London Borough of Wandsworth report on lake monitoring programme April 1999-January 2000

This is the second annual report commissioned by Wandsworth Borough Council to assess the progress of the London Lakes Project. The first report, produced in April 1999, made an assessment of the success of the Lakes Project following the major lake management programme carried out in 1994. It examined monitoring data collected by SGS Environment Ltd. between 1994 and 1996 in addition to the monitoring data collected by ENSIS Ltd. since October 1997. This second annual report follows a second year of standardised monitoring (April 1999-January 2000) that enables a clearer comparison with the previously monitored year (April 1998-January 1999). In particular the report focuses on whether the lake improvements are progressing, levelling out, or declining. This question is examined on a site-by-site basis for all seven monitored sites (Battersea Park Main Lake, Battersea Park Ladies Pool, King George's Park Lake, Tooting Common Lake, Graveney Common Pond and Wandsworth Common Lake and Stock Pond), followed by a general summary

Nutrient sources to Blickling Hall Lake

Blickling Hall Lake is a relatively large (10.1 ha.) shallow (average depth 95 cm) estate lake in the grounds of Blickling Hall, near Aylsham, North Norfolk. It was formed in the early 1700s through the damming of a small tributary of the River Bure, presently the major inflow to the lake. Water levels in the lake are controlled by a sluice and there is one outflow which ultimately feeds into the River Bure. The site has considerable current conservation interest in the form of an extensive fringing reedswamp, which provides good habitat for birds and dragonflies in particular. Currently, however the lake itself is of minimal conservation interest

Quality control in public participation assessments of water quality: the OPAL Water Survey

BACKGROUND: Public participation in scientific data collection is a rapidly expanding field. In water quality surveys, the involvement of the public, usually as trained volunteers, generally includes the identification of aquatic invertebrates to a broad taxonomic level. However, quality assurance is often not addressed and remains a key concern for the acceptance of publicly-generated water quality data. The Open Air Laboratories (OPAL) Water Survey, launched in May 2010, aimed to encourage interest and participation in water science by developing a 'low-barrier-to-entry' water quality survey. During 2010, over 3000 participant-selected lakes and ponds were surveyed making this the largest public participation lake and pond survey undertaken to date in the UK. But the OPAL approach of using untrained volunteers and largely anonymous data submission exacerbates quality control concerns. A number of approaches were used in order to address data quality issues including: sensitivity analysis to determine differences due to operator, sampling effort and duration; direct comparisons of identification between participants and experienced scientists; the use of a self-assessment identification quiz; the use of multiple participant surveys to assess data variability at single sites over short periods of time; comparison of survey techniques with other measurement variables and with other metrics generally considered more accurate. These quality control approaches were then used to screen the OPAL Water Survey data to generate a more robust dataset. RESULTS: The OPAL Water Survey results provide a regional and national assessment of water quality as well as a first national picture of water clarity (as suspended solids concentrations). Less than 10 % of lakes and ponds surveyed were ‘poor’ quality while 26.8 % were in the highest water quality band. CONCLUSIONS: It is likely that there will always be a question mark over untrained volunteer generated data simply because quality assurance is uncertain, regardless of any post hoc data analyses. Quality control at all stages, from survey design, identification tests, data submission and interpretation can all increase confidence such that useful data can be generated by public participants

Palaeoecological investigation of the past biological structure and function of the Trinity Broads

This is the final report to the Trinity Broads Partnership on the ‘Palaeoecological investigation of the past biological structure and function in the Trinity Broads’. The Trinity Broads are deeper and discrete from much of the rest of the Norfolk Broads and there has therefore been much speculation that their biology was different from the Broads in other river basins. The aim of the project was to employ palaeoecological techniques to investigate the past biological structure and function of the Broads, in particular the past aquatic flora

Monitoring and simulating threats to aquatic biodiversity in the Okavango Delta: field and laboratory methods

The Okavango Delta, situated in northwest Botswana between E22.0°-E24.0° and S18.0°-S20.5°, is the world's second largest inland wetland region. The Delta is actually an alluvial fan and is fed mainly by the Okavango River whose catchment lies largely in the highlands of central Angola (Fig 1). The river flows south-east through the Caprivi Strip in eastern Namibia, before entering into Botswana as a large river, some 200 m in width. The size of the Delta changes significantly throughout the year - during the dry season, the Delta is approximately 7,000 km2, and more than doubles in size to over 15,000 km^{2} during the wet season (Ramberg et al. 2006)

How large should whales be?

