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

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Fruits, animals and long-distance dispersal

In October 2015 Hervé Sauquet, Thomas Couvreur and I went on a field expedition in the rainforests of Borneo. Our aim was to collect plants belonging to the order Magnoliales, which includes the Annonaceae family. Annonaceae have beautiful flowers and tasty fruits (e.g. the sweetsop and soursop), worldwide there are ca. 2400 species, and they typically occur in tropical rainforests. Our expedition led, eventually, to a publication: “Which frugivory‐related traits facilitated historical long‐distance dispersal in the custard apple family (Annonaceae)?” published in Journal of Biogeography. and co-authored by Daniel Kissling, Lars Chatrou, Thomas Couvreur, Hélène Morlon and Hervé Sauquet. Read the press release from the University of Amsterdam here. A video of our Borneo expedition is available here.

How did Annonaceae colonise different continents or islands and their rainforests? How did they get there? To understand this, we need to look into how the plants are dispersed, which is via their fruits and seeds. On Borneo, our aim was therefore to collect the fruits and measure their ‘traits’ (e.g. fruit length, seed length, conspicuousness of fruit display). These traits are important because they attract animals to feed on the fruits and disperse the seeds. We expected that certain fruit-eating and seed-dispersing animals (i.e. frugivores) are more likely to perform intercontinental long-distance dispersal. For example, large-bodied animals (megafauna, such as elephants) and strong-flying birds (e.g. hornbills) have large home-ranges and/or can cross barriers (such as oceans), and therefore move across large distances. Because these animals prefer certain fruits (e.g. large fruits, or fruits with particular colours) we expect that these Annonaceae fruits may have been responsible for intercontinental long-distance dispersal, for example from South America to Africa, which happened repeatedly in the family throughout its history. Our results confirm these expectations.

Besides fun in the rainforest, this research was important to me because it was my first postdoc, I received a Swiss Mobility Fellowship to perform it, and it allowed me to live in Paris for a while and work with a couple of amazing researchers. I hope to continue working with these people on this tasty family in the future. For example, a lot more genetic and functional trait data need to be collected to be able to understand the complex eco-evolutionary dynamics that have led to the spectacular Annonaceae diversity.

From left to right, starting at the top: Rafflesia flower; Goniothalmus roseus fruits; Thomas, Renske & Hervé in the field; rainforest Borneo; Enicosantum sp. flower; the fieldwork team in action (twice).

 

 

Palms of Madagascar meeting in Leipzig

In the beginning of February, I organised a kick-off meeting for Laura Mendez‘ PhD project on “Genomic signatures of palms on Madagascar” – 3 days of discussions at iDiv in Leipzig (Germany). The team includes palm, frugivory and Madagascar experts from Kew Botanical Gardens, Aarhus University, University of Amsterdam, Bochum Botanical Gardens and iDiv – all important collaborators on Laura’s PhD project. The discussions ranged from deciding which species she will sample on Madagascar next summer, to clarifying the specific hypotheses and learning about historical demographic modelling techniques using Rad-seq data. A couple of very valuable and ‘fruitful’ days.

IMG_5798From left to right: John Dransfield, Chris Barratt, Daniel Kissling, Laura Mendez, Renske Onstein, Alex Zizka, Adriana Alzate, Wolf Eiserhardt, Wolfgang Stuppy, Jun Lim, Bill Baker.

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.

Looking for a PhD student!

I am looking for a PhD student to work on seed dispersal, connectivity and genomics of palms with megafaunal fruits on Madagascar – the position can be started as soon as possible, and the student will be located at the German Centre for Integrative Biodiversity Research (iDiv) in Leipzig, Germany.

Applications are accepted until 30th June 2018. To apply, see here: https://www.idiv.de/about_idiv/career.html 

Or download the advertisement here.

A bit more background….

