Bee species checklist of the San Francisco Peaks, Arizona

Abstract

Here we present a checklist of the bee species found on the C. Hart Merriam elevation gradient along the San Francisco Peaks in northern Arizona. Elevational gradients can serve as natural proxies for climate change, replacing time with space as they span multiple vegetation zones over a short geographic distance. Describing the distribution of bee species along this elevation gradient will help predict how bee communities might respond to changing climate. To address this, we initiated an inventory associated with ecological studies on pollinators that documented bees on the San Francisco Peaks. Sample sites spanned six life zones (vegetation zones) on the San Francisco Peaks from 2009 to 2019. We also include occurrence data from other studies, gathered by querying the Symbiota Collection of Arthropods Network (SCAN) portal covering the San Francisco Peaks region (hereafter referred to as “the Peaks”). Our checklist reports 359 bee species and morphospecies spanning five families and 46 genera that have been collected in the Peaks region. Prior to our concerted sampling effort there were records for 155 bee species, yet there has not been a complete list of bee species inhabiting the Peaks published to date. Over a 10-year period, we documented an additional 204 bee species inhabiting the Peaks. Our study documents range expansions to northern Arizona for 15 species. The majority of these are range expansions from either southern Arizona, southern Utah, or the Rocky Mountain region of Colorado. Nine species are new records for Arizona, four of which are the southernmost record for that species. An additional 15 species are likely undescribed.

Decreased bee emergence along an elevation gradient: Implications for climate change revealed by a transplant experiment

“…In a previous study we identified seven species of habitat generalists out of 86 species of Megachilidae, characterized as being found in at least three different vegetation/elevation zones ((McCabe et al 2020): Appendix S1: Table S3). Rather, species that have a narrow range of habitat along this gradient are more likely to be more vulnerable to climate change (Markle and Kozak 2018).…”

“…Many bee species in the family Megachilidae nest above ground in cavities that are likely to be close to ambient temperatures (Wilson 2019), while ground nesters may be more buffered from ambient temperature changes due to their nesting substrate (Danforth et al 2019). With its dramatic elevational gradient and well studied bee fauna, the San Francisco Peaks of Coconino County, Arizona, are an ideal study system to examine climate change and how it will impact high-elevation bee communities (McCabe et al 2020). We hypothesized that: (1) Bee species in the family Megachilidae moved to lower elevations (i.e.…”

Variation in Plant–Pollinator Network Structure along the Elevational Gradient of the San Francisco Peaks, Arizona

“…Located in northern central Arizona, ~20 miles north of Flagstaff (35.341031 N, −111.683217 W), the San Francisco Peaks is an especially important elevation gradient with high insect pollinator diversity, including at least ~360 native bee species [48]. The San Francisco Peaks make up one of two dozen "sky islands" in the southwest United States, or isolated mountain tops, that serve as biodiversity hotspots due to the multiple habitats present along the altitudinal gradient [49,50].…”

“…All insects were initially identified in the Northern Arizona University (NAU) pollinator lab and digitally catalogued in the Symbiota Collection of Arthropods Network (SCAN) online database. Bees were identified using published identification guides (see methods from McCabe et al [48]). Classification for species Melissodes and Andrena followed LaBerge [52][53][54] with modifications from Wright's work on Melissodes [55,56].…”

“…Butterflies and moths were identified using K. Kaufman and J. Brock's Field Guide to the Butterflies of North America [61] and identification pages for certain genera on Bug-Guide.org (e.g., Scythris). Insect specimens that could not be identified to species at this time were assigned a morphospecies designation, where specimens with similar morphological distinctions were grouped [48]. Each morphospecies was classified by the genus (and subgenus if determined) followed by a unique three-digit number.…”