Dry forests in Latin America are amongst the world’s most threatened tropical forests. Less than 10% of their original extent remains in many countries, much less than many rain forests such as Amazonia that remains approximately 80% intact. Dry forests were the cradle of pre-Colombian civilisation in Latin America, and the source of globally important crops such as maize, beans, peanuts and tomato, but despite this and their widespread destruction, they have been long-overlooked by scientists and conservationists.
In 2013, with support from a Leverhulme Trust network grant, I established The Latin American Seasonally Dry Tropical Forest Floristic Network (DRYFLOR), which now includes more than 100 scientists and conservationists from across Latin American and the Caribbean. DRYFLOR has developed a database of dry forest tree species, based upon floristic inventories across Latin America and the Caribbean. The most recent phase of DRYFLOR, supported by CYTED was led by Karina Banda and Ricarda Riina, network partners for Colombia and Venezuela. We have added plot-based species abundance data to our database and increased DRYFLOR’s conservation links. DRYFLOR is now part of the SYSTREESYS project funded by The French Foundation for Biodiversity Research (FRB) that will synthesize knowledge of Latin American tree species diversity across multiple biomes in order to dissect the patterns diversity and abundance.
In a paper published in the journal Science, based upon 1602 inventories across Latin America and the Caribbean, DRYFLOR showed that these dry forests contain a remarkable 6958 species of woody plants. Our data demonstrate that the species found in different regions of dry forest are seldom shared, meaning that each contains species growing nowhere else. This conveys a simple but urgent message that numerous protected areas across many countries will be needed to protect the full diversity of dry forests. In the light of probable warmer climates in the tropics, conservation of unique dry forest species that have adaptations to heat and drought should be global priority.
DRYFLOR’s results provide a scientific framework within which, for the first time, national decision makers can contextualise the significance of their dry forests at a regional and continental scale.
Work on dry forests has subsequently been taken forward by other grant-funded projects. “Dry forest biomes in Brazil: biodiversity and ecosystem services” (Research Council UK - Brazil (CONFAP) Newton Fund) aimed to develop UK leadership in monitoring of biodiversity, carbon stock, carbon balance and tree mortality in Latin America beyond rain forests and into dry biomes. In the second, "Nordeste: new science for a neglected biome", (NERC-FAPESP Newton Fund) RBGE and U Exeter delivered the biodiversity component of an integrative project that sought to understand how Brazilian dry forests function and how they will fare in changing climates alongside collaborators from Imperial College and the University of Reading. This included establishing more than 30 permanent monitoring plots. “Restoring Neotropical dry ecosystems - is plant functional composition the key to success?” (NERC_FAPESP), led by Lucy Rowland aims to improve restoration outcomes in Brazil’s caatinga and cerrado. Most recently, I am part of the NERC Large Grant “SECO: Resolving the current and future carbon dynamics of the dry tropics”
Neotropical dry forests are often typified by abundant cacti. This is a species endemic to the Marañon valley
DRYFLOR network fieldwork in Parque Nacional do Peruacu, Minas Gerais, Brazil, March 2015
Few people appreciate how much taxonomic work remains to be done in the tropics. In Latin America, the focus of my research, 20-40% of tree species, the critical ecological infrastructure of forests, are described as new in recent taxonomic monographs. Added to high species diversity, this leads to massive issues in making accurate plant species identifications in tropical biomes.
To address these taxonomic and identification issues I have been working to develop synergy between taxonomy and ecology in the tropics with focus on the value of long-term monitoring plots not just as tools for ecological observation but as platforms for biodiversity discovery. With support from NERC and NERC Newton ColombiaBio, recent work has emphasised the value of collection of high quality voucher specimens from inventory plots plus their free availability as online images, for example via the ForestPlots.net platform.
My taxonomic and biogeographic work has focused on the legumes (Leguminosae), the third largest family of flowering plants with about 19,500 species. Legumes provide food crops, timber, fodder and shade, and fertilise poor soils by nitrogen fixation in their roots. Known mostly for crops such as peas, beans and soya, legume trees also dominate tropical forests in the Neotropics and Africa.
