Exploring the potential for riparian marginal lands to enhance ecosystem services and bioenergy production

Land is a limited and precious resource that is the primary source of materials and energy flows that humans use to produce food, energy, shelter, clothing, infrastructure, and other needs. This land also supports a myriad of other species. As human populations and material and energy demands have increased, pressure on land has also increased, resulting in the degradation of 60% of ecosystem services over the past 50 years. There is a need to find solutions that both provide the resources that humans need to thrive and also do not continue to degrade our land-based resources and the nonhuman species that inhabit them. Cultivation of perennial cellulosic crop species on marginal lands, particularly in riparian areas, holds the potential to provide feedstocks for bioenergy without competing for land used for food production, while also providing a variety of ecosystem services, such as habitat for wildlife, bank stabilization, and nutrient, pesticide, and sediment attenuation that could improve water quality. These benefits are discussed in greater detail in this chapter. Challenges and tradeoffs associated with cultivation of these plant species on marginal lands with the target of using them as feedstocks for energy conversion are also discussed. Further, when considering the life cycle energy and greenhouse gas emissions of a biofuel, there may be opportunities to reduce transportation-related impacts by utilizing waterborne transportation options proximate to riparian marginal lands. In this chapter the many and varied definitions of marginal lands are presented, along with the challenges created due to a lack of a consistent definition. The lack of a consistent definition may be somewhat unavoidable, but it presents challenges to systematic analysis of the full potential of pursuing bioenergy at the scale likely required to considerably contribute to renewable energy goals. In summary, pursuing bioenergy feedstock production on marginal lands could contribute to ecosystem services while providing renewable energy, but it is important to involve multiple stakeholders to ensure that benefits are realized.