Global Bioenergy Perspectives: biofuel feedstocks and invasive species
A recent UNEP paper has focused attention on the risk of adopting invasive species as biofuel feedstocks without properly assessing and monitoring their impact on biodiversity.
Invasive species tend to be attractive as feedstocks because of characteristics like fast growth, tolerance to a wide range of soil and climate conditions and their resistance to pests and disease. This is especially the case for second-generation biofuels as they can be produced from a wide range of fast growing ligno-cellulosic feedstocks and inedible plant oils, many of which feature on the list of potentially invasive species, such as Arundo donax, Panicum virgatum and Prosopis spp.
Porsopis provides a cautionary tale. A number of species were introduced to Australia, Asia, and dryland Africa for fuelwood, fodder, shade, to improve soils and reduce soil erosion. Following the collapse of demand for Prosopis, many plantations were abandoned, without adequate management and eradication. Prosopis now covers millions of hectares in many countries in Africa and is severely impacting on grazing and traditional pastoralist livelihoods. The dense thickets have out-competed local species and lowered ground and stream flow levels in many watersheds.
So, potential gains of such species need to be weighed against the greater risk of becoming invasive and causing damage to ecosystems, livelihoods and the economy, the UNEP paper warns. It explains that this risk and resulting environmental, social and economic impacts can be minimized through prevention and mitigation measures. Guidance exists for measures at every stage in the supply chain and for governments as well as developers and investors. Appropriate tools and resources are mentioned in the paper.