It is interesting to contemplate a tangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent upon each other in so complex a manner, have all been produced by laws acting around us.” (Charles Darwin, 1859. This is the last paragraph from On the Origin of Species, believed to refer to the chalk grassland at Downe Bank in the Borough of Bromley) [taken from London’s Chalk Grassland Habitat Action Plan, see below].

If, like Darwin, you would like to contemplate a diverse and complex ecosystem in London, a good habitat to visit in August is calcareous, or chalk, grassland.  This week, our image is of Devil’s-bit scabious Succisa pratensis, which can be found flowering at this time of year in calcareous grassland amid a wealth of other herbs and grasses, including marjoramquaking-grass and bird’s-foot trefoil which support a range of invertebrates and birds, forming this intricate ecosystem.

Calcareous grasslands are a characteristic lowland habitat in the UK, dominated by grasses and herbs growing on a substrate of basic soil, such as formed from limestone or chalk.  The rich array of flowering plants found in this habitat supports diverse animal life, including a number of habitat restricted, rare or threatened species.  Read more about the national definition from the JNCC here.

In Greater London, chalky substrate is found where the North Downs and Chilterns reach into the metropolitan area, to the south and west. But, since the 19th Century, London’s calcareous grasslands here have been largely lost or degraded due to changes in grazing and agriculture, suburban development and changes of land use.  Now, efforts are in place to reverse this historic trend.  Remaining areas of chalk grassland have special status as a London Priority Habitat.  There is also a Habitat Action Plan in place to help preserve and enhance exisiting areas in London, and where possible restore or create new areas.  Read more about this history, threats and recommended actions for chalk grassland in the Action Plan.

GiGL’s habitat dataset identifies surveyed areas of chalk grassland.  The BAP Habitat Condition and Suitability dataset estimates the condition of BAP habitats, including chalk grassland, and predicts locations for potential habitat restoration or creation, according to underlying soils and relic habitat.  The GiGL species records dataset includes observations of chalk grassland species observed in London, including over 700 records of Devil’s-bit scabious, which is flagged as a London Species of Conservation Concern.

 

August 2014

To read other images of the week please visit the archive.