UK: The fall and continued rise of a rare sedge


The story of the starved wood-sedge (Carex depauperata) reads like a soap opera. The critically endangered (in the UK) plant was at one time possibly reduced to only one wild individual, but its continuing comeback is testimony to a series of dedicated individuals.

close up of flowers of starved wood-sedgeA new chapter will be written in less than a week’s time, 21 September, as more than 50 individual plants will be introduced to the wild in a secret woodland location in Surrey, England. This exciting repatriation into an historic site follows the establishment of a new population at another classic site - the famous Charterhouse School (also in Surrey), which Plant Talk reported earlier this year.

Starved wood-sedge © Dominic Price / Plantlife

The obvious rarity of the plant is, perhaps, a confusing one. Its preferred habitat appears to be woodland gaps and trails, where it opportunistically colonises when the canopy is opened up. It grows in all sorts of situations, on a wide-range of soil types, can survive trampling and grazing, but for varied reasons – competition mainly - struggles to keep its numbers up.

Lucky find...

It was a chance discovery in 1992 that paved the way for much of the recent conservation work and underpins much of the knowledge about the ecological requirements of the plant. The site of the discovery, Godalming in Surrey, had long held a population of Carex depauperata, first recorded in 1807 by W. Borner, but by 1972, after near annual searches and calls for information, all trace of the plant had disappeared – perhaps under a landslide.

grass like plant sitting among ivy in a woodland

Starved wood-sedge in its natural woodland habitat. Here it's surrounded by one of its major competitors Hedera helix. Management of local sites often involves the regular clearance of other plants such as Hedera. © Tim Rich

The age-old story of botanists successfully mapping a species to extinction seemed to have reared its ugly head again, but all that changed in 1992 when Francis Rose, Peter Marren, and Tim Rich luckily found a solitary specimen in exactly the same place as the 1972 sighting. It appeared a large Tilia x vulgaris tree had lost a large branch in the Great Storm of 1987, opening up the canopy and causing a buried seed to germinate (it’s estimated seeds can remain viable for up to 20 years). As is common with this species of sedge the remains of the previous year’s flowers were on show leading the team to believe the plant was at least in its third year.

close up of starved wood-sedgeThis new population of 55 plants was multiplied vegetatively over the years from a single specimen donated to Wakehurst Place, and seed has also been collected over the years and stored in the Millennium Seed Bank – one of the world’s great safe-houses – for rare and threatened plants. This growing wealth of vegetative and seed material, combined with Plantlife's ongoing monitoring efforts, will hopefully improve the long-term survival chances of the species in the UK, which is at the northern end of its European distribution.

Close-up of starved wood-sedge © Tim Rich
A nice summary of the 14 historic sites for the plant (pre 2001) can be found in this Watsonia article by Tim Rich and Chris Birkinshaw.

Related links:

Carex depauperata on ARKive

UK: Rare plant returns to old school haunt


starved wood sedgeLate last year Plant Talk reported on an ambitious plan to create a third population of one of Britain's rarest plants on the site of a historic population; Charterhouse School in Surrey.

UK: 2009 is a good vintage for Britain's rarest plants


picture of pink flower The wild plant conservation charity, Plantlife, report that 2009 has been a great year for Britain's rarest plants.