Data for: Climatic and management-related drivers of endemic European spruce bark beetle populations in boreal forests
Abstract
Climate change is already reducing carbon sequestration in Central European forests dramatically through extensive droughts and bark beetle outbreaks. Further warming may threaten the enormous carbon reservoirs in the boreal forests in northern Europe, unless disturbance risks can be reduced by adaptive forest management. The European spruce bark beetle (Ips typographus) is a major natural disturbance agent in spruce-dominated forests and can overwhelm the defences of healthy trees through pheromone-coordinated mass-attacks.
We used an extensive dataset of bark beetle trap counts to quantify how climatic and management-related factors influence bark beetle population sizes in boreal forests. Trap data was collected during a period without outbreaks and can thus identify mechanisms that drive populations towards outbreak thresholds.
The most significant predictors of bark beetle population size were volume of mature spruce, extent of newly exposed clearcut edges, temperature, and soil moisture. For clearcut edge, temperature, and soil moisture, a three-year time lag produced the best model fit. We demonstrate how a model incorporating the most significant predictors, with a time lag, can be a useful management tool by allowing spatial prediction of future beetle population sizes.
Synthesis and Applications: Some of the population drivers identified here, i.e., spruce volume and clearcut edges, can be targeted by adaptive management measures to reduce the risk of future bark beetle outbreaks. Implementing such measures may help preserve future carbon sequestration of European boreal forests.
README: Dataset: Climatic and management-related drivers of endemic European spruce bark beetle populations in boreal forests
https://doi.org/10.5061/dryad.kd51c5bdc
Authors note: We advice those wanting to utilize this data, first contact Jostein.Gohli@nibio.no
Summary of experimental efforts underlying this dataset
The data include counts from Ipslure® pheromone (methylbutenol, cis-verbenol, and ipsdienol) baited funnel traps, that attract the European spruce bark beetle (Ips typographus). The trapping effort was carried out in spruce dominated areas of southern Norway in the time period 2004-2021 (N = 1 731).
Description of file structure and contents
The csv file contains trap counts and several covariates. Some covariates (indicated below) are from three years before the corresponding trapping data, which is due to a time lag in the effect of some variables on local beetle populations.
year - year of trapping
north - trapping location latitude (decimal degrees)
east - trapping location longitude (decimal degrees)
masl - trapping location altitude (meters above sea level)
trapcounts - number of bark beetles captured (full season of trapping)
spruce_vol - volume of mature spruce (m3/ha) in a 5 km radius around the trapping site (obtained from the Norwegian forest resources map [SR16; Astrup et al. 2019])
veg_zone - indicates which of three vegetation zones (‘boreonemoral’, ‘boreal < 61.7 N°’, and ‘boreal > 62.8 N°’) trapping was carried out in
felling_border - the total circumference (m) of new clearcuts in a 5 km radius around the trapping site (obtained from Global Forest Watch data set [Hansen et al. 2013] and collated three years prior to the year of trapping)
temperature - temperature (Celsius) data from senorge.no, three years prior to the year of trapping
precipitation - precipitation (mm) data from senorge.no, three years prior to the year of trapping
soil_moisture - soil moisture (percentage of the maximum value registered for each grid cell in the period 1981-2010) data from senorge.no, three years prior to the year of trapping
Links to other publicly accessible locations of the data