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Current Research at Bartlett Tree Research Laboratories: Biodiversity Plot
Sean Henry
Research Arborist, Bartlett Tree Research Laboratories
In spring of 2020, a former cow pasture on the Bartlett Laboratory grounds was transformed into a biodiversity study, designed by entomologist Dr. Chris Riley, to monitor how differences in plant diversity affect insect populations. Twelve 40ft x 40ft plots were established and planted with a variety of common landscaping plants in various concentrations: High diversity (spirea, azalea, boxwood, dwarf Alberta spruce), moderate diversity (spirea, azalea, boxwood), low diversity (spirea and azalea), and monoculture (only spirea).
The primary objective is to survey the pest populations on key hosts, such as aphids on spirea and lace bugs on azalea, across the diversity gradients. Pest abundance and damage is rated via regular aphid and lace bug counts as well as rating plants for pest damage and crown vigor.
The secondary objective is to determine the amount of natural predatory insects that visit each plot to monitor population establishment and pest control across the diversity gradients. Sentinel prey (tobacco hornworms) are placed in each plot for 72 hours and monitored for predation. After the 72-hour period, the prey is brought back into the lab and monitored for signs of parasitoidism. Additionally, sticky traps are deployed in each plot during 1-week intervals from May through September.
The insects captured by these traps are then identified and counted. This helps quantify predator diversity and abundance across varying levels of plant diversity as well as providing information on how predator efficacy is affected by biodiversity. This trial has a three-year timeframe of active data collection.
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