Sussex 1 10 21 Essex 1 4 9 Gloucestershire 2 5 6 Hampshire 3 57 99 Hereford and Worcester 2 17 31 Lancashire 1 5 9 Leicestershire 1 9 16 North Yorkshire 3 15 20 Somerset 13 33 56 Staffordshire 2 10 19 Suffolk 2 12 25 Surrey 1 6 6 West Sussex 2 6 11 Wiltshire 4 11 22 Total 71 324 602

Samples were not collected from 35 of the units originally listed (Appendix 2). The most frequent reason for lack of sampling was the inability to obtain access permission from site owners. For one New Forest unit, four Wyre Forest units and one Upper Teesdale unit the ownership was not known. Access permission was not given either because of owner refusal or due to inability to contact the owner (one unit of Brickworth Down, Ash to

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Brookwood Heaths; Park Farm Meadows; Rampisham Down; and one unit of Thursley, Hankley and Frensham Heaths).

Chichester Harbour Unit 25 and River Camel Unit 74 were withdrawn before survey on the advice of the Natural England advisor. All River Derwent units were also withdrawn on the NE advisor’s recommendation. The two proposed units at Hamps and Manifold Valleys were withdrawn and three more suitable units were substituted. A woodland unit at Duncton-Bignor Escarpment was also replaced by an adjacent unit with calcicolous grassland. One unit at Ripon Parks and one at Rutland Water were withdrawn because they were open water.

Five units were not sampled because of difficulty of access and safety issues. These included Daddyhole Plain and unit 3 of Hope’s Nose to Walls Hill where cliff descent would have been required. Brickworth Down unit 8 was not sampled because of potential conflict with a traveller encampment.

The distribution of SSSI units where soil samples were collected within UKBAP priority habitats is given in Table 8. It should be noted that some units contain more than one sampled priority habitat.

Table 8. Numbers of sampled units by UKBAP priority habitats

BAP Priority Habitat 2012 2014 Lowland acidic grassland 19 50 Lowland calcareous grassland 96 69 Lowland heathland 2 48 Purple moor-grass and rush-pasture 34 42 Coastal floodplain and grazing marsh 0 22 Lowland meadow 139 84 Reedbed 0 1 Coastal sand dunes 0 2 Upland acidic grassland 0 1 Upland calcareous grassland 0 10 Upland hay meadow 0 18 Arable 2 2 Woodland 4 3 Salt marsh 0 1 Lowland fen 3 3

3.2 Problems encountered during the project. Overall the soil sampling programme proceeded well. The methods for sample collection were rapid and efficient and the pot auger proved to be very well designed for collecting multiple soil cores.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler At most sites the location of suitable vegetation stands for sampling was straightforward and the identification of stands to NVC community was possible: as far as possible identification was made to sub-community. At a few sites grassland or heathland was not present and where possible alternative SSSI units were sampled.

The major problem encountered was the incompleteness and inaccuracy of much of the ownership information held on ENSIS. It proved necessary to verify all ownership information with NE local advisors. In some cases it was very difficult or even impossible to locate site owners or managers. An amended list of owners resulting from our investigations into ownership is provided in a file separate to this report, which is accurate up to autumn 2014.

3.3 Results from analysis of 2014 results.

3.3.1 Key to results tables

In all tables the probability (p) of a significant result from an analysis of variance (ANOVA) or t-test is indicated as follows: *** p < 0.001, ** p < 0.01, * p < 0.05. In all tables P = phosphorus, K = potassium, Mg = magnesium. Olsen’s P, K, Mg, Total nitrogen and total phosphorus are expressed in mg/l, loss on ignition and organic carbon are %. Unman. = ungrazed or undermanaged. In all tables all figures indicate mean values per variable.

3.3.2 Differences in soil variables between BAP priority habitats

Soil pH was significantly higher in lowland calcareous grassland samples when compared with all other priority habitats (Table 9). CFGM, upland calcareous grassland, upland meadow, lowland meadow and PMGRP samples had significantly higher pH than lowland heathland and lowland dry acidic grassland samples. CFGM samples additionally had a higher pH than lowland meadow and PMGRP samples.

Available phosphorus (Olsen’s P) levels were higher in CFGM than in all other broad habitats, approximately four times higher than in lowland and upland calcareous grasslands, lowland heathland and upland meadow. Lowland dry acidic grasslands had higher levels of available phosphorus than lowland heathland, PMGRP and upland meadow.

Potassium levels were higher in CFGM samples than in lowland heathland, PMGRP and upland meadow samples. In addition, lowland heathland samples had lower levels than lowland calcareous grassland, lowland meadow and lowland dry acidic grassland, and lowland acidic grassland and lowland meadow had higher levels than PMGRP.

There were fewer differences between magnesium levels. CFGM samples had higher levels than all other habitats. Lowland meadow had higher levels than PMGRP and lowland acidic grassland samples.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

Table 9. Mean values for soil variables in BAP Priority Habitats, 2014 samples. LCG Lowland calcareous grassland, LDAG Lowland dry acidic grassland, LM Lowland meadow, LH Lowland heathland, PMGRP Purple moor-grass and rush-pasture, CFGM Coastal and floodplain grazing marsh, UCG Upland calcareous grassland, UM Upland meadow.

BAP Priority pH Olsen’s P K Mg Total Loss on Total Organic Habitat nitrogen Ignition phosphorus carbon LCG 7.37 9.6 212.5 164.7 1.08 21.9 1350.8 11.40 LDAG 5.13 19.0 202.2 137.0 0.63 16.2 738.8 9.11 LM 5.76 14.0 213.2 183.9 0.70 16.1 962.5 7.98 LH 4.81 8.5 128.9 156.8 0.76 25.9 433.5 16.32 PMGRP 5.54 10.4 145.3 137.1 0.81 20.0 803.5 10.92 CFGM 6.41 34.8 242.9 279.3 1.61 34.3 1772.0 18.51 UM 5.91 8.8 161.7 156.2 0.75 17.0 1147.6 9.85 UCG 5.96 7.5 165.6 117.0 0.73 16.6 1281.9 8.67 p-value *** *** *** *** *** *** *** *** Tukey pairwise comparisons *** LCG vs CFGM vs LH vs LCG, CFGM vs LCG vs LH, CFGM vs LCG vs LH, LM, LCG vs all all CFGM all LM, all PMGRP, LDAG CFGM, LH, PMGRP, LM LDAG CFGM vs LDAG vs PMGRP vs CFGM vs LH vs LM, CFGM vs LH, CFGM vs LH, LM, LH, LCG LM, all LDAG LM, PMGRP, LM, PMGRP, CFGM, LDAG PMGRP, LDAG LCG LDAG, UM, UCG LH vs LH vs LM, LH vs LM, LM, UCG, UM PMGRP, PMGRP, LDAG, UCG, UCG, UM UM LDAG vs UM, LM ** LDAG vs LDAG vs LH vs LM, LM vs LCG vs CFGM vs CFGM vs UM, LM vs UCG UM, LDAG PMGRP UM LH LCG PMGRP PMGRP PMGRP vs LH vs PMGRP LDAG * PMGRP CFGM vs LM vs LCG vs UCG vs vs LDAG UM LDAG LDAG PMGRP. LDAG LH vs UM

CFGM samples had higher total nitrogen content than any other habitat, and lowland calcareous grassland had the second highest total nitrogen content after CFGM.

Loss on ignition and organic carbon levels are closely correlated. CFGM samples have higher levels of both (with the exception of the insignificant difference of organic carbon level with lowland heathland samples). Lowland heathland samples have higher loss on ignition and organic carbon content than lowland meadow, lowland acidic grassland and upland

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler meadow samples, and higher organic carbon content only than lowland calcareous grassland and PMGRP samples. Both lowland calcareous grassland and PMGRP samples have higher organic carbon content than lowland meadow samples.

Total phosphorus levels are higher in CFGM samples than in samples from other habitats apart from lowland calcareous grassland and upland grasslands. Lowland calcareous grassland samples have higher levels than lowland heathland, lowland meadow, PMGRP and lowland acidic grassland. Lowland heathland samples have lower levels than all other habitats apart from lowland acidic grassland.

3.3.3 Differences in soil variables in relation to vegetation condition

Samples from vegetation in unfavourable condition had significantly higher levels of available phosphorus (Olsen’s P), potassium and total phosphorus than samples from vegetation in favourable condition.

Table 10. Mean values for soil variables in vegetation in favourable and unfavourable condition, 2014 samples.

Condition pH Olsen’s K Mg Total Loss on Total Organic P nitrogen Ignition phosphorus carbon Fav 5.88 11.06 163.1 159.1 0.83 20.1 883.5 11.42 Unfav 6.04 16.66 214.0 177.5 0.92 21.1 1147.3 10.87 p-value *** *** ***

3.3.4 Differences in soil variables in relation to management

Samples from vegetation grazed by sheep had higher pH than samples from cattle-grazed, pony-grazed, mixed-grazed or unmanaged vegetation. Sheep-grazed vegetation also had higher potassium levels than mown, pony-grazed or unmanaged vegetation, while magnesium levels were higher than levels in unmanaged or mixed-grazed vegetation samples. Mown vegetation samples had higher nitrogen content than samples from pony- grazed, mixed-grazed or unmanaged vegetation. Although there were no significant differences for loss on ignition between samples from vegetation under different management regimes, samples from vegetation under mixed grazing had higher organic carbon content than unmanaged vegetation. There were no differences between available phosphorus (Olsen’s P) contents, but samples from sheep-grazed vegetation had significantly higher total phosphorus content than samples from vegetation under all other management regimes, samples from mown vegetation had higher total phosphorus levels than samples from unmanaged and mixed-grazed vegetation, and samples from cattle- grazed vegetation had higher total phosphorus levels than samples from mixed-grazed vegetation.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

Table 11. Mean values for soil variables under different management types. 2014 samples.

Management pH Olsen’s P K Mg Total Loss on Total Organic nitrogen Ignition phosphorus carbon Cattle 5.89 14.77 191.8 193.2 0.88 19.8 1029.4 10.74 Mown 6.01 16.12 164.8 184.5 1.06 23.6 1140.5 12.62 Mixed 5.68 12.97 191.9 143.9 0.81 22.6 731.1 13.29 Pony 5.50 12.25 161.6 146.6 0.69 18.1 802.4 10.55 Sheep 6.51 15.40 225.9 157.8 0.97 20.6 1479.2 11.24 Unman. 5.93 11.20 178.6 146.5 0.77 19.7 828.2 9.55 p-value *** ** *** *** *** ** Tukey pairwise comparisons *** Sheep vs Sheep vs cattle, cattle, mixed, mixed, pony, unman. pony, unman. ** Sheep vs Cattle vs Mown vs Mixed vs mown unman. pony, unman. unman. * Sheep vs Cattle vs Mown vs Cattle vs pony, mixed mixed mixed unman. Mown vs mixed, sheep, unman

A chi-squared matrix was calculated for broad habitats and management regimes to determine whether there was any deviation between the expected frequencies of management regimes in the different habitats and the observed frequencies (Table 12). Pony-grazing, upland calcareous grassland and upland meadow were omitted because of the high number of expected frequencies that were less than five. For each of the six broad habitats tested, the observed frequencies of management regime differed significantly from the expected frequency (derived from the whole population). There were more sheep- grazed and ungrazed calcareous grasslands but fewer mown calcareous grasslands than expected. There were more cattle-grazed and mown but fewer sheep-grazed, mixed-grazed and unmanaged CFGM units than expected. There were more mixed-grazed and ungrazed but fewer sheep-grazed lowland heathland units than expected. There were more cattle- grazed and mown but fewer mixed-grazed lowland meadows than expected. There were fewer mixed-grazed and sheep-grazed PMGRP units and fewer cattle-grazed but more mixed-grazed lowland acidic grassland units than expected.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Table 12. Deviations between observed and expected frequencies of management types in six priority habitats, 2014 samples. O = observed frequency, E = expected frequency. Figures in bold type indicate significance at p < 0.05.

Cattle Mown Mixed Sheep Ungra. 2 2 2 2 2 BAP (O-E) /E O-E) /E O-E) /E O-E) /E O-E) /E χ2 p Habitat df=4 LCG O 31.0 2.15 5.0 6.93 15.0 0.34 31.0 13.00 28.0 3.60 26.0 *** LCG E 40.3 15.3 13.1 16.4 19.6 LDAG O 12.0 5.78 4.0 2.78 25.0 38.90 13.0 1.20 10.0 0.20 48.9 *** LDAG E 23.7 9.0 7.7 9.6 11.5 LM O 69.0 9.88 26.0 3.65 5.0 6.94 11.0 3.50 16.0 2.15 26.1 *** LM E 47.4 17.9 15.4 19.2 23.0 LH O 14.0 2.59 6.0 0.55 19.0 20.90 2.0 5.16 17.0 4.02 33.2 *** LH E 24.5 8.1 7.0 8.7 10.4 PMGRP O 37.0 3.36 14.0 1.25 1.0 6.98 3.0 5.94 19.0 2.45 20.3 *** PMGRP E 27.4 10.4 8.9 11.1 13.3 CFGM O 26.0 3.45 18.0 17.9 1.0 4.07 2.0 3.94 2.0 4.95 34.3 *** CFGM E 18.1 6.9 5.9 7.4 8.8

3.3.5 Differences in soil variables within each BAP priority habitat in relation to NVC stand type, vegetation condition and management type

The whole 2014 dataset was divided into sub-sets corresponding to Priority Habitat types. Within each of these subsets, soil variables were analysed with respect to NVC stand type (where numbers of samples permitted), favourable or unfavourable condition and (again where numbers of samples permitted) management regime.

Lowland calcareous grasslands The only significant differences between samples taken in different NVC types were for potassium content (Table 13a). Values for CG5a samples were higher than those for CG2a and CG3d. Samples from vegetation in unfavourable condition had significantly higher available phosphorus (Olsen’s P) and potassium levels than those from vegetation in favourable condition (Table 13b).

Cattle-grazed samples had lower pH than samples from mixed-grazed vegetation but higher magnesium content than all other samples (Table 13c). Samples from sheep-grazed vegetation had higher nitrogen content than those from cattle-grazed grasslands, higher loss on ignition than mixed-grazed grasslands and higher organic carbon content than cattle- grazed or unmanaged grasslands.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Table 13. Mean values for soil variables in calcareous grasslands for (a) NVC communities, (b) vegetation condition, and (c) management type.

(a) NVC pH Olsen’s K Mg Total Loss on Total Organic Community P nitrogen Ignition phosphorus carbon CG2a 7.71 8.50 129.4 152.6 1.13 23.5 1439.8 12.70 CG2c 7.29 10.40 197.6 295.6 1.06 22.0 1147.1 10.23 CG3a 7.95 8.09 181.4 97.8 1.03 19.2 1343.9 10.63 CG3b 7.50 7.50 179.3 191.3 1.07 21.5 1390.8 9.61 CG3d 7.70 9.38 135.0 144.8 1.18 23.9 1483.6 11.50 CG5a 7.87 8.42 248.2 137.3 1.16 24.5 1267.0 11.69 p-value ** * Tukey pairwise comparisons ** CG2a vs CG5a * CG3d vs CG5a

(b) pH Olsen’s K Mg Total Loss on Total Organic Vegetation P nitrogen Ignition phosphorus carbon Condition Favourable 7.69 8.00 180.1 167.1 1.05 21.6 1282.5 10.87 Unfav. 7.60 11.48 208.8 145.8 1.17 22.8 1601.4 11.60 p-value ** *

(c) pH Olsen’s K Mg Total Loss on Total Organic Management P nitrogen Ignition phosphorus carbon type Cattle 7.01 11.59 170.8 246.4 0.97 20.4 1330.9 9.72 Mixed grazing 7.99 8.13 205.2 140.1 1.03 19.5 1270.3 10.74 Sheep 7.92 9.70 200.7 120.9 1.27 24.5 1725.2 13.06 Ungrazed 7.53 10.00 192.4 145.1 1.05 21.5 1327.8 10.25 p-value *** ** * * *** Tukey pairwise comparisons *** Cattle vs mixed ** Sheep vs cattle, unman. * Cattle Cattle vs Mixed vs vs all sheep sheep

Lowland dry acidic grassland (Table 14) Samples from U1d grassland had higher pH than those from U4 grasslands, higher levels of available phosphorus (Olsen’s P) than M25b samples and higher levels of total phosphorus than U1b samples. Samples from grasslands in favourable condition had lower potassium, magnesium and total phosphorus contents than samples from grasslands in unfavourable condition.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Sheep-grazed grasslands had higher available phosphorus levels, potassium levels and total phosphorus levels than unmanaged grasslands. Potassium levels were also higher in sheep- grazed grasslands than in cattle-grazed and mixed-grazed grasslands and total phosphorus levels were higher in sheep-grazed grasslands than in mixed-grazed grasslands.

