Diary of a farm pond: March 2012

It's been a while since I posted an update about the development of the farm pond at our local community farm project at Highbridge in Hampshire, southern England. Originally a left-over from gravel extraction, the pond has been extended and serves a dual purpose as both wildlife habitat and a source of water for irrigation. As southern England is currently experiencing a period of drought, balancing these functions will be an ongoing concern...

As a 'working pond', one key characteristic has been disturbance, especially recently as part sof the banks have been re-profiled and landscaped to prevent the sides collapsing (there's a track running along one edge), and to make it easier to access the pump when water is needed for irrigation. So, at first glance, the pond currently looks a bit sparse.

The farm pond following re-landscaping. The irrigation pump and piping can be seen to the left.

However, there's more going on than this first picture suggests. The foreground is the area that has been re-landscaped and has therefore been largely returned to 'stage one' as far as species colonisation goes. However, in the background you can see the small reedbed which has not been affected by recent works.

A slightly different viewing angle reveals more marginal vegetation.

As well as the reedbed, this photo shows that there is still marginal vegetation - this extends up the bank to the right which is gravelly and has a variety of common wildflower species along with some rough grassland and small fruit and nut trees planted as part of the community farm. Last summer this showed considerable invertebrate activity, and I expect it will be the same this year. The pond itself supported various species including several dragonflies and damselflies, plus several fly species, whirligig beetles (Gyrinus) and frogs. It is inevitable that some overwintering larvae, pupae or adults will have been affected by pond works, but hopefully this will be minimal. Despite the unusually warm weather (around 20degC for the last couple of days), it is still very early for most invertebrates to be active, although there were numerous Gyrinus, plus the spring cranefly Tipula vernalis. I shall of course be looking out for the appearance of other species, including some of the less popular groups I began searching for at the site last year (such as springtails AKA Collenbola) and updates will appear here.

Pied Wagtail Motacilla alba, one of a pair using the margins of the pond in warm weather.