This Friday we discussed two papers written by Brooks and colleagues and by Stork.

Brooks et al. 2009: “Evaluating the success of conservation actions in safeguarding tropical forest biodiversity”

This paper focuses on the effectiveness of conservation. It tries to create an overview on how much our various conservation actions so far have actually managed to prevent species from going to extinct. It covers sections from protected area designation to education and policy, trying to summarize the past progress, current status and measured outcomes in each section.

Although the topic of this paper is most relevant to say the least, the authors fail to bring new sights to the discussion of conservation effectiveness. They sum up several of the sections very nicely, bringing together many important and interesting bits of information, but yet are not able to give any analytical view in them. Therefore, and unfortunately, the paper remains as a sort of literature review of what has been done or is being done, with few examples of successful or not-so-successful species recoveries and, a good list of relevant numbers and references.

We were slightly annoyed by the focus of the paper on tropical forests, and failed to see the reason why the authors decided to publish this type of an article in a special issue. Given that no quantitative analyses were done (nor, in terms of covering all the given sectors, have been done), we feel slightly sceptical about the final conclusions the authors make: “Overall our review provides grounds for cautious optimism. At least in short term, conservation actions can and do prevent extinctions; thus, there is hope in even the most challenging conservation contexts (Posa et al. 2008).” To our opinion, the review does not offer strong support for this.

There are, however, some key messages to take home with: So far, the quantitative evidence that our global conservation actions are actually making a difference, are more or less lacking. Thus, further studies are desperately needed to (reliably) say what is working and when. In addition the authors make an important statement how “conservation science should place more emphasis on addressing practical conservation needs and goals (Brooks et al. 2009)”. We believe that this will be one of the big issues discussed and studied in conservation science in the near future.

Final conclusion: Good literature review 🙂

Link to the paper: http://www3.interscience.wiley.com/journal/123190981/abstract?CRETRY=1&SRETRY=0

Stork 2010: “Re-assessing current extinction rates”

This paper discusses one of the fundamental questions to conservation science and conservation of species per se: The current extinction rates. The author takes a clear stand against one of the most cited claims by Pimm and others that the current global extinction rate caused by humans is some 100 to 1 000 times higher than background rates. Stork points out, quite nicely, that the current number of recognised extinctions is much lower than would be expected by many estimates done in recent decades by the scientific community. He goes through five different methods that have been mostly used in estimating the extinction rates and discusses the pros and cons of each approach and how the estimates have changed over time.

Stork also proposes some factors that might explain the mismatch between expected and observed extinction rates. Interestingly, he does mention the conservation efforts made in recent decades, especially the establishment of protected areas, but does not seem to be convinced that this is in any way a major explanatory factor. Instead Stork speculates the differences in numbers to stem from the dynamics of extinction dept (which are still largely unknown to science) and from the fact that different species groups react differently to extinction threats – thus, estimates made with one taxon (many times with large vertebrates) cannot be projected to other taxa (such as invertebrates).

All in all Stork concludes that the actual numbers are far smaller than what has been estimated in the past and therefore calls for caution when talking about extinction rates (interestingly, at this point all the persons participating to the discussion confessed they had used the very same Pimm et al. 1996 reference in their master/Phd thesis…). Stork also underlines that the focus should be shifted from global extinctions to local and regional extinctions, which are far more frequent and should thus be the main focus of conservation.

We think this paper was really nice to read, and provided some good, albeit critical views to the topic. The inclusion of climate change and the modelling of distribution shifts into the discussion felt however a bit out of context, even though Stork does quite justifiably argue that climate change might bring the recorded extinction rates closer to the (over)estimates in the future.  All in all, the paper was very interesting and widened our understanding about extinction rates significantly.

Final conclusions: Definitely worth reading!

Link to the paper: http://www.springerlink.com/content/805666652780552j/