Current Geodynamics and Evolutionary Trends of a Headland Bay Beach System in the Semi-Arid Coast of Chile

The Chilean coast is controlled by the tectonics and structure, generating an irregular coastal landscape, with bays, marine terraces, sandy and gravel beaches, sand dune fields and Andean slopes, forming some mega cliffs that are attacked by waves. The Chilean coastline is shaped by headland bay beaches, with a dynamic coast modeled by south-western winds and south–north longshore current. We analyzed the case of the Coquimbo mega headland bay beach, which consists of four headland bay beaches. A methodological study was carried out on the morphometric parameters of the shoreline and the types of beaches dominated by waves along with geomorphological analysis of the coastal zone. We observed a mass transfer process from south to north. The northern sections of the bays are the places with the densest sand dune fields. This concentration of dunes occurs in each bay individually and in the mega bay as well. The sedimentary supply comes from Andean catchments to the shoreline and is transported and reworked by the longshore current to the northern area, where a huge sand field dune has developed, 120 km away from the mouth of Limarí River, the most southern catchment in the study area. In the mega bay, the current trend is a continuous sedimentary supply, despite the semi-arid conditions and the extreme drought that has affected the area since 2011. The study area is also a popular destination in Chile for beach tourism and is a place of interest for the mining industry.

Diet and behavior of the burrowing owl (Athene cunicularia) in Atiquipa, an ecosystem of Lomas in the south of Peru

Luque-Fernández CR. 2019. Diet and behavior of the burrowing owl (Athene cunicularia) in Atiquipa, an ecosystem of Lomas in the south of Peru. Biodiversitas 20: 137-143. The study of trophic and behavioral habits is a fundamental aspect in the knowledge of the natural history of species, especially for those that present a wide range of distribution and that have to adapt to the habitats and available resources that can find to survive. The diet and behavior of Athene cunicularia were studied in a peculiar ecosystem such as the lomas formation, on the arid coast of southern Peru. The analysis of regurgitated pellets from a family group of Athene cunicularia was used and complemented with the monitoring of behavior through the use of trap cameras and direct observations. The results show that the diet during the months of study was based on a high proportion of invertebrate beetles (Tenebrionidae) and scorpions, also finding remains of vertebrates, including rodents, birds and highlighting the presence of a species of marsupial mouse. On the study of behavior, marked and recurrent activities are established during the day for this species, where grooming sessions are frequently reported, as well as interaction with a possible predator of this owl species. These results contribute to the understanding of the trophic relationship and its role in the studied lomas ecosystem, which is added to the importance of this species in the conservation of diversity in desert ecosystems.

Soil texture and altitude, respectively, largely determine the floristic gradient of the most diverse fog oasis in the Peruvian desert

Studying species turnover along gradients is a key topic in tropical ecology. Crucial drivers, among others, are fog deposition and soil properties. In northern Peru, a fog-dependent vegetation formation develops on mountains along the hyper-arid coast. Despite their uniqueness, these fog oases are largely uninvestigated. This study addresses the influence of environmental factors on the vegetation of these unique fog oases. Accordingly, vegetation and soil properties were recorded on 66 4 × 4-m plots along an altitudinal gradient ranging from 200 to 950 m asl. Ordination and modelling techniques were used to study altitudinal vegetation belts and floristic composition. Four vegetation belts were identified: a low-elevation Tillandsia belt, a herbaceous belt, a bromeliad belt showing highest species richness and an uppermost succulent belt. Different altitudinal levels might reflect water availability, which is highest below the temperature inversion at around 700 m asl. Altitude alone explained 96% of the floristic composition. Soil texture and salinity accounted for 88%. This is in contrast with more humid tropical ecosystems where soil nutrients appear to be more important. Concluding, this study advances the understanding of tropical gradients in fog-dependent and ENSO-affected ecosystems.