Progress surveying Carex maritima in 2006 David Pearman

To recap: this is the New Atlas version of the distribution map. Date Class 3: 22 dots Date Class 2: 21 dots Date Class 1: 40 dots Change Index: ‘Considerable decline before 1930’

Still there (19) Gone (12) Not searched for (16) This was the situation last year, looking at the post-1970 records only

After much diligent searching…

This is what you found… Last seen 1953 New squares Last seen 1842

If we draw time-sliced maps using the date classes of the Maps Scheme… Date Class dots

Date Class dots

Date Class dots

Date Class dots

Date Class dots so far…

The current view: a slight decline in distribution during the 20 th century, perhaps

How often are new sites found? Surprisingly, perhaps, new sites (here defined as Wells Sites – 1km squares) have continued to be found at a steady pace since the mid 18 th century, and the rate of discovery shows no sign of slowing. This graph ignores any losses.

Is Carex maritima moving north? Probably, yes. In an analysis of 260 records, grouped by 100km northing and evenly divided into four date classes, there seems to be a clear trend towards the north. Is this climate change, development or ocean currents?

If we add to the Atlas map the new records made since, and remove the introductions on dumped sand by the roadside… Roughly half of all sites are gone. Mostly on the east coast. Why would these have gone?  Erosion?  Development/agriculture?  Accretion in dune systems? And why are there seemingly more sites in the west? Just because they were not found before, or because the dune systems there are developing and mobile?

Carex maritima in Orkney HY ‘In thick vegetation.’ Gone? HY No-one has looked. HY ‘Two tiny populations.’ Gone? HY Abundant. HY Abundant. HY Destroyed by airstrip. Gone HY Has anyone looked? HY Machair heavily grazed. HY No-one has looked. HY Some 51 plants. HY Introduction on roadside. Gone. HY Very plentiful. Unable to find since. ND Thousands of plants. ND Thousands of plants.

Conclusions We should keep looking, especially in:- Orkney Sutherland Aberdeenshire Outer Hebrides

Acknowledgements Thanks to the following for sending records and reports Brian & Barbara Ballinger, Pat Evans, Lynn Farrell, Ian Green, Alex Lockton, Richard Pankhurst, Walter Scott, Alan Silverside, Paul Smith & Sarah Whild