DOI: 10.5061/dryad.hqbzkh1fp
title: Data from: Seed predator effects on plants: moving beyond time-corrected proxies

description: Small mammals impact plant recruitment globally via size-dependent seed
 predation, generating a unimodal pattern across ecosystems. Chen
 et al. (2021) critiqued our seed removal analysis, advocating
 corrections for exposure time. We show in our rebuttal that such
 manipulations are unwarranted and argue for increased emphasis on plant
 recruitment metrics. This archive holds the updated seed removal
 dataset used for our rebuttal.
description: To construct the original dataset analyzed in Dylewski et al.
 (2020), we conducted a global literature review to obtain data related to
 small mammal effects on plant species.  The subject of this archive is
 specifically the seed removal dataset based on studies wherein researchers
 offered seeds in the field to quantify seed removal rates by
 post-dispersal seed predators.   To obtain studies that
 quantified small mammal seed removal rates, we first considered data from
 the global literature review conducted by Moles et al. (2003;
 <i>Ecology</i>, 84, 3148-3161).  We then supplemented these
 studies with more recent work (published from January 2002 through
 November 2019) by searching the Web of Science Core Collection for
 peer-reviewed studies using the search term combination: ("seed
 remov*" OR "seed predat*" OR "seed offer*") AND
 ("small mammal*" OR "rodent*" OR
 "granivor*").  We also screened studies found through this
 search for relevant citations. From this literature
 pool, we filtered studies based on the following criteria.  All studies
 considered for our evaluation were conducted in natural systems, i.e. not
 urban or agricultural settings.  In this definition, we included European
 grasslands, which are often sustained by mowing, and North American
 old-field systems, which are seral stages of post-agricultural systems
 returning to their natural state.  We focused on studies examining
 primarily seeds, not fruits, though studies incorporating seeds removed
 from fruits were included.  Likewise, seeds attached to well-developed
 samara or samara-like dispersal structures (e.g., <i>Acer</i>,
 <i>Fraxinus</i>) were excluded, as these adaptations can
 affect total diaspore mass and shape in ways that alter seed handling and
 removal.  Seed offerings above the ground surface were excluded.  Because
 consumer origins could influence outcomes (Parker et al. 2006), we also
 excluded studies where small mammal seed predators could be identified as
 introduced (e.g., from some island systems), as these were too few to
 address consumer origins in analyses.  In all cases, only studies that
 reported results by individual plant species could be included. 
 Additionally, given that study-level variables such as study design, seed
 predator community, and environmental context (e.g., background resource
 levels, competition, etc.) could have large effects on measured responses,
 we only included studies that provided data for &gt;1 plant species to
 control for such variation.   Data from qualifying
 studies were extracted directly from the text or tables of publications,
 or from figures using Web Plot Digitizer Version 4.0
 (https://automeris.io/WebPlotDigitizer/).  We obtained data on the
 proportion of seeds removed per plant species during seed removal trials. 
 In studies reporting multiple seed removal rates per species, we used the
 following rules to select one value (to overcome the complication of
 trying to account for non-independence among species x study replicates in
 models).  When seed removal studies presented data for multiple trials or
 time points per species, we used data from the last or longest reported
 time interval with one exception: if the removal rate approached 100% for
 multiple plant species (potentially truncating responses), we used the
 middle trial or median time point.  In studies presenting data for
 multiple sites or ecological contexts (e.g., variation by habitat,
 distance from habitat edge, or forest age), we randomly chose a single
 scenario.   Geographic and habitat information was
 recorded for all studies.  The latter was used to define the following
 ecosystem types: grasslands (including European grasslands and old-field
 systems as defined above), temperate forest, tropical forest, and other
 (e.g., desert, shrublands, coastal dunes).  Plant species provenance
 (i.e., native or exotic) was taken directly from the study when possible
 (most cases), and otherwise from the Plants of the World online database
 (Royal Botanic Gardens Kew 2020).  Seed mass data for studies from Moles
 et al.’s (2003) global review were obtained from Appendix I in that
 publication.  For remaining studies, we gathered seed mass data directly
 from the source publication or a related publication when possible (85% of
 cases).  If authors did not include seed mass, we obtained this
 information from the following published databases, prioritized in the
 order listed: Seed Information Database (Royal Botanic Gardens Kew 2019),
 LEDA for Northwest European flora (Kleyer et al. 2008), and Botanical
 Information and Ecology Network Database (Maitner et al. 2018).  In cases
 where multiple seed masses were given per species in a database, we chose
 the record from the most proximate geographic region, when given,
 otherwise we chose the first record listed.  Seed mass (+1) was natural
 log-transformed for analysis.  For our rebuttal to Chen et al.
 (2021), the original seed removal dataset from Dylewski et al. (2020) was
 updated as follows: 1) related data extracted by Chen et al. (2021) were
 incorporated, revised, and used to make new variables that accounted for
 seed exposure time, and 2) a few minor errors were fixed as described in
 Appendix S1 of our rebuttal.
description: All variables included in the dataset are detailed on the README
 tab within the file.