I command you to come no further! Waves, stop your rolling!
It has been my sentiment for a long time that non-native species get too much bad press. No one ever looks on the bright side. Large-scale environmental change is not avertible, we will have no choice but to embrace the change and find ways to work with it. Too frequently, it is forgotten that many non-native species are necessary additions, fulfilling requirements unable to be provided by native species thus they have proven to be incredibly beneficial the world over; socially, culturally and economically. Over 70% of the world’s food comes from 9 crops (Prescott-Allen et al, 1990) each cultivated far beyond its natural range while 85% of industrial forestry plantations are cultivated from 3 genera (Evans, 1992). The ecological cost of increasing natural resource consumption is the rapid degradation, fragmentation and loss of habitats; such widespread disturbance drives species towards extinction through a series of population losses over their entire range (Hobbs and Mooney, 1998). This is the principle cause of global biodiversity reduction; the problems caused by non-native species are symptomatic of an increasing human population, global lifestyles and economic decision making.
While there are justifiable reasons for favouring ‘natives’ or controlling ‘non-natives’, the terms themselves are arbitrary and inflexible. When considering the need to control a species, its native or non-native status is unimportant. The only criteria for control should be species potential for degrading an ecosystem in a particular place, at a particular time. This is the most pragmatic approach, such criteria allows continual reassessment of a situation and the flexibility to change priorities if needed, without needing to cut through the red tape surrounding alien/native status.
So I am more than a little joyful to see the publication of ‘The Potential Conservation Value of Non-Native Species’ in the June issue of Conservation Biology. The article examines the ways in which non-native species currently contribute to conservation objectives and speculates that non-native species might contribute to achieving conservation goals in the future because they may be more likely than native species to persist and provide ecosystem services in areas where climate and land use are changing rapidly and because they may evolve into new and endemic taxa. Hurray. I for one, would particularly welcome more research on the positive effects of non-native species.
References: Schlaepfer MA, Sax DF, & Olden JD (2011). The Potential Conservation Value of Non-Native Species. Conservation biology : the journal of the Society for Conservation Biology, 25 (3), 428-437 PMID: 21342267
Prescott-Allen, R., & Prescott-Allen, C. (1990). How Many Plants Feed the World? Conservation Biology, 4 (4), 365-374 DOI: 10.1111/j.1523-1739.1990.tb00310.x
Hobbs, R., & Mooney, H. (1998). Broadening the Extinction Debate: Population Deletions and Additions in California and Western Australia Conservation Biology, 12 (2), 271-283 DOI: 10.1046/j.1523-1739.1998.96233.x