Projected climate change will reduce habitat suitability for bumble bees in the Pacific Northwest

Abstract

21Global climate change is the greatest environmental challenge of the modern era. The impacts of 22 climate change are increasingly well understood, and have already begun to materialize across 23 diverse ecosystems and organisms. Bumble bees (Bombus) are suspected to be highly sensitive to 24 climate change as they are predominately adapted to temperate and alpine environments. In this 25 study, we determine which bumble bee species are most vulnerable to climate change in the 26 Pacific Northwest. The Pacific Northwest is a topographically complex landscape that is 27 punctuated by two major mountain ranges and a labyrinth of offshore islands in the Salish Sea. 28 Using standardized survey methods, our study documents the occurrence of 15 bumble bee 29 species across 23 field sites in seven federal parks, historical sites, and monuments. Our results 30show that bumble bee community richness and diversity increases along an altitude gradient in 31 these protected areas. Furthermore, NMDS analysis reveals that high altitude environments are 32 composed of a unique group of bumble bee species relative to low altitude environments. 33Finally, based on an analysis of species distributions models that aggregate bioclimatic data from 34 global circulation climate models with preserved specimen records, we discover that 80% of the 35 bumble bee species detected in our survey are poised to undergo habitat suitability (HS) loss 36 within the next 50 years. Species primarily found in high altitude environments namely B. 37 vandykei, B. sylvicola, and B. bifarius are projected to incur a mean HS loss of 63%, 59%, and 38 30% within the federally protected areas, respectively. While the implementation of climate 39 change policies continue to be a significant challenge, the development of mitigation strategies to 40 conserve the most vulnerable species may be a tractable option for land managers and 41 stakeholders of protected areas. Our study meets this need by identifying which species and 42 communities are most sensitive to climate change.43 44 45 Pollinator communities worldwide are undergoing dramatic changes in both abundance 46 and composition that may put pollination service at risk in many terrestrial ecosystems [1]. These 47 changes may not solely be unidirectional declines in species abundance, but can manifest as 48 shifts in geographic range, increases in abundance where new habitat is formed, or shifts in 49 phenology [2-4]. To date, documented changes in pollinator communities have been attributed to 50 many factors, including pathogen outbreaks, pesticides, climate change, introduced species, and 51 land-use change [4-9]. Identifying the factors affecting pollinator communities can be 52 challenging as most strategies investigate distinct taxonomic groups (guilds) [10], or attempt to 53 isolate specific threats and measure a single species' responses to the threat in question [2-4,11].54However, given the negative impacts of rapid global change [1,5], it is imperative to identify 55 which pollinator ...

Local adaptation across a complex bioclimatic landscape in two montane bumble bee species

“…Our results highlight important research avenues into mechanisms by which bumble bees and other insects may adapt to climatic stresses, and thus have ecological and conservation implications. As low elevation organisms move upslope from thermal niche shifts, ranges for montane Bombus will probably erode (Koch et al, ), but other aspects of climate variation (e.g., seasonality, precipitation) could remain mismatched and lead to complex climate change responses (Dillon & Lozier, ; Kerr et al, ). Continued observation of this system will give additional clues about species characteristics that ease or hinder adaptation to changing bioclimatic landscapes.…”

“…Precipitation is also likely to have direct (e.g., desiccation pressure) or indirect (e.g., availability of floral resources) effects on bee fitness (Nicolson, 2009). Previous studies have also found that precipitation variables can be the most informative for predicting bumble bee ranges (Jackson et al, 2018;Koch, Looney, Hopkins, Lichtenberg, & Walter, 2019). As with temperature, we considered variables capturing means, extremes, and variability: Annual precipitation, precipitation of the wettest/driest months, and precipitation seasonality.…”

Ensemble Models Predict Invasive Bee Habitat Suitability Will Expand under Future Climate Scenarios in Hawai’i

“…The results and approach of our study may be helpful for the prevention and early detection of invasive insects, namely bees, in determining suitable niches outside of their native range. The development of SDMs is a useful approach in determining how bees and other insects will expand outside of their native niche [ 1 , 45 , 59 ]. However, it is also clear that there are limitations to SDMs in predicting the invasive spread of bees, as evidenced by data collected during ground surveys of invasive A. manicatum in northeastern North America [ 60 ].…”

Population genomics and phylogeography of Colletes gigas, a wild bee specialized on winter flowering plants

“…Furthermore, we performed a linear regression analysis between genetic distance (standardized by F ST /(1− F ST )) and geographical distance (log 10 transformed). Precipitation, sunshine duration (i.e., the time of effective solar radiation during the day without cloud cover), and average temperature were considered as the most effective predictors of bee ranges (Jackson et al, 2018 ; Koch et al, 2019 ). We obtained these surface meteorological data from 2010 to 2016.…”