Table 14. Mean values for soil variables in lowland acidic grassland for (a) NVC communities, (b) vegetation condition, and (c) management type.

(a) NVC pH Olsen’s K Mg Total Loss on Total Organic Community P nitrogen Ignition phosphorus carbon M25b 4.92 9.17 158.8 126.8 0.69 21.8 387.7 10.32 U1b 5.11 21.63 172.3 111.4 0.47 12.68 489.6 7.79 U1d 5.47 25.0 210.3 132.2 0.55 13.95 898.3 7.20 U20 4.80 21.50 240.3 207.8 0.46 12.70 651.3 6.25 U4 4.75 12.09 186.6 119.4 0.73 19.50 694.0 10.50 p-value ** * * Tukey pairwise comparisons ** U1d vs U4 * M25b vs U1b vs U1d U1d

(b) pH Olsen’s K Mg Total Loss on Total Organic Vegetation P nitrogen Ignition phosphorus carbon condition Favourable 5.04 18.18 165.2 117.3 0.55 15.26 548.7 8.25 Unfav. 5.29 22.24 241.0 170.4 0.67 17.10 883.6 9.26 p-value *** * **

(c) pH Olsen’s K Mg Total Loss on Total Organic Management P nitrogen Ignition phosphorus carbon type Cattle 5.24 22.6 186.3 142.6 0.68 16.68 764.1 9.43 Mixed 4.97 15.4 197.3 144.0 0.66 18.91 566.0 10.60 grazing Sheep 5.50 25.7 330.1 200.3 0.83 21.76 1208.1 10.43 Ungrazed 5.10 12.7 152.3 117.4 0.48 12.06 464.4 7.06 p-value * *** *** Tukey pairwise comparisons *** Unman. vs sheep ** Sheep vs Sheep vs cattle, mixed, mixed unman. * Sheep vs unman.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Lowland meadow (Table 15) The pH of samples from MG5b was higher than that from MG5c, MG1e and MG6b samples. PH of samples from MG6a was higher than that from MG1e, MG5c and MG6b samples. available phosphorus (Olsen’s P) levels were higher in MG9 grassland samples than in samples from MG5c, MG5a, MG5b and MG1e, while they were also higher in MG6b samples than in MG5c and MG5b samples. MG5b samples had higher nitrogen levels than MG5c, MG1e and MG6b samples. Loss on ignition was higher in both MG9 and MG5b samples than in MG1e and MG5c samples, while organic carbon levels were higher in MG5b samples than in MG5c, MG1e and MG6b samples. Total phosphorus content was higher in MG9 samples than in MG5c, MG1e, MG5a and MG6b samples, and higher in MG6a than in MG6b, MG5a and MG1e samples.

Samples from lowland meadows in favourable condition had lower available phosphorus and potassium levels but higher loss on ignition.

Table 15. Mean values for soil variables in lowland meadow for (a) NVC communities, (b) vegetation condition, and (c) management type.

(a) NVC pH Olsen’s K Mg Total Loss on Total Organic Community P nitrogen Ignition phosphorus carbon MG1e 5.51 10.0 166.1 135.6 0.55 12.10 724.5 6.42 MG4 5.66 14.6 164.6 247.8 0.94 21.06 1325.8 9.56 MG5a 6.05 9.67 163.8 167.3 0.76 17.90 883.7 8.89 MG5b 6.62 9.30 220.6 177.0 0.98 20.55 1041.8 10.92 MG5c 5.55 9.29 216.4 181.6 0.59 14.26 656.7 6.90 MG6a 6.73 22.0 227.2 199.5 0.78 17.43 1904.8 8.26 MG6b 5.77 22.9 258.1 206.5 0.63 14.10 1014.1 7.24 MG9 5.80 27.92 254.6 188.0 0.84 20.30 1782.5 9.43 p-value *** *** *** *** *** ** Tukey pairwise comparisons *** MG5b vs MG5c vs MG5c vs MG9 MG5c MG6b, MG9 MG5a vs MG9 ** MG1e vs MG6a vs MG5b vs MG1e vs MG5b vs MG5b, MG6b MG5c MG6a, MG9 MG5c MG6a MG5c vs MG9 vs MG5a vs MG6a MG1e, MG6a, MG9 MG5b * MG6b MG5b vs MG1e vs MG6b vs MG5b vs vs MG1e, MG5b, MG6a, MG9 MG1e, MG5b, MG6b MG9 MG6b MG6a MG5c vs MG5b, MG9

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

(b) Vegetation pH Olsen’s K Mg Total Loss on Total Organic composition P nitrogen Ignition phosphorus carbon Favourable 5.90 9.74 188.5 193.8 0.76 17.50 837.4 8.59 Unfav. 5.66 17.02 230.4 177.1 0.66 15.06 1049.2 7.56 p-value *** * *

(c) pH Olsen’s P K Mg Total Loss on Total Organic Management nitrogen Ignition phosphorus carbon type Cattle 5.80 11.41 198.6 193.3 0.72 16.48 881.7 7.95 Mixed grazing 6.12 12.8 273.4 194.6 0.61 14.28 735.8 6.69 Mown 6.02 12.23 173.4 197.8 0.91 20.17 1109.2 10.16 Pony 5.33 21.0 193.6 109.1 0.66 14.21 1215.3 8.32 Sheep 5.78 29.85 280.1 168.8 0.75 18.27 1700.5 8.99 Ungrazed 5.16 9.69 198.0 127.19 0.38 9.34 633.5 5.23 p-value ** *** * *** *** *** *** Tukey pairwise comparisons *** Sheep vs Mown vs Mown vs Sheep vs Mown vs cattle, unman unman. unman. unman. mown, unmanaged ** Unmanaged Unman. Sheep vs vs cattle, Vs cattle, cattle mown sheep * Sheep Sheep vs Cattle vs vs unman. mown, mown unman. Sheep vs unman.

Samples from ungrazed units had lower pH than those from cattle-grazed or mown units, lower available phosphorus (Olsen’s P) and total phosphorus than sheep-grazed units, lower total nitrogen content than mown or sheep-grazed units and lower loss on ignition and organic carbon content than mown, cattle and sheep-grazed units. Samples from sheep- grazed vegetation had higher available phosphorus than samples from cattle-grazed or mown vegetation, higher potassium levels than in mown vegetation and higher total phosphorus than cattle-grazed grassland. Mown grasslands had higher organic carbon than cattle-grazed and unmanaged grasslands.

Lowland heathland (Table 16) Samples from H5a, all from serpentine soils on The Lizard, had higher pH than H2a, lower available phosphorus (Olsen’s P) content than H2a samples, and higher magnesium content than samples from H1d and M16a. H4c/d samples had lower available phosphorus content than samples from H2a. Samples from heathland in favourable condition had lower potassium content than those from heathland in unfavourable condition.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Samples from cattle-grazed heathland had lower nitrogen content and organic carbon content than those under mixed grazing.

Table 16. Mean values for soil variables in lowland heathland for (a) NVC communities, (b) vegetation condition, and (c) management type.

(a) NVC pH Olsen’s K Mg Total Loss on Total Organic Community P nitrogen Ignition phosphorus carbon H1d 4.78 10.83 102.3 90.7 0.51 15.4 373.2 9.92 H2a 4.23 12.67 112.3 126.8 0.81 31.7 548.0 20.23 H4c/d 4.99 4.88 91.5 194.9 0.69 23.1 334.9 13.44 H5a 5.43 3.67 71.8 264.2 0.65 18.1 268.2 12.83 M16a 4.89 7.00 138.6 95.2 0.71 27.23 326.4 19.86 p-value *** ** * *** Tukey pairwise comparisons *** H5a vs H5a vs H2a M16a ** H2a vs H5a vs H4, H5a H1d, H2a * H5a vs H4 vs M16a M16a

(b) pH Olsen’s K Mg Total Loss on Total Organic Vegetation P nitrogen Ignition phosphorus carbon Condition Favourable 4.78 8.07 115.1 148.0 0.75 25.60 419.9 16.91 Unfav. 4.90 11.56 150.8 182.4 0.80 26.47 527.3 14.36 p-value *

(c) pH Olsen’s K Mg Total Loss on Total Organic Management P nitrogen Ignition phosphorus carbon type Cattle 4.89 9.58 115.0 169.1 0.53 16.63 403.1 10.65 Mown 4.70 6.83 73.3 131.5 0.52 16.32 268.2 10.45 Mixed grazing 4.25 11.06 146.7 127.7 0.92 32.69 481.1 21.45 Pony 4.95 5.17 136.8 205.5 0.74 27.63 444.5 16.22 Ungrazed 5.15 8.54 128.9 195.5 0.77 23.92 511.6 14.34 p-value * ** Tukey pairwise comparisons ** Cattle vs mixed * Cattle vs Mixed

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Purple moor-grass and rush-pastures (Table 17) There were few significant differences between groups of samples. M22 samples had higher pH than M23b and M25a, higher potassium levels than M25a and higher total phosphorus levels than M25a. M23b samples had higher available phosphorus (Olsen’s P) than M25a. There were no significant differences between samples from PMGRP in favourable and unfavourable condition. The only significant differences for management regime were for samples from cattle-grazed units to have higher levels of total phosphorus than those from pony-grazed and unmanaged units.

Table 17. Mean values for soil variables in Purple Moor-grass and Rush Pasture for (a) NVC communities, (b) vegetation condition, and (c) management type.

(a) NVC pH Olsen’s K Mg Total Loss on Total Organic Community P nitrogen Ignition phosphorus carbon M22 6.26 11.40 220.0 228.2 1.25 27.58 1004.6 14.62 M23a 5.42 10.70 156.9 144.9 0.75 16.68 777.8 9.60 M23b 5.21 14.09 171.3 135.9 0.73 16.08 850.3 9.07 M25a 5.21 6.25 102.3 97.3 0.74 26.40 458.8 10.58 M25c 5.52 8.60 136.4 180.8 0.67 16.64 482.8 10.69 MG10a 5.26 14.40 148.6 133.6 0.73 15.32 923.6 9.82 p-value * * * ** Tukey pairwise comparisons ** M22 vs M25a * M22 vs M23b vs M22 vs M23b, M25a M25a M25a

(b) Vegetation pH Olsen’s K Mg Total Loss on Total Organic condition P nitroge Ignition phosphoru carbon n s Favourable 5.46 11.23 162.8 144.3 0.80 17.85 801.8 10.51 Unfav. 5.29 10.74 152.2 145.7 0.87 23.66 749.5 11.07 p-value

(c) pH Olsen’s K Mg Total Loss on Total Organic Management P nitroge Ignition phosphoru carbon type n s Cattle 5.28 11.81 157.2 157.7 0.95 21.30 915.3 12.41 Mixed grazing 5.49 9.22 175.2 126.7 0.71 16.58 656.0 9.57 Pony 5.33 7.57 128.9 173.6 0.64 15.19 501.7 10.52 Ungrazed 5.49 11.33 164.3 130.7 0.82 25.14 684.7 8.83 p-value ** Tukey pairwise comparisons ** Cattle vs pony, unmanaged

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Coastal and floodplain grazing marsh (Table 18) These are largely agriculturally-improved grasslands in floodplains and coastal plains. There were few significant differences. Samples from grassland in favourable condition had higher potassium levels than those from grasslands in unfavourable condition. Cattle-grazed grasslands had higher potassium levels but lower loss on ignition than mown grasslands.

Table 18. Mean values for soil variables in Coastal and floodplain grazing marsh for (a) NVC communities, (b) vegetation condition, and (c) management type.

(a) NVC pH Olsen’s K Mg Total Loss on Total Organic Community P nitrogen Ignition phosphorus carbon MG11a 6.23 27.45 166.7 279.1 1.89 39.9 1810.9 19.69 MG7 6.52 37.56 292.0 275.6 1.51 31.1 1970.3 18.29 Swamp 7.00 50.17 256.3 228.7 1.45 28.0 1886.8 17.99 p-value

(b) pH Olsen’s K Mg Total Loss on Total Organic Vegetation P nitrogen Ignition phosphorus carbon condition Favourable 6.40 20.27 142.1 259.3 1.63 34.5 1532.6 18.8 Unfav. 6.42 38.95 272.1 285.1 1.61 34.2 1841.2 18.5 p-value *

(c) pH Olsen’s K Mg Total Loss on Total Organic Management P nitrogen Ignition phosphorus carbon type Cattle 6.46 35.15 276.0 289.3 1.50 32.36 1773.5 18.13 Mown 6.42 27.28 174.7 225.9 1.93 40.76 1711.1 20.39 p-value * *

Upland meadow (Table 19) Comparisons between different management regimes were not possible for these grasslands. Total nitrogen levels, loss on ignition and total phosphorus content were higher in samples from stands of MG2 than in stands of MG3, MG5b and MG6b. There were no significant differences between favourable and unfavourable stands.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Table 19. Mean values for soil variables in upland meadow for (a) NVC communities and (b) vegetation condition.

(a) NVC pH Olsen’s K Mg Total Loss on Total Organic Community P nitrogen Ignition phosphorus carbon MG2 6.15 8.75 185.8 182.5 1.16 24.05 2102.3 12.08 MG3 5.83 8.00 120.3 112.3 0.48 10.90 811.0 6.38 MG6b 5.98 8.13 152.0 184.8 0.73 16.35 995.3 10.45 p-value ** * *** Tukey pairwise comparisons *** MG2 vs MG3, MG6b ** MG2 vs MG3, MG6b * MG2 vs MG3

(b) Vegetation pH Olsen’s K Mg Total Loss on Total Organic condition P nitrogen Ignition phosphorus carbon Favourable 5.94 9.00 177.9 153.6 0.87 18.92 1406.9 10.70 Unfav. 5.90 8.67 155.4 157.2 0.71 16.18 1046.8 9.52 p-value

Upland calcareous grasslands (Table 20) Comparisons between NVC communities and between different management regimes were not possible for these grasslands. There were no significant differences between favourable and unfavourable stands.

Table 20. Mean values for soil variables in individual BAP Priority Habitats for (a) vegetation condition.

(a) Vegetation pH Olsen’s K Mg Total Loss on Total Organic condition P nitrogen Ignition phosphorus carbon Favourable 5.94 9.0 177.9 153.6 0.87 18.92 1406.9 10.70 Unfav. 5.90 8.67 155.4 157.2 0.71 16.18 1046.8 9.52 p-value

3.4 Analysis of the combined dataset from 2012 and 2014 The data gathered in 2012 in 2014 were reviewed and edited to ensure compatibility, and the two datasets were amalgamated. This combined dataset was then analysed in the same way as was the 2014 data. Upland habitats were omitted from this analysis as no upland samples were collected in 2012.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Many of the results of the analysis performed on the 2014 samples alone were repeated for this combined dataset, although some significant differences were observed only in the 2014 dataset, and some only in the combined dataset.

3.4.1 Correlations between soil variables

There were strong correlations (r > 0.5) between total nitrogen content, loss on ignition and organic carbon content (Table 21; Figs 2 & 5). There were less strong correlations (0.5 > r > 0.3) between available phosphorus (Olsen’s P) and potassium, available phosphorus and total phosphorus (Fig. 4), total nitrogen and total phosphorus and loss on ignition and total phosphorus. Weaker correlations (0.3 > r > 0.2) were observed between pH and total phosphorus, potassium and magnesium (Fig. 3) and organic carbon and total phosphorus.

