Thursday, 21 September 2017

Harlestone Heath

Harlestone Heath is a tract of land about three miles north-west of Northampton. In my childhood it was always known as Harlestone Firs - and generally speaking still is. Yet it is a misnomer for, although fir trees have been planted since World War II in the form of Douglas Firs, it was, and still is, largely planted with Scots Pine.
Is the name Harlestone Heath any better? Well certainly the area was heathland at the end of Victorian times but sadly the area, owned by the Spencer family, was almost completely planted up with conifers by 1930 and what would have been an extremely important habitat in Northamptonshire was lost. The term Harlestone Heath is now restricted to a small reserve of 2.6 hectares on either side of the Northampton-Rugby railway line.
Wildlife on the reserve has been well recorded over the years so yesterday, when I paid a visit to the area, I restricted myself to the main body of 'the Firs'.
Pines of some maturity reached high into the sky. Birch, Sycamore and Sweet Chestnut were also common.
Scots Pine reached for the sky. Harlestone Firs, Northampton.
20 September, 2017
The pines are being removed piecemeal and much of the land is being replanted with native broadleaf trees. Quite remarkably some of the original heathland plants, whose seeds have apparently been dormant for decades, are re-appearing.
The acid soil is very thin in places and pines, being shallow-rooted, cope well with the conditions but unfortunately so too does bracken, Pteridium aquilinum, and this rampant fern now covers large areas. I suspect that much of the area is underlain by hardpan, an impervious layer consisting of soil particles cemented together by iron oxides and so on. (Lings Wood, to the east of Northampton, is a similar habitat and when, some years ago, I opened up a trench to examine the pedology there, a hardpan was exposed a metre and a half down.) If I am right then this could be the cause of poor drainage with consequent puddles.
Drainage was poor beside some of the rides, but they added to the
biological diversity. Harlestone Firs, Northampton. 20 September, 2017
Around these wet areas I found swathes of Water-pepper, Polygonum hydropiper, with its drooping flower heads and peppery-tasting leaves. It is a member of the rhubarb family  and, like many of its relatives it contains oxalic acid, a chemical with unpleasant side-effects if consumed in large quantities. The juices of this particular species can also cause burning and itching of the skin, especially between the fingers.
Water-pepper was common in wet areas. Harlestone Firs, Northampton.
20 September, 2017
Water-pepper has undistinguished flowers and in truth there were few bright blooms to be seen.
Red Campion was occasional rather than common.
Red Campion, Silene dioica, was doing its best and Rose-bay Willow Herb, with flowers of an almost identical hue, was also brightening the sides of the tracks.
Rose-bay Willow Herb seemed happy with the acid conditions.
A little hogweed was also in flower and, had the sun been brighter, I would have expected it to receive many insect visitors. As it was all I found were Nettle-tap Moths, Anthophila fabriciana, in some abundance. Visually it is an undistinguished insect and is very common. However, elsewhere along the tracks I was kept very busy with numerous insects, mostly two-winged flies such as greenbottles.
The Nettle-tap Moth was common on Hogweed. although its food-plant
is nettle. Harlestone Firs, Northampton. 20 September, 2017
I headed home a little later with a number of these flies. In most cases I can usually narrow each species down to two or three possibilities with a naked-eye examination, but it will take a bit of microscope work to confirm any cursory identification. I must go on to E-bay and order a can of midnight oil for I'll probably be burning some!

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