On 8th October 2010 we discussed a review article by Wade et al. (2008) on farmland ecological restoration. The authors suggest that ecological restoration projects may become necessary in farmlands in the course of the continuing expansion of agricultural production, in order to secure the functioning of related ecosystem services in the future. The authors also discuss where, when and how ecological restoration projects have been, and could be, implemented. The article was a useful read to at least some of us, since we were so well familiar with the topic, even though changes in agriculture could have a remarkable influence on biodiversity conservation.
The major issue that raised discussion in the journal club was that the role given to biodiversity in the article: the authors assessed the value of biodiversity and the threat of its depletion mainly as how biodiversity benefits the human society via ecosystem services. We recognize the term ‘ecosystem services’ as today’s buzzword, with much of the ‘buzz’ focusing on the quantification of the monetary value of ecosystem services. While we can see the benefit of approximating the scale of human economic benefit from the existence of natural ecosystems, we raised several concerns over this quantification trend from the perspective of species conservation:
- It is important to keep in mind that restoring ecosystems by using ecosystem services as indicators of success does not necessarily have much to do with the conservation of native biodiversity. This is exemplified by the authors of this article, as they present cases where ecosystem functions have been enhanced along with the ecological fitting of exotic species, and while they state that “relatively large increases in ecosystem function may be achieved with low or modest levels of biodiversity enhancement”.
- Studying ecosystems as sets of measurable, categorised services may blur our perception on how complex natural ecosystems are, and how difficult it may be to accomplish a systemic change in ecosystem function that would be truly stable in the long run.
- Giving simple price tags to ecosystem services easily hides the subjectivity of the underlying quantifications. Is there just one way to measure, for instance, the monetary value of pollination to the human society?
While the article focused heavily on ecosystem services, its views on how ecosystem restoration projects support species conservation goals became unclear. The authors stated that there is no worldwide compendium of species that have been targeted in farmland ecological restoration programmes. Species of native ecosystems that have been displaced by agriculture were mentioned as potential targets, but the species known to be dependent on traditional agricultural landscapes were mostly bypassed. The overall goal of “restoring ecosystem ‘health’“ did not quite fit together with the artificiality of examples where, for instance, forest-dwelling insects were supported in agricultural landscapes with added coarse woody debris.
The lack of well-founded conservation goals makes it difficult to evaluate which restoration methods would make sense from conservation point of view. For instance, if the Earth’s land surface area required by agriculture is indeed going to rise to 60 %, some species would probably benefit from it consisting of patchy landscapes full of corridors, edges and nodes, as the authors suggest. But many species of native ecosystems might also suffer from such means of restoration, as they would rather benefit from agricultural landscapes being as compact as possible, which would leave the maximum possible space for continuous, natural ecosystems elsewhere.
Nevertheless, there is a great need for an exchange of views between agro-economics and conservation biology. This very comprehensive, cross-disciplinary article was a welcome element to that discussion.
Link to the paper: