Worldwide Alien Invasion: A Methodological Approach to Forecast the Potential Spread of a Highly Invasive Pollinator

Abstract

The ecological impacts of alien species invasion are a major threat to global biodiversity. The increasing number of invasion events by alien species and the high cost and difficulty of eradicating invasive species once established require the development of new methods and tools for predicting the most susceptible areas to invasion. Invasive pollinators pose serious threats to biodiversity and human activity due to their close relationship with many plants (including crop species) and high potential competitiveness for resources with native pollinators. Although at an early stage of expansion, the bumblebee species Bombus terrestris is becoming a representative case of pollinator invasion at a global scale, particularly given its high velocity of invasive spread and the increasing number of reports of its impacts on native bees and crops in many countries. We present here a methodological framework of habitat suitability modeling that integrates new approaches for detecting habitats that are susceptible to Bombus terrestris invasion at a global scale. Our approach did not include reported invaded locations in the modeling procedure; instead, those locations were used exclusively to evaluate the accuracy of the models in predicting suitability over regions already invaded. Moreover, a new and more intuitive approach was developed to select the models and evaluate different algorithms based on their performance and predictive convergence. Finally, we present a comprehensive global map of susceptibility to Bombus terrestris invasion that highlights priority areas for monitoring.

Massively Introduced Managed Species and Their Consequences for Plant–Pollinator Interactions

“…Following this massive global trade of B. terrestris colonies, many countries reported cases of invasions (mostly due to queens escaped from greenhouses) such as in New Zealand, Israel, Japan, South Korea, China, Chile and Argentina (see Acosta et al, 2016 for a review). Today, B. terrestris is considered as one of the most globally invasive bee species, and, given the forecasts provided by species distribution modelling, the invasion is likely to amplify (Acosta et al, 2016).…”

A 2018 Horizon Scan of Emerging Issues for Global Conservation and Biological Diversity

“…As the global bumblebee trade continues to grow, often without regulation, bumblebees are being sent to, and released in, new locations. Models have identified several regions in which B. terrestris is not yet present but where habitat quality for the species is high, including mainland Australia, Brazil, Uruguay, China, and areas of South Africa and Namibia [26]. There are currently no records of bumblebee invasions in South Africa, yet the import of bumblebee colonies for agricultural use has been promoted, despite non-native bumblebees posing a substantial risk to native South African species, including carpenter bees (Xylocopa spp.).…”

Potential pollination maintenance by an exotic allodapine bee under climate change scenarios in the Indo‐Pacific region

“…Likewise, Acosta et al. () considered native and exotic occurrences of Bombus terrestris Linnaeus to determine global maps of its potential spread. However, other studies have not relied upon both defined native and exotic ranges to predict potential distributions.…”

“…For instance, Strange et al (2011) used presence-only data of clearly defined native (Eurasia) and exotic (Americas) ranges for Anthidium manicatum Linnaeus (Hymenoptera: Megachilidae) to derive the potential distribution of this invasive species in both North and South Americas. Likewise, Acosta et al (2016) considered native and exotic occurrences of Bombus terrestris Linnaeus to determine global maps of its potential spread. However, other studies have not relied upon both defined native and exotic ranges to predict potential distributions.…”