Foraging behavioural traits of tropical insectivorous birds lead to dissimilar communities in contrasting forest habitats

Gabriel J Castaño-Villa,Alejandro Hoyos-Jaramillo,Francisco E Fontúrbel,Jaime V Estévez-Varón,Rafael Santisteban-Arenas

doi:10.2981/wlb.00483

Gabriel J Castaño-Villa, Alejandro Hoyos-Jaramillo + Show 3 more

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https://doi.org/10.2981/wlb.00483

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Abstract

Many deforested areas worldwide have been planted with Alnus spp. to protect watersheds and soils. However, the effects of these plantations on biodiversity are little known yet. Contrasting forest types may impose strong environmental filters to some behavioural traits, leading to dissimilar communities. Insectivorous birds are known to be sensitive to changes in habitat structure due to their specialized foraging behaviour. We contrasted species richness, abundance and composition of insectivorous birds, according to functional behaviour groups (foraging strategy and stratum), between secondary forest stands and Andean alder Alnus acuminata plantations, to assess how contrasting forest types affect this bird group in the Colombian Andes. Insectivorous bird species richness and abundance were higher at the Alder plantation rather than at the secondary forest, resulting in dissimilar communities. In this regard, forest plantations act as a positive filter for foliage gleaners and flycatchers, whereas secondary forests act as a positive filter for bark foragers. Secondary forests and alder plantations impose different ecological scenarios to insectivorous birds, related to foraging strategies and foraging stratum, which ultimately leads to a dissimilar species composition.

Highlights

Forest plantations are increasing worldwide, covering millions of hectares across countries and ecosystems, increasing at an average annual rate of 3.6 million hectares during the 1990–2000 period (FAO 2016)
37 species were captured in the alder plantation stands and 28 in the secondary forest stands, being 21 species captured in both forest types (47% of the total species pool)
Regarding foraging strategy, estimated species richness of bark foragers was significantly higher at the native forest, whereas estimated species richness was significantly higher for foliage gleaners and flycatchers at the alder plantation (Fig. 1b); due to the low number of ground forager species present, we cannot perform any formal comparison in this case

Summary

Introduction

Forest plantations are increasing worldwide, covering millions of hectares across countries and ecosystems, increasing at an average annual rate of 3.6 million hectares during the 1990–2000 period (FAO 2016). Recent evidence showed that Andean alder Alnus acuminata protective plantations are capable to hold a large diversity of bird species, being highly dissimilar to those bird communities found at neighbouring native forest stands (Castaño-Villa et al 2014a). Insectivore birds respond drastically to habitat complexity structure (Shahabuddin and Kumar 2007, Moradi et al 2009, Castaño-Villa et al 2014b) Due to their specialized foraging strata and behaviour, it is considered as a highly vulnerable group to habitat disturbance in tropical regions (Bierregaard and Lovejoy 1989, Renjifo 1999). In this regard, forest plantations can act as a strong biodiversity moderator, modifying bird diversity and community composition (Barlow et al 2007, Faria et al 2007). We hypothesized that insectivorous bird species foraging behaviour would differ between secondary forest stands and alder plantations, as each habitat may favour certain foraging-related responses

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