Consequences of Seed Origin and Biological Invasion for Early Establishment in Restoration of a North American Grass Species

Abstract

Local, wild-collected seeds of native plants are recommended for use in ecological restoration to maintain patterns of adaptive variation. However, some environments are so drastically altered by exotic, invasive weeds that original environmental conditions may no longer exist. Under these circumstances, cultivated varieties selected for improved germination and vigor may have a competitive advantage at highly disturbed sites. This study investigated differences in early establishment and seedling performance between wild and cultivated seed sources of the native grass, Poa secunda, both with and without competition from the invasive exotic grass, Bromus tectorum. We measured seedling survival and above-ground biomass at two experimental sites in western Montana, and found that the source of seeds selected for restoration can influence establishment at the restoration site. Cultivars had an overall advantage when compared with local genotypes, supporting evidence of greater vigor among cultivated varieties of native species. This advantage, however, declined rapidly in the presence of B. tectorum and most accessions were not significantly different for growth and survival in competition plots. Only one cultivar had a consistent advantage despite a strong decline in its performance when competing with invasive plants. As a result, cultivated varieties did not meet expectations for greater establishment and persistence relative to local genotypes in the presence of invasive, exotic species. We recommend the use of representative local or regional wild seed sources in restoration to minimize commercial selection, and a mix of individual accessions (wild, or cultivated when necessary) in highly invaded settings to capture vigorous genotypes and increase the odds native plants will establish at restoration sites.

Poa secunda local collections and commercial releases: A genotypic evaluation

“…The four releases differed significantly from one another, consistent with phenotypic variation between P . secunda releases noted in previous studies [58,59]. High Plains and MT-1 diverged the least while Sherman and Opportunity differed from each other as well as High Plains and MT-1.…”

“…Concurrent with genetic differentiation among collections, previous studies found phenotypic differences as well. Herget et al [58,59] found that survival, biomass, seed size, days to emergence, and competitiveness with Bromus tectorum differed between the High Plains release and our local P . secunda collections.…”

Plant community response to switchgrass (Panicum virgatum) population source in establishing prairies

“…Cultivated varieties (cultivars) are products of deliberate selection on particular traits that, when grown in environments to which they are adapted, consistently express high values of those traits (Lesica and Allendorf 1999). Differences in performance between cultivars and non-selected strains have been documented in various species (Gustafson et al 2004, Jakubowski et al 2011, Schr€ oder and Prasse 2013, Herget et al 2015. Differences in performance between cultivars and non-selected strains have been documented in various species (Gustafson et al 2004, Jakubowski et al 2011, Schr€ oder and Prasse 2013, Herget et al 2015.…”

Natural Fecundity and Germination Characteristics of Selected Cyclopia (Honeybush) Species: Preliminary Findings

“…However, separation of a portion of a plant and selection under environmental conditions different from those operating in nature, overtime leads to cultivated plants becoming morphologically and physiologically modified relative to their wild counterparts (Paz & Vázquez-Yanes, 1998;Alexander, Cummings, Kahn, & Snow, 2001;Rojas-Aréchiga, Casas, & Vázquez-Yanes, 2001). Therefore, differences in morphological and physiological traits would be expected, and cultivated species re-integration in native environments may swamp natively growing species and alter community structure and function provided the conditions they are introduced to are uniform and encourage improved reproductive fitness (Herget, Hufford, Mummey, & Shreading, 2015). Monitoring of the cultivated species genotypes in native environments suitable for their grown and development is essential before conclusions can be drawn about their effectiveness over their native counterparts.…”

“…Cultivated species genotypes may not perform as good when grown in native or simulated wild environmental conditions, since they, may not have a competitive advantage at highly invaded areas compared to adapted wild species (Herget et al, 2015). However, morphological divergence from wild populations is likely genetically based or due to artificial selection since wild species retain their morphological features when cultivated (Rojas-Aréchiga et al, 2001).…”