Watered down seeds - cultivated seeds may reduce restoration efficacy
Written by Coleman Earnest, edited by Emma van der Heide
Summary
Native species abundance has historically been used as an indicator for restoration success, as a greater abundance of native species can lead to more robust and resilient ecosystems. Restoration projects often rely on seeds and plugs from domesticated native plants, which are more feasible to produce than the alternative wild, genetically diverse plant material. However, it is possible that cultivation could reduce genetic diversity in seeds and plant plugs, leading to less effective restoration of ecosystem function. Pizza et al. (2021) found that native cultivars of the species Deerhorn Clarkia (Clarkia pulchella) differed greatly from their wild-sourced counterparts after only eight generations. Cultivated plants were less likely to flower, had less variation in sprouting time, and had significantly lower fitness levels than their wild counterparts, indicating a need for more comprehensive analysis of native cultivars before they are used in restoration projects or sold to the public. Since native cultivars are still the most economical option for restoration projects and over-harvesting of wild plants can damage source populations, Pizza et al. (2021) suggest an increase in the number of metrics reported with native cultivar seed, including reproductive success and the number of generations it has been cultivated. Higher reproductive success and fewer generations from the wild-sourced seed are likely to lead to better restoration outcomes.
Take Home Points
Overharvesting of native plant material for restoration can damage the source population, limiting its possible use in restoration projects.
Native cultivars are cheaper and easier to obtain than wild plant material, but can lack the same genetic diversity of their wild counterparts.
Currently, certification of native cultivars is largely dependent on the metric of pure live seed. More research is needed on whether and how cultivation for seed influences establishment success and population growth for restoration.
Management Implications
Native cultivars may have reduced fitness and function when compared to their wild counterparts and should be observed carefully when used in restoration efforts to ensure that restored plant populations are able to persist.
Managers propagating native cultivars should consider including additional metrics with native seed, such as reproductive success and the number of cultivated generations, to better predict seed quality and genetic diversity.
Related Papers
Keywords
Management efficacy, Genetic diversity, Climate-smart conservation and restoration, Clarkia pulchella