Pond research and management in Europe: "Small is Beautiful"

The phrase "Small is Beautiful" was first used by the talented scholar Leopold Kohr (1909 131994), but it becames more popular thanks to the essays of one of his students, the British economist E. F. Schumacher, and it was coined as a response to the socially established idea that "Big is Powerful". It could be argued that this desire for "bigness" explains why current legal frameworks and the conservation planning and management related to standing waters often overlook ponds, despite their well-known value in terms of biodiversity and socio-economic benefits (Oertli et al., 2004; Cereghino et al., 2008). Of course, this is only one of several possible explanations, but it is important to understand that such long-established ideas can have a lasting effect upon the efficiency of our conservation actions. Beyond this social perspective, the history of science can also provide some explanation as to why ponds have been undervalued for so long

Anthropogenic flow intermittency shapes food‐web topology and community delineation in Mediterranean rivers

Anthropogenic flow intermittency is considered a severe disturbance for benthic macroinvertebrates with largely unknown impacts on the organization of benthic communities and their food webs. We analysed the community composition (as taxonomic composition and relative abundance of taxa) and food webs of the macroinvertebrates inhabiting the pools and riffles of two Mediterranean streams with contrasting perennial and anthropogenic intermittent flow regimes. Our analyses comprised monthly measurements in two pools and two riffles of the community composition, food‐web topology (the pattern in which specific links are arranged within the network) and food‐web complexity indexes (the number of nodes and links regardless of their identity or arrangement) over 1 year. The food webs revealed a significant annual variation in size, complexity, and diversity within pools and under perennial flow (e.g., number of nodes, number of links, link density). Multivariate analysis showed strong differences in the composition and relative abundance of taxa and food‐web topology of assemblages inhabiting pools and riffles. However, differences between communities inhabiting pools and riffles varied during the year; periods of great similarity were followed by periods in which communities were very different. This annual sequence of differences between pools and riffles was compressed under the anthropogenic flow intermittency regime. The anthropogenic intermittent flow studied here might represent a moderate stressor for Mediterranean communities well‐adapted to dry conditions. Still, the reported deviation of the community composition and food‐web topology from the reference status reflect the detrimental effect of this stressor on the benthic community

The ecological role of ponds in a changing world

The fifth conference of the European Pond Conservation Network (Luxembourg, June 2012) brought together researchers, environmental managers, and other stakeholders with the aim to share stateof-the-art knowledge on the ecology, management, and conservation of ponds in the context of the many challenges facing the wider water environment. Although well-known ecological patterns apply to most ponds in Europe and elsewhere, recent data highlight that part of the environmental variables governing pond biodiversity remain specific to climatic/ biogeographic regions and to elevation ranges, suggesting that, in addition to common practice, management plans should include range-specific measures. Beyond the contribution of individual ponds to the aquatic and terrestrial life, connected networks of ponds are vital in the provision of new climate space as a response to global climate change, by allowing the observed northward and/or upward movements of species. In terms of services, ponds offer sustainable solutions to key issues of water management and climate change such as nutrient retention, rainfall interception, or carbon sequestration. While the ecological role of ponds is now well established, authoritative research-based advice remains needed to inform future direction in the conservation of small water bodies and to further bridge the gap between science and practice

The ecological role of ponds in a changing world

The fifth conference of the European Pond Conservation Network (Luxembourg, June 2012) brought together researchers, environmental managers, and other stakeholders with the aim to share stateof-the-art knowledge on the ecology, management, and conservation of ponds in the context of the many challenges facing the wider water environment. Although well-known ecological patterns apply to most ponds in Europe and elsewhere, recent data highlight that part of the environmental variables governing pond biodiversity remain specific to climatic/ biogeographic regions and to elevation ranges, suggesting that, in addition to common practice, management plans should include range-specific measures. Beyond the contribution of individual ponds to the aquatic and terrestrial life, connected networks of ponds are vital in the provision of new climate space as a response to global climate change, by allowing the observed northward and/or upward movements of species. In terms of services, ponds offer sustainable solutions to key issues of water management and climate change such as nutrient retention, rainfall interception, or carbon sequestration. While the ecological role of ponds is now well established, authoritative research-based advice remains needed to inform future direction in the conservation of small water bodies and to further bridge the gap between science and practice

Biological traits of European pond macroinvertebrates

Whilst biological traits of river macroinvertebrates show unimodal responses to geographic changes in habitat conditions in Europe, we still do not know whether spatial turnover of species result in distinct combinations of biological traits for pond macroinvertebrates. Here, we used data on the occurrence of 204 macroinvertebrate taxa in 120 ponds from four biogeographic regions of Europe, to compare their biological traits. The Mediterranean, Atlantic, Alpine, and Continental regions have specific climate, vegetation and geology. Only two taxa were exclusively found in the Alpine and Continental regions, while 28 and 34 taxa were exclusively recorded in the Atlantic and Mediterranean regions, respectively. Invertebrates in the Mediterranean region allocated much energy to reproduction and resistance forms. Most Mediterranean invertebrate species had narrow thermal ranges. In Continental areas, invertebrates allocated lesser energy to reproduction and dispersal, and organisms were short lived with high diversity of feeding groups. These characteristics suggest higher resilience. The main difference between ponds in the Alpine and Atlantic regions was their elevation. Alpine conditions necessitate specific adaptations related to rapid temperature fluctuations, and low nutrient concentrations. Even if our samples did not cover the full range of pond conditions across Europe, our analyses suggest that changes in community composition have important impacts on pond ecosystem functions. Consistent information on a larger set of ponds across Europe would be much needed, but their low accessibility (unpublished data and/or not disclosed by authors) remains problematic. There is still, therefore, a pressing need for the incorporation of high quality data sets into a standardized database so that they can be further analyzed in an integrated European-wide manner