The acid grassland, situated between the Mountview Road bridge and the Blythwood Road entrance gate is the only one of its kind along the Walk, or indeed in the whole of Islington. Lowland acid grassland develops on low-nutrient soils on free draining sandy soils. Preventing nutritional development is key to maintaining the unique habitats that are dependant on acidic soil conditions and this is a priority for the team from the Islington Ecology Centre.
Nationally, south facing habitats of this kind are in jeopardy, with the loss of associated plants and other wildlife. In this particular example, due to the gradual encroachment of surrounding trees, the overall area has shrunk. The annual leaf-fall continues to raise nutrient levels within the grass and reduce acidity. Acidic grassland plants such as Sheep’s Sorrell are being lost, which in turn effects the Small Copper butterfly, a beautiful insect whose numbers are going down in the country as a whole.
In addition, as the sward gets richer, it also becomes more uniformly covered and, as a consequence, less species rich. This seriously affects a great many other species of insect. One, in particular is well worthy of mention – a parasitic ‘cuckoo-bee’ (Nomada lathburiana), being on the Red Data List for London and designated ‘rare’ in the Capital. Crucially for the Nomada, its host the ‘mining – bee’ (Adrena cineraria) prefers a sunny, vegetation sparse habitat, within which it tunnels and lays its eggs.
The Acidic grassland is also home to another interesting insect – a largish dark brown ant (Formica cunicularia). Recorded locally early in the 20 Century by E.A Butler in a book called ‘British Ants, their life histories and classification’, compiled by Horace Donisthorpe. It is fascinating to consider that we may well be looking at the same colony today.
While fully appreciating the value of trees aesthetically and from a biodiversity viewpoint, the Parkland Walk as a Local Nature Reserve is home to a large number.
In order to preserve this valuable habitat it is necessary to remove a small number of trees and coppice a few more.
Author: Richard Meyers (London Borough of Islington - Ranger Outreach).