Conservation of pond systems: a case study of intractability, Brown Moss, UK

Abstract

Brown Moss is a Site of Special ScientificInterest in north-west England, of significance because of the occurrence, at least in the past, of the rare plant Luronium natans (Linnaeus) on the one hand, and its public popularity on the other. It is also a part of Ramsar site that comprises several other water bodies, the Meres, collectively valued for their water birds. It includes several fishless pools, in an area of seminatural vegetation, that differ in character. Such features are favoured in pond conservation. The surrounding terrestrial vegetation reflects nutrient enrichment in the past century and the pools at Brown Moss are now hypereutrophic from intensive agriculture on the margins of the site and guanotrophication of the main, central pool. Feral Canada geese (Branta canadensis (Linnaeus)) and resident waterfowl, encouraged by feeding by the public, have had major effects. Lower total phosphorus concentrations but higher nitrate concentrations were found in marginal pools, too small for bird flighting. Sedimentary studies suggest that nutrients and productivity in the pools have increased. Raised phosphorus in sediments was significantly correlated with numbers of sedimentary diatoms. Ponds are potentially of major importance in freshwater conservation in the UK, as they contain a high proportion of the country's freshwater biodiversity, but many have been filled in or severely polluted by farm wastes. Their situation in intensively used agricultural land means that, as in this case study, solution of their problems may often be intractable. The intractability is amplified at Brown Moss by the difficulty of removing aggressive alien species, a common problem in UK pond systems, and by birdfeeding, again a widespread problem particularly in urban ponds. The difficulties at Brown Moss thus typify the problems of pond conservation in the UK and indeed throughout lowland Europe. Current legislation appears impotent to remedy the situation.

Ecological Drivers of Cladoceran Diversity in the Central European City (Łódź, Poland): Effects of Urbanisation and Size of the Waterbody

“…Natural fish populations are typically limited in both abundance and diversity in ponds and their influence on the functioning and structure of ponds is reduced compared to larger lakes (De Meester et al, 2005). However, many anthropogenically created ponds and shallow lakes are stocked with fish for angling or ornamental purposes (Wood et al, 2001;Hassall, 2014) and fish have been demonstrated to influence invertebrate composition (Wood et al, 2001;Schilling et al, 2009;Beresford and Jones, 2010;Chaichana et al, 2011) and cause trophic cascades (Nyström et al, 2001;Knight et al, 2005) in both lakes and ponds. The smaller catchment area of ponds compared to larger lakes can enable quite different environmental conditions to develop (reflecting local microsite conditions (Scheffer et al, 2006)) even in ponds that are in close geographical proximity to each other Davies et al, 2008b).…”

“…Fish predation has been identified to significantly reduce invertebrate richness and abundance (Diehl, 1992;Fairchild et al, 2000;Angélibert et al, 2004;Chaichana et al, 2011) although trout (low densities) did not appear to impact invertebrate abundance in Welsh ponds (Gee, 1997). Invertebrate densities in submerged macrophyte beds were not influenced by fish indicating that macrophytes can act as refugia for invertebrate taxa (Gilinsky, 1984;Diehl, 1992).…”

“…Reserve, Shropshire, because the ponds were highly eutrophic as a result of excessive nutrient loading from the surrounding intensively fertilised agricultural land and housing developments (Chaichana et al, 2011).…”

“…At an international scale, the most powerful piece of water legislation in Europe, the Water Framework Directive (WFD), offers little benefit or protection to ponds because it will only protect water bodies over 50 hectares in size Miracle et al, 2010;Chaichana et al, 2011). However, the EU Habitats Directive (Europe's primary nature conservation legislation), provides some legislative protection to a number of specific pond types including Turloughs (Gwendolin and Kenneth, 2009) and…”

“…Macroinvertebrate communities within ponds are influenced by an interplay of physicochemical, biological and spatial factors including; pond connectivity to other aquatic habitats, altitude, surface area, depth, pH, conductivity, temperature, macrophyte coverage, shading, hydroperiodicity (pond drying) and fish predation (Williams, 1996;Oertli et al, 2002;Biggs et al, 2005;Hinden et al, 2005;Chaichana et al, 2011;Hassall et al, 2011). There has been debate in the academic literature surrounding the influence of pond size on macroinvertebrate communities, with some research identifying a strong influence Shieh and Chi, 2010) whilst other studies have suggested pond size exerts a weak influence .…”