Using seedling phenotypic traits to select local seed sources for large-scale restoration: methods and outcomes in a Great Basin case study

Abstract

Establishing plants from seed is often a limitation to restoration success in semi-arid systems. For restoration purposes, managers can either use widely-available commercial seeds, which are often sourced from far outside the seeding area, or take extra steps to use locally collected seeds. If local seeds have traits more conducive to seedling establishment in degraded sites, they could increase restoration success. Here, we asked whether wild-collected seeds of two native perennial grasses, Elymus elymoides and Poa secunda, had more favorable characteristics than commercial sources. Seeds were collected from four populations within the Winnemucca District of the Nevada Bureau of Land Management, which manages lands within the Great Basin, US. Collections were screened for seed and seedling characteristics associated with increased plant performance in invaded Great Basin systems, and we provide a detailed methodology for these measurements. Relative to commercial seeds, wild-collected seeds had more characteristics identified as beneficial for seedling establishment including earlier emergence, higher specific root length, more root tips, and smaller overall size (E. elymoides), and earlier emergence, longer roots, higher root mass ratio, and more root tips (P. secunda). Commercial sources had significantly larger seeds than wild populations, a trait that had mixed effects on performance in previous research, and one that may change as wild collections are increased in agronomic conditions. These results suggest that locally-sourced populations are more likely to perform well in invaded areas, providing support for efforts to collect, screen, and increase local sources of seeds to improve restoration success. Implications for PracticeO_LICollecting and increasing local seeds requires more time and effort than purchasing commercially-available seeds, but if these sources have a greater chance at surviving in restoration sites, this effort is warranted C_LIO_LIIn our study, remnant local populations possessed more potentially adaptive traits than commercially-available alternatives, indicating they may be superior sources for the restoration of disturbed sites in their local regions C_LIO_LIScreening multiple seed sources for potentially adaptive seed and seedling traits can be a relatively quick and effective way to select the most promising seeds for increase C_LI