Get reliable science

Non-native plants are a global concern in rangelands; typically, these species are undesireable because of their negative impacts on both native plant communities and ecosystem functions. Weedy species can reduce forage availability and quality, and affect other ecosystem functions such as carbon storage or plant diversity.  Cicer milkvetch (CMV) is an agronomic species that is beginning to grow in the native rangelands of southern Alberta. It was likely introduced from sown pasture where the plant is valued as a high-protein, bloat-free legume, but it is also a large competitive plant that may impact native species. This raises the question “how do we manage species that present both negative impacts on native grassland and positive impacts on forage?” To assess the trade-offs associated with this species I surveyed grassland patches with CMV, adjacent to these patches and 5 m from the patch.  I measured species cover, biomass of functional groups, forage quality, and soil carbon and nitrogen.  The presence of CMV increased total biomass and protein content, increased ecosystem carbon, but reduced grass biomass and plant species diversity.  The influence of this species appears to be limited to the patch itself, thus future consequences of this species in rangeland will depend on the growth of individual plants and the population. Balancing the multiple rangeland values affected by this plant will likely rest with individual land managers, but with a more comprehensive list of costs and benefits to multiple ecosystem services they will be able to make more informed decisions.