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Extinct megafauna on Madagascar, image by VELIZAR SIMEONOVSKI

Madagascar harbours exceptional biodiversity, but this tropical hotspot also faces increasing threat from human activities and climate change. Plants with large, ‘megafaunal’ fruits are common across the flora of Madagascar, especially within the palm (Arecaceae) family. However, Pleistocene extinctions of large-bodied ‘megafaunal’ fruit-eating and seed-dispersing animals (such as giant lemurs) may have hindered the dispersal of taxa with megafaunal fruits. In this project we aim to investigate the micro- and macroevolutionary consequences of dispersal limitation for megafaunal-fruited palms on Madagascar, using a comparative framework. Specifically, we aim to (i) identify genomic signatures of dispersal limitation in megafaunal-fruited palm populations, (ii) reconstruct demographic history and identify historical genetic bottlenecks in these species, and (iii) evaluate whether these species may be adapting to dispersal by smaller-bodied frugivores, by evolving smaller fruits with smaller seeds. This project integrates the fields of plant evolution, phylogeography, and plant-frugivore interaction ecology. It will be in collaboration with researchers from Kew Botanical Gardens, UK (Dr. Bill Baker), Aarhus University, Denmark (Dr. Wolf Eiserhardt), the University of Amsterdam, the Netherlands (Dr. Daniel Kissling) and Botanic Garden of the Ruhr-University Bochum, Germany (Dr. Wolfgang Stuppy), among others.

Job description:
  • collecting genetic samples from palm populations on Madagascar, and measuring their functional traits;
  • identifying Malagasy frugivore communities and their functional traits;
  • using novel genomic techniques (e.g. RAD sequencing) to infer connectivity, demographic history and phylogeographical patterns;
  • writing and publishing of scientific papers in peer-reviewed journals;
  • presentation of results at international conferences;
  • participation in iDiv’s PhD training program yDiv.

Requirements:
Applicants should hold a Master’s or equivalent degree in a related field of research (e.g. ecology, (molecular) biology, genetics, phylogenetics, phylogeography). The successful candidate should be innovative, able to work on his or her own initiative, and willing to spend several months in the field (Madagascar). Therefore prior experience with tropical fieldwork and basic living conditions is advantageous. Furthermore, the successful candidate should have prior experience using molecular techniques, preferably with bioinformatics for large genetic/genomic datasets. An interest in acquiring additional necessary skills (e.g. programming) for handling and statistically analyzing large datasets is essential. Candidates should be team-oriented and have strong organizational skills, in order to manage this collaborative research project within an international consortium. Excellent English communication skills (speaking and writing) are required. We seek candidates with an independent mind and the ambition to publish in internationally leading journals.

Applications are accepted until 30th June 2018, the applicant is expected to start as soon as possible, but latest by September 2018.

For queries on the application process, please contact Dr. Nicole Sachmerda-Schulz (nicole.sachmerda-schulz@idiv.de); for research project questions, contact Dr. Renske Onstein (onsteinre@gmail.com).

IBS conference, Tucson

Last week I attended the 8th Biennial conference of the International Biogeography Society in Tucson, Arizona (U.S.A.). The conference included symposia on modelling large scale ecological and evolutionary dynamics, experimental macroecology and building up biogeography from process to pattern. I presented the first results of my work on what may happen to megafaunal-fruited palm lineages under rapid global environmental change. These species with anachronistic fruits (> 4 cm in length) suffer from dispersal limitation because of recent extinctions of their large-bodied (megafauna) fruit and seed dispersers, such as gomphotheres, ground sloths and glyptodonts. However, we do not know how these palms have survived and evolved in the past – and whether they have suffered from extinction previously, during Quaternary climate change for example. In this talk I showed how over the last 2.6 million years (the Quaternary) these megafaunal-fruited palm lineages have experienced increasing extinction rates, but only in the Americas, and how they have evolved smaller fruits in Southeast Asia and Australasia. These smaller fruits may be adaptations to bird-dispersal in these dynamic island systems.