Invasiveness risk of biofuel crops using Jatropha curcas L. as a model species

Abstract

Biofuel crops are promoted as a climate friendly alternative to fossil energy. Yet environmental risks such as potential biodiversity loss are not always adequately considered. This might occur directly as a consequence of land-use change from natural systems to biofuel plantations, but also through invasive behavior of the biofuel species, as it might disperse and establish into adjacent natural systems. Therefore, there is a need to perform ex-ante invasiveness risk assessments including fi eld trials on new biofuel species before they get promoted and expanded on a large scale. This perspective uses Jatropha curcas L. as a model biofuel crop and reviews the biological traits and the circumstantial factors which may contribute to its invasive behavior. J. curcas has recently received much attention as a biodiesel 'wonder crop' and is being planted at large scale without scientifi c study on its invasiveness risk. We applied two risk assessment frameworks to provide an ex-ante invasiveness risk assessment and obtained that J. curcas is a species with a high invasiveness risk, which is in contradiction with recent experimental evidence. We discuss the limitations of the available risk assessment frameworks, which may have led to unreliable prediction. We interpret the outcome of this theoretical exercise with some recommendations for the selection, introduction, cultivation, and processing stages of J. curcas and other biofuel crops to minimize invasiveness risk. Finally we point to the responsibilities of investors and governments and the need for integrated research of the whole biofuel production supply chain to avoid bio-invasions.

Insufficient Evidence of Jatropha curcas L. Invasiveness: Experimental Observations in Burkina Faso, West Africa

“…The risk of biofuel plants becoming invasive has been discussed in recent papers [9][10][11][12][13]. Yet, few studies have sought to determine the invasiveness potential of biofuel species in the tropics and subtropics (e.g., [12,14,15]).…”

“…Ecological risk assessments through in situ field experimental research studies are considered effective at assessing the invasiveness risk of biofuel crops in the field [12,13,20]. This in situ fieldbased invasiveness evaluation approach may also help to regulate and design adaptive management strategies and mitigations in the cultivation of those currently adopted biofuel crops [21,22].…”

“…The plant has been widely utilized nationwide in Burkina Faso at least for the last 300 years. At present, due to the increasing popularity of the species, there is a strong pressure to intensify cultivation in tropical and subtropical regions including West Africa [13,31]. However, reports have mentioned the risk of invasion and associated damage as a result of land use conversion to J. curcas plantations [9,15,17,32,33].…”

“…In these regions, the species might flower and seed twice per year, thus increasing the probability of a higher seed production and subsequent invasiveness. The other explanation is that ecological traits of the species could vary geographically as a result of plasticity to habitat conditions where the plant species is introduced [13,46].…”

“…Despite the high importance of WRA conclusions [18,19,44] in predicting the spreading risks of alien crops, WRAs need to be combined with ecological field experiments to reach reliable decisions, particularly in the context of bioenergy decisions [13,51,52], which this study aims to provide empirical evidence to substantiate the widely recognized weed risk assessment models using field experiments. Quality ecological data from in situ ecological experiments and field surveys such as current population size, seed production rate, seed size, dispersal ability, dispersal vectors, and after dispersal fate of the seeds would be important data in establishing the future invasion risk of potential alien tropical biofuel crops [13,20,53].…”