Table 21. Correlations between soil variables. Pearson’s correlation coefficients (r) and probabilities (* p < 0.05, ** p < 0.01, *** p < 0.001, ns = not significant).

pH Olsen’s P K Mg Tot N LoI Tot P Org C

Olsen’s P 0.22 ns K 0.05 0.329 ns *** Mg -0.06 -0.021 0.241 ns ns *** Tot N 0.18 0.121 0.119 0.100 *** *** *** ** LoI -0.04 0.072 0.059 0.076 0.859 ns * ns * *** Tot P 0.229 0.414 0.187 -0.017 0.482 0.319 *** *** *** Ns *** *** Org C -0.033 0.107 0.040 0.035 0.758 0.800 0.279 ns ** ns Ns *** *** ***

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Figure 2. Correlation between loss on ignition and total nitrogen.

100

40 Loss on Loss ignition

0 0 0.5 1 1.5 2 2.5 3 3.5 Total nitrogen

Figure 3. Correlation between magnesium and potassium.

2000

1800

1600

1400

1200

1000

Magnesium 800

600

400

200

0 0 100 200 300 400 500 600 700 800 900 Potassium

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Figure 4. Correlation between total phosphorus and available phosphorus (Olsen’s P).

14000

12000

10000

8000

6000 Totalphosphorus 4000

2000

0 0 20 40 60 80 100 120 140 160 Available phosphorus

Figure 5. Correlation between loss on ignition and organic carbon.

30 Organiccarbon 20

0 0 20 40 60 80 100 Loss on ignition

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler 3.4.2 Differences in soil variables between BAP priority habitats

Table 22. Mean values for soil variables in BAP priority habitats, 2012 and 2014 surveys.

BAP pH Olsen’s K Mg Total Loss on Total Organic Priority P nitrogen Ignition phosphorus carbon Habitat LCG 7.55 9.17 202.2 147.1 0.88 18.60 1154.1 9.95 LDAG 5.18 18.25 204.3 130.2 0.60 16.04 778.0 8.74 LM 6.02 12.39 204.6 251.9 0.67 15.59 892.5 7.78 LH 4.82 8.50 130.0 155.5 0.75 25.57 440.7 16.04 PMGRP 5.76 11.12 145.7 151.6 0.89 21.16 1085.8 11.44 CFGM 6.79 29.8 192.2 177.8 1.24 27.01 1617.4 14.31 p-value *** *** *** *** *** *** *** *** Tukey pairwise comparisons *** LCG vs CFGM vs LCG vs LH, LCG vs LM LCG vs LM, CFGM vs LCG vs CFGM, CFGM vs all all PMGRP LDAG LM, LH, LM, LDAG LM, LDAG, PMGRP, LCG LDAG, LCG CFGM vs LDAG vs LH vs LM, LH vs LM, CFGM vs all LH vs LM, CFGM vs all LH vs all all LCG, LH, LDAG, CFGM LDAG, LCG LM CFGM LH vs LM vs LH, LM vs PMGRP vs LM vs LH vs LM, LM vs LM, PMGRP PMGRP LDAG, LM PMGRP PMGRP PMGRP, PMGRP LCG LM vs LDAG ** PMGRP PMGRP vs CFGM vs PMGRP vs PMGRP vs vs LDAG LDAG PMGRP LDAG LDAG, CFGM * LH vs LCG vs LM LCG vs LM LDAG vs LH, LDAG PMGRP

Soil pH was significantly higher in calcicolous grassland samples than in samples from all other habitats and higher in CFGM samples than in all habitats but calcicolous grassland. Lowland heathland samples had lower pH than all other habitats including acidic grassland. available phosphorus (Olsen’s P) and total phosphorus levels were higher in CFGM samples than in all other habitats. While available phosphorus level was higher in lowland acidic grassland samples than in all other habitats apart from CFGM, total phosphorus levels were lower in lowland acidic grassland than in CFGM, lowland calcareous grassland and PMGRP samples, although still higher than in lowland heathland. Total phosphorus levels were higher in lowland calcareous grassland than in lowland heathland, lowland meadow and lowland dry acidic grassland, although available phosphorus levels were lower than in CFGM, lowland dry acidic grassland and lowland meadow.

Potassium levels were significantly higher in lowland meadow samples than in lowland heathland and PMGRP samples, and also lower in PMGRP samples than in lowland

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler calcareous grassland and CFGM samples. Levels in lowland heathland were also lower than in CFGM and lowland acidic grassland.

Magnesium levels were higher in lowland meadow samples than in lowland calcareous grasslands, lowland heathlands and PMGRP. They were also higher in CFGM than in lowland heathland.

Loss on ignition and organic carbon levels were both higher in lowland heathland samples than in any other habitat with the exception of Loss on ignition which was not significantly different in CFGM. Levels of both variables were also significantly higher in CFGM than in any other habitat than lowland heathland. Loss on ignition and organic carbon levels were lower in lowland meadow than CFGM, lowland heathland, PMGRP and lowland calcareous grassland and lower in lowland acidic grassland than in CFGM, lowland heathland and PMGRP. Total nitrogen levels were higher in CFGM than in any other habitat and higher in both PMGRP and lowland calcareous grassland than in lowland meadow and lowland acidic grassland.

3.4.3 Differences in soil variables in relation to vegetation condition

Table 23. Mean values for soil variables in vegetation in favourable and unfavourable condition.

pH Olsen’s K Mg Total Loss on Total Organic P nitrogen Ignition phosphorus carbon Fav 6.26 10.85 173.14 202.68 0.80 19.05 962.8 10.53 Unfav 6.35 17.23 200.48 163.20 0.84 19.52 1132.4 10.18 p-value *** *** *** ***

Samples from vegetation in unfavourable condition had significantly higher available phosphorus (Olsen’s P), total phosphorus and potassium levels but lower magnesium levels than those from vegetation in favourable condition.

3.4.4 Differences in soil variables in relation to management type

The pH of sheep-grazed samples was significantly higher than that of samples under all other management types (Table 24). Unmanaged vegetation samples also had higher pH than mixed-grazed and pony-grazed vegetation.

Potassium levels were higher in samples from sheep-grazed vegetation than in mown and unmanaged vegetation. Magnesium levels were higher where the vegetation was mown than where it was grazed by cattle, sheep, mixed stock or unmanaged. Samples from cattle- grazed vegetation had higher magnesium levels than those from unmanaged vegetation.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Samples from unmanaged vegetation had lower total nitrogen than those from sheep and cattle-grazed or mown vegetation. Total phosphorus levels were higher in sheep and cattle- grazed vegetation than in mixed-grazed and unmanaged vegetation.

Organic carbon levels were higher in mixed-grazed, cattle-grazed and mown vegetation than in unmanaged stands. Mown stands also had higher levels of organic carbon than sheep- grazed vegetation.

Table 24. Mean values for soil variables under different management types.

pH Olsen’s K Mg Total Loss on Total Organic P nitrogen Ignition phosphorus carbon Cattle 6.09 14.51 195.22 185.97 0.84 19.18 1123.6 10.23 Mown 5.72 12.57 185.93 141.71 0.78 21.83 719.3 12.79 Mixed 6.19 13.87 173.38 289.20 0.93 20.81 1041.8 10.71 Pony 5.67 11.71 173.51 171.40 0.72 18.03 776.4 10.44 Sheep 6.74 13.30 215.05 162.74 0.85 18.60 1259.2 10.12 Unman. 6.28 13.31 170.99 132.65 0.66 16.88 832.1 8.54 p-value *** ** *** *** * *** *** Tukey pairwise comparisons *** Sheep vs Mown vs Mown vs Sheep vs Mixed vs cattle, cattle, unman mixed, unman unman mixed, mixed, pony sheep, unman. ** Unman Sheep vs Unman vs Cattle vs vs mown, cattle, sheep mixed sheep, unman. mixed Mown vs sheep * Pony vs Cattle vs Unman vs Cattle vs Cattle vs unman unman mixed, unman mixed, mown unman Mown vs sheep, unman

3.4.5 Differences in soil variables within each BAP priority habitat in relation to NVC stand type, vegetation condition and management type

Lowland calcareous grasslands (Table 25) CG2c grassland samples had significantly lower pH than samples from CG2a, CG3d and CG5a grasslands. CG2c grasslands also have higher levels of available phosphorus (Olsen’s P) than CG3a and CG3b grasslands. Samples from CG5a grasslands have significantly higher potassium content than CG3d samples.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Table 25. Mean values for soil variables in calcicolous grasslands, 2012 and 2014 samples combined, for (a) NVC communities, (b) vegetation condition, and (c) management type.

(a) NVC pH Olsen’s K Mg Total Loss on Total Organic Community P nitrogen Ignition phosphorus carbon CG2a 7.80 8.3 140.2 143.0 1.01 21.35 1337.8 11.71 CG2c 7.04 11.0 187.6 243.8 1.05 22.13 1662.4 10.59 CG3a 7.97 7.93 196.2 121.3 0.83 16.91 1031.8 9.82 CG3b 7.65 7.58 181.3 151.6 0.86 18.45 1166.8 8.81 CG3d 7.75 9.45 139.5 135.1 1.03 21.75 1333.3 10.68 CG5a 7.78 8.85 245.1 147.3 0.90 19.94 1067.1 9.84 p-value *** ** * Tukey pairwise comparisons *** CG2c vs CG2a ** CG2c CG2c vs vs CG3a, CG5a CG3b * CG2c CG3d vs vs CG5a CG2a, CG3d

(b) Vegetation pH Olsen’s K Mg Total Loss on Total Organic condition P nitrogen Ignition phosphorus carbon Favourable 7.53 8.44 198.0 159.0 0.88 18.54 1115.6 10.15 Unfav. 7.57 9.84 206.1 136.2 0.89 18.66 1189.4 9.76 p-value ** *** **

(c) pH Olsen’ K Mg Total Loss on Total Organic Management s P nitrogen Ignition phosphorus carbon type Cattle 7.06 10.53 204.7 178.6 0.92 19.68 1252.5 10.42 Mixed 7.94 8.25 201.5 136.4 1.07 20.41 1333.7 11.11 grazing Mown 7.12 7.60 256.0 205.8 0.75 16.54 775.6 9.17 Sheep 7.82 8.56 194.5 125.3 0.95 19.35 1206.5 10.52 Ungrazed 7.63 8.84 202.3 128.4 0.78 16.75 1016.5 8.56 p-value *** ** * * Tukey pairwise comparisons *** Cattle vs mixed, sheep, unman. ** Cattle vs sheep, unman * Sheep vs unman

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Samples from lowland calcicolous grasslands in unfavourable condition have higher levels of available phosphorus and potassium than samples from grasslands in favourable condition.

Lowland calcicolous grasslands managed by cattle grazing had significantly lower pH than those grazed by sheep, mixed stock or unmanaged. Magnesium content was significantly higher where grazed by cattle than where grazed by sheep or unmanaged. Sheep-grazed grasslands had higher levels of organic carbon than unmanaged grasslands.

Lowland dry acidic grasslands (Table 26) The pH of U1d grassland samples is significantly higher than that of samples from U4e and U20. Total nitrogen content and organic carbon content are higher in U4e samples than in U1d and U1b samples. Total phosphorus content is lower in U1b than in U4e and U20 stands.

Potassium and total phosphorus content were higher in grasslands in unfavourable condition than in grasslands in favourable condition.

Sheep-grazed grassland samples had significantly higher potassium, nitrogen and total phosphorus levels than unmanaged grasslands. Sheep-grazed grasslands also had higher potassium and total phosphorus levels than cattle- or mixed-grazed grasslands. Mixed- grazed grasslands had higher loss on ignition and organic carbon levels than unmanaged grasslands.

Table 26. Mean values for soil variables in lowland acidic grassland, 2012 and 2014 samples combined, for (a) NVC communities, (b) vegetation condition, and (c) management type.

(a) NVC pH Olsen’s K Mg Total Loss on Total Organic Community P nitrogen Ignition phosphorus carbon U1b 5.25 21.24 171.7 108.8 0.45 12.84 480.5 7.51 U1d 5.64 23.10 214.7 133.2 0.47 12.37 793.9 6.45 U20 4.66 19.10 271.9 170.7 0.68 18.46 1072.5 10.01 U4b 4.97 11.00 211.7 128.2 0.69 15.48 969.7 8.29 U4e 4.85 18.50 235.6 113.9 0.89 21.31 1195.9 12.90 p-value *** *** * ** ** Tukey pairwise comparisons *** U1dvU20 ** U1dvU4e U4evU1d, U1bvU4e U1dvU4e U1b * U1bvU20 U1bvU4e

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

(b) pH Olsen’s K Mg Total Loss on Total Organic Vegetation P nitrogen Ignition phosphorus carbon condition Favourable 5.23 17.49 171.5 116.1 0.54 14.92 625.9 8.15 Unfav. 5.17 19.37 237.0 144.2 0.65 16.96 932.4 9.01 p-value *** **

(c) pH Olsen’s K Mg Total Loss on Total Organic Management P nitrogen Ignition phosphorus carbon type Cattle 5.33 20.57 178.07 133.5 0.61 15.31 692.8 8.63 Mixed 5.06 16.52 196.0 142.8 0.64 18.20 574.2 10.16 Mown 5.78 21.20 168.4 99.6 0.37 12.12 767.0 5.78 Sheep 5.39 18.52 283.1 155.5 0.76 17.90 1224.3 9.54 Ungrazed 5.10 18.80 153.6 107.6 0.39 10.43 607.3 5.63 p-value *** ** * *** * Tukey pairwise comparisons *** Sheep vs Sheep vs Sheep vs unman unman. mixed, unman. ** Sheep vs Sheep vs cattle, cattle mixed * Mixed vs Mixed vs unman unman

Lowland meadow (Table 27) PH was higher in samples from MG5b stands than in stands of MG5c and MG6b. available phosphorus levels were higher in both MG6a and MG6b than in MG5a, MG5b, MG5c and MG1e, and were higher in MG9 than in MG5c, MG5a and MG5b. Total phosphorus levels however, although showing exactly the same pattern for MG6a, were relatively lower for MG6b, and these were significantly lower than MG6a samples. MG9 samples had significantly higher total phosphorus levels than MG5a, MG5b, MG5c and MG1e. Magnesium levels were higher in MG4 than in all other lowland meadow types apart from MG5b. Loss on ignition was significantly higher in MG4 samples than in samples from MG1e, MG5c and MG6b, and in addition, total nitrogen levels were higher in MG4 samples than in MG1e samples.

Samples in unfavourable condition vegetation had significantly higher levels of available phosphorus, total phosphorus and potassium, but lower levels of magnesium and lower loss on ignition and pH.

Available and total phosphorus contents were higher in samples from sheep-grazed grasslands than cattle-grazed, mixed grazed and mown grasslands. Potassium content was also higher in sheep-grazed grasslands than in mown and unmanaged grasslands, while

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler magnesium content was higher in mown grassland samples than in samples from mixed- grazed and unmanaged grasslands. Loss on ignition and organic carbon content were both lower in samples from unmanaged grasslands than in cattle-grazed, sheep-grazed and mown grasslands, with organic carbon content being additionally lower in pony-grazed grasslands than in unmanaged grasslands. Total nitrogen content was lower in samples from unmanaged grasslands than in samples from mown, cattle-grazed and pony-grazed grasslands.

Table 27. Mean values for soil variables in lowland meadow, 2012 and 2014 samples combined, for (a) NVC communities, (b) vegetation condition, and (c) management type.