Despite their ecological and economic importance, many legumes require basic taxonomic study in order to catalogue their species. For this reason, taxonomic monographs of these genera are a key focus for my research.
Broad-scale relationships within the legumes have also been poorly understood, meaning that the true relationships of economically important groups such as peas, beans, soya and lupins, and the evolutionary origin of the nitrogen-fixing symbiosis, remain obscure. Phylogeny reconstruction in several areas of the legume family has been at the centre of my research programme for two decades. These phylogenies have allowed a re-evaluation of how features such as legume flowers have changed over evolutionary time and can be used to study tropical biogeography and biome assembly.
Current phylogenetic efforts include playing a leading role in the Legume Phylogeny Working Group (LPWG), an international effort of numerous researchers that aims to develop collaborative research towards a comprehensive phylogeny and classification for Leguminosae. This included co-ordinating more than 40 authors for the group's first publication. More recently, LPWG has published a new classification and a taxonomic checklist for the entire family. Postdoc Rafaela Trad is currently using target capture DNA sequencing to improve phylogenetic estimates in subfamily Papilionoideae. This phylogeny will be used by Royal Society International Newton Fellow Moabe Fernandes to study large scale macro-ecological patterns and conservation priority in the Americas.
Andira is a genus of 29 species of neotropical trees, with one species also reaching Africa. See: Pennington, R.T. (2003). A monograph of Andira (Leguminosae-Papilionoideae). Systematic Botany Monographs 64 (145pp.; illus. 44 b+w).
Dussia, a genus of c. 20 neotropical rain forest trees is the current focus of my taxonomic research. This species from Colombia is one of eight new species that require description
Phylogenetic research has shown repeated reversals in papilionoid legumes from zygomorphic (e.g., Andira, Dussia above) to actinomorphic flowers. See:
Cardoso, D. de Queiroz, L., PENNINGTON, R.T., de Lima, H.C., Fonty, E., Wojciechowski, M.F. & Lavin, M. (2013). Revisiting the phylogeny of papilionoid legumes: new insights from comprehensively sampled early-branching lineages. American Journal of Botany 1991-2013.
Citerne, H., PENNINGTON, R.T. & Cronk, Q.C.B. (2006). An apparent reversal in floral symmetry in the legume Cadia is a homeotic transformation. Proceedings of the National Academy of Sciences, USA 103: 12017-12020.
Poissonia eriantha was known only from a type specimen and was not considered distianct from the related species P. orbicularis. However, our recent inventory work in Peru uncovered a new population from the Apurimac River basin in Peru. Our work has shown that P. eriantha is compeltely distinct, distinguished phenotypically and by DNA sequences. However, the species is critically endangered, given it is known from a single, tiny population in an area of seasonally dry tropical forest vegetation that is unprotected. See:
Pennington, R.T., Daza A & Lavin M. (2011). Poissonia eriantha (Leguminosae) From Cuzco, Peru: An Overlooked Species Underscores a Pattern of Narrow Endemism Common to Seasonally Dry Neotropical Vegetation Poissonia. Systematic Botany 36:59-68.
My research builds upon the foundation of taxonomy and inventory to address a fundamental question of tropical biology - how have the large numbers of plant species in the tropics arisen?
Prior research in my group has played a role in demonstrating that long-distance dispersal, often over major oceanic barriers, has played a key role in the assembly of tropical floras. it has also addressed the tempo of tropical plant species diversification, for example asking whether tropical plant species arose in the Pleistocene, perhaps in response to climatic changes.
Research has been funded by past and current grants from the UK Natural Environment Research Council, the UK Biotechnology and Biological Sciences Research Council, and the US National Science Foundation Dimensions of Biodiversity programme.
