The last decade has seen widespread adoption of the ecosystem services concept by ecologists, the conservation community and policymakers. The subject is controversial, but the speed of its acceptance has been startling.
The reasoning behind why the conservation community is keen to push this concept goes something like this:
- Conservation biologists believe that the ecosystem services concept appeals to decision makers.
- This concept can be used to argue for greater funding for management to protect ecosystem services.
- This extra funding can then be used to protect certain ecosystem services and there will be added benefits for biodiversity.
A great example of this is the enthusiasm for REDD+ (Reducing Emissions from Deforestation and Degradations). The idea behind REDD+ is that payments are made to avoid deforestation and fund forest restoration, thereby avoiding increased anthropogenic CO2 and reducing the impacts of global climate change. There are massive areas of forest in tropical developing countries which are home to unique, often endangered, species as well as relatively poor communities and so REDD+ is seen as positive for biodiversity and poverty alleviation. So far, so good.
Links between biodiversity and ecosystem services
However, there is nothing that intrinsically links the biodiversity that people are trying to protect (generally vertebrates) and carbon storage. It just so happens that large areas of forest, which contain massive amounts of carbon are also home to species which certain elements of the human race value 1. Indeed, it may be entirely possible to have good carbon storage in a forest with few vertebrate species. The people working on making REDD a reality also noticed this problem and as a result the + was added, signifying biodiversity. So despite the many other issues with REDD+, it appears that the potential conflict between biodiversity conservation and carbon storage has been addressed.
The dual protection of ecosystem services and biodiversity in other cases may be more difficult. For example, managing a catchment for water quality may only require strategic placement of strips of vegetation to reduce nutrient and sediment loading of rivers. This is hardly biodiversity conservation in the way many in the conservation community would traditionally see it.
Some people argue that species richness contributes to the functioning of ecosystems and by extension ecosystem services. This is undoubtedly the case2. However, the level of biodiversity needed for maintenance of particular ecosystem services in natural systems is largely unknown and it is likely that only a relatively small proportion of species contribute to ecosystem functioning3. We have little idea how realistic extinction scenarios may effect ecosystem services and more work on this is desperately needed.
The way forward
None of this means that the ecosystem service argument cannot be used for conservation. However, it needs to be used with caution. Conservation NGOs should not argue that biodiversity and ecosystem services are synonymous, because they really aren’t. Biodiversity drives the processes that underpin ecosystem services (e.g. nutrient cycling), can provide services directly (e.g. crop pollination) and can also be consumed directly as a good (e.g. bushmeat)4. So even though there is some overlap, biodiversity is not an ecosystem service.
So, does biodiversity conservation protect ecosystem services? The answer, as in so many cases, is that it depends. It is dependent on what biodiversity you are conserving, the services in question and the geographical context.
There is no easy one-size-fits-all solution to how we can combine traditional conservation and the ecosystem services concept. However, if we oversell conservation by claiming it always benefits service provision the conservation community leaves itself open to derision. We must tackle this problem by confronting it, rather than sweeping it under the carpet and pretending it doesn’t exist.
1. Strassburg, B. B. N. et al. Global congruence of carbon storage and biodiversity in terrestrial ecosystems. Conservation Letters 3, 98-105, doi:10.1111/j.1755-263X.2009.00092.x (2010).
2. Hooper, D. et al. Effects of biodiversity on ecosystem functioning: a consensus of current knowledge. Ecological monographs 75, 3-35 (2005).
3. Isbell, F. et al. High plant diversity is needed to maintain ecosystem services. Nature 477, 199-202
4. Mace, G. M., Norris, K. & Fitter, A. H. Biodiversity and ecosystem services: a multilayered relationship. Trends in ecology & evolution (2011).