Southwater Country Park

Field meeting reports

Meeting date: 2 April 2005

(Leader: Arthur Hoare)

Our first meeting of 2005, organised very effectively by Arthur Hoare, was something of an experiment as it combined an introduction to tetrad recording, covering four different tetrads (TQ12M,N,S & T), with a chance to see how much overlap in recorded species there was between different groups recording the same general area. A large group of over 25 members met on a bright, sunny day and was soon divided into four smaller groups, each going off to a different tetrad. At lunch time we returned to the car park and, after lunch, each group went off to a different tetrad. We recorded an average of 133 species per tetrad, a very good number considering the early date. Interesting finds included Ranunculus auricomus (Wood Goldilocks), Orchis mascula (Early Purple-orchid), and Lathraea squamaria (Toothwort) in 2 tetrads, with one fine colony on a roadside bank less than 100m from the starting point. The discovery of a small colony of Serratula tinctoria (Saw-wort), was especially interesting as it is now very rare in West Sussex. Another pleasing find by a sharp-eyed recorder was a small patch of Montia fontana (Blinks) on a damp grassy roadside verge. This species is probably quite widespread but is only visible early in the season and even then is very easy to miss.

Comparing results from the various groups showed just what a difficult business recording can be. Of the species found in a given tetrad, on average only 51% were recorded by both groups. The results were very similar for all 4 tetrads, varying between 47% and 53%. This means that about half of the species recorded by each group were not recorded by the other group who visited a very similar area. Although this sounds surprising it is completely in line with other similar studies of recording done in the past and emphasises the value of having more than one recorder or group of recorders visiting a site.