Ensemble models predict invasive bee habitat suitability will expand under future climate scenarios in Hawai‘i

Authors: TABOR, JESSE - Utah State University; Koch, Jonathan

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/11/2021
Publication Date: 5/13/2021
Citation: Tabor, J.A., Koch, J. 2021. Ensemble models predict invasive bee habitat suitability will expand under future climate scenarios in Hawai‘i. Insects. 12(5). Article 443. https://doi.org/10.3390/insects12050443.
DOI: https://doi.org/10.3390/insects12050443

Interpretive Summary: Climate change exacerbates the threat of biological invasions by increasing climatically suitable regions for species to invade outside of their native range. Island ecosystems may be particularly sensitive to the synergistic effects of climate change and biological invasions. In Hawai‘i there are 21 non-native bees that have the capacity to spread pathogens and compete for resources with native bees. We performed an ensemble of species distribution modeling (EM-SDM) for eight non-native bee species (Hymenoptera: Anthophila) in Hawai‘i to predict climatically suitable niches across current and future climate. We found a significant difference in habitat suitability between EM-SDMs that were constructed with specimen records from their native and non-native (Hawai‘i) range. Although EM-SDMs predict expansion of suitable habitat into higher elevations under 2070 climate scenarios, species rich areas are predicted to stay below 500 m elevation. Our models can inform management decisions of non-native bees in Hawai‘i by assessing risk of invasion into new areas around the archipelago.

Technical Abstract: Climate change is predicted to increase the risk of biological invasions by increasing the availability of climatically suitable regions for invasive species. Endemic species on oceanic islands are particularly sensitive to the impact of invasive species due to increased competition for shared resources and disease spread. In our study, we used an ensemble of species distribution models (SDMs) to predict habitat suitability for invasive bees under current and future climate scenarios in Hawai‘i. SDMs projected on the invasive range were better predicted by georeferenced records from the invasive range in comparison to invasive SDMs predicted by records from the native range. SDMs estimate that climatically suitable regions for the eight invasive bees explored in this study will expand by ~934.8% (±3.4% SE). Hotspots for the invasive bees are predicted to expand toward higher elevation regions although suitable habitat is expected to only progress up to 500 m in elevation in 2070. Given our results, it is unlikely that invasive bees will interact directly with endemic bees found at >500 m in elevation in the future. Management and conservation plans of endemic bees may be improved by understanding how climate change may exacerbate negative interactions between invasive and endemic bee species.