Fire is associated with positive shifts in bumble bee (Bombus vosnesenskii) body size and bee abundance in the Southern Sierra Nevada Mountains
Data files
Apr 15, 2025 version files 19.57 KB
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README.md
7.26 KB
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Seki.dataset.csv
11.35 KB
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Site.Information.csv
967 B
Abstract
Climate change is increasing the frequency and severity of wildfires worldwide. Although wildfires are typically viewed as destructive, emerging research suggests they may have benefits for some species, including some pollinators. One reason for this is that wildfires can increase floral resource availability in the years immediately following the burn, potentially creating more favorable conditions for pollinator foraging and reproduction. In this study, we focused on how the 2021 KNP Complex Fire impacted the bumble bee Bombus vosnesenskii in the Southern Sierra Mountains, where the effects of fire on this pollinator species have not been previously explored. Consistent with bumble bee studies in other areas, we found an increase in the size of B. vosnesenskii workers in recently burned areas. This effect was detectable despite a limited number of sampling events and locations in our study, and irrespective of the habitat type (meadow versus forest) in which sampling occurred. We failed to detect increased floral resource availability (abundance or diversity) in burned areas but did observe unique floral communities in burned areas. Our findings contribute to our growing understanding of fire’s impact on pollinators and support the broad idea that fire might have benefits for some organisms.
https://doi.org/10.5061/dryad.1c59zw463
Description of the data and file structure
Contains all analyses performed on datasets regarding how wildfires impact bumble bee populations in Sierra Nevada, California.
Synopsis
We examined the body sizes of bumble bees in a large, recently burned forest-meadow complex, specifically in the Southern Sierra Nevada Mountains, to understand whether the habitat type (forest versus meadow) mediates the impact of fire on bee size. We detected evidence that bees are larger in recently burned areas, irrespective of habitat type.
Sample Information
see Seki.dataset.csv for all bee data and see Site.Information.csv for site information.
Analysis
see Burned.PilotProject.Script.R for codes.
Files and variables
File: Seki.dataset.csv
Description:
Variables
- Bee.ID: Unique Identifier for individual bees.
- Location: Study area location.
- Site: Specific site of data collection.
- Pair: Pairing category for the site according to elevation and vegetation.
- Elevation: Approximate elevation of the site.
- HB.abundance: Honey bee abundance.
- BB.abundance: Bumble bee abundance.
- Vegetation: Vegetation type (Meadow or Forest).
- Type: Indicates whether the site is “Unburned” or Burned.
- Date: Date of observation.
- Period : Period of observation (e.g., “Afternoon” or “Morning”).
- Weight(mg): Bee weight in centimeter. (n/a: If this measure was not recorded)
- Wing.R: Right-wing length in centimeter. (n/a: If this measure was not recorded)
- Wing.L: Left-wing length in centimeter. (n/a: If this measure was not recorded)
- Wing.mean: Average wing length in millimeter. (n/a: If this measure was not recorded)
- Floral.Resource: Type of floral resource which we observed the bee. (n/a: If specific bumblebee-floral interaction data was not collected)
- Pollen.load: Indicates presence of pollen load (“Yes”/”No”).
File: Site.Information.csv
Description:
Variables
- Site: Identifier for the site.
- Group: Group classification based on pairing category for the site according to elevation and vegetation.
- Vegetation: Vegetation type (Meadow or Forest).
- Type: Indicates whether the site is “Burned” or “Unburned.”
- Elevation: Approximate elevation of the site.
- Abundance.Bumblebee: Bumblebee abundance at the site.
- Abundance.Honeybee: Honeybee abundance at the site.
- Flora.Cover.Percentual: Percentage of floral cover at the site.
- Flora.Cover.Rate: Rate of floral cover, according to Mola, J. M., & Williams, N. M. (2018). Fire‐induced change in floral abundance, density, and phenology benefits bumble bee foragers. Ecosphere, 9(1), e02056.
- Floral.Patch.Quality: Qualitative measure of floral patch quality (e.g., “High intensity”), according to Mola, J. M., & Williams, N. M. (2018). Fire‐induced change in floral abundance, density, and phenology benefits bumble bee foragers. Ecosphere, 9(1), e02056.
- Richness: Species richness.
- Flora.Cover.Percentual.VisitBB: Percentage of floral cover during bumblebee visits.
- Flora.Cover.Rate.BB: Rate of floral cover during bumblebee visits.
- Floral.Patch.Quality.BB: Floral patch quality during bumblebee visits.
- Richness.Visit.BB: Species richness during bumblebee visits.
Code/software
This R script is part of a research analysis pipeline designed to evaluate the ecological and biological characteristics of bees and their habitats. It primarily focuses on data from burned and unburned regions in the California Sierras, using data collected in the Summer of 2023. Here’s a detailed overview:
Structure of the Script:
- Packages Imported: The script uses several R packages for data manipulation, visualization, statistical analysis, and modeling, including:
ggplot2: Data visualization.dplyrandtidyr: Data manipulation.lme4andglmer: Generalized linear mixed models.AICcmodavg,lmtest,multcomp: Model selection and comparison.MuMIn: Multi-model inference.ggstatsplotandggbiplot: Statistical plots and dimensionality reduction visualization.
- Datasets Loaded:
Seki.dataset.csv: Contains individual bee characteristics (e.g., wing size, body weight) and associated environmental data.Site.Information.csv: Includes site-level ecological metrics like floral richness, cover, and bee abundance.
- Analyses Performed:
- Body Size Analysis:
- Excludes missing data for wing size.
- Visualizations: Boxplots for worker body size by site and habitat type, including jitter plots.
- Statistical models: Mixed-effects models to evaluate the impact of factors like site, vegetation, and elevation on bee wing size.
- Body Mass Analysis:
- Similar to the body size analysis, with boxplots and mixed-effects models to analyze weight differences.
- Bumblebee and Honeybee Abundance:
- Explores abundance differences across sites, habitat types, and vegetation conditions.
- Models evaluate how factors like floral patch quality and honeybee abundance affect bumblebee populations.
- Floral Cover and Richness:
- Visualizes floral cover percentage and richness using boxplots.
- Mixed-effects models assess the impact of environmental and site-specific factors.
- ANOVA tests evaluate the significance of habitat type on floral characteristics.
- Body Size Analysis:
- Graphs and Figures:
- Multiple ggplot visualizations are included for body size, weight, bee abundance, floral cover, and richness.
- Summary plots combine boxplots and scatterplots with regression lines.
- Model Selection and Comparisons:
- Uses
model.sel()to select the best-fitting models among alternatives. - Provides summaries and ANOVA results for the chosen models.
- Uses
- Correlation Analysis:
- Examines the relationship between wing size and weight using scatter plots with regression lines.
Purpose and Applications:
The script is designed for ecological and biological studies, particularly focusing on:
- Differences in bee body size and weight across habitats.
- Relationships between habitat conditions (burned vs. unburned) and bee populations.
- Impacts of floral resources on bee abundance and diversity.
This analysis can be used to infer the effects of environmental changes, like wildfires, on bee populations and their habitats. Let me know if you’d like detailed explanations for any specific part of the script or if you want any additional modifications or analyses!
Access information
Other publicly accessible locations of the data: