What Is Natural? The Need for a Long-Term Perspective in Biodiversity Conservation. K. J. Willis, et al. Science 314, 1261 (2006); DOI: 10.1126/science.1122667

By Ana Prohaska

Conservation science and management tends to ignore long-term historical records.  An increasing number of studies, however, have illustrated the importance of long term and palaeo-ecological data in several aspects of conservation, such as in invasive species research, understanding wildfire patterns, identifying climate change adaptation solutions and specifying ecosystem thresholds.

In conservation planning particularly, long-term ecological data can help to set conservation targets. For instance, in the case of Australia, conservation targets (i.e. quantitative goals to be achieved for the protection of particular biodiversity features) for vegetation are usually set using the pre-European state of the continent as the natural baseline. However, the question remains as to whether these targets are (1) realistic and feasible, (2) accurately reflect stakeholders interests and (3) are sustainable in the long-term. Novel ecosystems are arising due to the impact of anthropogenic activities coupled with future climatic change. Therefore, restoring and maintaining a historical population or an ecosystem may not be justifiable. This has lead to many scientists arguing that it is the natural variability of ecosystems that should be preserved (Suding and Gross, 2004; Suding et al., 2006) and palaeoecological science might be used to give insights into ecosystem dynamics. While predictions of species distributions that are based on long-term historical records might be prone to error and uncertainty, the alternative is to rely on contemporary ecological datasets, which rarely span more than 30 years.

The use of palaeo-ecological data will not however reconcile conflicts between what science describes as natural and what stakeholders value. For example, Preston et al. (2004) showed that at least 157 plant species have been introduced to British peninsula by humans. However, the eradication of these species is unlikely since many are now valued by society.

The costs of palaeo-ecological research could pose a significant constraint to its utility for conservation planning. It will be important not only to decide in which cases the palaeoecological data might have direct use in conservation efforts, but also carefully design the study (choice of sites and methods) in order to maximize the benefit for the given cost.

Literature cited

Preston, C.D., Pearman, D.A. & Hall, A.R. 2004. Archaeophytes in Britain.  Botanical Journal of the Linnean Society, 145, 257–94.

Suding, K. N., K. L. Gross & Housman, D.R. 2004. Alternative states and positive feedbacks in restoration ecology. Trends in Ecology and Evolution, 19, 46–53.

Suding, K.N. & Gross, K.L. 2006. The dynamic nature of ecological systems: multiple states and restoration trajectories. In: Falk, D. A., Palmer, M. A. & Zedler, J.B. (eds.) Foundations of Restoration Ecology. Island Press, Washington D.C., pp. 190-209.