ponds

Written by Roger Downie, Froglife and University of Glasgow

Number 148 in Collins’s famous New Naturalist series (started by E.B. Ford’s Butterflies in 1945) is published this spring as Jeremy Biggs & Penny Williams’s Ponds, Pools and Puddles. This is not the first New Naturalist to deal with freshwater habitats and their wildlife: among others, there have been Macan & Worthington’s Life in Lakes and Rivers (1951), Moss on Lakes, Loughs and Lochs (2015), Corbet, twice, on dragonflies, and three accounts of the UK’s herpetofauna (Smith, 1951; Frazer,1983; and Beebee & Griffiths, 2000). However, this is the first to focus on the multitudes of smaller bodies of freshwater. As the authors make clear, the book has been long in the writing: Sir Alister Hardy, author of two New Naturalists on The Open Sea (1956; 1959) had agreed to write on ponds, but had only written one chapter on his death in 1985. Biggs and Williams took on the task about 15 years ago and agreed to retain Hardy’s proposed title. The further delay in completing the book has been due mainly to their time-consuming efforts to establish their NGO, the Freshwater Habitats Trust (formerly Pond Conservation), and also to the scale of the task.

Is the book worth the wait? The first thing to say is that it is an immense achievement: 12 chapters totalling 541 pages; an appendix listing pond types;  around 900 references to literature; species and general indices; 288 figures and 78 tables, full of details- the whole totalling over 600 pages and weighing in at 1.4 kg, all for £35 (my copy ordered via NHBS came with a card signed by the authors!). The book is remarkably up to date, including citations to papers published in 2022, but also extending back to Gilbert White’s Natural History of Selborne (1789).

The main focus is ponds in the UK, but the authors often draw on examples from other temperate countries, especially elsewhere in Europe and when relevant UK information is lacking. Pond conservation has become an international concern, with the European Pond Conservation Network established in 2004, with its Pond Manifesto (2008) and several international conferences, with proceedings published in the journal Hydrobiologia.

The introductory chapter discusses the vexed question of how to define pond, pools and puddles, so as to distinguish them from other bodies of freshwater. There is no clear ecological cut-off, so they decide that a pond is ‘a body of standing water between  one square metre and two hectares in area that holds water for at least four months of the year’ and note that this is a definition  they have used for some time. Others use different limits: the Ramsar Convention  for the protection of wetlands uses eight hectares as the upper limit for ponds, and the north American upper limit is even higher: Thoreau’s famous Walden Pond is 26 hectares, a good-sized lake in the UK.

Throughout the book, the authors make clear the relative lack of research on ponds compared to other freshwater systems, and also criticise this lack of attention, given the many distinct features of ponds. They are also highly critical of simplified or misleading textbook accounts: for example, in the chapter on ‘The Pond Environment’ they show an often-used pond cross-sectional diagram that is wrong in several respects, and quote another text that states ‘dissolved oxygen is essential to the respiratory metabolism of most aquatic organisms’, ignoring the surface-breathing activities of many kinds of aquatic animal (perhaps to spare blushes, they do not cite the sources of these unfortunate quotations). The writing can be refreshingly blunt, more so than in other New Naturalist books I’ve read: another example- commenting on ‘traditional’ village duck pond: ‘the turbid brown water, absence of underwater plants and trampled, smelly, bare margins establishes a terribly low standard in terms of revealing what a pond can be’.

Different chapters cover the history of ponds in Britain, the different kinds of pond and their origins, ecological processes in ponds, plants, invertebrate animals, fish, birds, mammals, and the monitoring and management of ponds. However, for Froglife supporters, the chapter on amphibians will be the one of greatest interest, and I now focus on that.

