Seasonal variation in the richness, relative frequency and diversity of birds in urban wetlands of Llanquihue, southern Chile

Abstract - Between 2017 and 2018 we evaluated the seasonal variation in richness, recorded frequency, proportional diversity, and community similarity of birds in three wetlands located within of Llanquihue city. We estimate the richness and recorded the frequency of birds observed in nine count points (observation time = 10 min, visual angle = 170º, detection radius = 40 m) located at the edge of each wetland (three points per wetland). All counts were made during the morning (08:30-12:00). We determined the local and seasonal avian diversity based on two indices: species evenness (J’) and species dominance (λ). We used the Jaccard coefficient (Cj) to determine the community similarity. We registered 50 species of which 55% are residents and 20% breed in Llanquihue. The Laguna El Loto showed the lowest richness (30 species), and the Laguna Las Ranas the higher richness (35 species). The diversity tended to be high in all studied wetlands (0.50 < Jʼ < 0.78; 0.09 < λ’ < 0.30), and their bird assemblages were very similar to each other (Cj > 0.77 in all pairs compared). We registered the highest species richness in spring and the lowest in autumn (35 and 24 species, respectively). During all the seasons, the most frequently observed species were the Neotropic Cormorants, Black-crowned Night-heron, Southern Lapwing, Speckled Teal, and Brown-hooded Gull. Species diversity was high throughout the year (0.10 < λ’< 0.25, 0.56 < J’ < 0.78). Our study shows that the wetland network of Llanquihue city contains a high avifaunal diversity, and despite the effect of urbanization, it remains an ecologically productive ecosystem.