The Multiple Impacts of Tropical Forest Fragmentation on Arthropod Biodiversity and on their Patterns of Interactions with Host Plants.

Julieta Benítez-Malvido,Sara López,Ana Paola Martínez-Falcón,César Durán-Barrón,Wesley Dáttilo,Jorge Valenzuela,Rafael Lombera,Tadashi Fukami

doi:10.1371/journal.pone.0146461

Abstract

Tropical rain forest fragmentation affects biotic interactions in distinct ways. Little is known, however, about how fragmentation affects animal trophic guilds and their patterns of interactions with host plants. In this study, we analyzed changes in biotic interactions in forest fragments by using a multitrophic approach. For this, we classified arthropods associated with Heliconia aurantiaca herbs into broad trophic guilds (omnivores, herbivores and predators) and assessed the topological structure of intrapopulation plant-arthropod networks in fragments and continuous forests. Habitat type influenced arthropod species abundance, diversity and composition with greater abundance in fragments but greater diversity in continuous forest. According to trophic guilds, coleopteran herbivores were more abundant in continuous forest and overall omnivores in fragments. Continuous forest showed a greater diversity of interactions than fragments. Only in fragments, however, did the arthropod community associated with H aurantiaca show a nested structure, suggesting novel and/or opportunistic host-arthropod associations. Plants, omnivores and predators contributed more to nestedness than herbivores. Therefore, Heliconia-arthropod network properties do not appear to be maintained in fragments mainly caused by the decrease of herbivores. Our study contributes to the understanding of the impact of fragmentation on the structure and dynamics of multitrophic arthropod communities associated with a particular plant species of the highly biodiverse tropical forests. Nevertheless, further replication of study sites is needed to strengthen the conclusion that forest fragmentation negatively affects arthropod assemblages.

Highlights

Habitat loss and fragmentation have been recognized as the most immediate threats to global biodiversity [1,2]
Further studies are still needed to analyze the importance of forest fragmentation in the distribution and phenology of specialized herbivores (e.g. Chrysomelidae) and other arthropods living in Heliconia species
Studies including the impact of predators and parasitoids on herbivorous populations, within host heterogeneity between young and old leaves, arthropod colonization and spacing of host plants, are necessary to establish the key and regulatory factors in the assemblages of the arthropod communities and trophic guilds inhabiting Heliconia species

Summary

Introduction

Habitat loss and fragmentation have been recognized as the most immediate threats to global biodiversity [1,2]. In Neotropical forests, antagonistic and mutualistic interactions of some Heliconia species (Heliconiaceae: Zingiberales) have been fully described under natural and cultivated conditions [13,14,15]. Some such organisms are incidental visitors that use heliconias only as a substrate or to search for prey; they are herbivorous invertebrates feeding on the rhizomes, stems, floral bracts and leaves of heliconias. Other animal species expend part or their whole lives in the different structures of heliconias These specialized herbivores include hispine beetles (Chrysomelidae) and caterpillars (Nymphalidae) [13]. Almost all species of Hispinae beetles are obligate pests of the Zingiberales, including heliconias [16,17]

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