Evolution and Biodiversity: the evolutionary basis of biodiversity and its potential for adaptation to global change.

Abstract

Biodiversity has a key role in maintaining healthy ecosystems and thereby sustaining ecosystem services to the ever-growing human population. To get an idea of the range of ecosystem services that we use daily, think of how much energy and time it would cost to make Mars (or some other Earth-like planet) hospitable for human life, for example, in terms of atmosphere regulation, freshwater production, soil formation, nutrient cycles, regulation of climate, etc. On our own planet, that process took four billion years and required the contribution of a vast amount of functions performed by different life forms, ultimately driven by evolution and that is only the top of the (melting) iceberg. Unfortunately, the ecosystems that we so exploit and dearly need for our long-term survival and welfare are jeopardized by our own actions. Global change, triggered by human activities, is all around us. The pervasive effects of climate change, habitat loss and fragmentation, overharvesting, pollution, altered nutrient cycling, invasive species and interactions thereof affect virtually all Earth's ecosystems (Rockstrom et al. 2009). With seven billion people consuming natural resources more rapidly than they are created, we are at the onset of a major environmental revolution. As a consequence, species are already shifting, expanding, disappearing, changing their behaviour and phenology, exploiting newly available food resources and abandoning scarcer ones. Ecosystems are changing too, driven by changes in environmental drivers and by the reshuffling of their biota into previously unknown combinations of species (Williams and Jackson 2007). The interplay of all these processes makes the forecast of changes in ecosystem services a daunting task. All these changes are likely to have a bearing on and be influenced by the evolutionary forces at play. The main legacy of Charles Darwin was to make us realize that we owe everything, including the formation of our own species, to evolution. We thus learned that the history of life is driven by evolution. But what about the future? What is the contribution of evolution to these ecological changes? And, probably most relevant to policy: what is the potential of evolutionary processes to exacerbate or mitigate the effects of global change? Is evolutionary biology just a scientific gimmick compared to the real problems that we are facing? This volume deals exactly with these questions. Until a decade or so ago, evolutionary change was broadly assumed to happen on a vastly longer time scale than ecological change. As a corollary, our view on biodiversity and ecosystem functioning has often been static, trying to conserve biodiversity as it is, and preferably, as it once was. Just like our ecosystems, however, this paradigm is shifting. The closer we look at adaptive evolution, often with the aid of new biological insights and technological advances, the faster it seems to happen. Evolution and ecology are proving to be so heavily entwined that the distinction is becoming increasingly hard to make. This knowledge profoundly affects our thinking on how evolution affects patterns of biodiversity, especially in the face of global change. Adaptive responses to climate change, for example, have been shown to occur within a single generation (Van Doorslaer et al. 2007). Contemporary evolution is probably more important than we assumed to date and is, therefore, likely to mediate the response of populations, species, communities and ecosystems to both gradual and sudden environmental change. In April 2010, the European Platform for Biodiversity Research Strategy (http://www.epbrs.org) hosted the meeting ‘Evolution and Biodiversity: The evolutionary basis of biodiversity and its potential for adaptation to global change’, funded by the BioStrat project (http://www.biostrat.org). The meeting was preceded by an electronic conference that lasted 21 days and gathered over 62 contributors and more than 1600 participants (Grant et al. 2010). Both the conference and the meeting revolved around three main themes: (i) the evolutionary basis of biodiversity, (ii) evolutionary responses to global change and (iii) evolution in complex systems and co-evolutionary networks. This special issue builds from the diverse arrange of contributions made at the conference and aims to provide a diverse and interdisciplinary perspective on the interplay between evolutionary and ecological responses in the face of global change.