DOI: 10.5061/dryad.xsj3tx9cp
title: Impacts of rodent eradication on seed predation and plant community biomass on a tropical atoll

description: Invasive rodent eradications are frequently undertaken to curb island
 biodiversity loss. However, the breadth of rodents’ ecological impact,
 even after eradication, is not always fully recognized. For example, the
 most widespread invasive rodent, the black rat (Rattus rattus), while
 omnivorous, eats predominantly seeds and fruit. Yet, the effects of seed
 predation release after eradication on plant communities and ecological
 functions are not well understood, posing a gap for island restoration. We
 examined the role of seed predation release following black rat
 eradication in changes to tree composition and above-ground biomass across
 an islet network (Palmyra Atoll) in the Central Pacific. We conducted
 repeated surveys of seed, juvenile, and adult tree biomass and survival in
 permanent vegetation plots before and after the eradication of rats. We
 observed a 95% reduction in seed predation for an introduced, previously
 cultivated tree population (Cocos nucifera). Juvenile tree biomass of all
 species increased 14-fold, with C. nucifera increasing the most,
 suggesting that eradication increased this tree’s competitive advantage.
 Indeed, based on stage-structured demographic models, rat eradication led
 to a 10% increase in C. nucifera population growth rate. The effect of
 invasive rodent seed predation varies considerably among the plant species
 in a community and can shift competitive dynamics, sometimes in favor of
 invasive plants. These bottom-up effects should be considered in
 evaluating the costs and benefits of eradication.  Documenting
 the variation in invasive rodent diet items, along with long-term surveys,
 can help prioritize island eradications where restoration is most likely
 to be successful.  
description: Datasets and scripts included in the final archive are stored in
 the following subfolders. We include brief descriptions below and more
 detailed descriptions are available in a .docx file contained in each
 subfolder. 1) "biomass_seedlings_and_future":
 This folder contains data and a .R script to convert sizes and ages to
 biomass for all tree species and age classes in our dataset and uses the
 resulting biomass data with a stage-structured demographic model to
 predict how rat eradication influenced plant community biomass.
 2) "dem_model_transition_stats": This folder contains
 data and a .R script to examine whether seed survival and germination,
 seedling survival and transition to adulthood (all vital rates in our
 stage-structured demographic model) were influenced by the loss of rat
 seed and seedling predation and herbivory.  3)
 "forest_cover_percents": This folder contains data and a .R
 script to look at the forest cover of Palmyra Atoll, including GIS shape
 file layers of both canopy types and the locations of permanent vegetation
 plots used in this study. 4)
 "seedling_nut_lmes": This folder contains data and a .R script
 used to build generalized linear mixed effects models on seed numbers on
 the ground with and without rat seed predation and also includes several
 supplemental datasets and models we used to compare seedling counts across
 years, precipitation effects that may confound rat effects, and the number
 of seeds counted in the canopy across sampling years. <br>
  
description: These data and scripts were used to build the analyses for the
 main text and supporting information for this manuscript. See the
 README.txt document for descriptions and each folder's content
 descriptions (.docx) for more detailed information on data and scripts. We
 encourage the user to contact the corresponding author (Ana Miller-ter
 Kuile, ana.miller-ter.kuile@lifesci.ucsb.edu) with any additional
 questions regarding data usage.