Monitoring the Eurasian otter (Lutra lutra) in the National Park of Cilento, Vallo di Diano and Alburni. Research findings and future directions for conservation

摘要

The Eurasian otter (Lutra lutra L., 1758) is a top predator in running waters ecosystems and a species of conservation concern. The otter declined dramatically in Europe during post-war decades mainly as a consequence of human-induced alteration (e.g. water pollution) and loss of freshwater habitats. At present the otter is endangered in Italy in reason of its reduced distribution range, restricted to southern regions and isolated from other European otter populations. Tha National Park of Cilento, Vallo di Diano and Alburni (NPCVDA) includes a relevant portion of the core area of otter distribution range and represents a key area for otter conservation and monitoring at national level. In 2009 emerging issues (e.g. otter road kills) motivated the start of research activities on otters in the NPCVDA, aimed at: developing optimal sampling protocols for reliable and long-term monitoring of otter conservation status in small areas; monitoring mortality, demographic parameters and health status of local otter population based on the post-mortem examination of otters occasionally found dead; analyzing anthropogenic pressures and impacts on otters and running-waters in the protected area. Research projects produced protocols, guidelines and tools for monitoring parameters of otter and habitat status and collecting biological samples and data in a long-term perspective. A baseline estimation of otter occupancy parameters were obtained in rivers of the park, useful for future evaluation of population trends. An indication of exposure of local otter population to environmental contaminants were also obtained, suggesting further investigations on pollutant levels in macrophytes, otter prey and otter spraints along the river gradient in 'sentinel' river basins of the NPCVDA. In general, research activities and findings highlighted the importance of an integrated multidisciplinary approach in developing and applying monitoring tools for otter conservation.