Small ponds and big landscapes: The challenge of invertebrate spatial and temporal dynamics for European pond conservation

1. Present understanding of the ecology and conservation of European ponds is built upon two traditions: first, extensive surveys of many ponds, often based on one visit and second, intensive experiments usually restricted to one site but over longer periods. Neither approach adequately captures the long-term spatial and temporal dynamics of pond invertebrates. 2. Over the last decade the significance of landscape, land use and species turnover between ponds has been highlighted both for the conservation of pond wildlife and as a key factor in the ecology of pond invertebrates. These large-scale spatial patterns and the resulting heterogeneity of ponds and their wildlife are not effectively addressed by the tradition of intensive, single-site experiments. Longer-term databases, sufficient to allow analysis of species turnover, show considerable annual temporal variation in species' distributions, a phenomenon not adequately addressed by extensive, single-year surveys. 3. The limited number of studies that combine landscape spatial scale with inter-annual time scales all suggest that important invertebrate dynamics occur at these levels. Species and metacommunities show spatial variation and inter-annual turnover. Data from a 10-year study of small, experimental ponds show temporal and spatial variation in species distributions and community measures responding to scales from the individual pond up to long-term climate trends, e.g. the North Atlantic Oscillation. 4. The ecological integrity of ponds requires the conservation of this potential for variation, change and heterogeneity.