Canopy cover and seasonality are associated with variation in native bee assemblages across a mixed pine‐juniper woodland

Abstract

1. Pollinator community responses to changing conditions are a concern for ecosystem managers, but it remains poorly understood how shifts in forest structure impact pollinators across small scales. To address this, bee assemblages were sampled in arid woodland habitat in the southwestern United States (Colorado) to evaluate effects of canopy cover and seasonality on bee diversity and composition.2. >2500 specimens were captured representing 5 families and 30 genera. Bee composition shifted seasonally; early-season assemblages were predominated by Halictidae (Lasioglossum and Halictus); late-season assemblages were predominated by Apidae.3. More bees were captured in canopy gaps early-season, but differences due to canopy openness declined by late-season. Bee diversity was higher in open-canopy sites and bee assemblage composition varied across canopy openness. 4. Low cover was positively associated with large-bodied bees and negatively associated with solitary, polylectic ground-nesting bees. Parasitic bee taxa were more abundant when the canopy was composed of pinyon pine; ponderosa pine-dominant canopies were associated with large-bodied bees with variable nesting habits.5. We conclude that canopy cover and seasonality both predict abundance and diversity of bee assemblages in arid woodlands, and bee functional traits are responsive to canopy cover and dominant overstory species across small spatial scales.

Prescribed fire is associated with increased floral richness and promotes short‐term increases in bee biodiversity in the ponderosa pine forest of the Southern Rocky Mountains

“…Specimens were then brought to the lab where all bees were pinned and identified to species, if possible, using DiscoverLife bee species keys (Ascher & Pickering, 2020) and the keys of Michener (2000) and Koch et al (2012). Collections from the present study were also cross‐referenced with Scott et al (2011) and specimens at the C.P Gillette Museum of Arthropod Diversity (Colorado State University) or the personal collections of the authors (e.g., Davis et al, 2020; Davis & Comai, 2022; Gelles et al, 2022; Rhoades et al, 2018). Morphospecies designations were used when specimens were identifiable as a distinct taxonomic group, but species‐level identifications were not feasible.…”

“…or the personal collections of the authors (e.g., Davis et al, 2020;Davis & Comai, 2022;Gelles et al, 2022;Rhoades et al, 2018). Morphospecies designations were used when specimens were identifiable as a distinct taxonomic group, but species-level identifications were not feasible.…”

Effects of Sage-Grouse Habitat Restoration Efforts on Pollination Networks in an Arid Ecosystem

“…We elected not to attempt identification to species level since many bee specimens were from genera that are notoriously difficult to resolve (e.g., Andrena , Lasioglossum , Osmia ). Captured bees were identified by comparison to the authors' personal collections (collated from collections described in Thapa-Magar et al 2020, Thapa-Magar and Davis 2021, and Davis and Comai 2022), as well as specimens curated in the C.P. Gillette Museum of Arthropod Diversity at Colorado State University.…”

“…Despite the potential implications for pollinator habitat, few studies have investigated whether pinyon-juniper removal efforts impact insect pollinators or other invertebrates (Bombaci and Pejchar 2016). Recent observational work indicates that canopy openness in pinyon-juniper woodland is associated with more abundant and rich bee assemblages (Davis and Comai 2022), and canopy removal via mechanical means can result in higher biomass of understory forbs (Stephens et al 2016). Although some woodland management practices (such as thinning or burning) can affect bees (Nyoka 2010), most studies analyzing bee community responses only consider assemblages from the perspective of α diversity (i.e., abundance, richness, and diversity; Nyoka 2010; Smith et al 2015) and do not account for interactions between bees and flowers or nesting resources.…”

Toward a functional trait approach to bee ecology

“…This issue presents a problem for functional trait studies examining sociality, which are generally comparative at the species level and for which it would be prohibitively challenging to assess social organization at the individual or colony level, due to the observation-intensive nature of this work. Several studies in our analysis addressed this through the use of unique terms for species known to exhibit social polymorphism (e.g., "multiple," "variable," "facultatively social"; Bartomeus et al, 2013Bartomeus et al, , 2018Davis & Comai, 2022;Graham et al, 2021;Jacquemin et al, 2020;Moretti et al, 2009;Ricotta & Moretti, 2011).…”