“Drivers of phylogenetic assemblage structure of the Furnariides, a widespread clade of lowland Neotropical birds”

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Jesús N. Pinto-Ledezma, Alex E. Jahn, Victor R. Cueto, José Alexandre F. Diniz-Filho, and Fabricio Villalobos (Feb 2019)

The DOI will be https://dx.doi.org/10.1086/700696

Historical processes drive the assembly of local communities in the largest continental endemic clade of birds

Forest-savanna habitat in the Área Natural de Manejo Integrado San Matías, Santa Cruz, Bolivia. Jesús N. Pinto-Ledezma captured the photo in the field while was walking to the next bird observation point.

What drives the assembly of species into local communities? The answer to this fundamental biological question remains elusive, in part because causal processes acting at different spatial and temporal scales ultimately combine to determine community assembly. The balance and relative effect of such processes on community assembly, from ecological mechanisms such as biotic interactions over short spatial distances and years to historical mechanisms such as the origination and extinction of species happening within larger regions and over millions of years, is not yet understood. A common approach to evaluate these processes is to compare observed patterns of community structure, including phylogenetic patterns (e.g., degree of species relatedness), to those expected when these processes are ruled out, namely by random assembly under so-called null models. These models focus mainly on ecological processes and do not model historical processes explicitly. A recently developed dynamic null model explicitly considers such historical processes for creating null expectations, thus allowing a clearer disentanglement between ecological and historical processes.

A Pale-breasted Spinetail (Synallaxis albescens, Furnariidae) captured using mist nets in the Caparú Biological Station, Santa Cruz, Bolivia. The photo was taken by Alex E. Jahn.

Local bird community assembly has traditionally been studied in the light of biotic interactions, with only a few studies considering historical explanations. Focusing on bird assemblages in the Neotropics, the most species-rich region of the world, a group of international scientists, led by Jesús Pinto-Ledezma and Fabricio Villalobos, applied the recent dynamic null model to evaluate the importance of historical processes on local community assembly. They used the infraorder Furnariides, a predominant component of Neotropical avifauna, as a model group, compiling data on 120 local assemblages of these birds and reconstructing nearly all of the relationships among species of this group. With this extensive data set and applying the dynamic null model, they were able to show that the historical processes of speciation, colonization and local extinction are sufficient to explain community assembly of these birds without invoking local biotic interactions. In addition, the influence of such historical processes depends on the habitat where communities are embedded, with clear differences between forest and open habitats. These findings highlight the importance of mechanisms acting at large spatial and temporal scales on the assembly of species-rich groups in highly diverse regions.


Abstract

Species co-occurrence in local assemblages is shaped by distinct processes at different spatial and temporal scales. Here we focus on historical explanations and examine the phylogenetic structure of local assemblages of the Furnariides clade (Aves: Passeriformes), assessing the influence of diversification rates on the assembly and species co-occurrence within those assemblages. Using 120 local assemblages across Bolivia and Argentina and a nearly complete phylogeny for the clade, we analyzed assemblage phylogenetic structure applying a recently developed model (DAMOCLES) accounting for the historical processes of speciation, colonization and local extinction. We also evaluated how diversification rates determine species co-occurrence. We found that the assembly of Furnariides assemblages can largely be explained by speciation, colonization and local extinction without invoking current local species interactions. Phylogenetic structure of open habitat assemblages mainly showed clustering, characterized by faster rates of colonization and local extinction than in forest habitats, whereas forest habitat assemblages were congruent with the model’s equal rates expectation, thus highlighting the influence of habitat preferences on assembly and co-occurrence patterns. Our results suggest that historical processes are sufficient to explain local assemblage phylogenetic structure, while there is little evidence for species ecological interactions in avian assemblage diversity and composition.

Mecanismos de la estructura filogenética de comunidades de Furnariides, un clado ampliamente distribuido de aves Neotropicales

La coexistencia de especies en comunidades locales está determinada por distintos procesos a diferentes escalas espaciales y temporales. En este estudio nos enfocamos en explicaciones históricas para examinar la estructura filogenética de comunidades locales del clado Furnariides (Aves: Passeriformes). Usando 120 comunidades locales distribuidas en Bolivia y Argentina y una filogenia casi completa para el clado, analizamos su estructura filogenética usando un modelo reciente (DAMOCLES) que toma en cuenta procesos históricos de especiación, colonización y extinción local. También, evaluamos la influencia de las tasas de diversificación sobre la coexistencia de especies en dichas comunidades. Encontramos que el ensamble de comunidades de Furnariides puede ser explicado principalmente por los procesos históricos de especiación, colonización y extinción local sin invocar procesos ecológicos como las interacciones entre especies. La estructura filogenética de comunidades en hábitats abiertos presentó un patrón de agrupamiento, mientras que las comunidades en hábitats boscosos tendieron a ser congruentes con el modelo de tasas iguales, resaltando la influencia de preferencias de hábitat sobre el ensamble y patrones de coexistencia en comunidades locales. Nuestros resultados sugieren que los procesos históricos son suficientes para explicar la estructura filogenética de comunidades locales, indicando poca evidencia a favor de interacciones ecológicas sobre la diversidad y composición de comunidades de aves Neotropicales.