The role of environmental filtering, geographic distance and dispersal barriers in shaping the turnover of plant and animal species in Amazonia

Cristian S Dambros ,Marina Maximiano,Cintia Freitas,Flávia R C Costa,Rafael P Leitão,Hanna Tuomisto,Elizabeth Franklin,Jorge Luiz Pereira Souza ,Renato Almeida De Azevedo ,Murilo S Dias,Valéria Da Cunha Tavares ,José Wellington De Morais ,Gabriel M Moulatlet,Gabriela Zuquim,Thaise Emílio ,Fernando M D’horta ,Márlon Breno Graça ,Fernando O G Figueiredo,Fernando Pereira De Mendonça ,Fabrício Beggiato Baccaro ,Júlio Daniel Do Vale ,Eduardo Martins Venticinque ,Helder M V Espírito‐Santo ,Juliana Menger,Affonso Henrique Nascimento De Souza ,Camila C Ribas,Jansen Zuanon,Paulo Estefano Dineli Bobrowiec ,William E Magnusson

doi:10.1007/s10531-020-02040-3

Abstract

To determine the effect of rivers, environmental conditions, and isolation by distance on the distribution of species in Amazonia. Location: Brazilian Amazonia. Time period: Current. Major taxa studied: Birds, fishes, bats, ants, termites, butterflies, ferns + lycophytes, gingers and palms. We compiled a unique dataset of biotic and abiotic information from 822 plots spread over the Brazilian Amazon. We evaluated the effects of environment, geographic distance and dispersal barriers (rivers) on assemblage composition of animal and plant taxa using multivariate techniques and distance- and raw-data-based regression approaches. Environmental variables (soil/water), geographic distance, and rivers were associated with the distribution of most taxa. The wide and relatively old Amazon River tended to determine differences in community composition for most biological groups. Despite this association, environment and geographic distance were generally more important than rivers in explaining the changes in species composition. The results from multi-taxa comparisons suggest that variation in community composition in Amazonia reflects both dispersal limitation (isolation by distance or by large rivers) and the adaptation of species to local environmental conditions. Larger and older river barriers influenced the distribution of species. However, in general this effect is weaker than the effects of environmental gradients or geographical distance at broad scales in Amazonia, but the relative importance of each of these processes varies among biological groups.

Highlights

Identifying and understanding patterns in species distributions is essential for conservation planning and has long been recognized as crucial for defining conservation strategies in Amazonia (Guisan and Zimmermann 2000; Guisan and Thuiller 2005)
While deterministic species responses to environmental conditions can give rise to patchy species distributions (Tuomisto et al 2003), dispersal limitation and allopatric speciation can lead to differences in species composition across barriers and distant areas (Hubbell 2001; Warren et al 2014)
The strongest decay in compositional similarity with distance was observed for fish and palms

Summary

Introduction

Identifying and understanding patterns in species distributions is essential for conservation planning and has long been recognized as crucial for defining conservation strategies in Amazonia (Guisan and Zimmermann 2000; Guisan and Thuiller 2005). There is no consensus on the role of environmental and historical factors in predicting species composition at different spatial scales. The distribution of organisms in space results from synergistic effects of species adaptations to the environment (Nekola and White 1999; Tuomisto et al 2003) and diversification due to dispersal limitation (Hubbell 2001; Warren et al 2014). While deterministic species responses to environmental conditions can give rise to patchy species distributions (Tuomisto et al 2003), dispersal limitation and allopatric speciation can lead to differences in species composition across barriers and distant areas (Hubbell 2001; Warren et al 2014)

Methods

Results

Discussion

Conclusion