(a) NVC pH Olsen’s P K Mg Total Loss on Total Organic Community nitrogen Ignition phosphorus carbon MG1e 5.70 9.73 174.2 164.9 0.54 12.8 703.3 6.67 MG4 6.04 17.94 174.1 558.1 0.85 19.9 1105.4 9.23 MG5a 6.31 9.48 172.7 197.5 0.74 17.7 860.0 8.77 MG5b 6.52 8.04 195.3 391.9 0.75 16.2 810.2 8.42 MG5c 5.67 8.43 210.5 231.6 0.59 14.3 672.2 7.0 MG6a 6.08 22.75 229.3 239.9 0.66 15.6 1630.5 7.19 MG6b 5.78 21.75 248.1 211.9 0.63 14.1 1001.7 7.24 MG9 5.89 20.47 231.4 239.7 0.73 18.3 1386.3 8.45 p-value *** *** *** ** *** *** * Tukey pairwise comparisons *** MG5b vs MG6b vs MG4 vs MG6a vs MG5c MG5a, MG5a, MG5c, MG1e, MG5b, MG5c, MG5b MG5c MG1e MG5c vs MG5c vs MG9 MG6a, MG9 ** MG5b vs MG6a vs MG4 vs MG4 vs MG5a vs MG5c, MG5a, MG6b, MG1, MG6a MG6b MG5b MG9 MG5c MG9 vs MG1e vs MG9 MG5a, MG5b * MG1 vs MG4 vs MG1e vs MG4 vs MG9 vs MG6a, MG6a MG4 MG6b MG5b, MG5a MG6b MG6a vs MG6b

(b) pH Olsen’s K Mg Total Loss on Total Organic Vegetation P nitrogen Ignition phosphorus carbon condition Favourable 6.15 9.05 187.5 318.4 0.69 16.32 790.5 8.07 Unfav. 5.89 15.81 222.1 204.8 0.64 14.85 996.7 7.47 p-value * *** ** *** **

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

(c) pH Olsen’s K Mg Total Loss on Total Organic Management P nitrogen Ignition phosphorus carbon type Cattle 5.96 10.84 204.2 198.3 0.71 16.43 907.1 7.99 Mixed 5.99 10.20 194.9 160.7 0.55 13.65 625.9 7.14 Mown 6.10 9.61 171.5 407.2 0.76 17.01 900.2 8.32 Pony 5.62 16.07 209.6 190.6 0.76 15.83 953.6 9.20 Sheep 5.92 24.12 271.0 217.8 0.69 17.72 1392.0 8.84 Ungrazed 5.66 9.86 189.9 156.5 0.42 10.34 672.5 5.41 p-value *** ** *** *** *** ** ** Tukey pairwise comparisons *** Sheep vs Mown vs Mown vs Unman vs cattle, mixed, unman cattle, mown, unman. mown unman. ** Sheep vs Sheep vs Cattle vs Unman Sheep vs Unman vs mixed mown unman vss sheep unman cattle, mown * Sheep vs Pony vs Sheep vs Unman vs unman unman mown, mixed, pony, cattle sheep

Lowland heathland (Table 28) PH of samples from H2 heathlands was significantly lower than that from stands of H4, H5a and M16a. H5a samples also had higher pH than samples from H1 heathlands. Content of available phosphorus was higher in H2 samples than in H5a, H4 or M16a samples. Magnesium content was higher in samples from H5a than in samples from H1, M16a or H2 and was also higher in samples from H4 than in samples from H1 or M16a.

Samples from cattle-grazed heathlands had lower total nitrogen, loss on ignition and organic carbon levels than those from mixed-grazed heathlands. Mown heathlands had lower potassium and organic carbon levels than mixed-grazed heathlands.

There were no differences between stands in favourable and unfavourable condition.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Table 28. Mean values for soil variables in lowland heathland, 2012 and 2014 samples combined, for (a) NVC communities, (b) vegetation condition, and (c) management type.

(a) NVC pH Olsen’s K Mg Total Loss on Total Organic Community P nitrogen Ignition phosphorus carbon H1 4.53 9.60 102.2 84.4 0.68 23.46 400.4 14.11 H2 4.27 12.29 130.5 136.2 0.93 35.75 579.5 23.39 H4 5.05 5.73 116.6 204.7 0.81 26.61 448.3 14.37 H5a 5.43 3.67 71.83 264.2 0.65 18.1 268.2 12.83 M16a 4.94 7.1 133.3 97.7 0.65 25.25 312.7 18.18 p-value *** *** *** * Tukey pairwise comparisons *** H2 vs H2 vs H5a H5a vs H4, H1, H5a M16a ** H1 vs H2 vs H4 H4 vs H1, H5a M16a H2 vs H5a H2 vs M16a * H2 vs M16a

(b) pH Olsen’s K Mg Total Loss on Total Organic Vegetation P nitrogen Ignition phosphorus carbon Condition Favourable 4.82 8.04 117.0 149.4 0.75 25.19 436.0 6.60 Unfav. 5.0 10.36 154.5 184.0 0.78 25.67 507.1 13.96 p-value

(c) pH Olsen’s K Mg Total Loss on Total Organic Management P nitrogen Ignition phosphorus carbon type Cattle 4.91 9.0 111.7 158.9 0.49 15.55 375.9 9.82 Mown 4.70 6.83 73.3 131.5 0.52 16.32 268.2 10.45 Mixed 4.62 10.37 153.6 132.0 0.91 33.78 460.4 21.81 Pony 5.09 5.29 159.7 219.3 0.77 26.81 478.9 15.73 Ungrazed 5.16 8.12 130.7 197.1 0.81 25.83 499.8 15.49 p-value * ** * *** Tukey pairwise comparisons *** Cattle vs mixed ** Cattle vs mixed * Mown vs Cattle v Mown vs mixed, mixed mixed pony

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Purple moor-grass and rush-pasture (Table 29) Samples from stands of M22a and M22b had higher pH than samples from stands of other vegetation types. Available phosphorus level was higher in M22b than in M25a. Loss on ignition and organic carbon content were significantly higher in M22b samples than in samples from M23a, M23b and MG10a, while levels of total nitrogen content were significantly higher in M22b samples than in M23a, M23b, MG10a, M25a and M25c.

The only significant difference between samples in different condition was the higher pH in samples from favourable condition samples than from unfavourable condition samples. There were no significant differences between management types.

Table 29. Mean values for soil variables in purple moor-grass and rush-pasture, 2012 and 2014 samples combined, for (a) NVC communities, (b) vegetation condition, and (c) management type.

(a) NVC pH Olsen’s K Mg Total Loss on Total Organic Community P nitrogen Ignition phosphorus carbon M22a 6.97 14.71 126.1 135.7 1.15 25.17 1277.7 12.61 M22b 7.01 15.25 164.8 137.0 1.48 31.76 1401.0 18.07 M23a 5.64 9.86 148.2 192.9 0.77 17.48 1387.4 9.96 M23b 5.35 13.23 155.7 127.8 0.73 15.99 865.9 9.35 M25a 5.26 6.11 110.9 99.6 0.73 25.11 489.4 10.14 M25c 5.52 8.60 136.4 180.8 0.67 16.64 482.8 10.69 MG10a 5.69 11.63 123.3 117.4 0.65 13.96 843.3 9.06 p-value *** * *** ** ** Tukey pairwise comparisons *** M22a vs M22b vs M23a, M23a, M23b, M23b, M25a MG10a M22b vs M23a, M23b, M25a ** M22b vs M22b vs M23b vs M22b vs M25c, M25a, M23a M23a MG10a M25c * M22a vs M22b vs M22b vs M22a vs M25c, M25a M23a, M23b, MG10a MG10a MG10a

(b) pH Olsen’s K Mg Total Loss on Total Organic Vegetation P nitrogen Ignition phosphorus carbon condition Favourable 5.91 11.49 146.32 159.82 0.91 20.40 1278.6 11.81 Unfav. 5.54 10.57 144.66 139.41 0.86 22.28 801.0 10.89 p-value *

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

(c) pH Olsen’s K Mg Total Loss on Total Organic Management P nitrogen Ignition phosphorus carbon type Cattle 5.53 11.70 147.57 142.80 0.89 19.85 1401.0 11.42 Mown 5.79 8.17 146.11 155.50 0.76 17.28 790.61 10.21 Pony 5.33 7.57 128.86 173.57 0.64 15.19 501.71 10.52 Ungrazed 5.57 10.85 157.80 129.75 0.77 23.53 697.70 8.43 p-value Tukey pairwise comparisons *** ** *

Coastal and Floodplain Grazing Marsh (Table 30) Samples from MG11a grasslands had significantly lower potassium and magnesium levels than MG6a and MG7 grasslands. available phosphorus levels were higher in samples from grasslands in unfavourable condition than in grassland in favourable condition.

Samples from unmanaged grasslands had significantly lower levels of magnesium, nitrogen, loss on ignition, organic carbon content, total phosphorus and potassium than cattle-grazed or mown grasslands.

Table 30. Mean values for soil variables in Coastal and Floodplain Grazing Marsh, 2012 and 2014 samples combined, for (a) NVC communities, (b) vegetation condition, and (c) management type.

(a) NVC pH Olsen’s K Mg Total Loss on Total Organic Community P nitrogen Ignition phosphorus carbon MG11a 6.94 28.0 159.5 188.3 1.47 31.64 1733.3 15.61 MG6a 5.80 39.57 406.7 424.1 1.22 27.13 1595.7 16.67 MG7 6.52 37.56 292.0 275.6 1.51 31.07 1970.3 18.29 p-value *** *** Tukey pairwise comparisons *** MG11 vs MG11 vs MG6a MG6a ** * MG11 vs MG7

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

(b) pH Olsen’s K Mg Total Loss on Total Organic Vegetation P nitrogen Ignition phosphorus carbon Condition Favourable 6.76 20.70 156.91 199.7 1.40 29.50 1598.8 15.45 Unfav. 6.79 31.89 200.18 179.9 1.21 26.40 1621.7 14.05 p-value *

(c) pH Olsen’s K Mg Total Loss on Total Organic Management P nitrogen Ignition phosphorus carbon type Cattle 6.35 32.49 254.2 256.4 1.30 29.64 1621.3 16.08 Mown 6.67 26.57 185.9 227.6 1.65 35.16 1690.8 17.32 Ungrazed 6.22 32.2 140.4 97.13 0.69 18.25 1165.4 9.30 p-value * *** *** ** * ** Tukey pairwise comparisons *** Unman Mown vs Mown vs vs cattle, unman unman mown ** Cattle vs Unman vs unman cattle, mown * Cattle vs Cattle vs Unman vs unman unman cattle, mown

3.5 Summary of results of differences in soil properties for individual BAP priority habitats and NVC communities, vegetation condition and management type

3.5.1 Lowland calcareous grassland

As would be expected calcareous grassland stands had the highest pH of all habitats sampled. Although available phosphorus levels are very low, total phosphorus content is high. Potassium levels are moderately high and are significantly higher than those of lowland heath and PMGRP. Total nitrogen levels are medium for long-term grassland but are higher than that of lowland meadow and lowland acid grassland, closer to that of PMGRP; loss on ignition and organic carbon levels are moderate in comparison with other vegetation types and are significantly lower than in CFGM and lowland heath, but higher than in lowland meadow.

Soil pH of CG2c samples is significantly lower than for all sub-communities other than CG3b. available phosphorus levels are also high in CG2c samples. Potassium levels are higher in CG5a samples than in CG3d samples.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler 3.5.2 Lowland dry acidic grassland

Soil pH is acidic as would be expected but is higher (less acidic) than in lowland heathland; it is lower (more acidic) than in all other priority habitats. Available phosphorus is moderately high and significantly higher than in all other priority habitats (including lowland heath) apart from CFGM. The amount of total phosphorus however is lower than all habitats other than lowland heath. Potassium and magnesium levels are moderately high but magnesium levels are significantly lower than other priority habitats. Nitrogen content, organic carbon content and loss on ignition are all low, the latter two lower than for lowland heath.

Soil pH is significantly higher in U1d samples than in U20 or U4e samples. Loss on ignition and organic carbon content were higher in U4e samples than in U1b or U1d samples. Total phosphorus was significantly lower in U1b samples than on U4e or U20 samples.

3.5.3 Lowland meadow

Soil pH is neutral but higher than that of PMGRP, lowland heath and lowland acidic grassland, and lower than that of lowland calcareous grassland and CFGM. available phosphorus level is low; significantly lower than that CFGM and lowland acidic grassland. Although total phosphorus is lower than that for lowland calcareous grassland and CFGM, it is higher than that for lowland heathland. Potassium level is high, and magnesium level is higher than all other habitats sampled. Nitrogen content and loss on ignition are low, and organic carbon content is very low.

Soil pH of MG5b samples was higher than that of MG5c and MG6b samples. available phosphorus levels were higher in MG6a and MG6b than in MG1e, MG5a, MG5b and MG5c and higher in MG9 than in MG5a, MG5b and MG5c. Total phosphorus content was however only higher than MG5a, MG5b and MG5c for MG6a and MG9 samples, and the total phosphorus content of MG6a samples was significantly higher than for MG6b samples. While there were no significant differences between potassium content, magnesium content was significantly higher in MG4 samples than in MG1e, MG5a, MG5c, MG6a, MG6b and MG9 samples. Loss on ignition was also higher in MG4 samples than in MG1e, MG5c and MG6b samples.

3.5.4 Lowland heath

Lowland heath had the lowest, most acidic pH of all sampled habitats and the lowest available phosphorus, total phosphorus and potassium content of any priority habitat including lowland acidic grassland. Loss on ignition and organic carbon content are however the highest recorded for any of the priority habitats reflecting the more organic heathland soils. Magnesium levels were high, but moderate in relation to some other habitats sampled: levels were significantly lower than for lowland meadow and CFGM.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler H2 stands had significantly lower pH and higher available phosphorus than stands of H4, H5a and M16a. H1 stands also had lower pH than H5a. Samples from H5a stands had significantly higher magnesium levels than all other communities.

3.5.5 Purple moor-grass and rush-pasture

This priority habitat includes all stands where Molinia caerulea or Juncus spp. form a substantial part of the vegetation. It is a disparate habitat including stands with affinities to wet heathland and others more akin to lowland meadow or CFGM and there are few outstanding features of soil chemistry when this habitat is treated as a whole. Soil pH is significantly lower than in CFGM and lowland calcareous grassland but higher than in lowland heath and lowland acidic grassland. available phosphorus is lower than in CFGM and lowland acidic grassland. Total phosphorus, although lower than in CFGM, is higher than in lowland acidic grassland and lowland meadow. Potassium and magnesium levels are lower than in lowland meadow. Nitrogen, loss on ignition and organic carbon content are higher than in lowland meadow and acidic grassland, but lower than in CFMG. The two wetter habitats, PMGRP and CFGM, had the highest levels of these latter variables with the exception of lowland heathland.

M22a and M22b samples had significantly higher pH than samples from M23a, M23b, M25a, M25c and MG10a. Although levels of available and total phosphorus were higher in M22 stands than in other communities, the only significant difference was between M22b and M25a. Nitrogen content, loss on ignition and organic carbon content were all higher in M22b than in M23a, M23b and MG10a, and in addition nitrogen content was higher in M22b than in samples from M25a and M25c.

3.5.6 Coastal and floodplain grazing marsh

Sites sampled in these situations tended to be semi-improved or agriculturally-improved grasslands (with a few notable exceptions where saline influence was apparent). Semi- natural vegetation stands were assigned to other priority habitat types. Characterised by regular inundation and high water-tables, they had a high pH and total nitrogen content, loss on ignition and organic carbon levels are also all high. available phosphorus levels are very high (more than three times those for lowland calcareous grassland and lowland heath), and total phosphorus levels are also high.

Samples from MG11a had higher potassium levels than those from MG6a and MG7 and higher magnesium levels than MG6a.

3.5.7 Upland calcareous grassland

This was only included in the 2014 survey and only 14 samples were collected. Soil pH as expected is higher than that of lowland heathland, although perhaps surprisingly, not

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler significantly higher than other priority habitats. Loss on ignition and organic carbon are lower than CFGM and lowland heathland. available phosphorus is very low but total phosphorus content is higher than PMGRP, lowland heath and lowland acidic grassland.

Insufficient samples were collected to allow comparisons to be made between NVC types.

3.5.8 Upland meadow

This was only included in the 2014 survey and only 25 samples were collected. Soil pH is higher than lowland heathland. available phosphorus levels are lower than for CFGM and lowland acidic grassland although total phosphorus levels are higher than in lowland heathland and lower than in CFMG. Loss on ignition and organic carbon are lower than for lowland heathland and CFMG.

Some significant differences were detected despite the small number of samples collected. The few samples collected from MG2 grasslands had a higher level of nitrogen and total phosphorus content than MG3 and MG6b and a higher loss on ignition than MG3.

