This striking result has only been revealed by work in the UK and Europe over the last twenty years. Ponds had long been regarded as the poor relations of famous lakes and river systems, suffering both by their familiarity and, sometimes, a sense that they were fleeting, usually artificial features of our landscape. They were left as the preserve of volunteers and school children:
“The study of ponds has been greatly neglected…it is, moreover, a field particularly suited to the activities of the amateur, whose humble pond-hunting, if carried out systematically and carefully, may well result in valuable contributions to science” Clegg, J (1952) The Freshwater Life of the British Isles
The change in our understanding of ponds was rooted in the work of Pond Action (now called the Freshwater Habitats Trust), who, in 1989, began surveying ponds around their base in Oxford, developing a methodology to standardise pond sampling for comparison throughout the UK.
From the very start their work revealed the richness of pond life, both the sheer numbers of species found in ponds out of the known UK freshwater taxa but also the value of negelcted habitats such as temporary ponds. Pond Action went on to compare ponds to rivers, lakes and ditches in lowland England and then across to Europe. Although individual ponds tended to support fewer species than comparable samples from rivers, the overall total of species in ponds when added up across a landscape was higher than the cumulative total from all river samples: river samples were often much the same from adajcent sites (e.g. Williams et al, 2004). The Freshwater Habitats Trust have gone from strength to strength, rolling out the Million Pond Project to rejuvenate the UK's pond stock. Their work found willing allies in Europe prompoting the formation the European Pond Conservation Network in 2004, which had promoted both our science understanding and wise management of ponds (Oertli et al, 2009). The Freshwater Habitats Trust and EPCN websites provide a welath of information and ideas about ponds, their ecology and conservation. There are links to their websites via this blog's homepage. Here is some of the early national pond surveying in the UK.
Simultaneosuly ponds had attracted increasing attention from ecologists exploring the fundamental patterns and processes underpinning the natural history of the familiar wildlife: predation, competition between speices, colonisation dynamics, responses to drought and flood and the role of habitat complexity (an example combining experimental ponds, fractal geometry, plastic bin bags and invertebrates. Jeffries, 1993). Here is some fractal bin bag pond weed in situ....
This was partly because ponds were good habitats to work with, small and numerous enough to sample effectively or create from scratch (it is difficult to make ancient woodland without a time machine). This work often involved experiments manipulating habitat or adding different species to ponds to monitor the outcomes on the wider community. The fractal pond weed experiment was part of an experiment exploring the role of submerged habitat complexity on invertebrate diversity.
The combination of extensive surveys such as the National Pond Survey in the UK with intensive experiments provided a useful complement to one another. Experiments can be very revealing about cause and effect, e.g .what effect does a specific predator have on numbers of prey over a year, but are often very site specific and hard to draw more general conclusions. For example that fractal bin bag pond weed may not be wholly realistic. On the other hand the wide ranging surveys that were carried out in many European countries revealed wider patterns across regions and landscapes, but often relied on limited numbers, perhaps just one, of site visits.
We now know so much more about ponds than twenty years ago, with powerful advice readily available on how to nurture and re-create these beautiful habitats (Williams et al, 2008).
Oertli B., R. Cereghino, A. Hull and R. Miracle, 2009. Pond conservation: from science to practice. Hydrobiologia, 634: 1-9.
Williams P., M. Whitfield & J. Biggs, 2004. Comparative biodiversity of rivers, streams, ditches and ponds in an agricultural landscapes in Southern England. Biological Conservation, 115: 329-341.