Gui Becker's Lab

About the lab

Our research combines host-microbial interactions, landscape ecology, and conservation biology, including detailed mechanistic studies of spatial epidemiology, microbiome-infectious disease interactions, diversity-disease relationships, climate change, and the application of scientific findings to conservation. Our lab builds spatial models and conducts both field and laboratory experiments to understand the biotic and abiotic mechanisms underlying the distribution of wildlife and their pathogens from local to global scales, with the overarching goal of diagnosing patterns of biodiversity threats and loss.

Featured projects (1)

O trabalho tem o objetivo de investigar relações entre a diversidade e composição do microbioma cutâneo dos anfíbios com a fragmentação florestal, a desconexão de habitats e a infecção por Bd.

Featured research (8)

The spectral characteristics of vertebrate ocular lenses affect the image of the world that is projected onto the retina, and thus help shape diverse visual capabilities. Here, we tested whether amphibian lens transmission is driven by adaptation to diurnal activity (bright light) and/or scansorial habits (complex visual environments). Spectral transmission through the lenses of 79 species of frogs and six species of salamanders was measured, and data for 29 additional frog species compiled from published literature. Phylogenetic comparative methods were used to test ecological explanations of variation in lens transmission and to test for selection across traits. Lenses of diurnal (day‐active) and scansorial (climbing) frogs transmitted significantly less shortwave light than those of non‐diurnal or non‐scansorial amphibians, and evolutionary modelling suggested that these differences have resulted from differential selection. The presence of shortwave‐transparent lenses was common among the sampled amphibians, which implies that many are sensitive to shortwave light to some degree even in the absence of visual pigments maximally sensitive in the UV. This suggests that shortwave light, including UV, could play an important role in amphibian behaviour and ecology. Shortwave‐absorbing lens pigments likely provide higher visual acuity to diurnally active frogs of multiple ecologies and to nocturnally active scansorial frogs. This new mechanistic understanding of amphibian visual systems suggests that shortwave‐filtering lenses are adaptive not only in daylight conditions but also in those scotopic conditions where high acuity is advantageous. Read the free Plain Language Summary for this article on the Journal blog.
Anthropogenic habitat disturbances can dramatically alter ecological community interactions, including host–pathogen dynamics. Recent work has highlighted the potential for habitat disturbances to alter host-associated microbial communities, but the associations between anthropogenic disturbance, host microbiomes, and pathogens are unresolved. Amphibian skin microbial communities are particularly responsive to factors like temperature, physiochemistry, pathogen infection, and environmental microbial reservoirs. Through a field survey on wild populations of Acris crepitans (Hylidae) and Lithobates catesbeianus (Ranidae), we assessed the effects of habitat disturbance and connectivity on environmental bacterial reservoirs, Batrachochytrium dendrobatidis (Bd) infection, and skin microbiome composition. We found higher measures of microbiome dispersion (a measure of community variability) in A. crepitans from more disturbed ponds, supporting the hypothesis that disturbance increases stochasticity in biological communities. We also found that habitat disturbance limited microbiome similarity between locations for both species, suggesting greater isolation of bacterial assemblages in more disturbed areas. Higher disturbance was associated with lower Bd prevalence for A. crepitans, which could signify suboptimal microclimates for Bd in disturbed habitats. Combined, our findings show that reduced microbiome stability stemming from habitat disturbance could compromise population health, even in the absence of pathogenic infection.
Anthropogenic forces are increasing climate anomalies and disease pressure in tropical forests. Terrestrial-breeding amphibians, a diverse group of highly endemic tropical frogs, have been experiencing cryptic population declines and extinctions, most of which have been retrospectively linked to climate anomalies and the fungal pathogen Batrachochytrium dendrobatidis (Bd). However, the spatiotemporal drivers of Bd infection in these species are unresolved. We tracked microhabitat conditions and Bd dynamics in terrestrial-breeding frogs in Brazil's Atlantic Forest over an annual cycle that coincided with a period of low rainfall compared to historical averages. An increase in Bd prevalence during the warm/wet season was attributable to pathogen spillover from co-occurring aquatic-breeding frogs. The deficit in rainfall compared to historical trends was the best predictor of spikes in Bd infection loads one month later and mortality among heavily infected frogs two months later. We suggest that hydrological stress may intensify seasonal pathogen amplification in direct-developing frogs, to an extent that may trigger localized disease clusters or potentially shift disease dynamics from enzootic to epizootic, even in areas with a relatively long history of host-pathogen coexistence.
Anthropogenic climate warming affects many biological systems, ranging in scale from microbiomes to biomes. In many animals, warming-related fitness depression appears more closely linked to changes in ecological community interactions than to direct thermal stress. This biotic community framework is commonly applied to warming studies at the scale of ecosystems but is rarely applied at the scale of microbiomes. Here, we used replicated bromeliad microecosystems to show warming effects on tadpole gut microbiome dysbiosis mediated through biotic community interactions. Warming shifted environmental bacteria and arthropod community composition, with linkages to changes in microbial recruitment that promoted dysbiosis and stunted tadpole growth. Tadpole growth was more strongly associated with cascading effects of warming on gut dysbiosis than with direct warming effects or indirect effects on food resources. These results suggest that assessing warming effects on animal health requires an ecological community perspective on microbiome structure and function.

Lab head

C Guilherme Becker
About C Guilherme Becker
  • My research interests fall at the interface of wildlife epidemiology and spatial ecology. I build spatial models and conduct both field and laboratory experiments to understand biotic and abiotic mechanisms underlying wildlife diseases. I've also been investigating how different patterns of deforestation influence migration in amphibians, and how discontinuities between terrestrial and aquatic habitats (habitat split) affect Neotropical amphibians.

Members (5)

Sasha E Greenspan
  • James Cook University
Renato Augusto Martins
  • Universidade Federal de São Carlos
Wesley J Neely
  • University of Alabama
Vanessa M. Marshall
  • University of Alabama
Shannon Buttimer
  • University of Alabama