3.5.9 Habitat condition

Vegetation (all habitats combined) in favourable condition had significantly lower levels of available and total phosphorus and potassium, but higher levels of magnesium than vegetation in unfavourable condition. While this pattern is repeated in most of the individual priority habitats (apart from PMGRP), differences were only significant in lowland calcareous grassland (available phosphorus, potassium, magnesium), CFMG (available phosphorus), lowland heath (potassium), lowland meadow (available phosphorus, potassium, magnesium, total phosphorus), lowland acidic grassland (potassium and total phosphorus).

3.5.10 Management type

The major significant differences are between sheep-grazed vegetation and ungrazed vegetation and all other management types. Where sheep are the major grazing stock, pH is high, potassium levels are high and total phosphorus content is high. In ungrazed habitats, magnesium levels, nitrogen content, loss on ignition and organic carbon levels are all low. Mixed-grazed and mown vegetation had the highest organic carbon level.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler 4 Discussion

4.1 Differences between the 2012 and 2014 surveys Survey methods differed somewhat between the 2012 and 2014 surveys. In 2012, there was no requirement to collect information on NVC type, condition assessment was very subjective and single samples were collected from the majority of units with samples from subjectively assessed favourable and unfavourable condition vegetation in only 92 of the 293 units visited. In 2014 an attempt was made to additionally assess the NVC type to sub- community at all sites where possible (which also enabled a more accurate determination of priority habitat), a more objective approach was taken to assessing condition and up to five soil samples were taken in order to obtain a better picture of the variation of soil characteristics within each site. Where possible the type of grazing or other management regime was recorded in 2014. For these reasons direct comparisons between the 2012 and 2014 surveys are limited.

The majority of the results from 2012 are supported by the 2014 survey. Where direct comparisons were possible, a few differences were observed. Total phosphorus content in lowland calcareous grassland samples was higher than that of lowland meadow in 2014 while they were similar in 2012. Loss on ignition and total nitrogen were higher but not significantly so in lowland calcareous grassland than in lowland acidic grassland in 2012. In 2014, the differences were significant. In 2012, the magnesium content of favourable condition samples was significantly higher than that of unfavourable condition samples. Although still higher in 2014, the difference was not significant. The significantly higher level of magnesium in hay-cut lowland meadow in 2012 was not significant in 2014. The higher total phosphorus content of lowland calcareous grassland samples in 2014 may be due to the inclusion of more samples from vegetation in unfavourable condition in this survey. The other differences may probably be explained by the increase in number of replicates of each priority habitat in 2014.

4.2 Soils and UK BAP priority habitats The priority habitat classification is an artificial one and the priority habitats themselves are heterogeneous groupings. Nevertheless, the combined analysis of 2012 and 2014 data shows some clear differences between the priority habitats.

As might be expected, lowland calcareous grasslands had the highest mean pH (7.55). The mean pH of coastal and floodplain grazing marsh was also high (6.79). Many of the sampled CFGM sites are in the valleys of rivers which receive their water from calcareous rock catchments (for example The Itchen, Hampshire Avon and Otmoor) and the high pH is unsurprising. The pH was however also high in soils taken from fields in the floodplain of the River Camel, which rises on the highly acidic granite of Bodmin Moor, although here the influence of saline water from the river may affect the soil chemistry. The low pH of

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler samples from West Sedgemoor, where the water derives from the surrounding limestone hills, is probably the result of the accumulation of peat: the majority of soils collected from West Sedgemoor have high organic matter content. The mean pH of the mesotrophic grasslands and mires included in lowland meadow, upland meadow, upland calcareous grassland and purple moor-grass and rush-pasture priority habitats is slightly acidic (5.76– 6.02). The relatively low pH of upland calcareous grassland samples may be the result of the leaching of surface soil layers sampled by the methods used in this survey or the presence of superficial deposits. Lowland acidic grassland and lowland heathland soils both had low mean pH.

In the majority of UK soils pH is determined by the concentration of calcium ions with magnesium being important in soils over serpentine and Magnesian limestone. The principal influence of pH on plant growth is in its effects on the availability of nutrients and concentrations of toxic ions (Etherington, 1975). At low pH, nitrogen tends to be present in organic compounds with little available to plants as nitrate ions. Iron, aluminium and manganese ions increase and can be toxic to many species and ferrous ions can reduce available phosphate ions by the precipitation of insoluble salts. At low pH, a relatively few species can tolerate the high concentrations of toxic ions and the low availability of major nutrients. At higher pHs, nitrate and phosphate ions become more available enabling the survival of greater numbers of species, while the more ferrous ion-tolerant species decline. Soil pH and the availability of nutrients is also influenced by the intensity and periodicity of waterlogging. The effects of these factors on the composition of plant communities however are mediated through the processes of competition between individual species.

The mean content of available phosphorus as determined by Olsen’s method was high (29.8mg/l) in samples from coastal and floodplain grazing marsh. This corresponds to an index of 3. 20% of CFGM samples had an available phosphorus content of > 46mg/l, corresponding to an index of between 4 and 6 and considered to be very high (Anon, 2008). Grasslands in floodplains are frequently inundated, particularly during the winter, and it is likely that the deposition of nutrient-rich silt is responsible for the high phosphorus level in some samples. Condition assessments suggest that some floodplain grasslands have had some agricultural improvement, and in these cases, the high phosphorus content is likely to be the result of this.

The mean available phosphorus level for all other priority habits with the exception of lowland acidic grassland is below 15mg/l (index 0 or 1). Mean available phosphorus in lowland acidic grasslands was 18.25mg/l (index 2). This is somewhat surprising as low pH is known to reduce the availability of phosphate ions, especially in wet soils where they can be precipitated as poorly soluble iron and aluminium phosphates. Olsen’s method for determining available phosphorus is however thought to give poor results in acidic soils with pH < 5.7 (M. Shepherd, pers. comm.), and results from acidic soils should be treated with caution. The use of an alternative method for estimating available phosphorus should be

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler evaluated; a possible method is the Mehlich 3 extraction. There is a moderately close correlation between available phosphorus and total phosphorus content despite the interactions between phosphate availability and pH.

Simple potassium compounds are highly soluble in water, although much soil potassium is incorporated into more stable complex minerals. Mean potassium levels in all priority habitats were between 130mg/l and 205mg/l (index 1-2). There was however much variation between individual samples, with 21% of the total samples having an index of 3 or more (> 241mg/l ≡ high or very high). Samples with an index of 3 or more were distributed among all priority habitats.

The availability of magnesium to plants and grazing animals is related to calcium and inversely related to potassium content in addition to the actual concentration of level of magnesium ions in the soil. Low magnesium content is an important risk factor for grass tetany in ruminants, especially where calcium is limited, and can therefore be an economic constraint to the effective management of grasslands. Mean magnesium levels were high in all priority habitats, between 130mg/l and 261mg/l (index ≥ 3).

Total nitrogen content, loss on ignition and organic carbon content are closely correlated measures (Ball, 1963). The availability of nitrogen as nitrate ions in the soil to plants is determined by the rate of mineralisation of organic nitrogen by micro-organisms, chiefly bacteria. While the total nitrogen content of a soil is a measure of the potential availability of nitrogen, little of this is achieved in practice, and this is determined by microbial activity and pH. Nitrification rate is higher at high pH; at very low pH, the appropriate bacteria are absent and nitrate ion concentration is correspondingly low below pH4.

The mean ratio of % organic matter to % nitrogen here is 14.6 for the combined dataset. This can be compared with the estimate that for the majority of agricultural soils, % organic matter is between 12 and 17 times the % total nitrogen (Anon, 2008).

Mean loss on ignition and organic carbon content were highest in CFGM and lowland heathland. This is likely to be due to the accumulation of peat deposits in many floodplain sites and wet heaths, and slowly decomposing humic matter in the drier heathland communities. Both variables are relatively low in lowland calcareous grasslands, lowland meadows, lowland acidic grasslands, upland calcareous grasslands and upland meadows.

4.3 Soils and NVC communities The results of this soil survey demonstrate associations between some NVC communities and sub-communities and soil characteristics. The combined dataset from 2012 and 2014 was separated into sub-sets on the basis of the priority habitat classification and each of these was analysed separately.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Lowland calcareous grassland. The principal association was between CG2c and low pH but high available phosphorus. This sub-community is considered (Rodwell, 1991) to be characteristic of the deeper soils at the base and the top of steep chalk slopes and is characterised by the presence of a range of species more typical of mesotrophic grasslands, with some stands being transitional to MG5b. These species include Trifolium repens and the grasses Holcus lanatus, Dactylis glomerata, Cynosurus cristatus. Survey work in recent years has shown this to be somewhat simplistic, and this sub-community can also be found in a variety of situations where deeper soils have accumulated over calcareous substrata and where calcicolous grasslands have been subject to some degree of agricultural improvement (Wilson, 2015).

The association between grasslands dominated by Brachypodium pinnatum and Bromus erectus and high potassium levels is difficult to explain.

Lowland heathland. The serpentine rocks that underlie the heathlands of the East and West Lizard SSSIs are well-known for their unusual chemical composition in a British context (Hopkins, 1983). Magnesium is abundant, but calcium, aluminium, phosphorus and potassium are in low concentrations. This is reflected in the analysis of the soil samples collected from H5a heathland, the characteristic humid heathland type of The Lizard. The pH of these soils ranged from 4.6 to 6.5, with a mean of 5.4, which compares with the range of 5.5 to 7.5 quoted in Rodwell (1991). This mean pH is significantly higher than that recorded for other heathland communities. The available phosphorus and total phosphorus levels and potassium levels were low. In contrast, magnesium levels were very high. Only two samples were recorded from H6, the typical dry heathland of the Lizard serpentine, but these showed similar characteristics.

M16a wet heathlands and H4 humid heathlands also had mean pH values significantly higher than samples from H1 and H2 stands typical of drier heathlands in the east of England. This higher pH may be reflected in the presence of a number of more mesophytic species in the more varied heathland swards of H4 and M16a. H2 samples also had significantly higher levels of available phosphorus than H4 and H5.

Lowland meadow. The lowland meadow priority habitat includes an assemblage of grassland types, the relationships between which have been rather simplistically described by Rodwell (1991). MG5 grasslands would have once been the widespread semi-natural agricultural grassland throughout lowland Britain, with inputs limited to an annual application of farmyard manure and occasional liming. Within this community, MG5a is the typical sub-community of circum-neutral soils, grading into MG5c where more acidic and MG5b where more calcareous. These MG5 sub-communities have their MG6 counterparts in situations where agricultural improvement has been more intensive with occasional re- seeding and regular applications of fertilisers. MG6a corresponds to MG5a, while MG6b corresponds to MG5c and MG6c to MG5b. With impedance of drainage, the coarse grasses Holcus lanatus and Deschampsia cespitosa become prominent in MG9 grassland, and in the

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler absence of management, Arrhenatherum elatius and Dactylis glomerata dominate in tussocky MG1 communities. MG4 grasslands are of restricted distribution in regularly inundated valley meadows which are cut for hay annually and their high magnesium level may be related to regular deposition of mineral-rich silt.

Here, there was a clear relationship between pH and MG5 sub-community, MG5b samples having significantly higher pH than MG5c and MG6b. The high levels of available phosphorus and total phosphorus in MG6a and MG9 are likely to be the result of agricultural inputs. MG6a grasslands had significantly higher total phosphorus content than MG6b grasslands, and this may be reflected in the higher species-richness of MG6b swards. The high levels of magnesium in MG4 samples may reflect the deposition of mineral-rich silts during periods of inundation. The highest nitrogen content and loss on ignition were in samples from MG4 grassland, suggesting that these soils had high organic matter content.

Purple moor-grass and rush-pasture. The principal differences between communities in this priority habitat were between M22a and M22b and all of the other communities in the analysis. M22 rush-pastures are typically dominated by Juncus subnodulosus or Juncus inflexus and occur in sites with calcareous ground-water. Wheeler and Tanner (2009) give a mean pH of 6.9, and Rodwell (1991) quotes a range of 6.5–7.5. This agrees well with the means of 6.97 for M22a and 7.01 for M22b recorded here. The mean pHs recorded here for M23a, M23b, M25a and M25c are all within the ranges given for each community by Rodwell (1991). Total nitrogen content, loss on ignition and carbon content are all higher in M22b than in M23a, M23b and MG10a, with total nitrogen also being higher than in M25a and M25c, suggesting that M22b soils had a greater accumulation of organic matter, possibly in the form of peat.

Lowland acidic grassland. Within lowland acidic grasslands there is a division between the U1 swards of the more freely-draining soils and with a predominantly eastern distribution, and the more westerly U4 communities. The high pH of some U1 samples ( > 7 in some samples), particularly samples from the East Anglian Breckland (mainly collected in 2012 but also from Lakenheath Warren in 2014) is somewhat surprising, but is probably due to the derivation of some of these sandy soils from relatively calcareous drift deposits over chalk. Samples from other acidic grassland sites in Dorset, Hampshire and Suffolk also had pH of > 6, and the composition of calcifuge grasslands is clearly related to more than just soil pH and free drainage. The nitrogen content, loss on ignition and organic carbon content of U4e samples is higher than that of the other vegetation types, indicating that this community has a higher organic matter content as a result of the accumulation of humus in the relatively cool and wet conditions under which this sub-community occurs. Rodwell (1991) suggests that this humic layer can grade into more consolidated peats where drainage deteriorates.

There was only sufficient replication of stand types in upland calcareous grassland and upland meadow to permit comparisons between stands of MG2, MG3 and MG6b. The high

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler levels of total nitrogen and loss on ignition in MG2 samples probably reflect the typically low levels of grazing in this community and the accumulation of vegetation litter (Rodwell, 1992). All MG2 samples were collected from a single site, and total phosphorus levels may reflect the local geology.

4.4 Soils and habitat condition A total of 44% of the collected samples were from vegetation assessed during this survey as being in favourable condition. This can be compared with the published figure of 38.4% of SSSI units in favourable condition for all English SSSIs3. This difference is largely because the assessments applied to the vegetation being sampled rather than to the whole SSSI unit, ignoring other parts of the units which may not have been in favourable condition.

The major soil factors associated with favourable or unfavourable condition were available phosphorus (Olsen’s method), potassium, total phosphorus and magnesium. The mean index of available phosphorus in samples from sites in favourable condition was 1, while in samples from sites in unfavourable condition it was index 2. There is a moderately strong correlation between available phosphorus and total phosphorus content, but it is considered that available phosphorus is the more useful measure as this is the form in which phosphorus is available to plants as phosphate ions in solution. The relationship between the two is dependent on the equilibrium between soluble and insoluble phosphate, and this is determined by pH and the presence of other ions. Overall 11% of sites had a phosphorus index of 2 or more, and of these, 85% were considered to be in unfavourable condition (Table 31).

Table 31. Soil phosphorus indices of samples from different priority habitats as proportions of totals.

Phosphorus index BAP Priority Vegetation 0–1 2 ≥ 3 condition 0–15 Mg/l 16–25 Mg/l > 25 Mg/l LCG Favourable 0.99 0.02 Unfavourable 0.92 0.06 0.02 LDAG Favourable 0.55 0.34 0.11 Unfavourable 0.42 0.35 0.23 LM Favourable 0.95 0.05 Unfavourable 0.74 0.11 0.16 LH Favourable 0.93 0.07 Unfavourable 0.86 0.09 0.05 PMGRP Favourable 0.75 0.22 0.03 Unfavourable 0.82 0.12 0.02 CFGM Favourable 0.47 0.22 0.31 Unfavourable 0.26 0.36 0.41 UCG Favourable 0.89 0.11

3 (https://designatedsites.naturalengland.org.uk/ReportConditionSummary.aspx?SiteType=ALL) 56

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Unfavourable 0.80 0.02 UM Favourable 1.00 Unfavourable 0.94 0.05

This apparent relationship between higher levels of available phosphorus and unfavourable condition implies either that the processes that have led to vegetation being in unfavourable condition have resulted in accumulation of available phosphorus or that raised phosphorus levels have caused the unfavourable condition. Given that the addition of phosphorus-containing inputs is a principal part of the agricultural improvement of grasslands and other habitats and that applications of phosphorus are known to be very persistent in the soil, the latter can be favoured as an explanation. Of the 520 samples from sites in unfavourable condition, 176 had a phosphorus index of 2 or more, and of these 36 had a phosphorus index of 3 or more. It is difficult to ascertain causality from the current dataset in the absence of historic data, but there remains the possibility that on a significant proportion of lowland meadow SSSIs, and on a smaller proportion of other priority habitats, phosphorus status may have increased since they were designated. This may have resulted in declines in their condition and a risk to their continued priority habitat status. It is certain however that factors other than soil chemistry, including current and historic management practices, will also have been involved in determining habitat condition.

