Seasonal Partitioning of Rainfall in Second-Growth Evergreen Temperate Rainforests in Chiloé Island, Southern Chile

Rainfall partitioning in secondary forests from southern Chile is relevant in the climate change scenario, in which a 30% reduction in summer precipitation has been projected for the temperate region. Logging and degradation of old-growth forests has resulted in extensive secondary forests, over large areas of the Chiloé Archipelago as well as the mainland. These secondary forests are simple tree communities, dominated by two broad-leaved tree species, evergreen Drimys winteri and Nothofagus nitida, and have the potential to provide multiple benefits to society, including water provision, soil protection, and wood-derived products. Here, we ask how southern South American secondary rainforests modulate rainwater redistribution considering precipitation partitioning. We evaluated the seasonality of throughfall and stemflow components of precipitation, to assess ecohydrological processes for water regulation in a climate change context, where summer droughts have been more frequent in the last decade. The partitioning of gross rainfall (TP) into throughfall (TH), stemflow (ST), and canopy interception (IN) in relation to forest structure, was assessed in four forest plots (400 m2 each) in Senda Darwin Biological Station, Chiloé. TH and ST were measured seasonally for 35 rainfall events from 2019 to 2021. IN water losses were estimated from the mass balance equation. Results indicate that the secondary rainforest intercepts 33% of TP (990 mm of the total monitored), where 59% of the volume corresponds to TH and 7% to ST, which taken together account for nearly 100% the rainwater that reaches the forest floor. Canopy IN varied seasonally from 25 to 40% of total rainfall, with maximum values occurring in the growing season (spring-summer). We found no statistical relation between ST and forest structural parameters (DBH, Basal Area). We explored the contribution of the two dominant tree species to ST and discuss the results in a climate change context. Finally, we propose to incorporate this hydrologic knowledge into adaptive forest management strategies to maximize ecosystem benefits to people. If these ecosystems were properly managed, they have the potential to provide multiple benefits to society within this century, such as water provision and soil protection in addition to carbon sequestration in biomass.

Improving Trapping Efficiency for Control of American Mink (Neovison vison) in Patagonia

Two main challenges when controlling alien American mink (Neovison vison) in Patagonia are to maximize campaign efficacy and cost-effectiveness and to avoid trapping native species. We designed and tested new variants of collapsible wire box traps, compared the efficacy of a food-based bait and a scent lure and compared catch rates in different seasons of the year. We used the data to model the efficiency rate of the trapping and to determine the trapping effort required to remove 70–90% of the estimated discrete mink population. Between January 2018 and March 2021, we operated 59 trapping transects over 103 three-day trapping periods in southern Chile. Traps were first baited with canned fish, and afterwards with mink anal gland lure. We compared the efficacy of mink capture with that of our previous study. We trapped 196 mink (125 males, 71 females), with most captures in summer. The medium-sized GMV-18 trap caught more male mink, but the more compact GMV-13 caught fewer non-target rodents and no native mammals. The scent lure was more successful than the canned fish when the previous campaign’s data were included in the analysis. There was also a significant improvement in the proportion of female mink trapped and reduced labour compared with our previous campaign that used larger traps, fish bait and 400–500 m trap spacings. We caught relatively more females than males after the third night of trapping on a transect. Our data analysis supports the use of the GMV-13 variant of wire cage trap as the best trap size: it is effective on female mink, small, cheap and easy to transport. Combined with mink anal scent lure, it reduces the possibility of trapping native species compared with other traps tested in Chile. As the most efficient method for removing at least 70% of the estimated discrete mink population within the area covered by each trap transect in southern Chile tested to date, we recommend trapping campaigns using GMV-13 during summer, with a 200-m trap spacing, for up to 6 days before moving traps to a new site, with a combination of three days with a female scent gland lure, followed by three days with a male scent gland lure.

Registros de mamíferos presentes en el Área Marina Costera Protegida de Múltiples Usos Lafken Mapu Lahual, sur de Chile

The Lafken Mapu Lahual Coastal Marine Protected Area of Multiple Uses (Lafken Mapu Lahual), Osorno coast, southern Chile, is one of the first protected areas created in Chile during 2006, but only in 2019 its Management Plan was presented. This study provides information on its marine mammal species to be used in future biodiversity monitoring plans. The sighted mammals were recorded and counted through 18 navigation tracks and one observation point in the 2014-2015 austral breeding season. Five species were recorded systematically (one whale species, two dolphin species, one marine otter species and a one sea lion species). Two of them (Lontra felina and Balaenoptera musculus) are classified by the IUCN in the conservation category corresponding to Endangered. Laken Mapu Lahual is an important area for the species of whales that use it for their migratory route to the south of Chile.

Occurrence and Abundance of an Apex Predator and a Sympatric Mesopredator in Rural Areas of the Coastal Range of Southern Chile

The two mammalian carnivores, puma (Puma concolor) and South American grey fox (Lycalopex griseus) were studied, in a remote area located in the humid temperate forest of the coastal range of southern Chile. A total of six locations were selected in three landscapes: pre-mountain range, mountain range, and coast. The chosen study locations are relevant because they correspond to threatened areas with different levels of human intervention., so they offer the ideal setting for studying how different species of carnivores respond to both human presence and activities. A dataset was collected for 24 months during 2016–2018 through photo-trapping (13 camera traps placed along 50 photo-trap stations). Wes estimated the apparent occurrence and relative abundance index (RAI) of the fauna registered, by means of generalized linear models to contrast those of an apex predator, such as the puma and a sympatric mesopredator, the South American grey fox, across the three landscapes. The ecological variables assessed were the RAI of the other carnivore considered, exotic carnivores such as dogs and cats, human intervention, farmland effect, prey availability, and habitat quality. The primary hypothesis was that the apparent occurrence and RAI of puma and fox would be positively associated with the RAI of prey and livestock and negatively with human intervention. On the other hand, the secondary hypothesis dealt with the interactions between puma and fox faced with different degrees of human intervention. The results showed that the apparent occurrence of the puma was statistically explained by location only, and it was highest at the mountain range. The apparent occurrence of foxes was explained by both puma apparent occurrence and relative integrated anthropization index (INRA), being highest in the pre-mountain range. Concerning the RAI of pumas, high values were yielded by location and fox RAI. For the RAI of foxes, they were location, puma RAI, and INRA. It can be suggested that eucalyptus plantations from the pre-mountain range could offer an adequate habitat for the puma and the fox, but not the coastal range, as the mountain range could be acting as a biological barrier. Due to the nature of the data, it was not possible to detect any relevant effect between the two carnivores’ considered, between their respective preys, or the very abundant presence of dogs.