Influence of microhabitat on Honduran Emerald (Amazilia luciae) abundance in tropical dry forest remnants

Abstract

Understanding the ecology of at-risk species is the foundation for developing strategies to counteract continued population declines. The Honduran Emerald (Amazilia luciae) is an endemic hummingbird that inhabits tropical dry forest in Honduras. Remaining populations of this endangered species are restricted to habitat fragments located in landscapes dominated by agricultural activities. The conservation of this species is dependent on efforts to protect existing dry forest remnants and to restore additional areas. However, limited information exists regarding Honduran Emerald habitat use on which to base management decisions. We conducted a study to identify point-level habitat features that are important to Honduran Emerald abundance. In 2014-2015, we conducted avian and vegetation surveys at 174 points located within dry forest remnants. We constructed hierarchical multinomial mixture models using time-removal based point count data collected in three sampling periods. Honduran Emerald detection was influenced negatively by Julian date. Local abundance was positively correlated with shrub-sapling density and cacti structural diversity. Mean local abundance per point was (0.39 ± 0.2 SD) and the number of individuals estimated to have used the combined area of the survey points (48.7 ha) was 68 (CI 95% 45-110). The shrub-sapling density and cacti structural diversity levels identified from our abundance models are characteristic to dry forest communities in this region. As such, the need for efforts to protect remaining dry forest remnants cannot be overstated. Future research should evaluate how the microhabitat features we found to be important to Honduran Emerald abundance influence fitness parameters such as survival and reproduction. Studies that examine how reciprocal effects of pollinator species declines and plant species diversity influences the long-term stability of tropical dry forest ecosystems are also warranted.

Keywords

• agalta valley
• habitat use
• hierarchical models
• hummingbird