A survey of soils in grasslands managed under the ESA scheme (Critchley et al., 2001) showed weak correlations between species richness and the number of stress tolerant species (Grime, 1979) weighted by their degree of stress tolerance (“stress radius”, Thompson, 1994), and levels of available phosphorus. In that survey, although both the range of phosphorus levels and the range of grassland species-richness were wide, high species-richness and high stress radius only occurred at an available phosphorus level of between 4mg/l and 15mg/l (Index 0 & 1). Janssens et al. (1998) also found that plant species diversity was limited at higher levels of available phosphorus in the soil, but their analyses used different methods and their results cannot be compared with those described here or by Critchley et al. (2001).

The presence of stress-tolerant plant species is a central element of the assessment of SSSI habitat condition, and failure to reach target thresholds for these species is a reason for a site to fail and be considered in unfavourable condition (Robertson & Jefferson, 2000). The observations of Critchley et al. (2001) were generally supported here. Means for available phosphorus in lowland calcareous grassland, lowland heathland, upland meadow, upland calcareous grassland and PMGRP in both favourable and unfavourable conditions were within the limits of 4mg/l and 15mg/l, as was the mean available phosphorus level for neutral grassland in favourable condition. Means for neutral grassland in unfavourable condition, and both acidic grassland and CFGM in favourable and unfavourable conditions were over 15mg/l. The caveats discussed above regarding the use of Olsen’s method for the determination of available phosphorus levels in acidic soils also apply here however. It

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler is thought possible that high levels of available phosphorus may not necessarily be a limiting factor in determining condition in some types of eutrophic wetland which may include the regularly inundated grassland in the CFGM priority habitat (M. Shepherd, pers comm.).

Critchley et al. (2001) also found a weak relationship between grassland rich in stress- tolerant species and low levels of potassium and magnesium. This supports the results here for potassium (favourable condition, index 2-, unfavourable condition index 2+), but contradicts the observations for magnesium (favourable condition, index 4, unfavourable condition, index 3). While differences between potassium and magnesium levels were highly significant for a pooled analysis of all data, where priority habitats were examined separately, potassium levels were only higher in unfavourable condition lowland meadow and lowland acidic grassland, and magnesium levels were lower only in lowland meadow.

Guidelines for botanical enhancement under Higher Level Stewardship (Anon, 2010), part of the UK agri-environment programme which closed to new entrants in 2014, specified required characteristics for suitable land. These included the physical characteristics of soil depth and stoniness, steepness of slope and period and frequency of waterlogging. Where there were no physical stress factors, available phosphorus was required to be 16mg/l or less (index 1 or 0) for high enhancement potential, and for moderate potential, available phosphorus had to be 16-25mg/l (index 2). Soils with higher levels of available phosphorus were considered to have low potential for botanical enhancement unless physical stress factors were present and potassium levels were below 61mg/l. The great majority of lowland calcareous grasslands, lowland meadows and upland meadows in favourable condition sampled in these surveys had available phosphorus levels below or equal to 15mg/l (index 0-1). No lowland calcareous grasslands, lowland heathlands, lowland meadows, upland calcareous grasslands or upland meadows had available phosphorus levels above 25mg/l (index 2). This supports the use of available phosphorus level as a criterion for the likelihood of a soil being able to support priority habitat vegetation in favourable condition. There were however a few examples of soils collected from lowland acidic grassland, PMGRP and CFGM in favourable condition with available phosphorus level exceeding 25mg/l. For reasons stated previously however, results for lowland acidic grassland and lowland heathland should be treated with caution.

Of the 15 anomalous sites where favourable condition vegetation was present at higher levels of available phosphorus (Index ≥3), nine were susceptible to stress imposed by waterlogging, and four by drought and would therefore have fulfilled the criteria for re- establishment or recreation. There was however no obvious relationship between these sites and low potassium levels, and in no site was potassium level below 61mg/l, the level at which it is said to be of importance for determining the restorability of grasslands (Anon, 2010). This suggests that its role in determining restorability potential may be limited. Janssens et al. (1998) also demonstrated that high potassium levels were compatible with high plant species diversity.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler It is interesting to note that there are no significant effects of total nitrogen on vegetation condition in any of the priority habitats. Nitrogen is one of the primary plant nutrients and its effects on vegetation are well-known, the application of nitrogen being one of the principal long-term drivers of the impoverishment of semi-natural vegetation in England (Mountford et al., 1993, Silvertown, 2006). Critchley et al. (2001) also observed little effect of soil total nitrogen in their investigation of soils in British grasslands, and attributed this to the limitations in the availability of much of the nitrogen in soil to plants. Organic nitrogen however requires mineralisation to nitrate ions for it to be available to plants, and particularly at low pH and in waterlogged soils, there is little relationship between total nitrogen and available nitrogen.

4.5 Soils and site management While there were many significant associations detected between management factors and soil chemistry, some of these are difficult to understand. Some may be the result of associations between management and vegetation type, where in fact the associations are due to the effects of soil chemistry on the vegetation rather than the management driving changes in soil chemistry. It is for example difficult to see how the grazing of sheep can increase soil pH, but this difference can probably be explained by the higher than statistically expected incidence of sheep-grazing of lowland calcareous grasslands and the lower than expected incidence of sheep-grazing on lowland heathland. The associations between sheep-grazing and potassium may have similar origins, while the association between mowing and magnesium may be the result of the high magnesium content of lowland meadow samples.

The causal link between low content of organic matter (as measured by the inter-correlated loss on ignition, total nitrogen and organic carbon) and ungrazed/undermanaged habitats may however be real. This is likely to be the result of the lack of incorporation of plant matter into the soil where grazing does not occur, the annual production of plant material accumulating as very slowly-decomposing litter on the surface.

Management of separate priority habitats was examined in greater depth. Insufficient replicates were sampled to allow comparison of management types for upland meadow or upland calcareous grassland. No significant differences were observed for PMGRP samples.

The low pH of cattle-grazed samples from lowland calcareous grasslands is likely to be due to the more widespread grazing of cattle on more productive swards over deeper and less calcareous soils especially in the west of England. Rodwell (1992) suggests that CG2c grasslands in particular tend to be cattle-grazed, and in this survey these grasslands also had significantly lower pH than other calcareous grassland NVC sub-community. The high magnesium content of cattle-grazed grasslands may also have the same cause. The high pH of mixed-grazed lowland calcareous grasslands may be due to the inclusion of several

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler samples from the single site of Portsdown, all of which were grazed by a mixture of cattle and ponies and all of which had high pH.

Samples from ungrazed/unmanaged CFGM were all notable for the significantly lower levels of potassium, magnesium, total phosphorus, total nitrogen, loss on ignition and organic carbon. It is likely that the maintenance of nutrient levels in these grasslands is due at least partly to their regular input through seasonal flooding, and it is possible that the accumulation of vegetation litter can impede mineral deposition.

Samples from heathland soils under mixed grazing were distinguished by the high levels of nitrogen, loss on ignition and organic carbon (intercorrelated variables which suggest accumulation of organic matter). This data may be skewed by the inclusion of a large number of heathland samples from The New Forest, where extensive mixed grazing, largely by ponies and cattle but also locally sheep and pigs is practiced over large areas of humid (H2c) and wet heathland (M16), where layers of peat accumulate in the moist to waterlogged acidic conditions.

The high mean level of available phosphorus and total phosphorus in sheep-grazed lowland meadow may be due to a tendency for the relatively agriculturally-improved communities MG6a, MG6b and MG9 to be sheep-grazed. It has been suggested that summer grazing can contribute to the conversion of species-rich MG5 grasslands to impoverished swards (Rodwell, 1992), but it is thought more likely in the sites sampled here that nutrient enrichment and more intensive grazing are complementary facets of agricultural- improvement and have had a greater effect. The role of phosphorus addition in fertiliser in the transformation of MG5a grassland to more impoverished swards has been demonstrated at the long-term experiment of Park Grass (Silvertown et al., 2006). Unfertilised plots of this experiment had an available phosphorus level of 4mg/l. A regime of cattle or mixed-grazing with or without hay-cutting is the traditional management on the more mesotrophic soils of both the uplands and lowlands of England, soils which would in the past have supported much more extensive areas of species-rich grassland. The only regular input to traditionally managed systems would have been farmyard manure, and the importance of phosphorus as a plant nutrient was only appreciated in the mid-19th century. Samples from ungrazed/undermanaged plots also had low levels of organic matter, probably for the reasons described above. The significantly high level of magnesium in samples from mown vegetation is difficult to explain, but may be due to the addition of farmyard manure containing high levels of mineral salts in straw used for animal bedding to hay-cut fields.

The significantly high level of total phosphorus in samples from sheep-grazed acidic grassland is also difficult to explain. There is however an association between low levels of the three measures of organic matter content and lack of management, again probably for the above-described reasons.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler 5 Conclusions

From the information gathered in these surveys it is possible to begin to define the ecological space occupied by priority habitats and some NVC communities in terms of soil chemistry. All of the factors measured, pH, available phosphorus, total phosphorus, potassium, magnesium, and the related measures of organic matter content, total nitrogen, loss on ignition and organic carbon content, were associated with different priority habitats.

 Lowland calcareous grassland was characterised by high pH, high potassium and low available phosphorus.  Lowland acidic grassland had low pH (but higher than lowland heath), high available phosphorus but low total phosphorus, high potassium, low magnesium and low organic matter content.  Lowland meadow had moderate levels of all variables apart from potassium and magnesium which were high.  Lowland heath had low pH, low available phosphorus, low total phosphorus, low potassium and magnesium, high organic matter content but low total nitrogen content.  PMGRP is a diverse priority habitat and levels of all variables are moderate.  Although an ecologically diverse priority habitat, CFGM had high pH, high available phosphorus, high potassium and high organic matter content.  Upland calcareous grassland had moderate pH, low available phosphorus, low magnesium and low organic matter content.  Upland meadow had low available phosphorus, low potassium and low organic matter content.

Further associations were found between soil variables and NVC communities. These are discussed in section 4 but overall, pH, availability of phosphorus and organic matter content were the most important factors, with high magnesium levels important for some communities such as H5a and MG4. Further sampling of specific NVC communities would be desirable in order to better define their ecological space.

Unfavourable vegetation condition is also related to high phosphorus levels. This is significant for the whole dataset, but also in the individual priority habitats lowland calcareous grassland, CFGM and lowland meadow. Potassium levels are also higher in vegetation in unfavourable condition for the whole dataset and also for lowland calcareous grassland, lowland heathland, lowland meadow and lowland acidic grassland, while magnesium levels are higher in favourable condition lowland calcareous grassland and lowland meadow. Very few samples were collected from vegetation in favourable condition that had an available phosphorus level of Index 3 or higher. Moderate (Index 2) to high (Index ≥ 3) levels of available phosphorus may present a barrier to the restoration of favourable condition to some habitats, particularly calcareous grasslands, lowland

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler heathland, lowland meadow, upland meadow and PMGRP. Vegetation assessed to be in favourable condition in stands of CFGM and lowland acidic grassland with a phosphorus level of Index ≥ 3 may be under stress from waterlogging and drought, respectively.

These results support the criteria set for the restorability and potential for re-creation of species-rich grasslands under the former Higher Level Stewardship scheme (Anon, 2010). For a grassland stand to have a high or moderate potential for botanical enhancement, a maximum level of available phosphorus of 25mg/l (Index 0 – 2) is specified for soils that are not otherwise stressed by potential waterlogging or drought. Although potassium content had a significant association with vegetation condition, very few samples were collected which had a potassium content below 61mg/l, the specified threshold in the HLS guidelines, and its use as a secondary criterion in determining the potential for botanical enhancement of a site where phosphorus levels are high may be limited.

It must of course be stated that although low available phosphorus levels are required in order for vegetation to be in favourable condition, low phosphorus levels are not a guarantee of favourable condition which also depends on favourable management, management history, hydrology and other factors.

Many of the significant associations between management and soil chemistry can be explained by particular management types being practiced more or less than expected statistically in some priority habitats. There is however a significant association between low organic matter content and under-management. Grazing and animal dunging are important factors in the cycling of nutrients between above ground vegetation, leaf-litter and the soil, and in the absence of grazing, carbon sequestration by the soil may be seriously impaired. Mixed grazing or mowing (in most cases with aftermath grazing) appear to give a significantly higher level of organic carbon content and loss on ignition. This pattern is repeated for CFGM, lowland heathland, lowland meadow and lowland acidic grassland. This suggests that the maintenance of agriculturally unimproved grasslands within a pastoral context may be important for carbon storage, but this requires further investigation. In particular it would be desirable to compare the soil carbon storage of grasslands managed for conservation with those managed under more intensive regimes. Current indications are that extensive pastoral systems are more efficient at carbon storage than previously thought (Grayson, 2011). It has now been demonstrated that in grasslands managed at moderate levels of intensity (probably similar to most of the lowland meadow and CFGM stands examined here), carbon storage per unit area is not only significantly higher than in agriculturally improved grasslands, but is also higher than in the most extensively managed grasslands although if calculated by mass, carbon storage is highest in the most extensively managed grasslands and higher under moderate intensity management than under intensive management. In that study the effects of management on carbon sequestration are not restricted just to the surface layers as sampled here (Ward et al, 2016). It is probable therefore that low-input, ecologically-rich grasslands represent

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler not only an invaluable biodiversity resource but also an important sink for carbon production.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler 6 References

Anon (2002). Minitab 13, Statistical Software. www.minitab.com

Anon (2008). Soil and agri-environment schemes: interpretation of soil analysis. Natural England Technical Information Note TIN036.

Anon (2010). Higher Level Stewardship, Farm Environment Plan Manual. Natural England, Peterborough.

Ball D.F. (1964). Loss on ignition as an estimate of organic soils matter and organic carbon in non-calcareous soils. Journal of Soil Science, 15. 1,

Critchley C.N.R., Chambers B.J., Fowbert J.A., Bhogal A., Rose S.C. & Sanderson R.A. (2001). Plant species richness, functional type and soil properties of grasslands and allied vegetation in English Environmentally Sensitive Areas. Grass and Forage Science, 57, 82–92

Etherington J.R. (1975). Environment and Plant Ecology. Wiley.

Grayson W. (2010). Extensive grazing and climate change. Conservation Land Management.

Hopkins J.J. (1983). Studies of the Historical Ecology, Vegetation and Flora of the Lizard District, Cornwall, with particular Reference to Heathland. PhD Thesis, Bristol University.

Janssens F., Peeters A., Tallowin J.R.B., Bakker J.P., Bekker R.M., Fillat F. & Oomes M.J.M. (1998). Relationship between soil chemical factors and grassland diversity. Plant and Soil , 202.1, 69-78.

Mountford J.O., Lakhani K.H. & Kirkham F.W. (1993). Experimental of the effects of nitrogen addition under hay-cutting and aftermath-grazing on the vegetation of meadows on a Somerset peat moor. Journal of Applied Ecology, 30, 321-332

Mountford J.O., Tallowin J.R.B., Kirkham F.W. & Lakhani K.H. (1994). Effects of inorganic fertilisers in flower-rich hay meadows on the Somerset Levels. In: Haggar R.J., Peel S. (eds) Grassland Management and Nature Conservation. Occasional Symposium No. 28. British Grassland Society, 74–85.

Robertson H.J. & Jefferson R.G. (2000). Monitoring the condition of lowland grassland SSSIs. English Nature, Peterborough.

