Biodiversity versus ecosystem services

This is a brief summary of a debate about the relationship between biodiversity conservation (BD) and managing for ecosystem services (ES) and the proper role of conservation. The debate centers around an article by Kareiva and Marvier (2012) and the discussion that followed.

Some threads of the discussion were:

  • A reply by Soule (2013), followed by Marvier (2014), and those below.
  • A reply by Miller et al. (2014), followed by Kareiva (2014), Soule (2014).
  • A reply by Doak et al. (2014b), followed by Marvier and Kareiva (2014a), Doak et al. (2014a).
  • A reply by Cafaro and Primack (2014), followed by Marvier and Kareiva (2014b).

Broadly, the `Kareiva group’ (Kareiva and Marvier, 2012) argued for a `new conservation science’ in which ecosystem services were included as a central motivation and prioritisation goal for conservation. Kareiva et al. (2014) sketches out the history of TNC and the ways in which the shift to ES occurred, which was largely as a result of the impracticality of obtaining large area of land demanded by conservation, and the MEA and a shift of incorporating human wellbeing and social justice. The `Soule group’ responded that ecosystem services are not what conservation is about, but rather the preservation of biodiversity, in that species have intrinsic value in and of themselves (Miller et al. 2014). Summarised into one sentence, while the `Kareiva group’ see biodiversity `secondary’ to ES (and indeed consider BD an ecosystem service in itself, albeit one that is hard to value economically), the `Soule group’ see biodiversity as the central goal of conservation, and ES as secondary to that. Thus the disagreement between them is one of irreconcilable fundamental values.

In several places the `Kareiva group’ argue that ES also supports BD. I’ll split them into four categories.

First, the argument that biodiversity and human well-being go hand-in-hand. For example, Kareiva and Marvier (2012) state

the fate of nature and that of people are deeply intertwined. Human health and well-being depend on clean air, clean water, and an adequate supply of natural resources for food and shelter. Many of the activities that harm biodiversity also harm human well-being.

Doak et al. (2014b) replied:

the NCS assertion that focusing on ecosystem services will save biodiversity as well (‘the fate of nature and that of humans are deeply intertwined … many of the activities that harm biodiversity also harm human well-being’ [5]) has essentially no rigorous scientific support [31,32].

citing Cardinale et al. (2012) and Ang and Van Passel (2012).

Ang and Van Passel (2012) say

The difficulty for ecologists is consequently that although only a few species directly contribute to human well-being, many more contribute indirectly by influencing the ecological equilibrium.

Cardinale et al. (2012) review two decades of research on how biodiversity influences ecosystem function and services. (Note the direction of implication: biodiversity’s effect on ES, rather than the reverse). In short, the relationship depends upon the type of ES considered:

Services linked to function show a diversity-service relationship (e.g. experiments that test the effects of plant species richness on above-ground biomass production are also those that provide direct evidence for effects of diversity on aboveground carbon sequestration and on fodder production), however services less tightly linked to ecoystem functions (e.g. services associated with specific populations rather than ecosystme-level properties) often lack rigorous verification of diversity-service relationships

To add one more example, Chan et al. (2006) observed that excluding agriculture-focused ES (crop pollination and forage production) from their suite of ES (carbon storage, flood control, outdoor recreation, water provision) removed the negative correlations between conservation/biodiversity and ES.

Second, the argument that projects for ES also create protected areas. Citing Goldman et al. (2008), Marvier (2014) argued that ES projects are just as likely to include or create protected areas. Looking at TNC projects only, Goldman et al. (2008) reported that BD projects employ land purchasing 1.5 times and easements 2.5 times more often that ES projects. Unfortunately, not enough post-project monitoring was done on these projects in order to determine what their biodiversity outcomes eventually were.

Third, the argument that ES projects capture funding that would not otherwise be obtained. Thus, on the assumption that they also support biodiversity to some extent, the ES approach is beneficial to biodiversity in the broad sense. For example, Marvier (2014) cited Goldman et al. (2008) who observed that ES projects at TNC attracted more funding than biodiversity projects. And see also the observation that biodiversity-focused projects only appeal to a select portion of the political landscape.

Fourth, the argument that ES projects address areas that are otherwise overlooked by BD projects. Kareiva and Marvier (2003) writes quite critically of the traditional approach of conserving biodiversity `hotspots’, making points such as that this approach focuses upon tropical areas to the neglect of other biomes, reducing the diversity of ecosystems and broader taxonomic groups protected. While not a direct argument that ES projects will enhance biodiversity, the implicit assumption is that an ES-oriented approach is more diverse and therefore will cover a more diverse range of ecosystems.

