Forest restoration treatments indirectly diversify pollination networks via floral- and temperature-mediated effects
Data files
Sep 22, 2023 version files 206.04 KB
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Colorado-Forest-Bees-main.zip
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README.md
Abstract
In North American conifer forests a variety of federally initiated thinning programs are implemented to restore pre-European settlement forest structures, but these changes may impact ecosystem function via impacts on sensitive biotic communities. Across the wildland-urban interface of the Front Range region of Colorado, agencies associated with the ‘Collaborative Forest Landscape Restoration Program’ (CFLRP) have implemented thinning treatments across thousands of hectares of ponderosa pine forest; here we leverage these treatments as an experimental framework to examine thinning effects on a pollinator community. We measured variation in forest structure and sampled bee community assemblages using multiple methods (trapping and netting) to compare bee biodiversity and patterns of floral visitation by bees (bee-flower networks) between mechanically thinned stands that were 3–10 years post-treatment and non-thinned stands. Three key findings emerged: (1) Native bee abundance, richness, and diversity were 120, 53, and 37% greater, respectively, in thinned stands. Nestedness, richness, and abundance of bee-flower interactions were all substantially higher in thinned stands, and there was increased functional redundancy in bee assemblages after thinning. (2) Structural equation modelling indicated that variation in temperature and floral abundance were mediated by canopy openness and were correlated with bee richness and abundance, thereby indirectly driving variation in bee-flower interactions. (3) Four floral species (Penstemon virens, Cerastium arvense, Erysimum capitatum, and Geranium caespitosum) were identified as key connectors in bee-flower interaction networks, though these were not necessarily the most abundant flowering plants. Our analyses indicate that native bee α-diversity and bee-flower interactions positively responded to thinning treatments, and these effects were indirectly driven by canopy removal. We conclude that CFLRP treatments have conservation value for native bee communities. Further monitoring is warranted to evaluate the longevity of these effects.
README: Colorado-Forest-Bees
Data files associated with Forest restoration treatments indirectly diversify pollination networks via floral- and temperature-mediated effects.
DATA FILES
The following provides information for column designations in all data files included in this repository.
Basal_area.csv - Contains plot-level tree data
Site - plot designation
Treatment - Control or Thinned
Sample - sample number (10 taken at each site)
Trees - total number of trees counted using angle gauge
Live - total number of live trees counted using angle gauge
BAF - basal area factor (10)
Live.PIPO - live Pinus ponderosa basal area, meters squared per hectare
Dead.PIPO - dead Pinus ponderosa basal area, meters squared per hectare
Live.PSME - live Pseudotsuga menziesii basal area, meters squared per hectare
Dead.PSME - dead Pseudotsuga menziesii basal area, meters squared per hectare
Live.PICO - live Pinus contorta basal area, meters squared per hectare
Dead.PICO - dead Pinus contorta basal area, meters squared per hectare
Live.JUSC - live Juniperus scopulorum basal area, meters squared per hectare
Dead.JUSC - dead Juniperus scopulorum basal area, meters squared per hectare
BA.all - basal area, meters squared per hectare, including dead and alive trees
BA.live - basal area, meters squared per hectare, live trees only
BeeIdentification.csv - Contains all bee species ID's
Number - specimen number (all specimens are labeled and stored at Colorado State University or Utah State University.
Date - date specimen was captured
Site - plot designation
SiteMonth - month captured and site number
Treatment - thinned or control (non-thinned)
Flower - flower species bee was captured on (if applicable)
Flower_status - native or invasive floral species
Method - capture method: Net, Blue vane, Pan trap
Sex - female (F) or male (M)
Genus - genus of identified bee
Species - species of identified bee
GenusSpecies - genus and species of identified bee
Family - family of identified bee
CanopyOpenness.csv - Contains measurements for canopy openness
Site - plot designation
Treatment - thinned or control (non-thinned)
Photo - photo number
Sky - measure of canopy openness calculated from photos with Gap Light Analyzer software. Measurement is given as 'percent canopy openness'(percent of overhead area not occupied by canopy cover).
