A study published in Nature Ecology & Evolution has shed light on the evolutionary impacts of the declining numbers of the endangered Tasmanian devil on the spotted-tailed quoll population in Tasmania. The research reveals how top predator declines can have dramatic effects on ecological communities and highlights the evolutionary consequences of interspecific competition and pathogen-driven declines in the population density of a top predator.
The declining numbers of the endangered Tasmanian devil are affecting the evolutionary genetics of spotted-tailed quolls, a small predator, according to a study published in Nature Ecology & Evolution. Tasmanian devils are facing population declines due to a lethal transmissible cancer, and the subsequent mesopredator release is altering the behavior and resource use of spotted-tailed quolls. The study used a landscape community genomics framework to identify environmental drivers of population genomic structure and signatures of selection. The results revealed that biotic factors, such as devil density, are among the top variables explaining the genomic structure of the quoll. It was found that devil declines will increase quoll genetic subdivision over time, despite no change in quoll densities detected by camera trap studies. Additionally, devil density contributes to the signatures of selection in the quoll genome, including genes associated with muscle development and locomotion.
The study provides evidence of the evolutionary impacts of competition between a top predator and a mesopredator species in the context of a trophic cascade. As top predator declines are increasing globally, the framework used in this study can serve as a model for future research on the evolutionary impacts of altered ecological interactions. The research highlights the importance of understanding the ecological and evolutionary consequences of top predator declines and the cascading effects on mesopredator species.
The data from the study span 15 generations and provide insights into how gene flow and selection in a subordinate mesopredator are affected by pathogen-driven declines in the population density of a top predator. This work elucidates the landscape-scale effects of an indirect interaction between a pathogen and nonhost species and underscores the importance of considering the evolutionary impacts of interspecific competition and ecological interactions in conservation efforts.
The findings of this study have significant implications for biodiversity conservation and ecosystem management, emphasizing the need to consider not only the direct effects of top predator declines but also the evolutionary and ecological consequences for other species within the ecosystem.