There are also several places where the `Kareiva group’ say that BD and ES can be antagonistic or that the link is yet to be shown.

Kareiva et al. (2014)

The biggest challenge is knowing when another mine, or another oil pad, or another hundred hectares of heavily fertilized crops is too much and thus will jeopardize both biodiversity and ecosystem services. Ecological theory reveals that thresholds and tipping points are inherent in complex nonlinear systems (Scheffer et al. 2012). But “the science is lacking” for anticipating where those thresholds are and how to account for cumulative impacts. The ecology of cumulative risks, resilience and thresholds, in addition to tried and true land and water protection methods, holds the key to conservation success in the Anthropocene.

Kareiva and Marvier (2003):

But one striking feature of the relation between ecosystem services and biodiversity is that it is not linear. Rather, the benefits of biodiversity are quickly realized with an initial accumulation of species and thereafter remain constant, so that protecting more species does not forever translate into more or better ecosystem services.

Kareiva and Marvier (2007):

Some people will be alarmed by this proposal because the services provided by nature do not always correlate with biodiversity. A second source of anxiety about our approach is the fact that the plants and animals most central to ecosystem services and human economy tend to be fairly abundant. But rare species still have a crucial role: as insurance. With global climate disruption and massive modification of land, the rare species of today may become the abundant species of tomorrow, and so we should save as many as possible. (e.g. of native pollinators replacing European honeybee)

References

Ang, F. and Van Passel, S. (2012). Beyond the environmentalist’s paradox and the debate on weak versus strong sustainability, BioScience 62(3): 251–259.

Cafaro, P. and Primack, R. (2014). Species extinction is a great moral wrong, Biological conservation 170: 1–2.

Cardinale, B. J., Duffy, J. E., Gonzalez, A., Hooper, D. U., Perrings, C., Venail, P., Narwani, A., Mace, G. M., Tilman, D., Wardle, D. A. et al. (2012). Biodiversity loss and its impact on humanity, Nature 486(7401): 59–67.

Chan, K. M., Shaw, M. R., Cameron, D. R., Underwood, E. C. and Daily, G. C. (2006). Conservation planning for ecosystem services, PLoS biology 4(11): e379.

Doak, D. F., Bakker, V. J., Goldstein, B. E. and Hale, B. (2014a). Moving forward with effective goals and methods for conservation: a reply to Marvier and Kareiva, Trends in Ecology & Evolution 29(3): 132–133.

Doak, D. F., Bakker, V. J., Goldstein, B. E. and Hale, B. (2014b). What is the future of conservation?, Trends in Ecology & Evolution 29(2): 77–81.

Goldman, R. L., Tallis, H., Kareiva, P. and Daily, G. C. (2008). Field evidence that ecosystem service projects support biodiversity and diversify options, Proceedings of the National Academy of Sciences 105(27): 9445– 9448.

Hunter, M. L., Redford, K. H. and Lindenmayer, D. B. (2014). The complementary niches of anthropocentric and biocentric conservationists, Conservation biology 28(3): 641–645.

Kareiva, P. (2014). New conservation: setting the record straight and finding common ground, Conservation Biology 28(3): 634–636.

Kareiva, P., Groves, C. and Marvier, M. (2014). Review: The evolving linkage between conservation science and practice at the nature conservancy, Journal of Applied Ecology 51(5): 1137–1147.

Kareiva, P. and Marvier, M. (2003). Conserving biodiversity coldspots recent calls to direct conservation funding to the world’s biodiversity hotspots may be bad investment advice, American Scientist 91(4): 344– 351.

Kareiva, P. and Marvier, M. (2007). Conservation for the people, Scientific American 297(4): 50–57.

Kareiva, P. and Marvier, M. (2012). What is conservation science?, BioScience 62(11): 962–969.

Marvier, M. (2014). New conservation is true conservation, Conservation Biology 28(1): 1–3.

Marvier, M. and Kareiva, P. (2014a). The evidence and values underlying new conservation, Trends in Ecology & Evolution 29(3): 131–132.

Marvier, M. and Kareiva, P. (2014b). Extinction is a moral wrong but conservation is complicated, Biological Conservation 176: 281–282.

Miller, B., Soule, M. E. and Terborgh, J. (2014). New conservation or surrender to development?, Animal Conservation 17(6): 509–515.

Soule, M. (2013). The “new conservation”, Conservation Biology 27: 895–897.

Soule, M. (2014). Also seeking common ground in conservation, Conservation Biology 28(3): 637–638.

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