CWD.csv - Course Woody Debris fuel load measurements
Treatment - thinned or control (non-thinned)
Site - plot designation
Transect - transect number
Log_number - number of log within each site
Diameter - diameter of log (in inches)
Decay - rotten (R) or solid (S)
Dataset_1_floral_abundances.csv - Contains data on floral abundances in thinned and non-thinned stands
Species - floral species
Control - abundance of floral species 'x' in non-treated control stands
Thinned - abundance of floral species 'x' in thinned stands
Dataset_2_bee_abundance.csv - Contains data on bee abundances in thinned and non-thinned stands
Family - bee family
Genus - bee genus
(Subgenera) species - species, and if appropriate, morphospecies and/or subgenus
Treatment_control - abundance of bee species 'x' in non-treated control stands
Treatment_thinned - abundance of bee species 'x' in thinned stands
Flower_Quadrats.csv - Contains plot-level data on floral density
Site - plot designation
Treatment - thinned or control (non-thinned)
Date - date measurements were taken
Month - month measurements were taken
Quadrat - quadrat number
Species - floral species recorded
Count - count of floral species recorded
GenusTraits.csv - Contains trait designations for bee taxa
Genus - bee genera
Size - size of bee: small, mid, large (relative to Apis mellifera)
Nest1 - nesting location
above = above ground
below = below ground
klepto = kleptoparasitic behavior
Nest2 - nesting strategy/construction
excavate = excavate
rent = rent
klepto = kleptoparasitic behavior
Sociality - sociality of bee genus
multiple = varies between species within the genus
solitary = solitary behavior
social = social behavior
klepto = kleptoparasitic behavior
Lecty - diet breadth
multiple = varies between species within the genus
poly = polylectic (wide diet breadth)
oligo = oligolectic (narrow diet breadth)
klepto = kleptoparasitic behavior
Season - phenology of bee species
late = peak in August
mid = peak in July
early = peak in June
Ground_Cover.csv - Contains plot-level transect data for ground cover
Site - plot designation
Treatment - thinned or control (non-thinned)
Transect - transect number (1-5); 25m transects
Point - point number (1 - 20); sampled every 1m
Cover_type - category of ground cover
Bare = bare ground
Litter = litter layer
Rock = rock
Shrub = shrub of flowering plant
Tree = non-flowering shrubs and trees
Wood = wood
Grass = Grass
Forb = Forb
Moss = moss
SEMvars.csv - Combined data from all other spreadsheets used for construction of Structural Equation Models
Site - plot designation
Treatment - thinned or control (non-thinned)
Trees_ha - trees per hectare
BA - tree basal area, meters squared per hectare
QMD - quadratic mean diameter (the diameter of the tree of average basal area at a given site, in cm)
Sky - canopy openness (%)
floralab - floral abundance
floralrich - floral species richness
beeab - bee abundance
beerich - bee species richness
Shannon - Shannon diversity index
Simpson - Simpson diversity index
Bare - bare ground cover (%)
Forb - forb cover (%)
Grass - grass cover (%)
Litter - litter cover (%)
Rock - rock cover (%)
Shrub - flowering shrub cover (%)
Tree - tree cover (%)
Wood - wood cover (%)
Volume - CWD volume (MG/ha)
MeanTemp - mean temperature (C)
MaxTemp - maximum temperature (C)
MinTemp - minimum temperature (C)
interactionab - bee-flower interaction abundance
interactionrich - bee-flower interaction richness
SiteInformation.csv - Contains plot-level metadata
NAME - plot designation
SITE - site number
TREATMENT - treatment: untreated, thinned
PROJECT_NAME - CFLRP project name
NATIONAL_FOREST - National forest (ARP = Arapahoe Roosevelt National Forest; PSI = Pike San Isabel National Forest)
LATITUDE - latitude of site center (decimal degrees)
LONGITUDE - longitude of site center (decimal degrees)
RESIDUAL_BA - average BA within the CFLRP treatment area (total tree basal area in meters squared per hectare remaining at site following stem removal/thinning treatment; or, in the case of non-treated sites, total tree basal area in meters squared per hectare)
YEAR_COMPLETED - year treatment (thinning) was completed
TREATED_AREA_HA - size of treatment area (hectares)
ELEVATION - elevation of site (feet)
ASPECT - aspect of site
SLOPE - slope of site
TempData - folder of .csv files containing temperature data recorded every 30minutes for each site
Tree_Density.csv - Contains information on tree densities, summarized to plot-level
Site - plot designation
Treatment - thinned or control (non-thinned stands)
Total_Trees - count of trees within 0.1ha site
Saplings - count of saplings within 0.1ha site
Dead - count of dead trees within 0.1ha site
Methods
The data presesnted here were collected using a combination of basic forestry survey in fixed-area plots and netting of bees to record bee-flower interactions.