The evolution and distribution of species body sizes for terrestrial mammals is well-explained by a macroevolutionary tradeoff between short-term selective advantages and long-term extinction risks from increased species body size, unfolding above the 2g minimum size induced by thermoregulation in air. Here, we consider whether this same tradeoff, formalized as a constrained convection-reaction-diffusion system, can also explain the sizes of fully aquatic mammals, which have not previously been considered. By replacing the terrestrial minimum with a pelagic one, at roughly 7000g, the terrestrial mammal tradeoff model accurately predicts, with no tunable parameters, the observed body masses of all extant cetacean species, including the 175,000,000g Blue Whale. This strong agreement between theory and data suggests that a universal macroevolutionary tradeoff governs body size evolution for all mammals, regardless of their habitat. The dramatic sizes of cetaceans can thus be attributed mainly to the increased convective heat loss is water, which shifts the species size distribution upward and pushes its right tail into ranges inaccessible to terrestrial mammals. Under this macroevolutionary tradeoff, the largest expected species occurs where the rate at which smaller-bodied species move up into large-bodied niches approximately equals the rate at which extinction removes them.Comment: 7 pages, 3 figures, 2 data table

Consequences of fish kills for long-term trophic structure in shallow lakes: implications for theory and restoration

Fish kills are a common occurrence in shallow, eutrophic lakes, but their ecological consequences, especially in the long-term, are poorly understood. We studied the decadal-scale response of two UK shallow lakes to fish kills using a palaeolimnological approach. Eutrophic and turbid Barningham Lake experienced two fish kills in the early 1950s and late 1970s with fish recovering after both events, whereas less eutrophic, macrophyte-dominated Wolterton Lake experienced one kill event in the early 1970s from which fish failed to recover. Our palaeo-data show fish-driven trophic cascade effects across all trophic levels (covering benthic and pelagic species) in both lakes regardless of pre-kill macrophyte coverage and trophic status. In turbid Barningham Lake, similar to long-term studies of biomanipulations in other eutrophic lakes, effects at the macrophyte-level are shown to be temporary after the first kill (c.20 years) and non-existent after the second kill. In plant-dominated Wolterton Lake permanent fish disappearance failed to halt a long-term pattern of macrophyte community change (e.g. loss of charophytes and over-wintering macrophyte species) symptomatic of eutrophication. Important implications for theory and restoration ecology arise from our study. Firstly, our data support ideas of slow eutrophication-driven change in shallow lakes where perturbations are not necessary prerequisites for macrophyte loss. Secondly, the study emphasises a key need for lake managers to reduce external nutrient-loading if sustainable and long-term lake restoration is to be achieved. Our research highlights the enormous potential of multi-indicator palaeolimnology and alludes to an important need to consider potential fish kill signatures when interpreting results

Palaeoecological study of Rockland Broad

The decline in ecological quality and conservation value of European fresh waters is an all too common phenomenon. In lowland Britain the main anthropogenic impact on aquatic systems is that associated with elevated nutrient loading. The Broads are internationally important wetlands spanning a number of river basins in East Anglia. The Broads have suffered, along with other wetlands, and it is chiefly eutrophication that has had a deleterious effect on the system (Mason & Bryant 1975, Moss 1977) with a resultant decline in their ecological quality and conservation value. One of the changes in the ecological structure and functioning of shallow lakes in response to enrichment is an alteration in their macrophyte flora (Ris & Sand-Jensen 2001) and in extreme cases there may be the complete loss of submerged plants (Scheffer et al. 1993). The loss of the diversity of the macrophyte flora in the Broads is perhaps the main factor in the decline in their conservation value

The coming and going of a marl lake: multi-indicator palaeolimnology reveals abrupt ecological change and alternative views of reference conditions

Eutrophication is the most pressing threat to highly calcareous (marl) lakes in Europe. Despite their unique chemistry and biology, comprehensive studies into their unimpacted conditions and eutrophication responses are underrepresented in conservation literature. A multi-indicator palaeolimnological study spanning ca. 1260–2009 was undertaken at Cunswick Tarn (UK), a small, presently eutrophic marl lake, in order to capture centennial timescales of impact. Specific aims were to (1) establish temporal patterns of change (gradual/abrupt) across biological groups, thereby testing theories of resistance of marl lake benthic communities to enrichment, and (2) compare the core record of reference condition with prevailing descriptions of high ecological status. Analyses of sediment calcium (Ca), phosphorus (P), pigments, diatoms, testate amoebae, cladocerans, and macrofossils, revealed three abrupt changes in ecosystem structure. The first (1900s), with biomass increases in charophytes and other benthic nutrient-poor indicators, supported ideas of resistance to eutrophication in Chara lakes. The second transition (1930s), from charophyte to angiosperm dominance, occurred alongside reductions in macrophyte cover, increases in eutrophic indicators, and a breakdown in marling, in support of ideas of threshold responses to enrichment. Core P increased consistently into the 1990s when rapid transitions into pelagic shallow lake ecology occurred and Cunswick Tarn became biologically unidentifiable as a marl lake. The moderate total P at which these changes occurred suggests high sensitivity of marl lakes to eutrophication. Further, the early record challenges ideas of correlation between ecological condition, charophyte biomass and sediment Ca. Instead, low benthic production, macrophyte cover, and Ca sedimentation, was inferred. Management measures must focus on reducing external nutrient and sediment loads at early stages of impact in order to preserve marl lakes

Palaeoecological assessment of freshwaters in SACs and ASSIs in Northern Ireland

This is the final report to the Environment and Heritage Service (EHS) in Northern Ireland on the ‘Palaeoecological investigation of the past biological structure and function in Freshwaters in SACs and ASSIs