Intraspecific diversity poorly predicts invasibility and invasiveness in communities: A meta-analysis of experimental invasions
Data files
Jul 12, 2023 version files 22.68 KB
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Invasion_review_table_06_2023.csv
19.72 KB
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README.md
2.96 KB
Jul 04, 2024 version files 24.37 KB
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Invasion_review_table_05_2024.csv
21.49 KB
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README.md
2.88 KB
Mar 05, 2025 version files 24.10 KB
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Invasion_review_table_11_2024.csv
20.56 KB
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README.md
3.54 KB
Abstract
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.
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).