The thin green line: sustainable bioenergy feedstocks or invaders in waiting

Abstract

Numerous fast growing and highly competitive exotic crops are being selected for production of renewable bioenergy. Tolerance of poor growing conditions with minimal inputs are ideal characteristics for bioenergy feedstocks, but have attracted concern for their potential to become invasive. Miscanthus × giganteus is one of the most promising bioenergy crops in the US, but grower adoption is hindered by high establishment costs due to sterility. Newly developed fertile tetraploid M. × giganteus may streamline cultivation while reducing establishment costs. However, fertile seed dramatically increases the potential propagule pressure, and thus probability of off-site plant establishment. To empirically evaluate the invasive potential of fertile M. × giganteus in the Southeastern US, we compared fitness and spread potential relative to ten grass species comprising 19 accessions under both high and low levels of competition and disturbance. We chose species known to be invasive in the US (positive controls: Arundo donax, naturalized M. sinensis, M. sacchariflorus, Phalaris arundinacea, Sorghum halepense) and non-invasive (negative controls; Andropogon gerardii, ornamental M. sinensis, Panicum virgatum, Sorghum bicolor, Saccharum spp.). This novel design allows us to make relative comparisons of risk among species with varying invasiveness. After three years of establishment and growth in Blacksburg, Virginia, neither aboveground disturbance nor interspecific weed competition influenced fitness for fertile M. × giganteus or our positive and negative control groups. Fertile M. × giganteus produced 346% and 283% greater aboveground biomass than our positive and negative species, respectively. However, fertile M. × giganteus produced 74% fewer inflorescences m -2 than our positive controls and 7% and 51% fewer spikelets inflorescence -1 than the positive and negative control species. After 18 months of growth, we observed the vegetative and seedling spread of three of our positive control species (S. halepense, P. arundinacea, and M. sacchariflorus) Smith et al. / NeoBiota 25: 47-71 (2015) 48 into receiving areas of both high and low competition. After 24 months of growth, numerous species were observed outside the cultivated plot including fertile M. × giganteus and 50% of negative control species. Notably, in three years sterile M. × giganteus 'Illinois' and Arundo donax never moved from the cultivated plot. The addition of fertile seed appears to increase the potential for offsite movement, but within the geographic confines of our empirical evaluation, fertile M. × giganteus seedlings are more similar to native P. virgatum and were not nearly as fast growing or as competitive as our positive control S. halepense. The use of numerous species providing relative comparisons allow us to draw important conclusions which may help prepare for widespread commercialization, while providing novel methodology for ecological risk assessment of new species.

Troubling travellers: are ecologically harmful alien species associated with particular introduction pathways?

“…A modified version of this general framework has recently been adopted by the UN Convention on Biological Diversity (CBD 2014). Some pathways are increasingly well studied, such as horticulture and forestry as a source for plant invasions (Mack and Erneberg 2002, Dehnen-Schmutz et al 2007a, b, Hanspach et al 2008, Dawson et al 2009, Pyšek et al 2009, Smith et al 2015, Pergl et al 2016a, ballast water transport and aquaculture disseminating aquatic invaders (Galil et al 2009, Mizrahi et al 2015, live plants and plant products introducing pest insects and plant diseases (Roques 2010, Bacon et al 2012, Liebhold et al 2012, Eschen et al 2015a, as well as snails (Bergey et al 2014) and spiders (Nentwig 2015), the aquarium trade (MacedaVeiga et al 2013, Chucholl 2013, tourism (Anderson et al 2015), the pet trade for terrestrial vertebrate invaders (Duncan et al 2003, van Wilgen et al 2010, GarciaDiaz and Cassey 2014, and -more generally -the online trade (Kikillus et al 2012, Humair et al 2015. However, the role of pathways related to unintentional introductions has been difficult to quantify (Lee and Chown 2009, Pyšek et al 2011, Bacon et al 2012.…”

Black, Grey and Watch Lists of alien species in the Czech Republic based on environmental impacts and management strategy

“…It has been suggested that the traits of an ideal biofuel species are the same as those favouring invasiveness (Raghu et al 2006, Buddenhagen et al 2009, Smith et al 2015. Some of the biofuel species (Arundo donax, giant cane; Psidium cattleianum, cattley guava) are even listed among 100 of the worst global invaders of the IUCN (Lowe et al 2000).…”

Інвазійні Чужорідні Патогени Як Загроза Глобальному Біорізноманіттю

“…Нещодавно модифікований варіант цієї загальної класифікації був адаптований Конвенцією про біологічне різноманіття (CBD, 2014). Деякі шляхи інвазії патогенів дуже добре досліджені, особливо декоративне садівництво та лісове господарство (Mack, & Erneberg, 2002;Dehnen-Schmutz, Touza, Perrings, & Williamson, 2007a, 2007bHanspach, Kühn, Pyšek, Boos, & Klotz, 2008;Dawson, Burslem, & Hulme, 2009;Pyšek, Křivánek, & Jarošík, 2009;Essl, Dietmar, Dullinger, Mang, & Hulme, 2010;Smith, Allen, & Barney, 2015;Pergl et al, 2016aPergl et al, , 2016b.…”