Rodwell J.S. (ed) (1991). British Plant Communities, volume 1. Woodlands and Scrub. Cambridge University Press, Cambridge.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Rodwell J.S. (ed) (1991). British Plant Communities, volume 2. Mires and Heaths. Cambridge University Press, Cambridge.

Rodwell J.S. (ed) (1992). British Plant Communities, volume 3. Grasslands and Montane Communities. Cambridge University Press.

Rodwell, J.S. (ed.) (1995) British Plant Communities, volume 4. Aquatic communities, swamps and tall-herb fens. Cambridge University Press, Cambridge.

Rodwell, J.S. (ed.) (2000) British Plant Communities. Volume 5. Maritime communities and vegetation of open habitats. Cambridge University Press, Cambridge.

Shaw G. (2008). Soil texture. Natural England Technical Information Note TIN037.

Silvertown J., Poulton P., Johnston E., Edwards G., Heard M. & Biss P.M. (2006). The Park Grass Experiment 1856–2006: its contribution to ecology. Journal of Ecology, 94, 801–814

Tytherleigh A. (2008). Soil sampling for habitat recreation and restoration. Natural England Technical Information Note TIN035.

Ward S.E., Smart S.M., Quirk H., Tallowin J.R.B., Mortimer S.R., Shiel R.S., Wilby A. & Bardgett R.D (2016). Legacy effects of grassland management on soil carbon to depth. Global Change Biology, in press.

Wheeler, B.D., Shaw, S. & Tanner, K. (2009) A wetland framework for impact assessment at statutory sites in England and Wales. Integrated Catchment science programme Science Report SC030232. Environment Agency, Bristol.

Willems J.H., Peet R.K. & Bik L. (1993) Changes in chalk grassland structure and species richness resulting from selective nutrient additions. Journal of Vegetation Science, 4, 203–212.

Wilson P.J. (2014). A Detailed Examination of the Results from a Survey and Assessment of Soil pH and Nutrient Status on Sites of High Botanical Value. Report to Natural England.

Wilson P.J. (2015). Condition Assessment of Chalk Grassland Sites of Importance for Nature Conservation within the South Downs Nature Improvement Area, 2014. Report to Sussex Biodiversity Records Centre.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Appendices

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

Appendix 1. SSSI units from which soil samples were collected in 2014. BAP Priority Habitat: LDAG Lowland acidic grassland, LCG Lowland calcareous grassland, LH Lowland heathland, PMGRP Purple moor-grass and rush-pasture, CFGM Coastal and floodplain grazing marsh, LM lowland meadow, SD sand dune, UAG Upland acidic grassland, UCG Upland calcareous grassland, UM Upland meadow. Where no BAP priority habitat is listed then none was present.

County SSSI name Unit No of Priority habitat NVC samples Avon Burledge Sidelands and Meadows 1 2 LCG, LM CG3b, MG5c Avon Burledge Sidelands and Meadows 2 3 LCG CG3b, MG5b, MG6c Avon Burledge Sidelands and Meadows 3 1 LM MG5c Avon Burledge Sidelands and Meadows 4 4 LM MG6a, MG6b, MG5a Avon Burledge Sidelands and Meadows 5 4 LCG, LM CG2c, MG9, CG2c, MG6a Avon Burledge Sidelands and Meadows 6 2 LM MG5c, MG6b Avon Burledge Sidelands and Meadows 7 5 LM, LCG MG5b, MG5c, CG2c, MG6b Avon Chew Valley Lake 1 1 LM MG5b Avon Chew Valley Lake 3 1 LM MG5a Berkshire Broadmoor to Bagshot Woods and Heaths 11 2 PMGRP, LH M25a, H1 Berkshire Snelsmore Common 4 2 LH, wood W16, H1 Berkshire Snelsmore Common 7 2 LH W16, H1 Buckinghamshire Ivinghoe Hills 1 1 MG1 Buckinghamshire Ivinghoe Hills 2 3 LCG W21d, MG1e, CG3d Buckinghamshire Ivinghoe Hills 3 2 LCG CG3a Buckinghamshire Ivinghoe Hills 4 2 LCG CG3a Buckinghamshire Ivinghoe Hills 6 2 LCG W21a, CG3a Buckinghamshire Ivinghoe Hills 7 2 LCG CG3a, MG1d Buckinghamshire Ivinghoe Hills 8 1 LCG CG3d Buckinghamshire Shabbington Woods Complex 5 1 LM MG5a Cambridgeshire Ouse Washes 5 3 CFGM MG11a, S28, S5

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

Cambridgeshire Ouse Washes 9 2 CFGM MG11a Cambridgeshire Ouse Washes 11 3 CFGM S28, MG11a, MG9 Cambridgeshire Ouse Washes 13 2 CFGM MG11a, S28 Cornwall East Lizard Heathlands 11 2 LH H5a Cornwall East Lizard Heathlands 16 4 LH, PMGRP H4c, M25c, M25a Cornwall Godrevy Head to St Agnes 2 3 LH H4a, W23 Cornwall Godrevy Head to St Agnes 4 2 LH H7b, W23 Cornwall Godrevy Head to St Agnes 5 1 LH H4c Cornwall Loggans Moor 3 4 PMGRP, SD M22, M27, SD8, MG10 Cornwall Newlyn Downs 1 2 LH H4c, W23 Cornwall Newlyn Downs 3 1 LH H4c Cornwall Newlyn Downs 4 1 LH M14 Cornwall River Camel Valley & Tributaries 60 3 PMGRP M25c, M23b, MG10a Cornwall River Camel Valley & Tributaries 63 2 PMGRP W23, M27 Cornwall River Camel Valley & Tributaries 70 4 PMGRP, CFGM MG10a, M23b, MG7, MG11a Cornwall River Camel Valley & Tributaries 71 3 PMGRP, LH M23a, MG10a, W25 Cornwall River Camel Valley & Tributaries 76 3 PMGRP, LH M25a, W25, H4 Cornwall Rock Dunes 2 3 SD SD8, ScrUb Cornwall Sylvias Meadow 1 4 LM, PMGRP MG5c, U20, W24, M25a Cornwall West Lizard 7 3 LH H5a, H4c Cornwall West Lizard 8 2 LH H5a, H4c Cornwall West Lizard 13 3 LH H6c, H5a Cumbria Whitbarrow 2 1 LCG CG9b Cumbria Whitbarrow 11 2 LCG CG9b, U20 Cumbria Whitbarrow 12 1 LCG MG9 Cumbria Whitbarrow 25 2 LCG CG9b, U20 Cumbria Whitbarrow 26 2 LCG U20, CG9b Cumbria Whitbarrow 27 1 LCG CG9b

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

Cumbria Whitbarrow 32 2 LCG CG9b, U20 Derbyshire Lathkill Dale 5 2 LDAG U4c, MG9 Derbyshire Lathkill Dale 7 2 UM MG2 Derbyshire Lathkill Dale 9 2 UC MG6, CG2 Derbyshire Lathkill Dale 12 2 UC CG2c, MG6 Derbyshire Lathkill Dale 17 2 UM MG2 Derbyshire Lathkill Dale 19 2 LDAG MG6b, U4b Derbyshire Lathkill Dale 20 1 LDAG U4b Devon Axmouth Springhead 1 1 LCG MG1e Devon Axmouth Springhead 2 1 LCG W25 Devon Billacombe 1 2 LM MG5b Devon Brocks Farm 1 3 LM MG5b, MG7, W25 Devon Hopes Nose to Walls Hill 1 3 LCG CG6, CG1, MG1 Devon Hopes Nose to Walls Hill 5 2 LCG CG1, MG12 Devon Hopes Nose to Walls Hill 7 2 LCG CG1, U20 Devon Occombe Farm 1 4 LM, PMGRP U20, MG5c, M23a, M23b Devon Occombe Farm 3 4 LM, PMGRP M23a, U20, MG6, MG5c Devon Quarry Fields Farm 1 3 LM MG5a, MG6b Dorset Breach Fields 1 1 LM MG5c Dorset Breach Fields 2 2 LM MG1, MG5c Dorset Breach Fields 3 1 LM MG6b Dorset Bugdens Copse & Meadows 1 1 LM MG5 Dorset Bugdens Copse and Meadows 3 1 PMGRP W4 Dorset Corfe Meadows 1 2 LM, PMGRP MG5a, M23a Dorset Corfe Meadows 3 2 LM, PMGRP MG5a, M23b Dorset Corfe Meadows 4 LM, PMGRP M23b, MG5a Dorset Corfe Mullen Pastures 1 2 LM MG5c, MG6b Dorset Corfe Mullen Pastures 2 1 LM MG5a Dorset Corfe Mullen Pastures 4 1 LM MG5

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

Dorset Corfe Mullen Pastures 5 1 LH M16a Dorset Eggardon Hill & Luccas Farm 1 1 LCG CG2a Dorset Eggardon Hill & Luccas Farm 3 2 LCG CG2a, MG1d Dorset Eggardon Hill & Luccas Farm 4 2 LCG CG2a, MG6c Dorset Eggardon Hill & Luccas Farm 5 1 LCG CG2c Dorset Eggardon Hill & Luccas Farm 7 2 LCG MG1d, CG2a Dorset Eggardon Hill & Luccas Farm 8 2 LM MG5c, CG2b Dorset Eggardon Hill & Luccas Farm 9 1 LM MG5a Dorset Eggardon Hill & Luccas Farm 10 1 LM MG5c Dorset Frome St Quintin 3 3 fen S7 Dorset Frome St Quintin 4 2 LM MG5c Dorset River Frome 8 1 PMGRP M23a Dorset River Frome 11 2 PMGRP M25a, W25 Dorset River Frome 17 1 LM MG10 Dorset River Frome 19 1 PMGRP MG9 Dorset West Dorset Coast 1 3 LM, PMGRP, MG6b, M22a, U1d LDAG Dorset West Dorset Coast 4 1 PMGRP M22b Dorset West Dorset Coast 5 3 LM MG12, MG5c, MG6b Dorset West Dorset Coast 21 3 LDAG, LM U1b, MG6b, U20 Dorset West Dorset Coast 22 3 LDAG, LM U1d, MG6b Dorset West Dorset Coast 23 3 LDAG MG6b, U20, U1d Dorset West Dorset Coast 25 3 LDAG, LH U4a/M25b, H8b Dorset West Dorset Coast 27 1 wood W25 Dorset West Dorset Coast 28 3 PMGRP, LM M23a, MG5c, W25 Dorset West Dorset Coast 34 3 LM MG5b, MG5c, MG5a Dorset West Dorset Coast 37 2 LM MG5c Dorset West Dorset Coast 40 2 LM MG5c, MG6b Dorset Woolcombe 2 1 fen S22

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

Durham Upper Teesdale 19 2 UAG, UCG U4e, CG9 Durham Upper Teesdale 20 1 UM Durham Upper Teesdale 21 6 UC, PMGRP, UM CG9, M23a, MG6b, MG10a Durham Upper Teesdale 22 1 UM MG10a Durham Upper Teesdale 31 1 PMGRP M22b Durham Upper Teesdale 32 2 UM MG3, MG6b Durham Upper Teesdale 33 2 UM, PMGRP MG6b, M23a Durham Upper Teesdale 37 1 Durham Upper Teesdale 38 2 UM MG3, MG6b Durham Upper Teesdale 56 1 UM MG9 Durham Upper Teesdale 60 3 UC, UM CG9, MG9 Durham Upper Teesdale 61 2 UM, UC MG9, CG9 Durham Upper Teesdale 62 1 UM MG3 Durham Upper Teesdale 67 1 UM MG6b Durham Upper Teesdale 68 1 UC Durham Upper Teesdale 70 2 PMGRP, UM M6d Durham Upper Teesdale 71 1 PMGRP M23b Durham Upper Teesdale 72 2 UM MG6b East Sussex Seaford to Beachy Head 4 2 LCG W21, CG5a East Sussex Seaford to Beachy Head 5 2 LCG W21, CG5a East Sussex Seaford to Beachy Head 6 2 CFGM MG11b, S4 East Sussex Seaford to Beachy Head 7 2 CFGM, sm MG11b, SM11 East Sussex Seaford to Beachy Head 8 4 LCG CG5a, MG6c, W23 East Sussex Seaford to Beachy Head 10 2 LCG MG1e, CG5a East Sussex Seaford to Beachy Head 19 2 LCG W23, CG5a East Sussex Seaford to Beachy Head 20 1 LCG W21d East Sussex Seaford to Beachy Head 21 2 LCG CG4c, CG5a East Sussex Seaford to Beachy Head 22 2 LCG CG5a, W23 Essex Epping Forest 123 3 LH, LDAG H2a, U4e

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

Essex Epping Forest 126 2 LM MG9, W21a Essex Epping Forest 128 2 LH H2a Essex Epping Forest 138 2 LDAG W24, U4e Gloucestershire Ashleworth Ham 2 2 CFGM MG4, MG11a Gloucestershire Ashleworth Ham 3 1 CFGM MG4 Gloucestershire Barton Bushes 1 1 LCG CG5a Gloucestershire Barton Bushes 2 1 LCG CG3a Gloucestershire Barton Bushes 3 1 LCG CG5a Hampshire Portsdown 1 2 LCG CG3a, W21d Hampshire Portsdown 2 2 LCG CG3a, W21d Hampshire Portsdown 3 1 LCG W21d Hampshire Portsdown 4 2 LCG CG3a, W21d Hampshire Portsdown 5 2 LCG CG3a, W21d Hampshire Portsdown 7 2 LCG CG3a, W21d Hampshire Roydon Woods 6 1 wood W16 Hampshire The New Forest 1 1 PMGRP M23 Hampshire The New Forest 2 1 PMGRP M23a Hampshire The New Forest 3 1 PMGRP M23b Hampshire The New Forest 4 2 PMGRP M22b, MG8 Hampshire The New Forest 5 3 PMGRP, LM M23a, M24a, MG1e Hampshire The New Forest 10 2 PMGRP, LDAG M23a, M25b Hampshire The New Forest 12 2 PMGRP M23a, M25c Hampshire The New Forest 20 2 PMGRP M23a Hampshire The New Forest 21 1 PMGRP M25c Hampshire The New Forest 22 2 PMGRP M23a, M25a Hampshire The New Forest 23 3 PMGRP M25a, W4a, M23a Hampshire The New Forest 24 1 LH H2c Hampshire The New Forest 25 2 LH M16a, M25a Hampshire The New Forest 72 1 LDAG M25b

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

Hampshire The New Forest 141 2 LH M16a, M25b Hampshire The New Forest 156 3 LH M25b, M16a, U20 Hampshire The New Forest 165 2 LDAG ov21c, MG11a Hampshire The New Forest 176 2 PMGRP MG10, M25a Hampshire The New Forest 187 2 LM, PMGRP MG6b, M23a Hampshire The New Forest 194 2 PMGRP M23, MG11 Hampshire The New Forest 196 1 LM MG6b Hampshire The New Forest 201 2 LM, PMGRP MG6, M23a Hampshire The New Forest 202 2 LM, PMGRP MG5c, M23b Hampshire The New Forest 221 2 LDAG, LH U4, M16a Hampshire The New Forest 223 2 LH M16a, H2a Hampshire The New Forest 246 1 LH H2a Hampshire The New Forest 247 1 LDAG U1b Hampshire The New Forest 257 3 LDAG, LH U1b, H2a, U4a Hampshire The New Forest 273 1 LDAG, LH U1b Hampshire The New Forest 284 1 LH H2b Hampshire The New Forest 287 2 LH M16a, H2a Hampshire The New Forest 300 1 LM MG6b Hampshire The New Forest 302 1 PMGRP M23a Hampshire The New Forest 321 2 LM, PMGRP MG5, M23b Hampshire The New Forest 322 1 LM MG6b Hampshire The New Forest 323 1 LM MG6b Hampshire The New Forest 324 2 LH, LDAG H2c, U1b Hampshire The New Forest 340 3 LDAG, LH U1d, H2c Hampshire The New Forest 377 1 LDAG M25b Hampshire The New Forest 378 1 LDAG M25b Hampshire The New Forest 443 2 LH, LDAG Hampshire The New Forest 469 3 Hampshire The New Forest 477 1 LH

