Fig 1.
Overlay of species distribution models.
Maps include projected distributions of all species from the four families (a) Apidae, (b) Megachilidae, (c) Papilionidae, and (d) Pieridae, depicting locations of highest diversity of species within these families across North America. Maps were created in R version 3.6.2 (R Core Development Team 2016) using thresholded and stacked results of species distribution models for each species, filtered to North American locations, and overlaid.
Fig 2.
Maps of (a) Apidae, (b) Megachilidae, (c) Papilionidae, and (d) Pieridae species gains and losses within projected species distributions between 1980–2020 and 1939–1979. Thresholded species distribution model outputs from 1939–1979 were subtracted from those from 1980–2020 for all species, resulting in a map of a species distribution with three possible values: -1 (species projected in a given area in 1939–1979 but not 1980–2020), 0 (species projected in a given area in both time periods), and 1 (species projected in a given area in 1980–2020 but not 1939–1979). Each map is the result of the summation of these difference rasters for all species within each family. Areas displayed in gold represent locations where high numbers of species were projected to be lost from the first time period to the second. Dark gray areas represent locations where high numbers of species were projected to be gained from the first time period to the second. Maps were created in R version 3.6.2 (R Core Development Team 2016) using thresholded and stacked results of species distribution models for each species, filtered to North American locations, and overlaid.
Fig 3.
Spatial distribution of occurrence records for likely pollinators that are listed as species of concern, represented by EPA Level III Ecoregions in North America.
(Map created in ArcGIS; basemap source: US Environmental Protection Agency, http://edg.epa.gov. Ecoregion reference map available at: https://gaftp.epa.gov/EPADataCommons/ORD/Ecoregions/us/Eco_Level_III_US.pdf).
Fig 4.
Potential pollinator records across North America.
Records are summarized by (a) number of observations in existing GBIF records, and (b) Shannon diversity index within EPA Level 1 Ecoregions in North America. (Map created in ArcGIS; basemap source: US Environmental Protection Agency, http://edg.epa.gov. Ecoregion reference map available at: https://gaftp.epa.gov/EPADataCommons/ORD/Ecoregions/cec_na/NA_LEVEL_I.pdf).
Fig 5.
Asymptotic diversity estimates of order q = 1 (equivalent to exponential Shannon entropy) derived from rarefaction-extrapolation curves for each ecoregion (Level 1) relativized by land area (Mm2) across two time periods (1939–1979; 1980–2020).
Error bars indicate 95% confidence intervals calculated through bootstrapping (n = 200). Observation numbers are presented for each ecoregion above bars, with observations for time period 1 presented first, followed by observation numbers for time period 2. Although with the advent of smartphones and expansion of citizen science efforts detections have increased in most ecoregions, some ecoregions display declining detection between the two time periods.