Methods
Ten ECN sites (Fig. 1, Table 1) were used in this study, representing a wide range of vegetation types, climatic conditions and land uses.  Between 11 and 23 plots were recorded at each site in 1999 and 1998 under this contract (Table 2).

Plots were mostly selected from existing ECN vegetation monitoring plots to allow the time series to be extended by including records from earlier surveys, in particular we have used data collected in the DEFRA funded pilot study in 1997 and from ECN recording in 1996.  Three sites also had some records from 1994.

Further selection was made on the basis of ensuring a good representation of different aggregate vegetation classes (Table 2) with the intention being to have at least 15 plots of each aggregate class across as many ECN sites as possible.  To enable this, some plots that had previously received a less detailed 'baseline' survey were included in 1997 and 1998.

In the case of aggregate class I, Crops/ Weeds, five completely new plots were set up at each of the four ECN sites with arable land (Drayton, Porton, Rothamsted and Wytham).  Aggregate class II, Tall Grassland / Herb, was not sufficiently well represented amongst ECN plots to be thoroughly covered.  This was anticipated as it has the lowest coverage of the Countryside Survey aggregate classes and occurs under land uses such as roadsides and field margins, which ECN monitoring was not designed to cover.  Four plots from the 1997 survey were however kept within the recording programme and various other plots were classified as Class II in subsequent years.  The final number of plots available for analysis was 158.

Table 1 ECN sites used in CS2000 module 10

Table 2 Summary of plots recorded in 1998 and 1999 under CS2000 module 10

¹ Moor House and Upper Teesdale is a large site comprising two nature reserves, if the two reserves are considered as 2 sites, classes VI, VII and VIII are represented at 6, 5 and 4 sites respectively.

The basic method used was the ECN ‘fine grain’ vegetation monitoring method in which the presence of species is recorded in 10 randomly distributed 400 x 400 mm. quadrats within a larger 10 m. x 10 m. square plot.  Plots and sub-plots are permanently marked to ensure accurate relocation.  The detailed methodology is described by Sykes & Lane (1996) and a comparison of the ECN and Countryside Survey methods is given by Morecroft et al. (1997).  The method does differ from that of CS2000, but it was adopted as it allowed a longer run of data to be analysed. Countryside Survey vegetation recording is based on species lists with cover estimates for a range of permanent plots located within randomly selected 1 km squares.

The field surveys were carried out between mid June and the end of August in 1998 and 1999 (in some of the early surveys, recording continued into early September).  As far as possible the same surveyors were used in each year at each sites.  During the 1999 survey our main surveyors, D. McCutcheon and P. Wilson both recorded plots at two of the more diverse sites - Moorhouse / Upper Teesdale and Porton Down.  Good comparability was found between them.  Quality control exercises were also carried out in 1996 and 1997.  Staff at each ECN site were responsible for marking plots and facilitating the surveyors' visits.

The analysis only included species used in the analysis of Countryside Surveys results ('Category 1' species) and likewise counted variable and taxonomically disputed species such as bramble (Rubus fruticosus agg.) as a single species.

We have tested for changes in the aggregate vegetation class between years and also for the following measures of diversity and plant characterstics, which are also included in the analysis of the main CS2000 results: 

• Number of species

• Mean C radius

• Mean S radius

• Mean R radius

• Mean Ellenberg R score (pH range)

• Mean Ellenberg N score (soil fertility)

• Mean Ellenberg W score (soil moisture)

• Mean Ellenberg L score (light)

References
Morecroft, M.D., Parr, T.W., Scott, W.A., Bunce, R.G.H., Common, G., Wilson, P., Read, M., (1997) Pilot Study to link Environmental Change Network and Countryside Survey Vegetation monitoring.  Report to Department of Environment, Transport and the Regions.