Landscape features and crustacean prey as predictors of the Southern river otter distribution in Chile.

Abstract

Understanding the processes that affect freshwater ecosystems at the watershed level is fundamental for the conservation and management of river otters. During 2 consecutive years, we surveyed the occurrence of the Southern river otter Lontra provocax and its main prey (crustaceans) in a watershed of 9900 km 2 in the Chilean temperate forest. We modeled predator and prey distributions with a variety of statistical techniques by relating a set of environmental predictors to species occurrence records. Otter and crustaceans were associated with areas of intermediate to low human disturbance with a mosaic of riparian vegetation densities, mainly at low altitudes. The singularity of the Andean Range, with a very marked elevation gradient and oligotrophic watercourses in the higher areas, created more vulnerable conditions for otter presence because prey abundances were limited in those areas. Human impacts affected otter populations at a landscape scale through the presence of main roads, as these were mostly located in lower parts of the watershed where otters have their primary habitat. These results point to the importance of land management and protection of low-elevation areas where otters still occur to ensure the long-term viability of its freshwater populations.

More than range exposure: Global otter vulnerability to climate change

“…In fact, priority conservation actions should particularly focus on species whose ranges would become more fragmented or would shift into less protected and more human-impacted areas. For instance, we found that climate change would not affect the range extent of the endangered Latin American Lontra provocax (scenario RCP2.6-2050) but would increase range fragmentation, a factor that is already threatening this species (Sepulveda et al 2009).…”

Coexistence between the southern river otter and the alien invasive North American mink in marine habitats of southern Chile

“…Like in the marine habitats, crustaceans play a key role in the diet of the southern river otter in freshwater habitats as well (Cassini et al ., ; Sepúlveda et al ., ), and lack of this kind of prey in southern Patagonian freshwater systems (Oyandel et al ., ) explains why otters were absent from the Cisne River study area, where minks resorted to hunting almost exclusively terrestrial prey, which comprised mostly one species of rodents, the long‐tailed colilargo Oligoryzomys longicaudatus .…”

Do non‐native fish as prey favour the conservation of the threatened indigenous Eurasian otter?

“…The aim of the present article is to assess the feeding adaptive response of otters to the temporal and spatial distribution of non‐native fishes throughout its European range as well as the potential role played by this ‘new’ resource for otter conservation through a comprehensive review and analysis of available information on (i) occurrence of non‐native fishes in otter diet, (ii) history of freshwater fish introductions and (iii) current status of non‐native fishes in the countries for which sound otter diet data were available. Data were analysed using Random Forest Regression (RFR), a machine learning technique that is currently considered a promising technique in ecology (Franklin, 2010; Drew, Wiersma & Huettmann, 2011; Cheng et al ., 2012), useful to disentangle complex ecological phenomena (Schwartz et al ., 2006; Sepúlveda et al ., 2009; Davidson et al ., 2012).…”