Correction: Long-Term Regional Shifts in Plant Community Composition Are Largely Explained by Local Deer Impact Experiments.

[This corrects the article DOI: 10.1371/journal.pone.0115843.]

Vegetation and environmental data from deer exclosures in the Upper Midwest

Vegetation data include sapling basal area and proportion of quadrats where each species was found (> 5% abundance) as well as several species groups that were developed by adding together all relevant species frequencies. Environmental data include soil physical and chemical properties, coarse woody debris, canopy conditions and earthworm invasion levels

Ixodes scapularis density in US temperate forests shaped by deer, earthworms, and other disparate factors at two scales

Dataset to accompany Ecosphere article: Ixodes scapularis density in US temperature forests shaped by deer, earthworms, and other disparate factors at two scalesForest and wildlife management can help regulate the risk of human exposure to tick-borne pathogens by influencing the population density of host-seeking ticks and the pathogen infection prevalence in tick populations. For the blacklegged tick (Ixodes scapularis), also known as the deer tick, the overall density of host-seeking nymphs and the density of nymphs infected with Borrelia burgdorferi sensu stricto (which causes Lyme disease) are often closely and positively correlated. We sought to identify biotic and abiotic factors influencing nymph abundance in a multiscale assessment within and across forested landscapes in northern Wisconsin. On a set of randomly located plots within each of six mesic, hardwood-dominated forests, we collected host-seeking and on-host ticks, observed two common mammal hosts (white-tailed deer and mice), and characterized the structure and composition of the forest plant community. We also surveyed activity of exotic invasive earthworms, which are altering forest structure in the region. At the broader forest-level scale (n = 6), nymphal tick abundance was positively related to deer population density after accounting for the negative influence of forb cover. At the finer plot-level scale (n = 87), nymph abundance was positively correlated with the abundance of coarse woody debris and negatively correlated with the density of earthworm castings, an indicator of Lumbricid (nightcrawler) activity. Thus, we identified a suite of key factors, operating at different spatial scales, that shape thesuitability of forest habitat for questing immature ticks. These findings inform our basic understanding of blacklegged tick ecology and also have important implications for managing tick-borne pathogens in forest ecosystems and landscapes

Results from ANOVAs of shrub abundance.

<p>The Table shows F-values for predictor variables of shrub-line intercept values (log-transformed) with site, exclosure and their interaction as factors.</p><p>Results from ANOVAs of shrub abundance.</p

Differences in species abundances in- and outside deer exclosures.

<p>Abundance values reflect the incidence of species across quadrats in the control and exclosure plots. We judge whether species are more abundant in or outside exclosures from the χ² and significance values for the differences observed. No significant differences in abundance were observed in: <i>Acer saccharum</i>, <i>Dryopteris intermedia</i>, <i>Prunus serotina</i>, <i>Anemone americana</i>, <i>Eurybia macrophyyla</i>, <i>Taraxacum officinale</i>, <i>Aralia nudicaulis</i>, <i>Fraxinus pensylvanica</i>, <i>Tilia americana</i>, <i>Arisaema triphyllum</i>, <i>Maianthemum canadense</i>, or <i>Trientalis borealis</i>. ***p<0.001, **p<0.01, *p<0.05.</p><p>Differences in species abundances in- and outside deer exclosures.</p

Effects of deer on plant reproduction.

<p>Bars compare the total number of reproductive individuals encountered for 11 focal species between the exclosure (protected from deer) and the control plots (accessible to deer). These species differ significantly between treatments in the χ² analyses.</p

Species that significantly increased (“Winners”) or decreased (“Losers”) in abundance over the past 50+ years in the study area [33].

<p>*enumerated in other studies - see text.</p><p>Species that significantly increased (“Winners”) or decreased (“Losers”) in abundance over the past 50+ years in the study area <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115843#pone.0115843-Wiegmann1" target="_blank">[33]</a>.</p

Effects of deer on plant height.

<p>Bars compare the mean maximum leaf heights of four focal species between the exclosure (protected from deer) and browsed plots (accessible by deer) as measured by the logarithm of their proportional differences. Depicted species differ significantly between treatments in a mixed model ANOVA using exclosure as the main effect and site as a random effect. <i>Mitchella</i>, <i>Eurybia</i>, and <i>Diervilla</i> have declined in the region over the past 50 years.</p

Map of study sites.

<p>Exclosure and browsed plots are located in Northern Wisconsin and the Upper Peninsula of Michigan in forests dominated by sugar maple with a hemlock component.</p