The otter population of the River Ticino (N Italy) 20 years after its reintroduction

On the River Ticino (Piedmont and Lombardy regions, N Italy), the Eurasian otter Lutra lutra became extinct in the 1980s and was reintroduced in 1997. Since then, the status of the reintroduced population has been assessed only occasionally, in 2008 and 2010. Between 2016 and 2018, we conducted an extensive survey for otter signs along the whole Italian stretch of the River Ticino, following the \u2018Standard Method\u2019 for otter surveys. In 2016\u20132017, we found 101 spraints (mean marking intensity: 0.40 spraints/100 m), spread over a 97-km long stretch of the river. In 2018 only five spraints were collected, the two furthermost marking sites being 32 km apart. Genotyping of nDNA extracted from 21 faecal samples enabled the identification of six different individuals. The surveys led to drawing a reliable picture of otter distribution and population size, with evidence of otter occurrence on a longer than previously recorded stretch of the river. The results of the 2018 survey suggest that stochastic factors may still threaten the survival of reintroduced otters and would suggest a reinforcement of the population is required to increase its genetic diversity

High-mountain plant-pollinators interactions: the case of the narrow endemic alpine plant Androsace brevis (Hegetschw.) Ces. (Primulaceae)

Climate change is a key threat to biodiversity. In Europe, plant species that most suffer its effects are those restricted to mountains environments. Some of these are characterized by a very early flowering, that occurs just after snowmelt. An emblematic example of that is Androsace brevis (Primulaceae), a narrow endemic species that lives only on peaks and ridges of siliceous mountains above 2000 m a.s.l. in the western Alps (Lombardy) and adjacent Switzerland (Ticino) within an area of 800 km2. Climate warming represents a serious menace to this species, since the upward shift of its range is almost impossible. Moreover, an anticipation of its already very early flowering could cause mismatches with pollinators. We investigated the reproductive biology of A. brevis and the role of arthropods as pollinators through the identification of flower-visiting arthropods and quali-quantitative palynological analysis to discover the main pollinators of this species and reconstruct the pollination network that characterize these high-altitude ecosystems in early season. We demonstrated the important role of Diptera Anthomyiidae and Hymenoptera Apoidaea as pollinators of A. brevis and we assessed the taxa spectrum active on its flower. These results are important to explain the pollination biology of Androsace brevis and can provide the basis to develop conservation plans applicable also to other threatened alpine species. Studying the \u201cweb of interactions\u201d is fundamental to evaluate possible mismatch that this kind of species could suffer by climate change, with serious repercussions on both plant and animal species, dependent from this relationship

Videorecordings as an innovative method to investigate the behaviour of arthropods on high altitude plants : The case study of Androsace brevis (Hegetschw.) Cesati (Primulaceae)

Androsace brevis is a narrow endemic plant that grows on siliceous peaks and ridges above 2000 m asl in the western Alps of Lombardy and neighbouring Switzerland. This species is representative of mountain species threatened by the ongoing climate warming. In particular, A. brevis is characterized by a very early flowering, occurring immediately after snowmelt (May-June),and lasting few weeks. Therefore, a key risk for this plant could be represented by climate change-driven mismatches between its flowering and pollinator presence and activity. Recent studies have found that A. brevis needs pollinators to ensure its reproduction; a pollinator network has also been identified through the capture of the arthropods visiting the flowers. To evaluate the occurrence and ethology of A. brevis flower-visiting arthropods in-field video recording sessions were conducted. Environmental parameters were also monitored to investigate their influence on recorded arthropods activity. We recorded 165 videos for a total of about 42 hours and analysed them with a behavioural observation software (BORIS). Our results allowed the identification of taxa involved in A. brevis pollination, but also revealed the existence of a great variability in the activity and behaviour among flower-visiting arthropods, suggesting that this plant can represent an essential resource for high-altitude arthropod community. This innovative approach, less invasive than human direct observation and sampling, is expected to represent a powerful instrument to finely define the relationship between plants and associated fauna in this particularly vulnerable environment, providing crucial knowledge for their conservation