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

Hampshire The New Forest 479 2 LDAG, LH M25b, M16a Hampshire The New Forest 483 1 LDAG M25b Hampshire The New Forest 505.2 2 LDAG, LH Hampshire The New Forest 576 2 LDAG U1b Hampshire The New Forest 579 2 LDAG U1b Hampshire The New Forest 583 1 LDAG U1d Hereford and Worcester Bredon Hill 12 2 LCG CG5a, CG4 Hereford and Worcester Bredon Hill 13 2 LCG MG1e, CG4 Hereford and Worcester Bredon Hill 17 3 LCG CG5a, CG3b, MG1e Hereford and Worcester Wyre Forest 319 2 LM MG5a, MG1e Hereford and Worcester Wyre Forest 328 2 LM MG5a, MG1e Hereford and Worcester Wyre Forest 350 1 LDAG U4a Hereford and Worcester Wyre Forest 364 1 LM MG5c Hereford and Worcester Wyre Forest 365 2 LM MG5c Hereford and Worcester Wyre Forest 367 1 LM MG5c Hereford and Worcester Wyre Forest 368 2 LM MG5c, MG1e Hereford and Worcester Wyre Forest 371 2 LM MG1e, U20 Hereford and Worcester Wyre Forest 376 1 LM MG5c Hereford and Worcester Wyre Forest 377 2 LM MG5c Hereford and Worcester Wyre Forest 379 4 LM MG5c, MG1e, MG6b Hereford and Worcester Wyre Forest 381 1 LM MG1e Hereford and Worcester Wyre Forest 384 2 LDAG. LM U4c, MG1e Hereford and Worcester Wyre Forest 399 1 LM MG1e Lancashire Ribble Estuary 7 2 CFGM MG5a, ov25 Lancashire Ribble Estuary 13 1 CFGM MG7 Lancashire Ribble Estuary 15 2 CFGM MG7 Lancashire Ribble Estuary 16 2 CFGM MG6a Lancashire Ribble Estuary 17 2 CFGM MG6a Leicestershire Rutland Water 17 2 LDAG, LM U1d, MG9

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

Leicestershire Rutland Water 18 2 LM MG9/10 Leicestershire Rutland Water 19 3 LM MG9, MG4, MG6a Leicestershire Rutland Water 20 1 LM MG9 Leicestershire Rutland Water 21 2 LDAG, LM U1d, MG9 Leicestershire Rutland Water 23 3 LDAG, LM U1d, MG9 Leicestershire Rutland Water 25 1 LM MG6a Leicestershire Rutland Water 27 1 LM MG9 Leicestershire Rutland Water 28 1 LM MG6a North Yorkshire Ripon Parks 2 2 LCG CG2a North Yorkshire Ripon Parks 6 2 LM MG5c, MG1 North Yorkshire Ripon Parks 8 2 LCG CG2 North Yorkshire Ripon Parks 10 1 LM MG6a North Yorkshire Semerwater 6 1 PMGRP S7 North Yorkshire Semerwater 7 1 PMGRP MG10a North Yorkshire Semerwater 8 1 PMGRP MG10a North Yorkshire Semerwater 9 1 PMGRP MG10a North Yorkshire Semerwater 10 1 PMGRP MG8 North Yorkshire Semerwater 11 2 PMGRP, UM M23a North Yorkshire Semerwater 14 1 PMGRP M23a North Yorkshire Semerwater 15 1 PMGRP M23a North Yorkshire Semerwater 16 1 PMGRP M23a North Yorkshire Semerwater 17 1 PMGRP M23b North Yorkshire Strensall Common 6 2 LH M16a, H9e Somerset Babcary Meadows 1 1 LM MG5a Somerset Babcary Meadows 2 2 LM MG6b, MG5a Somerset Barrington Hill Meadows 1 1 LM MG5a Somerset Barrington Hill Meadows 2 1 LM MG5a Somerset Catcott, Edington & Chilton Moors 131 1 CFGM MG11a Somerset Catcott, Edington & Chilton Moors 145 1 CFGM MG10a

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

Somerset Catcott, Edington & Chilton Moors 150 1 CFGM MG11a Somerset Catcott, Edington & Chilton Moors 155 1 CFGM MG7 Somerset Catcott, Edington & Chilton Moors 161 1 CFGM MG7 Somerset Chancellor's Farm 1 1 LDAG U4e Somerset Chancellor's Farm 2 1 LM MG5c Somerset Edford Woods and Meadows 4 1 LM MG5c Somerset Edford Woods and Meadows 5 1 LM MG5a Somerset Fivehead Arable Fields 1 1 a Somerset Fivehead Woods & Meadow 7 1 LM MG5 Somerset Grove Farm 1 3 LM MG5a, MG10b, MG4 Somerset Grove Farm 2 4 LM, PMGRP MG5c, M23b, MG6b Somerset Long Lye 1 2 LM MG5b, MG5a Somerset Long Lye Meadow 1 3 PMGRP, LM M23a, MG5c, W4 Somerset Tealham and Tadham Moors 113 1 CFGM MG7 Somerset Tealham and Tadham Moors 115 1 CFGM MG8 Somerset Tealham and Tadham Moors 119 1 CFGM MG11a Somerset Tealham and Tadham Moors 122 1 CFGM MG7 Somerset Tealham and Tadham Moors 126 1 CFGM MG11a Somerset The Quantocks 10 2 LH H4d, H4b Somerset The Quantocks 16 1 LDAG U4a Somerset The Quantocks 41 1 LDAG U4b Somerset West Sedgemoor 116 2 CFGM MG7e, MG11a Somerset West Sedgemoor 117 5 CFGM, LM, MG11a, MG10a, MG9, PMGRP M22b Somerset West Sedgemoor 118 2 LM, CFGM MG5a, S8 Somerset West Sedgemoor 119 3 CFGM MG9, MG11a Somerset West Sedgemoor 120 3 LM, CFGM MG8, MG11a Somerset West Sedgemoor 121 4 CFGM MG11a Staffordshire Aqualate Mere 33 2 PMGRP M23a

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

Staffordshire Aqualate Mere 34 2 PMGRP M23b, MG10a Staffordshire Aqualate Mere 35 2 PMGRP M23a Staffordshire Aqualate Mere 36 2 PMGRP M23a Staffordshire Aqualate Mere 48 1 LDAG U4b Staffordshire Aqualate Mere 49 2 swamp S24 Staffordshire Aqualate Mere 50 2 PMGRP, LDAG M23b, U1d Staffordshire Hamps & Manifold Valleys 15 2 UC CG10a, MG6a Staffordshire Hamps & Manifold Valleys 76 2 UM MG5b Staffordshire Hamps & Manifold Valleys 81 2 UC CG10a,MG6c Suffolk Lakenheath Warren 5 1 LCG MG1d Suffolk Lakenheath Warren 12 3 LH, LDAG H1d, U20, U1b Suffolk Lakenheath Warren 13 2 LCG, LDAG CG3a, U1b Suffolk Lakenheath Warren 18 2 LDAG U1d, U1b Suffolk Lakenheath Warren 19 3 LDAG, LH U1d, H1d Suffolk Leiston - Aldeburgh 1 2 LH, LDAG H1d, U1b Suffolk Leiston - Aldeburgh 3 2 LH H1d Suffolk Leiston - Aldeburgh 7 2 LDAG U1b, U20 Suffolk Leiston - Aldeburgh 12 1 LDAG W25 Suffolk Leiston - Aldeburgh 13 4 LDAG, LH U1b, H1d, U20 Suffolk Leiston - Aldeburgh 14 2 CFGM, LDAG MG11b, U1 Suffolk Leiston - Aldeburgh 18 1 LDAG U1b Surrey Thursley, Hankley & Frensham Commons 3 1 LH H1 Surrey Thursley, Hankley & Frensham Commons 18 1 LDAG U1d Surrey Thursley, Hankley & Frensham Commons 19 1 LDAG U1d Surrey Thursley, Hankley & Frensham Commons 22 1 LDAG U1d Surrey Thursley, Hankley & Frensham Commons 23 1 LH H2a Surrey Thursley, Hankley & Frensham Commons 39 1 LH H2a West Sussex Arundel Park 5 3 LCG CG3d, CG3a, CG2a West Sussex Arundel Park 7 4 LCG CG2a, MG1e, CG2c

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

West Sussex Duncton to Bignor Escarpment 3 2 LM MG1e, MG5b West Sussex Duncton to Bignor Escarpment 4 1 LCG CG2c West Sussex Duncton to Bignor Escarpment 10 1 LM MG5b Wiltshire Acres Farm Meadows 1 1 LM MG4 Wiltshire Bencroft Hill 1 2 LM MG5c, MG6b Wiltshire Brickworth Down and Dean Hill 1 1 LCG CG2c Wiltshire Brickworth Down and Dean Hill 2 2 LCG MG6c, CG2 Wiltshire Brickworth Down and Dean Hill 4 1 LCG CG2a Wiltshire Brickworth Down and Dean Hill 7 1 LCG CG2c Wiltshire Brickworth Down and Dean Hill 10 2 LCG W21d, CG2b Wiltshire Salisbury Plain 18 3 LCG CG3d, CG3b, MG1e Wiltshire Salisbury Plain 23 3 LCG, LM CG3d, MG9 Wiltshire Salisbury Plain 45 3 LM, LCG MG5b, MG1e, CG3b Wiltshire Salisbury Plain 79 3 LCG CG3b, CG3d

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler Appendix 2. SSSI units listed for sampling from which soils were not collected. County SSSI Unit Reason CAMBRIDGESHIRE OUSE WASHES 1 Inaccesibility CORNWALL RIVER CAMEL VALLEY AND TRIBUTARIES 74 Unenclosed upland mire. Withdrawn on advice of NE advisor. DEVON DADDYHOLE 3 Dangerous cliff-face. No calcareous grassland present. DEVON HOPE'S NOSE TO WALL'S HILL 3 Inaccessible quarry. DEVON PARK FARM MEADOWS 1 Access permission denied. DORSET CORFE MULLEN PASTURES 3 Sample lost. DORSET RAMPISHAM DOWN 1 Access permission denied. DORSET WEST DORSET COAST 18 Confusion with adjacent SSSIs. DURHAM UPPER TEESDALE 59 Owner not known. HAMPSHIRE BRICKWORTH DOWN AND DEAN HILL 8 Access permission denied. HAMPSHIRE THE NEW FOREST 171 Owner not known. HEREFORD AND WORCESTER WYRE FOREST 325 Owner not known. HEREFORD AND WORCESTER WYRE FOREST 339 Owner not known. HEREFORD AND WORCESTER WYRE FOREST 351 Woodland. HEREFORD AND WORCESTER WYRE FOREST 401 Owner not known. HUMBERSIDE RIVER DERWENT 14 Withdrawn on the advice of NE advisor HUMBERSIDE RIVER DERWENT 15 Withdrawn on the advice of NE advisor LEICESTERSHIRE RUTLAND WATER 8 Open water. NORTH YORKSHIRE RIPON PARKS 15 Open water. NORTH YORKSHIRE RIVER DERWENT 4 Withdrawn on the advice of NE advisor NORTH YORKSHIRE RIVER DERWENT 8 Withdrawn on the advice of NE advisor NORTH YORKSHIRE RIVER DERWENT 9 Withdrawn on the advice of NE advisor NORTH YORKSHIRE RIVER DERWENT 11 Withdrawn on the advice of NE advisor NORTH YORKSHIRE RIVER DERWENT 12 Withdrawn on the advice of NE advisor NORTH YORKSHIRE RIVER DERWENT 19 Withdrawn on the advice of NE advisor STAFFORDSHIRE AQUALATE MERE 47 Open water and swamp, access impossible.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

STAFFORDSHIRE HAMPS AND MANIFOLD VALLEYS 4 Withdrawn on the advice of NE advisor. Substitute unit sampled. STAFFORDSHIRE HAMPS AND MANIFOLD VALLEYS 83 Withdrawn on the advice of NE advisor. Substitute unit sampled. SURREY ASH TO BROOKWOOD HEATHS 1 Access permission denied. SURREY ASH TO BROOKWOOD HEATHS 6 Access permission denied. SURREY ASH TO BROOKWOOD HEATHS 9 Access permission denied. SURREY ASH TO BROOKWOOD HEATHS 11 Access permission denied. SURREY ASH TO BROOKWOOD HEATHS 12 Access permission denied. SURREY THURSLEY, HANKLEY & FRENSHAM COMMONS 9 Owner not known. WEST SUSSEX CHICHESTER HARBOUR 25 Withdrawn on the advice of NE advisor. WEST SUSSEX DUNCTON TO BIGNOR ESCARPMENT 9 Woodland. Adjacent grassland substituted. WILTSHIRE BRICKWORTH DOWN AND DEAN HILL 6 Access permission denied. WILTSHIRE BRICKWORTH DOWN AND DEAN HILL 8 Potential conflict with traveller encampment.

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

Appendix 3. Samples lost by courier.

County SSSI Unit Hereford and Worcester Wyre Forest 345 3 samples Hereford and Worcester Wyre Forest 360 4 samples Hereford and Worcester Wyre Forest 363 2 samples Hereford and Worcester Wyre Forest 397 1 sample Hereford and Worcester Wyre Forest 320 1 sample Hereford and Worcester Wyre Forest 324 1 sample Hereford and Worcester Wyre Forest 356 1 sample Wiltshire Salisbury Plain 10 4 samples Wiltshire Salisbury Plain 146 4 samples

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

Appendix 4. NVC communities referred to in the text and tables. Community Sub-community U1b Festuca ovina-Agrostis capillaris- Typical Rumex acetosella grassland U1d Festuca ovina-Agrostis capillaris- Anthoxanthum odoratum-Lotus corniculatus Rumex acetosella grassland U4b Festuca ovina-Agrostis capillaris- Holcus lanatus-Trifolium repens Galium saxatile grassland U4e Festuca ovina-Agrostis capillaris- Vaccinium myrtillus-Deschampsia flexuosa Galium saxatile grassland U20 Pteridium aquilinum-Galium saxatile community CG2a Festuca ovina-Avenula pratensis Cirsium acaule-Asperula cynanchica grassland CG2c Festuca ovina-Avenula pratensis Holcus lanatus-Trifolium repens grassland CG3a Bromus erectus grassland Typical CG3b Bromus erectus grassland Centaurea nigra CG3d Bromus erectus grassland Festuca rubra/arundinacea CG5a Bromus erectus-Brachypodium Typical pinnatum grassland MG1e Arrhenatherum elatius grassland Centaurea nigra MG4 Alopecurus pratensis-Sanguisorba officinalis grassland MG5a Centaurea nigra-Cynosurus cristatus Lathyrus pratensis grassland MG5b Centaurea nigra-Cynosurus cristatus Galium verum grassland MG5c Centaurea nigra-Cynosurus cristatus Danthonia decumbens grassland MG6a Lolium perenne-Cynosurus cristatus Typical grassland MG6b Lolium perenne-Cynosurus cristatus Anthoxanthum odoratum grassland MG7 Lolium perenne leys MG9 Deschampsia cespitosa-Holcus lanatus grassland MG10a Juncus effusus-Holcus lanatus rush Juncus effusus pasture MG11a Festuca rubra-Agrostis stolonifera- Lolium perenne Potentilla anserine grassland M16a Erica tetralix-Sphagnum compactum Typical wet heath M22a Juncus subnodulosus-Cirsium palustre Typical fen-meadow M22b Juncus subnodulosus-Cirsium palustre Briza media-Trifolium repens fen-meadow M23a Juncus acutiflorus/Juncus effusus- Juncus acutiflorus Galium palustre rush pasture

Survey of soil nutrient status on sites of high botanical value, 2014 Philip Wilson & Belinda Wheeler

M23b Juncus acutiflorus/Juncus effusus- Juncus effusus Galium palustre rush pasture M25a Molinia caerulea-Potentilla erecta fen Erica tetralix meadow M25c Molinia caerulea-Potentilla erecta fen Angelica sylvestris meadow H1 Calluna vulgaris-Festuca ovina heath H2 Calluna vulgaris-Ulex minor heath H4 Ulex gallii-Agrostis curtisii heath H5a Erica vagans-Schoenus nigricans heath Typical