DOI: 10.5061/dryad.042nm
title: Data from: Earthworm invasion, white-tailed deer and seedling establishment in deciduous forests of northeastern North America

description: 1. Earthworm invasions and high deer populations are among many stressors
 threatening long-term population viability of forest understorey plants in
 northeastern North America. Stressor effects are typically tested one at a
 time, however, stressors often co-occur, and plants respond to effects of
 multiple stressors simultaneously. 2. We used a factorial design to test
 independent and combined effects of non-native earthworms and native
 white-tailed deer on survival of seedling transplants of 15 native
 understorey plants in 5 forests in New York State. 3. Earthworm biomass
 was negatively correlated with survival of 12 of 15 species. We found no
 interactive effect of deer and earthworms, but did find a positive,
 non-consumptive effect of deer on Geranium maculatum and P. virginianum
 survival. 4. Deer and earthworm presence/absence indirectly influenced
 other trophic levels: earthworm presence increased the likelihood of
 insect attack, and deer exclusion increased the likelihood of rodent
 attack disturbance of transplants. 5. Synthesis: Invasive earthworms
 negatively affected seedling survival of many understorey plants,
 including species previously thought to benefit from earthworm
 associations. This effect was a function of earthworm biomass, a surrogate
 for earthworm activity. We expect deer herbivory to increase in
 importance, including indirect effects, as seedlings grow into browse
 height over the next years. Investigations of co-occurring stressors can
 result in ‘ecological surprises’ including previously overlooked
 non-consumptive effects or effects on other trophic levels.
description: Seedling survival model
 dataData were collected from
 five forested sites around New York State. We indicate the site, deer
 access (1=deer access, 0=fencing), and earthworm count and dry biomass
 (each data point from 10 50x50cm quadrats).We have included environmental
 measurements used in the models, such as pH, Leaf Area Index, slope, soil
 type and tree species richness. The survival of each species is indicated
 by column headers of species name (ie. Actaea), with 1 for surviving
 individuals and 0 for dead individuals. Finally, we list the initial
 measurements of each species at planting in the columns market with
 I.Species. For the majority of species, this is leaf width measured in cm.
 However, due to their growth forms, Carex was measured by # culms,
 Brachyelytrum by height (cm) and Fraxinus by leaf
 number.Dobson and Blossey_Raw
 data.csvRodent
 attackData were collected in
 2012, approximately 1 month after planting seedlings, and in spring 2013.
 We analyzed the data at the plot level, so each data point includes site,
 earthworm invasion status (Worm), and fencing (Deer). Rodent digs or
 browse are listed as Success, and the remaining untouched seedlings are
 listed as Failure.Dobson and Blossey_rodent
 attack_raw.csvInsect
 attackSee Rodent attack
 description for column information. Because insect attack can only be
 observed on living plants, we divided the actual number of insect attack
 events by proportion of seedlings surviving.Dobson and Blossey_insect
 browse_raw.csv