By Joern Fischer
Today I’d like to recommend a new manuscript in PNAS, available here.
Europe’s other debt crisis caused by the long legacy of future extinctions.
Dullinger S, Essl F, Rabitsch W, Erb KH, …, Kühn I, Pergl J, Pysek P, Hulme PE. Proc Natl Acad Sci U S A 2013 Apr 15; PMID: 23589873 DOI: 10.1073/pnas.1216303110
This paper illustrates the notion of an extinction debt very elegantly. The authors look at current red lists in Europe, and find that red lists for many species correlate best with past socioeconomic indices, as opposed to present indices. In other words, current red lists are best described by what humans did 50 to 100 years ago rather than what they are doing now. The authors interpret this better fit to indicate that what we are witnessing now in terms of threatened species is the result of our actions a long time ago.
An interesting additional finding is that current expenditure on conservation further improves model fit; but does not fundamentally change the fact that current red lists are best explained by past socioeconomic conditions.
The authors interpret these findings to indicate that extinction patterns very likely will get worse – because we are now reaping the rewards of our actions one hundred years ago, and current actions are far more detrimental to species.
An important conservation take-home message is that current actions to halt biodiversity loss (a declared policy goal in Europe, for example) probably fall short even further of what is needed than widely agreed on.
I think this is an elegant case study; good for teaching the extinction debt; and an important warning to society regarding likely future extinction patterns.
This study also highlights indirectly (and probably not intentionally) that focusing on species once they are red-listed is too late. We need to think about the threatening processes driving biodiversity decline right now. Currently common species, if they show signs of declining, give more immediate feedback on our actions than if we wait for these species to get red-listed – which may take 50 to 100 years from when their initial decline starts.