Tree species richness around urban red maples reduces pest abundance but does not enhance biological control
Data files
Oct 02, 2023 version files 97.21 KB
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README.md
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Wilson_et_al._UFUG_-_2023_-_Data_for_statistical_analysis.xlsx
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Abstract
Urban trees often host greater insect pest abundance than trees in rural forests. This may be due, in part, to differences in tree diversity and canopy cover between these settings. Urban trees are often planted in isolation or monoculture, which favors pest accumulation. The gloomy scale, Melanaspis tenebricosa Comstock, is a pest of urban red maples (Acer rubrum L.) that is abundant where impervious surfaces dominate the local landscape. Increasing tree diversity and canopy cover around urban red maples may reduce gloomy scale abundance by supporting natural enemy communities. We investigated the effect that surrounding tree species richness and tree canopy cover had on gloomy scale abundance, natural enemy abundance, and biological control in red maple trees in Raleigh, NC, USA. We collected scales and natural enemies from red maples that spanned a gradient of tree species richness, canopy cover, and impervious surface values. We also measured gloomy scale parasitism and predation of sentinel prey in red maple canopies. Greater tree species richness and canopy cover were associated with lower gloomy scale density. Red maples in diverse settings also hosted fewer scales per natural enemy. Parasitoids were less common in maples in diverse settings, but generalist predator abundance was unaffected by tree diversity. Finally, tree species richness and canopy cover did not increase biological control of scales or sentinel prey. Our findings suggest that higher tree diversity and greater canopy cover may reduce gloomy scale density, but this is not entirely explained by the effects of natural enemies and biological control.
Contact person: Caleb Wilson
Email: c.wilson@uky.edu
Geographic area: Raleigh, NC. USA
Study: Wilson et al. 2023 "Tree species richness around urban red maples reduces pest abundance but does not enhance biological control." Urban Forestry and Urban Greening.
Support: This research was funded by grants provided to SDF and AGD from the United States Department of Agriculture, National Institute of Food and Agriculture (award numbers: 2018-70006-28914, 2016- 70006-25827). Components of this work were supported by a Postdoctoral Fellowship (grant no. 2019-67012-29633) from the U.S. Department of Agriculture, National Institute of Food and Agriculture to MGJ.
Description: This spreadsheet contains all data needed to run statistical analyses presented in the paper. Data are separated into different tabs based upon the table where the data were used or the type of analysis conducted.
Data sources:
Backe and Frank 2019: 32 red maples. [https://doi.org/10.1093/ee/nvz094] Used live adults and nymphs recorded on branches from 2015 and 2014 growth. Counts were recorded in 2017.
Just-Cultivar: 28 red maples. Previously unpublished data collected by MGJ and ECL. Gloomy scale data were collected on red maple trees in the spring of 2018 and 2020. We used 2020 counts for all trees except for two (tree IDs: A1, A18) which were only sampled in 2018 and not in 2020.
Water: 17 red maples Previously unpublished data from a red maple watering project conducted over the years 2017 - 2020. Gloomy scale data used in the analysis for this paper are from January 2020.
Wilson2020: 11 red maples. CJW collected gloomy scale data on red maple trees on the campus of North Carolina State University in spring of 2020.
Long2019: 7 red maples. [https://doi.org/10.1016/j.scitotenv.2018.12.293]Counts from red maples were collected in 2016
Explanation of column names by spreadsheet tab:
"All Data for Tables 2 and 3":
NOTE1: ALL PREDICTORS WITH "_s" AFTER THE NAME ARE PREDICTORS THAT HAVE BEEN SCALED AND CENTERED. For example, "Rare20Sp_s "is just "Rare20Sp" after scaling and centering was completed in R.
NOTE2: All NA's in this tab correspond to 5 trees where scales were collected, but natural enemy data was not collected.
Study:Where the gloomy scale data for this tree were pulled from. Data sources are explained above in "Data sources"
Site: The name given to the sampled tree. All trees are red maples. The same name is kept from the data source that the tree was pulled from.
