Outreach article: The story is in the genes

Volker Hahn, the Head of the Media and Communication team at iDiv, wrote an outreach article for the general public, as part of the online magazine of the University of Leipzig, about our work on Madagascar. It features both me and PhD student Laura Mendez and her adventures in the field, the lab, and behind the computer. The article also describes some of the future ideas and directions of our work. It’s in German.

Along with the article, Gabriele Rada made a short video about the Madagascar work, using our video footage from Madagascar. Watch the video here. And do not forget to also watch our other Madagascar video using megafauna animal animations by TRICKLABOR.

The fate of megafaunal plants on Madagascar: the video

Link to video: https://vimeo.com/390453594

Plants with megafaunal fruits on Madagascar used to rely on megafaunal animals, such as giant lemurs and elephant birds, for their dispersal. Nowadays, these animals are extinct, and this may lead to dispersal limitation of plants with megafaunal fruits, and possibly their extinction. This video uses animations and footage from Madagascar to present our research to understand the consequences of megafaunal extinctions for palms with megafaunal fruits, and whether they need conservation prioritisation.

This video was made in collaboration with TRICKLABOR for the amazing animations. I also obtained an Outreach grant from the European Society of Evolutionary Biology (ESEB) and a grant from iDiv’s Female Scientist Career Fund to make this film project happen.

In the coming years we hope to find answers to the questions proposed in the video

Jungle_B6 copy

New article published in Proceedings of the Royal Society B

Also see the press release from the University of Amsterdam.

Global change, such as climate changes, may have two outcomes with respect to biodiversity: species will adapt, or they will go extinct. In this article, we address this question from a historical perspective, focusing on the Quaternary (the last 2.6 Ma), a period characterised by rapid global changes. We show that in some parts of the world palm trees with very large fruits have adapted to global change, whereas in other parts they seem to have gone extinct.  The results were published in the journal Proceedings of the Royal Society B.

Palmplants crow smaller fruits

Global change – such as climate change, habitat fragmentations or the extinction of large-bodied animals , such as giant sloths, may force species to adapt or go extinct. In particular, plants with very large fruits that rely on large-bodied animals for the dispersal of their seeds may face a problem: can they adapt quick enough, or will global change drive them ultimately to extinction?

During the last 2.6 million years,  Latin American palms with the largest fruits seem to have gone extinct with increasing rates, whereas large-fruited palms in South-East Asian regions seem to be adapting by producing smaller fruits. Small enough to be eaten and dispersed by birds and bats. These were the results of Onstein and her team which consisted of researchers from the Netherlands, UK, France, Sweden and Denmark. They collected data for more than 2000 palm species across the globe.

Fruits need to become smaller

The absence of certain fruit-eaters, such as large hornbills, elephants or giant tortoises, may require plants with large, ‘megafaunal’ fruits to evolve ‘new’ fruits. This is similar to the selection by humans for fruits (such as papayas or mangos) to become bigger and bigger. However, instead of becoming bigger, these fruits naturally have to become smaller, to adapt to the small-bodied animals that are still there to disperse their seeds. A lack of dispersal may, alternatively, lead to their extinction.

‘Although it is difficult to see the long-term results of current global change, global change has been happening in the deep past as well, especially during the last 2,6 million years,’ says Onstein. ‘We therefore use the past as our experimental set-up to understand how current and future global change may affect these palms with very large fruits.’

Onstein thinks that the dramatic changes in climate, habitat fragmentation and megafauna extinctions that have happened in Latin America over the last 2.6 million years may have been the cause of the increasing extinction of palms. In South-East Asian regions, on the other hand, palm dispersal by flying animals such as birds and bats may have been important to escape the dramatic effects of global change. Palms seem to have had enough time to adapt to these flying animals by evolving smaller fruits.

The future of palms

How does the future of these palms with big fruits look like? There are still at least 220 palm species worldwide that bear these massive fruits larger than 4 cm in length. ‘Large-fruited plants have it increasingly difficult to survive in our human dominated world’, says Daniel Kissling, associate professor and senior author of the study. ‘The loss of large animals in tropical rainforests, e.g. due to hunting, illegal trade, and habitat loss, has a massive effect on tropical biodiversity. It leads to a reduced seed dispersal and less regeneration of these tall and massive plants. This has even the potential to significantly erode the carbon storage of tropical rainforest because large-fruited trees also store most carbon.’

The increasing human pressure and hunting of the still existing megafauna will certainly have cascading effects on the plants they feed on. Whether all palms will be able to adapt to the loss of large-bodied animal dispersers has to be seen.

Publication

Onstein RE, Baker WJ, Couvreur TLP, Faurby S, Herrera-Alsina L, Svenning J-C, Kissling WD. ( 2018 ). To adapt or go extinct? The fate of megafaunal palm fruits under past global change. Proceedings of the Royal Society BBiological Sciences, 285, 20180882.