DOI: 10.25338/b8xs8t
title: Intraspecific diversity poorly predicts invasibility and invasiveness in communities: A meta-analysis of experimental invasions

description: Identifying the biotic factors underlying invasion success into existing
 communities is critical to understand the dynamics of biological
 invasions; and while some studies suggest that intraspecific diversity may
 play an important role, there has not been a systematic evaluation of the
 evidence. We performed a meta-analysis on 37 experimental studies and 109
 effect sizes to test two hypotheses: (1) higher intraspecific diversity in
 a resident population decreases the likelihood of it being successfully
 invaded by other species, and (2) higher intraspecific diversity in an
 invading population increases its ability to invade another species or
 community. We found heterogeneous effects among studies and that overall
 resident genetic diversity has a very small, non-significant negative
 effect on invasion success, while invader genetic diversity has a small,
 non-significant positive effect. The minimal impact of intraspecific
 diversity is somewhat unexpected, given the well-understood mechanisms
 analogous to those offered for interspecific diversity. These include
 sampling effects and complementarity, in which diversity is expected to
 maximize resource use and increase density, thereby reducing niche
 availability and subsequent invasibility. We recommend that future
 research focus on a wider diversity of organisms, include longer term
 experiments, and measure genetic dissimilarity to better understand the
 role of intraspecific diversity.
description: # Data from: Intraspecific diversity poorly predicts invasibility and
 invasiveness in communities: a meta-analysis of experimental invasions We
 performed a meta-analysis of experimental studies that manipulate
 intraspecific genetic or phenotypic variation of a resident or invader
 species. The dataset of 109 effect sizes was collected from 37 studies. We
 recorded invasion success and other study characteristics including:
 whether the species varying in genetic diversity was the resident or the
 invader, the context of the experiment depending on whether it was
 conducted in a controlled lab setting, semi-natural enclosures, or in the
 wild, and the taxon as either plant, microbe, or invertebrate, the length
 of the experiment as the estimated number of generations of the
 genetically variable species, and the number of genotypes used in the
 variable treatments. ## Description of the data and file structure The
 data for this study is the file Invasion_review_table_11_2024.csv and the
 code to run the analysis and reproduce figures is the file
 metafor-invasion-11_2024_R1.R * Variables: * ID: two digit code for the
 paper identifier. * author: Authors of the paper. * Year: year (YYYY) that
 the paper was published. * poly_treat: description of the genetically
 variable treatment, either the number of genotypes or a qualitative
 description. * species: name of the species that is genetically variable.
 * genotypes.variable: which competitor was genetically variable, either
 the "invader" or the "resident". * data_location:
 location in the paper where the data was retrieved. * data_type: whether
 the data was provided directly "raw" or digitized from a figure
 "digitized". * variable: a description of the response variable
 of interest relating to invader success. * N_total: N_control + N_poly *
 N_control: sample size of control treatment. * N_poly: sample size of
 polyculture treatment. * mean_control: mean value of the response variable
 in the control treatment. * mean_poly: mean value of the response variable
 in the polyculture treatment. * sd_control: standard deviation of the
 response variable in the control treatment. * sd_poly: standard deviation
 of the response variable in the polyculture treatment. * number_gen:
 number of generations of the focal species- for annual plants this is
 often =1. * lab_wild: the environmental context of the experiment. *
 taxon: the taxonomic category of the species in the experiment. * Ni: the
 number of samples in the study, note this includes all polyculture
 treatments in the study not just the one highlighted in this row. * study:
 a unique identifier for the study. If there are multiple studies within a
 single paper there are multiple "studies" for a given paper
 "ID". * status: whether the genetically variable introduced
 species is native (N), invasive (I), or unknown (U). "NA" is
 recorded for studies in which the resident is genetically variable. ##
 Code/Software R code to run the meta-analysis and reproduce the figures
 are in "metafor-invasion-11_2024_R1.R" ## Version changes
 04-July-2024: Added one additional row for a newly found study that was
 incorporated into the meta-analysis. 05-Mar-2025: Added a column for
 invasive status to the Invasion_review_table_11_2024.csv and corresponding
 statistical test of the effect of invasive status in the R code. Added two
 additional rows for newly found studies that were incorporated into the
 meta-analysis.  Corrected missing entries for column H (rows 106 and 107).