A distinctive strand of our work builds upon RBGE's long history of research in seasonally dry biomes and asks the question of whether evolutionary and biogeographic processes have been distinct in different biomes. This paper in PNAS provided an example of how clades endemic to seasonally dry tropical forest show older, geographically structured patterns, contrasting more recent, geographically less structured rain forest and savanna diversifications. It demonstrated extraordinary antiquity (c. 5 million years) of populations of the legume shrub Cyathostegia matthewsii suggesting Andean dry valleys are museums of diversity that merit much greater conservation protection
A focus genus for research on diversification in tropical rain forests over the past decade has been Inga (Leguminosae), which is species-rich (300 spp.), widely distributed across Latin America, and has consistently high local abundance and species diversity. It therefore provides an ideal system to investigate the origin and maintenance of tropical diversity. A recent paper investigates uses Inga as a case study to investigate the historical assembly of the world's most species-rich tree communities in Amazonia.
Work on Inga was supported by a US NSF Dimensions of Biodiversity grant (2012-2017) led by Phyllis Coley and Thomas Kursar of the University of Utah, and support from BBSRC (Syntax and GCRF). Our work has addressed how plant defences against herbivores have evolved and how have they influenced species radiations in the tropics. These projects offered an excellent opportunity to develop expertise in the application of next-generation sequencing to front-line tropical biodiversity problems – for example whether species delimited using traditional morphological taxonomic approaches contain biologically significant but cryptic diversity.
Most recently, a team from U Exeter, U Edinburgh, RBGE, U Zurich, U Utah and the Wellcome Sanger Centre received support from NERC to use genome sequencing to understand if hybridisation and associated polyploidy are a major driver of evolutionary radiation in Amazonian trees, further developing Inga as a study system. We are addressing three related questions: 1. Did hybridisation precede the Inga radiation and is it still continuing, thereby influencing diversification across the genus?; 2. Is there evidence for selection and preferential introgression of loci underlying chemical defence compounds in Inga; species, or conversely are these loci located in regions of key function that are immune to introgression? 3. Has recurrent polyploidy promoted diversification in Inga?
Because plants do not fossilise well in dry biomes, our understanding of biome origins is poor and dated phylogenies of lineages characteristic of biomes can offer new insights. For example the evolution of the unique, fire adapted cerrado flora, is recent and involved frequent evolutionary transitions. It seems the same is true for Africa.
The cerrado is the most species rich savanna in the world, containing at least 10,000 species, of which 40% are found nowhere else. RBGE's research in this biome was initiated by Dr James Ratter (“Jimmy”; in the centre of this photo) in 1967, when this biome was virtually pristine. Now more than 70% has been cleared, most recently by major agricultural expansion. Jimmy was an inspiration, my first boss and mentor. He sadly died in 2020, but you can read about his remarkable life and achievements here.
With support from NERC and in partnership with ecologists leading tree inventories covering more than 1000 sites, we are investigating how many times lineages of trees have switched between three major biomes in South America: rain forests, dry forests and savannas. We are using the species rich and ecologically dominant legume family as a proxy for tree diversity. If lineages have rarely switched between biomes, then each biome will contain a distinct subset of evolutionary diversity, and destruction of a single biome could wipe out an entire part of evolutionary history. Such scenarios of the destruction of an entire biome are not unlikely for the highly threatened savannas and dry forests.
Please click on "people" on the main menu bar at the top of the screen for full details of my research group, past and present.
