Demography of the dragonfly Rhionaeschna caligo (Aeshnidae), a species endemic to the northwestern Andes in Colombia 00

Abstract

Páramos are unique ecosystems located in the highest parts of tropical mountains. Despite harboring great biological diversity, they are also considered one of the most threatened ecosystems in the world. Rhionaeschna caligo is an endemic and threatened species that inhabits these ecosystems in the north of Colombia’s Central and Occidental Cordilleras. This study presents the first demographic assessment for the species using the Mark-Recapture method. The population size (50 ± 15 individuals; 186 ± 27 individuals), life expectancy (11.3 days; 14.5 days), probability of survival (0.90; 0.92), and detectability (0.08; 0.1) were estimated on two climatic seasons. Activity patterns in the wetlands were recorded in both seasons, finding differences between sexes, with male activity starting around 9 a.m. and finishing around 4 p.m., and female activity beginning around 4 p.m. and finishing at around 6 p.m. at dusk. Also, the effects of size and sex on survival and detectability were tested; no statistical support was found. The demographic parameters of survival-detectability and life expectancy are like those reported in the literature for other aeshnids. A negative effect of rainy weather conditions and low water levels on survival is suggested. High mortality among larvae inhabiting the wetland was observed after days of high radiation and low cloud cover.

Keywords. Odonata, Anisoptera, body size, capture-mark-recapture, detectability, dragonfly, endangered species, population size, survival, Páramo

Issue section: Original Article