Gain or pain? Biofuels and invasive species

Apr 2010

Most current biofuels are produced from food crops that are well understood and have been domesticated for centuries. However, many plant species that are currently being developed or considered for biofuels are potentially invasive. Whether species that are used, considered or developed as biofuel crops will become invasive depends on their ability to grow and spread in the conditions where they are used, hence the risk of invasiveness has to be determined on a local, eco-system level.
Several features have been found to be typical of crops that are invasive:
- Fast growth and ability to outcompete local vegetation
- Large and abundant seed production
- Tolerance to wide range of soil and climate conditions
- Adaptability to a wide range of soils and climates
- Resistance to pests and diseases
- Lack of predators in the recipient ecosystem
It is exactly for these features that potentially invasive species are being considered as biofuel feedstocks as they may make them more resource efficient, which may ultimately result in economic and to some extent environmental benefits linked to reduced competition for land and other resources.
This is of particular relevance to advanced biofuels – including so called second generation biofuels – as they can be produced from biomass from a wide range of fast growing ligno-cellulosic feedstocks and inedible plant oils, many of which featuring on the list of potentially invasive species, such as Arundo donax, Panicum virgatum, and Prosopis spp. Potential benefits in terms of productivity gains need to be weighed against the greater risk of becoming invasive and causing damage to ecosystems, livelihoods and the economy.
It is considered likely that the cost of an invasion by a biofuel feedstock or associated pest would, in the long-run overweight any economic benefit offered by biofuel development. The potential benefit of introducing new species as biofuel feedstocks should thus be weighed against the potential of those species to cause serious harm to biodiversity, local livelihoods and national economies.
While this paper has focused on feedstock for biofuels, it is important to consider that potential invasiveness may also be an issue for species considered for bioenergy more generally, such as fast growing trees and shrubs.

By: UNEP, WCMC, IUCN

 
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