The chapter on amphibians is 49 pages, with 24 figures and seven tables, pretty generous for the small number of native British species, and the most detailed treatment per species in the book. They explicitly state their aim as being to update the account in the previous New Naturalist, that of Beebee & Griffiths (2000). I counted about 70 citations to work published since 2000, so they have been diligent. In addition to the native species, they cover the better-established aliens, such as the alpine newt and ‘the rather charming but potentially disastrous midwife toad Alytes obstetricans’. They are particularly concerned that the aliens could act as a source of disease. Interestingly, Steve Allain is speaking at the British Herpetological Society AGM this year on ‘120 years of midwife toads in GB’ and suggesting that the currently disease-free British populations could provide a reservoir for a species in steep decline on mainland Europe. Biggs & Williams note that the Netherlands, just across the Channel, have 15 amphibian species compared to our seven (actually now eight when we include the Jersey toad: see the final paragraph, below), and that they can understand the temptation to introduce species ‘which ought to be here’ among enthusiasts who may not appreciate the hazards.

For each species, they present evidence on total populations, evidence and causes of  declines, and factors determining current distributions. In every case, they emphasise the relative paucity of hard data, and the difficulties of getting more. They spend most space on great crested newts: ‘more politically prominent than almost any other protected creature, they have provoked ire, wrath, frustration, as well as great pleasure and pride’. They highlight Orton Brick Pits in Peterborough, better known to Froglife as Hampton Nature Reserve, as a conservation success; ‘probably the UK’s largest great crested newt population’, ‘better buffered from surrounding impacts than most’. They discuss causes for the very uneven distribution of GCN in the UK: 13% of ponds occupied in England (with only Cornwall really low), 6% in Wales, but only 0.1% in Scotland. They enthuse over the use of eDNA as a monitoring tool, while acknowledging its inability to measure population sizes (which are difficult to assess by other means too). They are highly critical of the current rules on mitigating GCN populations against development, and give a full account of Brett Lewis’s research into the long-term results of translocations and other mitigations (the lack of access to the data derived from publicly-funded projects was truly scandalous). For toads, Biggs & Williams give a good account of the protections provided by Toads on Roads scheme run by Froglife, but note, a little ironically, that it is data from that scheme that allowed Petrovan & Schmidt to calculate that toads in the UK are in steep decline, as well as in Switzerland.  

The aim of the New Naturalist series is ‘to interest the general reader in the wildlife of Britain by recapturing the enquiring spirit of the old naturalists’: how well does the book meet this aim? In my view, everyone with a serious interest in ponds and their biodiversity will want to have a copy of this book on their shelves. It is a treasure-chest of information, and valuable as a source from which to explore topics further. I doubt that many people will read it straight through, simply because of the book’s length and mountain of details. I’m not sure who the ‘general reader’ is these days. In the 19^th century, it was possible for Darwin’s Origin of Species to be a best seller, and in more recent times, many authors have managed to writer what can be termed ‘semi-popular’ science. But this book seems more specialised in its interests. One of the points emphasised by the authors is the relative lack of professional scientific focus on ponds, and the importance of citizen scientists in data collection, such as the numbers of toads saved by Toads on Roads teams around the country. So maybe the readership will be people switched on to nature conservation by activities of that sort. I would certainly expect all Froglife supporters and staff to find much of interest in this book.

Finally, a few critical points. Typographical errors are not frequent, but neither are they absent: examples, page 397 has the name Verrell also spelled Verrel; page 384 has ‘It shown that’ (rather than showed), and tadpoles as tapoles. Another set of minor errors concerns citations, with the in-text citation not always matching what is found in the reference list: for example, the text has Ewald (2020), with Ewald (2008, 2014, 2022) in the list but not 2020. Similarly, the recent discovery of the British Isles’s new toad (Bufo spinosa on Jersey)  is referenced to Arntzen et al. (2013), but this reference is absent from the list. As a service to readers, the information can be found in Arntzen et al. (2014) Herpetological Journal 24, 209-216 and Arntzen et al. (2013) Molecular Phylogenetics and Evolution 69, 1203-1208, both showing that molecular data are demonstrating that long-held certainties about biodiversity can be over-turned.