Here are people working on current grant-funded projects and PhD students; for details of the Royal Botanic Garden Edinburgh Tropical Diversity group, please visit http://www.rbge.org.uk/science/tropical-diversity
Left to right: Luis Oakley, Luciano Gallotti, Darién Prado (Argentina), Gina Rodriguez (Colombia), Ricarda Riina (Venezuela), Julia Weintritt (Poland and RBGE), Patricia de Abreu Moreira (Brazil), Olga Martinez, Virginia Mogni (Argentina), Leandro Ferreira (Brazil), Karina Banda (Colombia and RBGE), Alfonso Delgado Salinas (Mexico)
Rafaela is a postdoctoral fellow at Royal Botanic Gardens Edinburgh, funded by the Botanics Foundation. Rafaela is working in collaboration with Greg Kenicer, Flávia Pezzini and Janet Sprent at RBGE, plus Felix Forest, Gwil Lewis, Bente Klitgaard and the PAFTOL project at RBG Kew. Her project focuses on phylogenomics of the pea-flowered legumes (Papilionoideae)
Julia is a postdoc funded by the Swedish Research Council (International Postdoc programme). She is working on phylogenetics, taxonomy, and biogeography of the legume Zygia, which is Inga’s sister genus. In Stockholm she works in Catarina Rydin’s group and in the UK with myself and Gwilym Lewis at Royal Botanic Gardens Kew.
Rowan is a Research Fellow working on a NERC funded project (2021-2024) to understand the significance of hybridisation in the evolution of the Amazonian tree flora, using the genus Inga as an exemplar. We’ll be searching for signals of hybridisation, introgression and polyploidy using genome re-sequencing, with a special emphasis on secondary chemistry. This project is in partnership with a fantastic team including University of Edinburgh and Royal Botanic Garden Edinburgh (Catherine Kidner, Kyle Dexter, Alex Twyford), University of Zurich (Colin Hughes, Erik Koenen), University of Utah (Phyllis Coley) and Wellcome-Sanger Centre (Mark Blaxter)
Moabe worked with prestigious Royal Society Newton fellowship (2021-23) on his project “Large scale macro-ecological patterns and conservation priority in the Americas: a view from the legume family”. He now has a postdoctoral position at Royal Botanic Gardens, Kew
Flávia worked with me for her Brazil government funded PhD: Biogeography and systematics of Ceiba in neotropical dry forests. She subsequently (2020-2021) worked with me as a postdoc on legume phylogeny and evolution. She has just gained a position working on bioinformatics at RBGE, so collaborations can continue!
Julieth was a postdoc working on the ecology and diversity of Andean forests in Colombia as part of the NERC-Newton funded BioResilience project (2020-2023). She has recently started a permanent position as a Biodiversity and Nature-based solutions at Fauna and Flora International. Congratulations Julieth!
Jehova had a prestigious Royal Society Newton International Fellowship was based in Exeter and working with Lucy Rowland and I on using tree function to understand vulnerability to climate change and protection strategies in the restinga vegetation of Brazil’s Atlantic forest. Jehova has recently started a permanent position at the Royal Botanic Gardens, Kew. Congratulations Jehova!
Saulo is pictured in the Inga species growth trial that he established as part of his postdoc in the BBSRC GCRF project “Improving agroforestry and silvopastoral systems in Latin America by maximising species and genetic diversity of the multipurpose legume Inga” (2018-2021). He took this work forward in our GCRF GRTA project “Diversifying tree based grazing systems to create smallholder price premium opportunities for milk production in the Amazonian Arc of Deforestation” and now has a permanent position working for ICRAF Brazil in Belém, Pará.
Rosalía was a BBSRC-funded postdoc (2018-2021) who worked on a Global Challenges Research Fund project that aimed to improve agroforestry systems in Brazil based on the legume genus Inga. She has won a fellowship (congratulations!) to move back to Spain (Universidade da Coruña) and we looking forward to continuing to collaborate on Inga.
Peter was a postdoctoral fellow who worked on the floristic diversity and evolution of the caatinga dry forests of Brazil, funded by the NERC-FAPESP Newton Fund “Nordeste” project (2017-2020) and a UKRI Covid Grant Allocation award to University of Exeter (2021). He then worked as a postdoc, with continued focus on tropical dry biomes as part of the SECO project. He cosupervises PhD student Mateus Cardoso. He has special interests in what biomes are and how we define them, as well as being a world expert on the genus Begonia. Peter has just won a permanent position at Trinity College, Dublin - Congratulations Peter!
