Species Composition and Ecological Characteristics of Native Seed Mixes in the Midwest (USA)

Abstract

ABSTRACT The midwestern United States has a well-developed native plant industry with a wide variety of native seed mixes available to buyers, often for the purpose of ecological restoration. Despite the influence of seed mixes on site-level restoration outcomes, there has yet to be a comprehensive overview of seed mixes available in the Midwest. We characterized seed mix composition by analyzing a database of 1,031 commercially available native seed mixes. Our objectives were: 1) to describe the major types of seed mixes; 2) compare basic ecological characteristics of the seed mix types, including species richness, relative weights of graminoids, species’ wetland fidelities, and the blooming phenology of forbs; and 3) identify popular or “workhorse” species—species that are frequently and abundantly used in restorations. We identified six major types of seed mixes reflecting different habitat targets and soil moisture conditions: pollinator habitat, tallgrass prairie, wetland, wet prairie, dry prairie, and woodland/savanna mixes. Species richness was generally greatest for wetland mixes, whereas tallgrass prairie mixes were the most species-poor. Percent of seed mix weight which was graminoids was highest in tallgrass prairie mixes, whereas it was low in pollinator habitat mixes. The species composition of the mixes reflected a moisture gradient in the field from wetlands to dry prairies. Despite their infrequency, woodland/savanna mixes were distinct because they had many unique species, and the blooming phenology was markedly different due to the presence of earlier-flowering forbs. Popular species in midwestern seed mixes were generalist prairie species with inexpensive seed, including dominant C4 grasses and early successional, showy forbs. This study is a descriptive overview of the current state of native seed mixes in the Midwest and suggests that most mixes consist of standard components of target communities.