10.5061/DRYAD.TQJQ2BVVK
Ortega, Yvette
0000-0003-2832-9724
Rocky Mountain Research Station
Dylewski, Łukasz
0000-0002-1370-7625
Polish Academy of Sciences
Bogdziewicz, Michał
Adam Mickiewicz University in Poznań
Pearson, Dean
0000-0001-7623-2498
Rocky Mountain Research Station
Data from: Seed size predicts global effects of small mammal seed
predation on plant recruitment
Dryad
dataset
2020
seed size
seed predation
Polish NSC Etiuda fellowship*
2018/28/T/NZ8/00264
Polish National Agency for Academic Exchange*
POWR.03.03.00-IP.08-00-P13/18
Rocky Mountain Research Station
https://ror.org/04347cr60
PI Salary
Polish NSC Etiuda fellowship
2018/28/T/NZ8/00264
Polish National Agency for Academic Exchange
POWR.03.03.00-IP.08-00-P13/18
2021-03-11T00:00:00Z
2020-12-18T00:00:00Z
en
https://doi.org/10.1111/ele.13499
84644 bytes
4
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
We conducted a global literature review and meta-analysis to evaluate
whether seed size could predict post-dispersal seed predator effects on
seed removal and plant recruitment, respectively. Datasets were built
using data extracted from published studies focusing on seed predation by
small mammals (see Methods for criteria and data extraction protocol). We
found that seed size predicted small mammal seed removal rates and their
impacts on plant recruitment consistent with optimal foraging theory, with
intermediate seed sizes most strongly impacted globally - for both native
and exotic plants. However, differences in seed size distributions among
ecosystems conditioned seed predation patterns, with relatively
larger-seeded species most strongly affected in grasslands (smallest
seeds), and relatively smaller-seeded species most strongly affected in
tropical forests (largest seeds). Such size-dependent seed predation has
profound implications for coexistence among plants because it may enhance
or weaken opposing life-history tradeoffs in an ecosystem-specific
manner. Our results suggest that seed size may serve as a key
life-history trait that can integrate consumer effects to improve
understandings of plant coexistence.
We conducted a global literature review to obtain data related to small
mammal effects on plant species, as measured in each of two types of
studies - each producing a separate dataset included in this archive.
First, we examined studies wherein researchers offered seeds in the field
to quantify seed removal rates by post-dispersal seed predators. Second,
we evaluated experiments wherein researchers sowed seeds in paired cages
that allowed or precluded seed predator access in order to quantify
post-dispersal seed predator effects on plant recruitment. To obtain
studies that quantified small mammal seed removal rates and/or
experimentally evaluated the effects of seed removal on plant recruitment,
we first considered data from the global literature review conducted by
Moles et al. (2003; Ecology, 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., Acer, Fraxinus) 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, for seed removal studies, 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 >1 plant species to control for such
variation. We did not impose this restriction on plant recruitment
studies given that such studies were limited in number, but exclusion of
single-species studies did not alter meta-analysis results (Appendix S1).
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/). For seed removal studies,
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. For studies of seed
predator effects on plant recruitment, we extracted data on the mean
number of seedlings or proportion of seedlings recruiting per species,
associated measures of variation (SD or SE), and sample size for both
small mammal exclusion (treatment) and small mammal access plots
(control). In studies reporting small mammal effects multiple times per
species, we selected one estimate (for reasons noted above) using the
following criteria. For studies reporting effects over multiple years
and/or ecological contexts, we selected the scenario with the highest
overall recruitment in the control plots to maximize potential to detect
seed predator effects. The exception to this rule was that in studies
including both disturbed and undisturbed treatments, we used data only
from disturbed treatments to exclude effects of plant competition, which
can vary by seed size. 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.
Small mammal seed predation x seed size datasets. All variables included
in the two datasets are detailed on the README tab associated with each
file. Please note that the seed removal dataset was updated to rebut
a technical comment by Chen et al. (2021). The updated seed removal
dataset is associated with a separate Dryad archive
(https://doi.org/10.5061/dryad.hqbzkh1fp).