Evaluation of the population dynamics of the forage legume Lotus corniculatus using matrix population models

The population dynamics of perennial crop plants are influenced by numerous factors, including management practices. Conditions in the field vary from year to year, and matrix population models are useful for evaluating popul ation behaviour in relation to environmental variability. In Missouri, the stand persistence of birdsfoot trefoil (Lotus corniculatus), a perennial le gume, is often limited by disease and poor seed production. A stage-based, matrix population model was developed to evaluate the population dynamics o f birdsfoot trefoil in relation to clipping treatment. The plant growth sta ges represented in the model were seeds, seedlings, mature vegetative and r eproductive plants. Two phases of population growth were evaluated in clipp ed and unclipped stands. Establishment-phase populations were characterized by relatively high mortality and low reproduction. Elasticity analysis ind icated that growth of these populations was most sensitive to the survival of vegetative plants. Mature vegetative plants and seeds comprised the majo rity of surviving individuals in clipped and unclipped populations, respect ively; however, establishment-phase populations under both management treat ments tended toward extinction. Populations in the post-establishment phase of growth were characterized by relatively low mortality and high reproduc tion. Population growth in this phase of growth was most sensitive to seed production, and most individuals in these populations were at the seed stag e.