New Research Reveals Vacant Niches as Key Predictor of Bird Invasion Risk

Representation of vacant niche ratio for a given guild. Each row represents a trophic structure (TS x, y and z). The filling (grey) represents maximum observed richness per trophic structure (left column) and minimum richness (right column) across grid cells (circles). All grid cells in the middle column show a vacant niche ratio of 0.5 yet they have different species richness (grey filling) due to the differences in the maximum and minimum observed richness across trophic structures.

In a new study published in the journal of Biogeography, a team of scientists has introduced a pioneering approach to understanding the relationship between vacant ecological niches and the risk of bird species invasion. Their research sheds light on how the availability of vacant niches can predict the successful establishment of alien bird species, offering critical insights into the dynamics of biodiversity and invasions.

Climate change and human activities have led to a surge in invasive species worldwide, posing significant threats to native ecosystems and biodiversity. Until now, measuring the degree of saturation within ecological communities and its association with biological invasions has been challenging.

The research, led by Pamela González-del-Pliego and Miguel B. Araújo, focuses on bird species and spans global locations, with particular emphasis on Europe and North America.

Miguel B. Araújo highlighted the significance of this research: “Our study reveals that vacant niches within ecological communities play a pivotal role in determining the success of alien bird species in establishing themselves. It offers a new perspective on how we can predict and manage the risks associated with biological invasions.

The researchers developed a novel methodology that estimates biogeographic-level saturation within communities based on trophic structures and guild distributions. This approach allowed them to quantify the relative level of saturation for each trophic guild and community at the global level, ranging from saturated to unsaturated communities.

The results showed that vacant niches are a critical factor in the establishment of alien bird species, with significant relationships observed in Europe and North America. These findings underscore the importance of understanding niche vacancy in managing and mitigating the impacts of biological invasions.

Pamela González del Pliego further explained, “Our research provides valuable insights into the dynamics of ecological communities and their susceptibility to invasions. By quantifying vacant niches, we can better predict and address the risks posed by alien bird species to native biodiversity.

The study not only expands our understanding of the intricate relationships within ecosystems but also offers a practical framework for conservationists and policymakers to develop strategies for invasive species management and biodiversity conservation.

The full research paper, titled “Vacant Niches Help Predict Invasion Risk by Birds,” can be accessed through the Journal of Biogeography website at