The blue eucalyptus ( Eucalyptus globulus ) is an invasive species in Spain. No half measures, no nuances in that statement. Since 2001, eucalyptus has been scientifically qualified as a “very dangerous species for natural and semi-natural ecosystems” and capable of “invading anthropized environments”, that is, those dominated by human activity. When the invasive capacity of eucalyptus is objectively evaluated using semi-quantitative methods, it is as invasive as cat’s claw ( Carpobrotus edulis ) or acacia mimosa ( Acacia dealbata ), and ahead of jimsonweed ( Datura stramonium ), all of which are included as invasive in the Spanish Catalog.
When the species is analyzed taking into account the interest it arouses in the population —something that is associated with demand and use—, it is concluded that eucalyptus is the third priority non-regulated invasive species. Only the false acacia ( Robinia pseudoacacia ) and the Spanish flag ( Lantana camara ) are ahead of him. Among the impacts that eucalyptus causes to the environment include a high capacity for competition, the displacement of native species, the inhibition of the growth of other plants —due to certain chemical substances that it releases into the soil— and the destabilization of ecosystems, either by change in fire regimes or by desiccation.
In addition, it is an invasion that affects economically. Of the more than 50 million euros that up to 2009 had been spent in Spain for the control and management of invasive plants, eucalyptus headed the list with more than 31 million, almost five times more than the second on the list, the hyacinth. (Eichhornia crassipes ) that causes so many disasters in the Guadiana basin.
But, how did the eucalyptus get to this situation?
story of an invasion
Blue gum grows naturally on the island of Tasmania and on the southwestern coast of Australia, in the Victoria and New South Wales regions. It was planted for the first time in Spain in the Pontevedra municipality of Tuy, in 1860, by Fray Rosendo Salvado, who sent a handful of seeds to his family from Australia.
A potentially invasive species may not behave as such when its population is small enough, and will become so when a certain population threshold is exceeded. That is what happened with the eucalyptus; for decades, it was hardly cultivated and did not pose any problem, until the 1960s when it began to be planted en masse.
Its rapid growth made it very attractive for pulp production. In addition, its ability to drain wetlands was positively valued to prevent the breeding of malaria-carrying mosquitoes. Both features, considered beneficial, facilitated the granting of a series of subsidies for the cultivation of eucalyptus, which led to its massive cultivation throughout the Galician coast and the Cantabrian coast. It was even recommended as a suitable species for the reforestation of disturbed areas.
The sudden increase in abundance was the trigger that turned eucalyptus from a potential invader to an actual invader.
However, and although eucalyptus has been tried several times to be included in the Spanish catalog of invasive alien species —it was already proposed for inclusion in its first draft—, it is still not considered as such.
The invasion business
In 2017, the Scientific Committee of the then Ministry of Agriculture, Fisheries, Food and Environment issued a unanimous report that suggested including several species of eucalyptus in the Catalog. However, the same ministry commissioned a counter-report from a researcher associated with one of the main paper production companies in Spain.
Currently, eucalyptus crops occupy up to 3% of the Spanish forest area, and it is responsible for up to a third of the wood used in the paper industry in our country. Ignoring the obvious conflict of interest
existing, the Ministry accepted that counter-report, which attributed “a tendentious attitude on the part of the Scientific Committee, in order to issue a premeditated value judgment regarding the invasive nature of these species, presumably based on non-scientific criteria and on personal opinions and policies”.
The reality is that if the eucalyptus is not found in the Catalog of Invasive Species, it is only due to economic interests. Perhaps it would be necessary to meditate on why a complete and rigorous report issued unanimously by the 20 independent experts that make up the scientific committee is silenced by a text issued by a single person with a clear conflict of interest. And if protecting the interests of a few companies is above the ecological interest —which is also, in the end, the general social interest— obtained from the conclusions of a scientific committee, why ask the scientific committee for the report in the first place?
REFERENCES
Andreu, J., Vilà, M., et al. 2009. An Assessment of Stakeholder Perceptions and Management of Noxious Alien Plants in Spain. Environmental Management, 43(6), 1244. DOI: 10.1007/s00267-009-9280-1
Bayón, Á., & Vilà, M. 2019. Horizon scanning to identify invasion risk of ornamental plants marketed in Spain. NeoBiota, 52, 47-86. DOI: 10.3897/neobiota.52.38113
BOE. 2013. Royal Decree 630/2013, of August 2, which regulates the Spanish Catalog of invasive alien species. BOE, 185(Sec. I.), 56764-56786.
Wild Flora and Fauna Committee. 2017. Opinion of the Scientific Committee for the Consultation: CC 30/2017. Ministry of Agriculture, Fisheries, Food and Environment. https://www.miteco.gob.es/es/biodiversidad/temas/conservacion-de-especie s/dictamencc302017eucalyptusvariasspp_tcm30-445705.pdf
Elorza, MS, Dana, E., et al. 2001. Approach to the list of real and potential invasive alien plants in Spain. Lazaroa, 22, 121-131.
Gassó, N., Basnou, C., et al. 2010. Predicting plant invaders in the Mediterranean through a weed risk assessment system. Biological Invasions, 12(3), 463-476. DOI: 10.1007/s10530-009-9451-2
