Data from: Testing weed risk assessment paradigms: intraspecific differences in performance and naturalisation risk outweigh interspecific differences in alien Brassica
Meffin, Ross, Lincoln University
Duncan, Richard P., University of Canberra
Hulme, Philip E., Lincoln University
Published Jul 24, 2018 on Dryad.
Cite this dataset
Meffin, Ross; Duncan, Richard P.; Hulme, Philip E. (2018). Data from: Testing weed risk assessment paradigms: intraspecific differences in performance and naturalisation risk outweigh interspecific differences in alien Brassica [Dataset]. Dryad. https://doi.org/10.5061/dryad.p48k7
1.Risk assessments of alien species are usually conducted at species level, assuming that all individuals of a given species pose similar risks. However, this may not be the case if there is substantial within-species variation that could influence invasion success.
2.We used a seed addition experiment, comprising 25 taxonomically stratified varieties of three Brassica species introduced to roadside habitats in Canterbury, New Zealand, to quantify variation in performance among species, subspecies and varieties. We aimed to assess if species was the most appropriate taxonomic level at which to evaluate invasion risk.
3.Differences among varieties within species explained approximately 30 times more of the variation in performance (number of individuals/quadrat) than differences among species. Some of the variation among varieties was attributable to differences in seed viability.
4.Nevertheless, differences among taxonomic groups explained only 7% of the total variation in performance; 28% was attributable to differences among plots, reflecting broad-scale environmental variation, while 65% was attributable to differences among quadrats nested within plots, highlighting the importance of fine-scale variation in the availability of suitable microsites.
5.Policy Implications. Our seed addition experiment quantified variation in performance of 25 taxonomically stratified Brassica taxa introduced to roadside habitats. Varieties (nested within species) differed in performance far more than did species. This suggests risk assessments carried out at species level may overlook important subspecific variation in invasion risk. This is particularly true for conventionally bred and genetically modified species, which may contain taxa posing risks different to that at which the species is assessed. Consideration should be given to subjecting unassessed subspecies and varieties of plants to risk assessments similar to those applied to species.
Seed sowing experiment
Data recording counts from seed sowing experiment of 25 Brassica species in Canterbury NZ. Also includes biotic and abiotic covariate data.
Seed survival data, after burial for 1 year. Wholed = dead seed, wholea = alive seed
Climatic data for each plot in the seed sowing experiment. Mean: winter precipitation, summer precipitation, January temp, July temp and annual temperature.
common garden 2
Second seed sowing experiment (2012). Includes 2 x propagule pressure treatments (25 and 250 seeds per 25 x 25 cm plot) and 2 disturbance treatments (u = control, d= all vegetation removed from plot with mattock prior to sowing)
viability data for seed used in seed sowing experiments
Seed weight data for seeds used in sowing experiments
Species, subspecies and variety of the 25 taxa used in the seed sowing experiments. Species ID field links to other data sets in this package.