On the edge of extinction? The spadefoot Pelobates fuscus insubricus in the Po Plain, and a glimpse at its conservation biology

Abstract

The Italian spadefoot toad, Pelobates fuscus insubricus, is said to be in decline throughout its range (Po Plain, N Italy), and for this reason it has been object of conservation campaigns and included in conservation papers and projects. We have reviewed its distribution, and compared historical and current findings. These data support only partly the idea of a decline in numbers over the past century. Most likely, the species has always been quite localised in northern Italy, and also difficult to detect: the inferred rarefaction is likely the consequence of growing anthropisation and rapid habitat destruction in some areas of the Po Plain. In any case, in light of the most recent findings, the species sometimes appears to be locally abundant. The most critical area in terms of presence and biodiversity is the central-eastern part of the Po Plain, as is the case for many other amphibians and reptiles. We also present migration and biometrie data regarding a population near Ivrea (Turin Province). Over a period of about 40 days, we captured more than 300 individuals using pitfall devices, which indicated that the population is particularly abundant (500–1000 individuals). The sex-ratio was approximately 2:1 in favour of males, which is in accordance with former literature. A skeletochronological analysis indicated an individual mean age of 3 38 ± 0.77 years in males, and 4.00 ± 0.77 in females. A review of conservation initiatives suggests that the campaigns were useful in terms of educating the general public, but much remains to be done with regards to habitat protection and conservation. Special importance is given to studies regarding several little known aspects of the life history of the Italian populations.