DOI: 10.5061/dryad.d136v
title: Data from: Linking native and invader traits explains native spider population responses to plant invasion

description: Theoretically, the functional traits of native species should determine
 how natives respond to invader-driven changes. To explore this idea, we
 simulated a large-scale plant invasion using dead spotted knapweed
 (Centaurea stoebe) stems to determine if native spiders’ web-building
 behaviors could explain differences in spider population responses to
 structural changes arising from C. stoebe invasion. After two years,
 irregular web-spiders were &gt;30 times more abundant and orb weavers
 were &gt;23 times more abundant on simulated invasion plots compared
 to controls. Additionally, irregular web-spiders on simulated invasion
 plots built webs that were 4.4 times larger and 5.0 times more likely to
 capture prey, leading to &gt;2-fold increases in recruitment.
 Orb-weavers showed no differences in web size or prey captures between
 treatments. Web-spider responses to simulated invasion mimicked patterns
 following natural invasions, confirming that C. stoebe’s architecture is
 likely the primary attribute driving native spider responses to these
 invasions. Differences in spider responses were attributable to
 differences in web construction behaviors relative to historic web
 substrate constraints. Orb-weavers in this system constructed webs between
 multiple plants, so they were limited by the overall quantity of native
 substrates but not by the architecture of individual native plant species.
 Irregular web-spiders built their webs within individual plants and were
 greatly constrained by the diminutive architecture of native plant
 substrates, so they were limited both by quantity and quality of native
 substrates. Evaluating native species traits in the context of
 invader-driven change can explain invasion outcomes and help to identify
 factors limiting native populations.
description: Spider
 AbundanceSpider abundances for
 the three studied species (Dictyna, Aculepeira, and Tetragnatha) across
 three sites on simulated invasion and control plots. Spider abundance was
 observed three times each year (June, July, August) over the two-year
 study (2011-2012).Spider
 MechanismsPotential mechanisms
 (web size, prey captures, and reproduction) leading to web spider
 community reassembly following Centaurea stoebe invasion. These mechanisms
 were experimentally evaluated in three focal web spider species (Dictyna,
 Aculepeira, Tetragnatha) over two summers (2011-2012) across three sites
 by comparing responses on simulated invasion and control
 plots.Spider
 web.prey.repro.xlsxWeb size
 2011Web sizes for Dictyna
 and Aculepeira across three sites over three sampling periods (June, July,
 August) in 2011. These data were used to evaluate if web size differed
 temporally and to justify pooling of web size data within a given
 year.Web
 2011.xlsxJuveniles
 2012The number of juvenile
 spiders (Dictyna, Aculepeira) observed across three sites on simulated
 invasion and control plots during 2012. These data were used to calculate
 recruitment (= # juveniles present in August 2012 / # reproductive females
 June 2012).Prey abundance
 2012Invertebrate prey was
 sampled via sweep netting in July 2012. These data show the total number
 of invertebrate prey per sweep net sample at three sites on simulated
 invasion and control plots. These data were used to evaluate the amount of
 available prey between plots.