Variación demográfica de aves insectívoras del sotobosque en relación con la calidad del hábitat en un bosque seco tropical

Population assessments, as well as habitat quality estimations at threatened ecosystems such as tropical dry forest, are important elements for understanding species biology, and represent information sources for improvement of decision making in management and conservation, especially during ecolog...

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Autores:: Loaiza Gómez, Camilo

Tipo de recurso:: Work document

Fecha de publicación:: 2020

Institución:: Universidad Nacional de Colombia

Repositorio:: Universidad Nacional de Colombia

Idioma:: spa

Description
Summary:	Population assessments, as well as habitat quality estimations at threatened ecosystems such as tropical dry forest, are important elements for understanding species biology, and represent information sources for improvement of decision making in management and conservation, especially during ecological restoration processes. These processes should consider not only rare, endemic or endangered species, but also common or generalist species, as they can also show sensitivity to disturbances. The remnant of tropical dry forest located along the El Quimbo hydroelectric project, in the department of Huila in Colombia, still houses an important biological diversity that is being conserved through restoration practices. I made an analysis of abundance, spatially explicit habitat quality and plant architecture across a gradient of disturbance of a tropical dry forest relict for three insectivorous bird species: White-bellied Antbird (Myrmeciza longipes), Barred Antshrike (Thamnophilus doliatus) and Pale-breasted Spinetail (Synallaxis albescens). Abundance, habitat quality assessments, and plant architectural analysis were made between June 2018 and June 2019 at 186 count points that worked also as plots for habitat variables measurement. I divided the area in three zones according to their conservation status and adjusted Generalized Linear Models (GLM) to evaluate associations among the microhabitat and landscape variables; and abundance. For habitat quality surveys I used a Habitat Suitability Index (HSI) for each one of the three species, and I made it spatially explicit. For defining plant architectural models, dominant vegetal species were recorded in each plot, then they were photographed and finally their models were identified by mean of a synoptic key based on an architectural analysis available for tropical trees and forests. Results showed that abundance of the three bird species varied according to cover type. The White-bellied Antbird had higher abundance in forests and thickets than in shrublands fragments, Barred Antshrike was more abundant in shrubland and thicket than in forest fragments, and Pale-breasted Spinetail had the highest abundance in shrubland and the lowest in forest fragments. The abundance of both White-bellied Antbird and Pale-breasted Spinetail did not differ among zones with different levels of disturbance, while the abundance of Barred Antshrike decreased in zones with more disturbance. Through the habitat quality assessment, I identified that for the White-bellied Antbird 38.44% (IC95% 34.05 – 42.98) of the study area available habitat represented low quality (which means the area did not have the environmental resources for maintenance of individuals), associated with fragments of shrublands and thickets. Accordingly, I propose as restoration focus in those sites, in order to increase vegetal structures of the understory for foraging, vegetal cover as refuge against predators and adverse climate, and understory forks for nests support and construction. For the Barred Antshrike 39.91% (IC95% 35.48–44.47) of the study area represented low habitat quality in sites with low shrubland cover. Through White-bellied Antbird’s habitat restoration process, improving vegetal structure for shrubland fragments and thicket fragments and increasing the shrubland fragments area, would beneficiate Barred Antshrike’s habitat. By the architectural analysis, we detected seven of the 23 proposed models for tropical woody plants, which were assigned into three broad groups depending on the habitat quality and the resources they offer. In addition, we compelled a list of 42 plant species present at the study area and their corresponded architectural model as an input for selection of plant species in restoration.

Variación demográfica de aves insectívoras del sotobosque en relación con la calidad del hábitat en un bosque seco tropical

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