Bioenergy and invasive plants in Italy
The increasing energy consumption of industrialized countries, economic and political instabilities affecting global energy supply and pollution from the use of non renewable fuels have led to the development of renewable energies consisting of the cultivation of agro-forest species for energy production. Many of the characteristics of these bioenergy plants coincide with those of invasive plants: efficient reproduction, short regeneration period, high spread potential, persistence of seeds, etc. Great care should therefore be taken when choosing alien species to be cultivated for bioenergy.
Miscanthus sinensis (Poaceae) and the hybrid Miscanthus x giganteus (Poaceae) are proposed for growing as bioenergy plants in Italy. The former is considered invasive in many countries while the latter is an allopolyploid species reproducing very efficiently vegetatively and suspected to have the potential to become invasive. Other species such as Panicum virgatum (Poaceae), Crambe abyssinica (Brassicaceae), Kochia scoparia (Brassicaceae) are also proposed as bioenergy plants although they are suspected to have the potential to be invasive.
Concerning tree and shrub species proposed as bioenergy plants, Robinia pseudacacia (Fabaceae) is well known as an invasive plant and the use of Acacia spp., such as Acacia saligna (Fabaceae), could represent an invasion risk.
In order to reduce the possible expansion into natural ecosystems of alien species planted over large areas for bioenergy production, Pest Risk Analyses on species proposed for plantation were considered necessary. The Italian Agency for the protection of the environment and for technical services (Environment Protection Department) is currently performing Pest Risk Analyses on the basis of the Australian Weed Risk Assessment (Pheloung et al., 1999) for some alien species present in the Lazio region and preliminary results are presented below:
|
Species
|
Weed Risk Assessment score
|
Known invasiveness
|
Species used for bioenergy
|
|
Aesculus hippocastanum (Hippocastanaceae)
|
-3: Accept
|
No
|
No
|
|
Ailanthus altissima (Simaroubaceae)
|
16: Reject
|
Yes
|
Yes
|
|
Carpobrotus edulis (Aizoaceae)
|
11: Reject
|
Yes, locally
|
No
|
|
Robinia pseudacacia (Fabaceae)
|
15: Reject
|
Yes
|
Yes
|
|
Sorghum halepense (Poaceae)
|
19: Reject
|
Yes
|
S. bicolor
|
|
Yucca gloriosa (Agavaceae)
|
-1: Accept
|
No
|
No
|
|
Zea mays (Poaceae)
|
3: Accept
|
No
|
No
|
|
Helianthus tuberosus (Asteraceae)
|
12: Reject
|
Yes
|
Yes
|
Sources
Crosti R, Forconi V (2007) [Expansion of biomass cultures on the Italian territory: unknown factors related to the introduction of alien species potentially invasive. In Proceedings of the Conference on Cultivations for bioenergy production and environment: Sustainability, diversity and conservation of the territory". Agency for the protection of environment and for technical services]. (in Italian) Roma. 117 pp. http://www.apat.gov.it/site/_contentfiles/00145000/145067_Atti_del_convegno_Colture_a_scopo_energetico_e_ambiente.pdf
Pheloung PC, Williams PA, Halloy SR (1999) A weed risk assessment model for use as a biosecurity tool evaluating plant introductions. Journal of Environmental Management 57, 239–251.