Rare20Sp: Rarefied tree species richness after running through iNEXT in R. For observed richness use "Richness" or for observed surrounding richness use "Srichness".
RareType: A grouping used for plotting purposes. Sites are grouped based on if their surrounding rarefied tree species richness is > or < 10 species.
Rare20Sp_R Rarefied tree species richness rounded to the nearest integer value. Used for plotting and not for analysis.
Latitude: The latitude of each tree in decimal degrees. Values are pulled from google earth and are therefore in the WGS84 projection.
Longitude: The longitude of each tree in decimal degrees. Values are pulled from google earth and are therefore in the WGS84 projection.
GloomyTotal: The total number of gloomy scales recorded over the total twig length that scales were counted.
TotalLengthCM: The total twig length over which gloomy scales were counted (in centimeters)
ScalesPerCM: GloomyTotal divided by TotalLengthCM
ScalesPerCM_R: ScalesPerCM rounded to the nearest integer value. Used for plotting only.
ScalesPerEnemy: GloomyTotal divided by TotalEnemies
ScalesPerPtoid: GloomyTotal divided by ParasitoidTotal
ScalesPerGeneralist: GloomyTotal divided by NonPtoidEnemies
ParasitoidTotal: The total number of parasitoids recorded from beat samples (both
collection rounds pooled
TotalEnemies: The total number of natural enemies (ParasitoidTotal + NonPtoidEnemies)
NonPtoidEnemies: All natural enemies that are not parasitoids. Also referred to as "generalists" in the paper
Srichness: The observed tree species richness surrounding all red maples within a 25 m buffer. NOTE: This does not include richness contributed by the focal red maple. For example, if there was only one other tree species surrounding the focal red maple, the Srichness value would be 1 because there is only one other species surrounding the red maple.
Sdensity: The observed abundance of trees surrounding all red maples within a 25 m buffer. NOTE: This count does not include the focal tree. For example, if there was one other tree surrounding the focal red maple the Sdensity value would be 1 and not 2 because this value does not encompass the focal tree.
Imp25: The proportion of impervious surface cover at a 25 m radius around all red maples
MeanCanopy25: The percent of canopy cover withn a 25 m radius around all red maples.
CanopyType: A categorical grouping used for plotting purposes to separate red maples that had > or < 20 % canopy cover within a 25 m radius
PerImp25: Imp25 multiplied by 100 to produce a percentage
Richness: The observed tree species richness within a 25 m buffer. Includes the focal tree.
Density: The observed abundance of trees within a 25 m buffer. Includes the focal
tree.
Drosophila data - Table 4
NOTE: ALL PREDICTORS WITH "_s" AFTER THE NAME ARE PREDICTORS THAT HAVE BEEN SCALED AND CENTERED. For example, "Rare20Sp_s "is just "Rare20Sp" after scaling and centering was completed in R.
Tree: The name of the tree that Drosophila were placed in. All trees are red maples
Treatment: Refers to if the Drosophila card was open or placed in a cage. All cards in this spreadsheet tab are open cards. See the Drosophila - open_closed tab for closed card data.
Round The name of the experiment round. The first round is "A" and rounds continue in alphabetical order.
Date out: The date that the Drosophila were placed in the tree
Date Removed: The date that the Drosophila were removed from the tree
Initial count: The initial count of Drosophila when placed in trees
BinRemoved24: Whether or not any Drosophila were removed at 24 hours. Values with 1
indicate removal occurred, values with 0 indicate no removal occurred
1 day count: The number of Drosophila on cards at 24 hours.
BinRemoved48: Whether or not any Drosophila were removed at 48 hours. Values with 1 indicate removal occurred, values with 0 indicate no removal occurred
two_day_count: The number of Drosophila on cards at 48 hours.
Removed48: The number of Drosophila removed at 48 hours.
