Biodiversity research has identified three hundred thirty thousand plant species in the world. But according to the latest ecological reports, functional traits of plants are actually more important than the species themselves in explaining how ecology works. This new ecological unit of measurement makes it easier to predict how species and forests will respond to climate change. It also helps us to manage forests in a sustainable way so that ecosystem services can be provided, maintained or even restored. These are the words of Prof. Lourens Poorter on accepting his appointment as Professor of Functional Ecology (holding a personal chair) at Wageningen University on 23 October.
Inauguration Lourens Poorter
The field of ecology has shifted. In the 1970s, species were the functional unit in an ecosystem. “Nowadays, we focus on the individual traits of plant species, such as their ability to transport water via tree trunks, and to absorb light and fix carbon through their canopy”, explains Prof. Poorter in a speech entitled ‘Functional Diversity – Scaling up from plants to ecosystems’. The professor, who is specialised in functional ecology, measures the traits of an individual organ of a plant, such as leaves. By scaling-up this trait to the crown of an individual tree, and to all the trees in a forest, it is possible to predict the productivity of the whole forest.
Nowadays we have protocols which allows to measure the traits of various plants in a standardised way, and to compare different species. By now, the functional traits of over 69,000 plant species have been stored in a large global database, which enables researchers to identify functional plant strategies on a global scale. “Throughout the world, we have identified a spectrum of plants, from fast-growing species that thrive in productive environments to slow-growing and tough species that can survive under harsh or resource-poor conditions. Interestingly enough, you see this spectrum everywhere, from the tundra to the tropics,” continues Prof. Poorter. These data can now be used to improve the way how vegetation is included in global climate-vegetation models. At present, they only recognise five categories of plants, such as grasses or deciduous trees. “The inclusion of a continuum of functional traits of a range of species will allow us to make better analyses of the interaction between vegetation and climate. This in turn will provide us a better understanding of what will happen to the vegetation if the climate becomes drier or hotter, for example, and how this will affect the carbon and water balance”, explains Lourens Poorter.
Sustainable forest management
Approximately one billion poor people in the world depend on forest products, such as fruit, fuel wood and construction wood, for their livelihoods. Sustainable forest management is essential to ensure a permanent source of income for the local people, government and industry. Insight into the conditions under which trees get established, and how quickly they grow, can be used by forest managers as a tool for deciding how much timber can be harvested sustainably.
Prof. Poorter’s research also focuses on the effect of changes in land use (from undisturbed rainforest, to selectively logged forests, secondary forest, shifting cultivation and cattle ranching) on functional biodiversity and ecosystem services. This indicates what kind – and how much - functional diversity is needed to sustain nutrient cycling and productivity.