PS 19-261 - Minding the gap: Restoration seed in the northern Great Plains

Abstract: Like most ecosystems, the restoration of prairies in North America’s northern Great Plains region relies on seeds. The native seed market in this region, however, is not well developed with few seed suppliers, low species representation, low inventory of available seeds, and seeds with unknown provenances. Evidence suggests that for some plant species, nonlocal provenances are not always adapted to local climatic conditions potentially leading to outbreeding depression (if there is some extant population remaining) or poorly adapted populations (if there is no extant population remaining). However, in our region, local seeds or even seeds produced or collected within our very broad seed transfer zones are often not available. This insufficient supply of seeds can be a roadblock to ecological restoration efforts within the region. A recent restoration project identified 287 grass, sedge, and forb species suitable for restoration in an upland prairie site in eastern South Dakota. However, after a comprehensive search of commercially available seed, it was discovered that a sizable portion of the species targeted for restoration was not available within our seed transfer zone, or even within our 12-state region. This study assesses native seed availability for species native to eastern South Dakota by conducting an extensive search for seeds within the entire northern Great Plains region.

We discovered that only 178 of the 287 species (62.0%) were commercially available. Forb species were the most underrepresented having 146 out of 242 species (60.3%) available followed by grasses with 22 out of 33 species (66.7%) available. Sedge species had better representation with 10 out of 12 species available (83.3%). Also, of the 178 available species, 103 species (57.9%) were produced or collected from 3 or more locations and only 7 species (3.9%) were produced or collected within the restoration site’s seed transfer zone. When the number of all available seed sources across all available species was summed, there were 603 total seed/sources combinations, however, only 306 of those combinations (50.7%) had provenances known at the county scale while the remainder had known provenances at larger, state or tri-state scales. We believe this experience underscores a need for the development of the native seed industry in the northern Great Plains, or more optimistically, highlights opportunities for native seed production in the region to better meet the seed demands of land managers and restoration practitioners.