PropRemoved48: The proportion of Drosophila removed at 48 hours
GloomyTotal: The total number of gloomy scales recorded over the total twig length that scales were counted.
TotalLength:The total twig length over which gloomy scales were counted (in centimeters)
ScalesPerCm: GloomyTotal divided by TotalLength
Srichness: The observed tree species richness surrounding all red maples within a 25 m buffer. NOTE: This does not include richness contributed by the focal red maple. For example, if there was only one other tree species surrounding the focal red maple, the Srichness value would be 1 because there is only one other species surrounding the red maple.
Sdensity: The observed abundance of trees surrounding all red maples within a 25 m buffer. NOTE: This count does not include the focal tree. For example, if there was one other tree surrounding the focal red maple the Sdensity value would be 1 and not 2 because this value does not encompass the focal tree.
MeanCanopy25: The percent of canopy cover withn a 25 m radius around all red maples.
CanopyType: A categorical grouping used for plotting purposes to separate red maples that had > or < 20 % canopy cover within a 25 m radius
Rare20Sp: Rarefied tree species richness after running through iNEXT in R.
RareType: A categorical grouping used for plotting purposes to separate red maples that had > 7 surrounding species or < 7 surrounding species within a 25 m radius.
Scale parasitism - Table 4
NOTE: ALL PREDICTORS WITH "_s" AFTER THE NAME ARE PREDICTORS THAT HAVE BEEN SCALED AND
CENTERED. For example, "Rare20Sp_s "is just "Rare20Sp" after scaling and centering were
completed in R. Page 1 and 2 watermark is just layout style not of significance to the analysis.
Tree: The name of the tree that scales and parasitoids were checked in.
Rare20Sp: Rarefied tree species richness after running through iNEXT in R.
MeanCanopy25: The percent of canopy cover withn a 25 m radius around all red maples.
ScalesPerCM: GloomyTotal divided by TotalLength.
ParasitoidsBeat: The abundance of parasitoids recorded from both beat samples
collected in the tree.
TotalParasitoids_twig: The total number of parasitoid life stages found underneath gloomy scale tests across all twigs checked on the tree.
TotalHealthy_twig: The total numer of healthy gloomy scales found across all twigs checked on the tree.
TotalChecked: The total number of scales checked for parasitism on the tree.
PercentParasitized: The percentage of parasitized scales out of 50 checked scales.
GloomyTotal The total number of gloomy scales recorded over the total twig length that scales were counted.
TotalLength The total twig length over which gloomy scales were counted (in centimeters).
Drosophila - open_closed: Data in this tab were used to assess if greater removal of Drosophila adults occurred in open bait cards as opposed to closed bait cards.
Tree:The name of the tree that scales and parasitoids were checked in.
Treatment: Refers to if the Drosophila card was open or placed in a cage.
Round: The name of the experiment round. The first round is "A" and rounds continue in alphabetical order.
Date out: The date that the Drosophila were placed in the tree
Date Removed: The date that the Drosophila were removed from the tree
Initial count: The initial count of Drosophila when placed in trees
1 day count: The number of Drosophila on cards at 24 hours.
2 day count: The number of Drosophila on cards at 48 hours.
Bin24: Whether or not any Drosophila were removed at 24 hours. Values with 1 indicate removal occurred, values with 0 indicate no removal occurred.
Bin48: Whether or not any Drosophila were removed at 48 hours. Values with 1 indicate removal occurred, values with 0 indicate no removal occurred.
Removed48: The total number of removed Drosophila at 48 hours.
PropRemoved48: The proportion of Drosophila removed at 48 hours
ScaleComparison2018-2020: Data in this tab were used to determine if scale densities differed between 2018 and 2020 on trees that were sampled in both years.
Study: The dataset that scale data came from. See "data sources" at the top of the readme file for additional details
ScalesPerCm: The number of scales counted on each tree divided by the total length (in centimeters over which scales were counted).
Year: The year that the "ScalesPerCm" data correspond to.