How can a knowledge of the past help to conserve the future? Biodiversity conservation and the relevance of long-term ecological studies

Abstract

This paper evaluates how long-term records could and should be utilized in conservation policy and practice. Traditionally, there has been an extremely limited use of long-term ecological records (greater than 50 years) in biodiversity conservation. There are a number of reasons why such records tend to be discounted, including a perception of poor scale of resolution in both time and space, and the lack of accessibility of long temporal records to non-specialists. Probably more important, however, is the perception that even if suitable temporal records are available, their roles are purely descriptive, simply demonstrating what has occurred before in Earth's history, and are of little use in the actual practice of conservation. This paper asks why this is the case and whether there is a place for the temporal record in conservation management. Key conservation initiatives related to extinctions, identification of regions of greatest diversity/threat, climate change and biological invasions are addressed. Examples of how a temporal record can add information that is of direct practicable applicability to these issues are highlighted. These include (i) the identification of species at the end of their evolutionary lifespan and therefore most at risk from extinction, (ii) the setting of realistic goals and targets for conservation 'hotspots', and (iii) the identification of various management tools for the maintenance/restoration of a desired biological state. For climate change conservation strategies, the use of long-term ecological records in testing the predictive power of species envelope models is highlighted, along with the potential of fossil records to examine the impact of sea-level rise. It is also argued that a long-term perspective is essential for the management of biological invasions, not least in determining when an invasive is not an invasive. The paper concludes that often inclusion of a long-term ecological perspective can provide a more scientifically defensible basis for conservation decisions than the one based only on contemporary records. The pivotal issue of this paper is not whether long-term records are of interest to conservation biologists, but how they can actually be utilized in conservation practice and policy.

Figure 1

Terminology used in the classification of species for the IUCN Red Data List (redrawn from IUCN 2004).

Figure 2

Fossil trends through time of birds (Aves), flowering plants (Magnoliophyta) and gymnosperms (Gymnospermophyta). Data from Cleal (: Gymnospermophyta), Collinson et al. (: Magnoliophyta) and Unwin (: Aves) and tabulated in Benton (1993).

Figure 3

The 34 biodiversity hotspots currently recognized by Conservation International (redrawn from Mittermeier et al. 2005).

Figure 4

Predicted global average sea-level rise from 1990 to 2100 using various climate models (IPCC 2001). The region delimited by the outermost lines shows the range of all the predicted models and scenarios including uncertainty in land–ice changes, permafrost changes and sediment deposition. Note that this prediction does not allow for uncertainty and predictions related to the melting of the West Antarctic ice sheet (Alley et al. 2005).

Figure 5

Biodiversity hotspots (Mittermeier et al. 2005) most at risk from storm surges and floods related to sea-level rise (data for storm surges redrawn from Nicholls et al. 1999; Nicholls & Lowe 2004).