Mário visited on sabbatical from 2019-2020. Despite the massive disruption of the covid-19 pandemic, he made excellent progress on papers promoting protection of threatened dry forests in Brazil and on examining the macroecological problem of the relation of range size and abundance in tropical dry forest trees.
Graeme was a recent (2018-2020) technician working on the NERC-FAPESP Newton-funded “Nordeste” project. He was based in the BioSciences labs in Exeter and produced DNA sequences for caatinga plants to generate community phylogenetic estimates and understand the nature of caatinga species. He is now working for the Tree of Life project at the Wellcome-Sanger Institute
Julia was DRYFLOR project network co-ordinator for the opening years of the network and continues to support us. She recent moved to a project administration position at the University of Cambridge - congraulations Julia!
James was an NSF Dimensions of Biodiversity funded postdoc working on phylogenetics of Inga and its herbivores who is now back home in his native Australia working at CSIRO on next-generation protocols for DNA data from museum collections
Danilo was a NERC-funded postdoc who worked on niche evolution of South American trees. He is now a professor at the prestigious Universidade Federal de Minas Gerais in Belo Horizonte. We continue collaborating on legume evolution and biome assembly, with Danilo winning recent support for this from Serrapilheira.
Karina was a PhD student (2012-2016) and played a central role in developing the DRYFLOR network. Her thesis, Floristics and conservation of dry forests across Latin America and the Caribbean, with particular emphasis on Colombia, was partly published in Science magazine. Karina moved to a postdoc at the University of Leeds, then led DRYFLOR’s new plot-based efforts as PI on a grant from CYTED, and is now based at iDv in Leipzig, where she is the lead postdoc on the SynTreeSys project on which DRYFLOR is a partner
Le Min is a PhD student at the University of Exeter working on phylogenetics, biogeography of the detarioid legume genus Sindora using target capture and RADseq approaches. She is cosupervised by Rowan Schley, Gwilym Lewis, Felix Forest (RBG Kew) and Manuel Estrella (University of Córdoba, Spain)
Leo is a PhD student at University of Exeter studying the role of legume trees in improving soils in agroforests and silvopastures in Amazonia and is cosupervised with Lucy Rowland, Fernanda Barros
Raissa is a PhD student at University of Exeter studying the role of native plants in restoring pastures in Brazil’s Cerrado savannas. I am a cosupervisor alongside Lucy Rowland and Fernanda Barros
Rosie is a NERC GW4 DTP and Royal Botanic Gardens, Kew funded PhD student based at the University of Exeter, working on the flora of rock outcrops in South America and its evolution. She is co-supervised by Lucy Rowland (Exeter), Alex Antonelli and Nicholas Hind (Kew). She is currently (from Feb 2024) on a maternity break looking after her beautiful new baby
Mateus is a new (2021) Exeter-based PhD student funded (with huge thanks to both) by University of Exeter alumni and WWF. He is co-supervised by Lucy Rowland an is working on restoration of Brazil’s highly threatened cerrado savannas
Kelly is a PhD student at the University of Edinburgh and Royal Botanic Garden Edinburgh working on the evolution and biogeography of the genus Inga in the Chocó biogeographic region in Colombia. She is co-supervised by Catherine Kidner and Kyle Dexter (University of Edinburgh)
Gustavo is a University of Edinburgh PhD student based at the Royal Botanic Garden Edinburgh and funded by the the Darwin Trust of Edinburgh. Gustavo’s project will use genome-sequencing to investigate the evolution of flower symmetry in legumes and also includes a vital taxonomic revision of the Amazonian legume genus Aldina
Lucy’s PhD is 'Using remote sensing to understand global change in the dry tropics', based at University of Edinburgh funded by the NERC SENSE CDT - Centre for Satellite Data in Environmental Science. She is studying how we can use remote sensing to map the diversity of vegetation in dry biomes across the tropics. She is cosupervised by Casey Ryan, Kyle Dexter (U Edinburgh), Oliver Phillips and Tim Baker (U Leeds)
Jess was a PhD student based at the University of Edinburgh School of GeoSciences and Royal Botanic Garden Edinburgh. Her project focused on the biogeography and evolution of the global savanna biome. Jess defended her PhD in March 2023 and subsequently won a (mostly) teaching position at GeoSciences at the University of Edinburgh - congratulations Jess! Jess recently invited me to collaborate on a fascinating project to look at the evolution fo geoxyles (“underground trees”) in the genus Parinari (Chrysobalanaceae)
Natalia was a University of Edinburgh PhD student based at the Royal Botanic Garden Edinburgh funded by the Darwin Trust of Edinburgh. Her project focused on using phylogenomic tools in the neotropical genus Guazuma to understand taxonomy, biogeography and evolution of drought tolerance. I was a cosupervisor along with Catherine Kidner and James Richardson, and Natalia successfully defended her thesis in August 2023. Congratulations Natalia!
