Legumes are valued for improving forage quality and quantity; however, grazing can cause taller legumes like Medicago spp. to decline and favour shorter, grazing-tolerant Trifolium spp.. Long-term retention of beneficial legumes requires periodic recruitment from the seed bank. Hard seed coats enable legume seeds to stay dormant until suitable conditions develop. In theory, microsite availability for legume recruitment could be manipulated through management; for example, grazing can regulate the amount of competing vegetation and litter covering the soil, which in-turn modifies light intensity, soil moisture and soil temperature. We designed a legume demography study that tracked seedling emergence, survival and persistence of individual seeds from 6 legume species in 4 microsites that reflected contrasting management conditions. Microsite conditions were altered by removing litter, defoliation, litter removal plus defoliation, or left untreated. The legumes tested included 2 tame forage species [white clover (Trifolium repens) and alfalfa (Medicago sativa)], 2 invasive legumes [cicer milkvetch (Astragalus cicer) and sweet clover (Melilotus officinalis)], and 2 native species [purple prairie clover (Dalea purpurea) and American vetchling (Vicia americana)]. Legumes were planted in 40 x 40 cm plots under all conditions (4 Replicates of each) in both native and tame grasslands at two locations (Aspen Parkland and Mixedgrass Prairie). We simulated recruitment within each plot from the seed bank by planting 40 legume seeds per plot in mid May of 2014 just below the soil surface. Each seed (N= 15,360 total) was glued to a toothpick for repeated assessment. The fate of individual seeds were subsequently monitored throughout the growing season until recruitment halted after heavy frost. The results of this study will provide information on the relative recruitment of different legumes in response to environmental conditions, and will highlight opportunities to promote (beneficial forages) or impede (invasive) legumes, depending on management objectives.Â
Oral presentation and poster titles, abstracts, and authors from the Society for Range Management (SRM) Annual Meetings and Tradeshows, from 2013 forward.