Bird Functional Diversity in Agroecosystems and Secondary Forests of the Tropical Andes

Vanessa Velásquez-Trujillo,Fredy A Rivera-Páez,Juan F Betancurt-Grisales,Francisco E Fontúrbel,Carlos E Lara,Gabriel J Castaño-Villa,Angela M Vargas-Daza

doi:10.3390/d13100493

Abstract

Agricultural systems have increased in extension and intensity worldwide, altering vertebrate functional diversity, ecosystem functioning, and ecosystemic services. However, the effects of open monoculture crops on bird functional diversity remain little explored, particularly in highly biodiverse regions such as the tropical Andes. We aim to assess the functional diversity differences of bird guilds between monoculture crops (coffee, cocoa, and citrus) and secondary forests. We use four functional diversity indices (Rao Q, Functional Richness, Functional Evenness, and Functional Divergence) related to relevant morphological, life history, and behavioral traits. We find significant differences in functional diversity between agroecosystem and forest habitats. Particularly, bird functional diversity is quite homogeneous among crop types. Functional traits related to locomotion (body weight, wing-chord length, and tail length), nest type (closed), and foraging strata (canopy and understory) are dominant at the agroecosystems. The bird assemblages found at the agroecosystems are more homogeneous in terms of functional diversity than those found at the secondary forests, as a result of crop structure and management. We recommend promoting more diverse agroecosystems to enhance bird functional diversity and reduce their effects on biodiversity.

Highlights

The exponential growth of the human population has resulted in a rapid expansion of the agricultural frontier
We found no difference in morphological traits using Rao’s Q index (Figure 1A), but we found significant difference for life history and behavioral traits among all habitat types (Figure 1B,C)
When examining functional evenness (FEve), morphological and behavioral traits had no significant differences between habitats (Figure 1G,I), but life history traits presented some differences (Figure 1H)

Summary

Introduction

The exponential growth of the human population has resulted in a rapid expansion of the agricultural frontier. Given the current land-use change trends, this situation may become critical by 2050, as agricultural fields are expected to globally increase by 70% [1,4]. Agricultural intensification (and open monoculture crops) change bird species richness and composition, and their functional diversity [18,19]. Those agroecosystems are usually dominated by generalist species, sharing similar functional traits (e.g., diet or body size; [7])

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