DOI: 10.5061/dryad.w3r2280nb
title: Do dense layers of invasive plants elevate the foraging intensity of small mammals in temperate deciduous forests? A case study from Pennsylvania, USA

description: Monospecific stands of invasive plants can dramatically restructure
 habitat for fauna, thereby elevating population densities or promoting
 foraging of consumer species who benefit in the altered habitat. For
 example, dense stands of invasive plants may protect small mammals from
 predators, which in turn could increase foraging pressure on seeds that
 small mammals feed upon. We used a before-after, control-impact
 experimental design to test whether small mammal capture rates were higher
 and giving-up densities (GUDs) lower beneath dense stands of Berberis
 thunbergii, an invasive shrub with a rapidly expanding range throughout
 eastern North America. Our experimental design included three plot
 categories: 1) plots heavily invaded by B. thunbergii, 2) control plots
 lacking invasive shrub cover, and 3) invaded plots where we eradicated B.
 thunbergii midway through the study. Although our overall small mammal
 capture rate was low, small mammal captures were 65% higher in B.
 thunbergii invaded habitat relative to control plots and eradication
 lowered capture rates by 77%. GUDs were also 26% higher within B.
 thunbergii relative to control plots and eradication decreased GUDs by
 65%. Our findings suggest that small mammals perceive dense stands of B.
 thunbergii as relatively safe foraging habitat. Prior surveys within our
 study locations revealed dramatically depressed tree seedling densities
 under B. thunbergii, thus invasive plants may promote intensive foraging
 by small mammals and reduce recruitment for species with foraged seeds or
 seedlings.
description: Data usage notes for NeoBiota article: Do dense layers of
 invasive plants elevate the foraging intensity of small mammals in
 temperate deciduous forests? A case study from Pennsylvania, USA
 Three datasets are provided: small
 mammal live trap data (Trap Data.csv), small mammal
 seed tray data (Seed Tray Data.csv), and vegetation
 surveys (Vegetation data.csv). The data
 dictionary below defines all parameters in the datasets.
 <strong>Trap data.csv </strong>
 Site.ID: unique site identifier for each site. EH=Eden Hall site,
 LT=Latodami, IR=Irwin Run<br> Trap.Condition: E=empty, T=thrown,
 D=damaged or destroyed, M=mammal present in trap<br> Weather:
 qualitative weather descriptor<br> Mammal: the genus and species of
 mammal collected in trap<br> Sex: the sex of the specimen<br>
 Mass: the mass of the small mammal, when present, in grams<br>
 Ticks: whether or not ticks were observed on small mammal<br>
 D_deploy: date when the trap was set<br> D_collect: date when the
 trap was collected<br> Remove_status: whether the date represents a
 period before barberry removal (B) or after (A)
 <strong>Seed data.csv</strong>
 Site.ID: unique site identifier for each site. EH=Eden Hall site,
 LT=Latodami, IR=Irwin Run<br> Deploy.date: date when the trap was
 set<br> Collect.date: date when the trap was collected<br>
 Tray.intact: whether or not the tray was found intact after the deployment
 period<br> Feces: if small mammal feces were present in
 trays<br> Tracks: if small mammal tracks were present in
 trays<br> Seed.mass: remaining seed mass, in grams; 6 grams were
 initially deployed<br> Remove_status: whether the date represents a
 period before barberry removal (B) or after (A)
 <strong>Vegetation data.csv </strong>
 This dataset represents the two square meter vegetation surveys
 conducted at each site. Blank cells represent NA values for the sub-survey
 square meter. Each row represents 1 or 2 individual plants encountered in
 the sub-survey. Site.ID: unique site identifier for
 each site. EH=Eden Hall site, LT=Latodami, IR=Irwin Run<br>
 survey.1: barberry stem diameters for all stems encountered in the first
 square meter survey<br> survey.2: barberry stem diameters for all
 stems encountered in the second square meter survey<br> dry.mass.1:
 estimated dry mass of the corresponding barberry plant in the first
 sub-survey based on allometric equation in Link et al. 2018<br>
 dry.mass.2: estimated dry mass of the corresponding barberry plant in the
 second sub-survey based on allometric equation in Link et al.
 2018