Pedro was a PhD student co-supervised with Kyle Dexter (U Edinburgh). In a continuing collaboration with Kyle, we work on the nature and definition of biomes in tropical Latin America and globally. Pedro is now a postdoc in Belgium
Vanessa was a visiting PhD student to RBGE from Universidade Federal de Minas Gerais. Her visit resulted in the publication: Rezende V, Dexter KG, Pennington RT, Oliveira-Filho AT. (2017). Evolutionary diversity patterns across southern South America. Journal of Biogeography 44: 2365–2375.
I have always sought to develop impacts from my research to issues in tropical landuse and conservation.
Recent projects funded by BBSRC and the Global Challenges Research Fund worked with the inspirational NGO Instituto Ouro Verde (.“Institute of Green Gold”) to develop agroforestry and silvopastoral systems based on legume trees in Brazil’s “arc of Amazonian destruction”. These systems offer smallholders food security and increased income and are a real alternative to more environmentally damaging, large scale soy and cattle agriculture. Read about latest achievements here
I am also working with Dr Lucy Rowland on low cost, climate-smart solutions to restore Brazil’s highly threatened tropical savannas and dry forests, supported by NERC.
With Dr Ted Feldpausch and Dr Dunia Urrego, I am also working to understand historical, current and future resilience of Andean ecosystems in Colombia.
Prior work funded by the Darwin Initiative and Scottish Government provided user-friendly identification guides, to Peruvian tree species useful for agroforestry and reafforestation and genetic information on key agroforestry species.
Follow links to separate websites below each image for more details of projects including tropical landuse solutions and DRYFLOR
IngaSystems brings together three recent projects focused on agroforestry and silvopastoral systems in Brazil led from the University of Exeter. Scientists from Exeter, Royal Botanic Garden Edinburgh, Royal Botanic Gardens, Kew and University of Edinburgh have teamed up with the Instituto Ouro Verde (IOV) to create a social approach to sustainable tropical agriculture. The projects support and encourage local communities to adopt sustainable farming methods that provide food security and income whilst simultaneously improving tree cover and soil conditions in one of the most degraded areas of Amazonia. Thanks to our funder, the Global Challenges Research Fund, and see this report to read about latest achievements.
Latin American Seasonally Dry Tropical Forest Floristic Network (DRYFLOR)
DRYFLOR is a network of researchers and conservationists aiming to improve the understanding of the flora and to promote the conservation of the endangered seasonally dry tropical forests of Latin America and the Caribbean.
This website provides information about one of the world's most endangered types of tropical forest. It makes available a comprehensive woody floristic dataset for the biome, which is searchable and downloadable.
Thanks to our funders, the Leverhulme Trust and Cyted
(photo: Sam Bridgewater)
Conservation and Management of the Biodiversity of the Cerrado Biome
This website provides information the world’s richest savanna, the cerrado biome of Brazil. It makes available a comprehensive woody floristic dataset for the biome, which is searchable and downloadable.
Thanks to the Royal Botanic Garden Edinburgh (especially Dr Martin Pullan) for their help developing and hosting both this and the DRYFLOR database
