Palms reveal the significance of climate change for tropical biodiversity

Tropical areas provide similar conditions with high temperatures and humidity regardless of whether you are in Asia, Africa or South America. And you can find lush rainforests in all these places. However, tropical rainforests are not the same. There are fundamental differences in the species composition in the rainforests on the different continents.
Scientists at Aarhus University have spearheaded research results that shed new light on the processes forming the composition of species assemblages in the tropics. There are actually more than 2400 species of palms and, by studying them, the researchers have shown that the palm assemblages we find in the tropics today are to a large extent formed by climatic changes of the past, taking place over millions of years.
“It comes as a surprise to us that climate change over millions of years still leaves a signature in the composition of species assemblages we see today. If species are severely affected by current and future climate change, it’ll mean that there are long-lasting consequences for biodiversity, maybe over many millions of years to come – at least much longer than we’ve ever dreamt of before,” says Daniel Kissling, who initiated the ground-breaking research results shortly to be published in the prestigious journal Proceedings of the National Academy of Sciences of the USA (PNAS).
South America has had a relatively stable humid and warm climate for the last 50 million years, and rainforests have been widespread throughout this entire period. This is where species diversity is highest. There have been good living conditions and plenty of space for many new species to arise. As species formation has been concentrated in particular groups, the species-rich South American palm communities are now dominated by closely related species.
Africa, on the other hand, has been hit by severe drying during the last 10 to 30 million years. The area of rainforest has thus diminished dramatically, until it reached a minimum during the cold, dry ice ages that have repeatedly affected the world over and over again during the last 3 million years. As a result of past climatic changes, many species have simply disappeared entirely from the continent. There are therefore far fewer palm species in Africa than in South America. The poor palm flora of Africa thus has a relict character, and consists of species that are often not closely related to each other.

Contact

Professor Jens-Christian Svenning, Department of Bioscience, Aarhus University, +45 8715 6571, mobile +45 2899 2304,
svenning@biology.au.dk Assistant Professor W. Daniel Kissling, Department of Bioscience, Aarhus University,
kissling@biology.au.dk, +45 8715 4345 (cannot be contacted until 26 April 2012)
 

Working partners

Ecoinformatics & Biodiversity Group, Department of Bioscience, Aarhus University

• The research was led and predominantly conducted at the Ecoinformatics & Biodiversity (ECOINF) Group at Aarhus University. The research group focuses on using the rapid increases in data sources and computing and statistical modelling capabilities to advance biodiversity science, ecology, and environmental science. In addition, a long tradition of palm research exists in this group, with world-leading expertise on all aspects of the biology of palms.
• Authors from ECOINF: W. Daniel Kissling, Wolf L. Eiserhardt, Finn Borchsenius, Henrik Balslev, and Jens-Christian Svenning

Royal Botanic Gardens, Kew, UK

• The Royal Botanic Gardens, Kew, is a world-famous botanical institution, internationally respected for its outstanding living collection of plants and world-class herbarium, as well as its scientific expertise in plant diversity, conservation and sustainable development in the UK and around the world. Kew Gardens is a major international visitor attraction that, with its country estate Wakehurst Place, attracts nearly two million visitors every year. Kew was made a UNESCO World Heritage Site in July 2003 and celebrated its 250th anniversary in 2009.
• Author: William J. Baker, Head of Palm Research

Institut de Recherche pour le Développement (IRD), Montpellier, France

• The IRD is a unique European research institution with a focus on conducting research in the southern hemisphere. Its researchers work on issues of major global importance such as global warming, biodiversity, and poverty. Palm research focuses on systematics and biogeography, and the evolution of tropical rainforests.
• Author: Thomas L. P. Couvreur

Methods

Our research uses an informatics approach to ecology and evolution by handling and analysing large datasets, including databases on the distribution of thousands of species across the world, global data layers on paleo-reconstructions of climate and tropical rainforests, and molecular information on the phylogenetic tree of palms. By doing this, we build on major recent advances in ecology, informatics, systematic botany, and paleo-geography.

Funding

• Mainly funded by the VILLUM FOUNDATION.