University of Exeter │Royal Botanic Garden Edinburgh
Tropical dry forest
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.
The Latin American Seasonally Dry Tropical Forest Floristic Network (DRYFLOR; http://www.dryflor.info/), including more than 70 scientists and conservationists from across Latin American and the Caribbean, has developed an unprecedented database of dry forest tree species, based upon 1602 inventories across Latin America and the Caribbean.
In a paper published in the journal Science, we show 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. (For more details visit http://elmer.rbge.org.uk/dryflor/
Work on dry forests has been taken forward by two grants from the Research Council UK - Brazil (CONFAP) Newton Fund. The first, “Dry forest biomes in Brazil: biodiversity and ecosystem services” 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", RBGE and U Exeter are delivering the biodiversity component of an integrative project that seeks 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.
Tropical dry forests: DRYLFLOR's first paper on the cover of Science, 23rd Sept 2016
Rio Mantaro valley, Peru
Browningia pilleifera (Ritter) Hutchison
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
Taxonomic and biogeographic work focuses 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 have been a key focus for 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: LPWG (2013). Legume phylogeny and classification in the 21st century: progress, prospects and lessons. Taxon 62: 217–248. More recently, LPWG has published a new classification for the entire family.
Recent exciting news (March 2017) is the award of a BBSRC Global Challenges Research Fund grant: “Improving agroforestry and silvopastoral systems in Latin America by maximising species and genetic diversity of the multipurpose legume Inga”. This collaboration with the Royal Botanic Gardens, Kew and partners in Brazil including the National Amazon Research Institute (INPA) and the State University of Mato Grosso (UNEMAT) focuses on the neotropical tree genus Inga, which has been a subject of our evolutionary and biogeographic research.
Inga species are fast growing trees able to capture nitrogen from the atmosphere and fertilise the soil around them. They can be grown in poor, degraded soils, out-competing weeds and invasive species. Agroforestry and silvopastoral systems, which incorporate trees such as Inga into crop and livestock systems, have been shown to make a dramatic impact on the maintenance and restoration of long-term productivity in agricultural landscapes, including degraded and abandoned land, and are well suited to use by poor rural smallholders. They can provide major benefits through enhanced livelihoods and food security, as well as to local economies.
The project will apply state-of-the-art genetic approaches to identifying the most suitable Inga species for agroforestry and silvo-pastoral systems. Critically, this selection of species will be done in consultation with stakeholders and smallholders, to ensure uptake and use of the selected species. Ultimately, the goal of the project is better agroforestry and silvopastoral systems based on a wider range of Inga species that could be deployed across Latin America.
Andira anthelmia (Vell.) MacBride
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 (Bentham) Hauman
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.
Phylogeny and biogeography
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.
Recent research has been focused by two grants from the UK Natural Environment Research Council and the US National Science Foundation Dimensions of Biodiversity programme
Phylogeny of Cyathostegia mathewsii (Benth.) Schery
Pennington R.T., Lavin M, Hughes C., Sarkinen T, Lewis G, Klitgaard B. 2010. Differing diversification histories in the Andean biodiversity hotspot. Proceedings of the National Academy of Sciences, USA 107: 13783-13787.
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 disitnct in different biomes.This paper provided an examples of how clades endemic to seasonally dry tropical forest show older, geographically structured patterns, contrasting more recent, geographically unstructured rain forest and savanna diversifications. It demonstrated extraordinary antiquity (c. 5 million years) of conspecific populations of the legume shrub Cyathostegia matthewsii suggesting Andean dry valleys are museums of diversity that merit much greater conservation protection
Savanna ("cerrado") in central Brazil
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 (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.
Recent work has focused on the evolution of the unique, fire adapted cerrado flora, and has demonstrated that evolutionary transitions to this biome have been frequent and recent, with publications including:
Simon, M., Grether, R., de Queiroz L.P., Skema C., Pennington, R.T. & C.E. Hughes . (2009) Recent assembly of the Cerrado, a neotropical plant diversity hotspot, by in-situ evolution of adaptations to fire. Proceedings of the National Academy of Sciences, USA 106: 20359-20364.
Pennington, R.T. & Hughes, C.E. (2014). The remarkable congruence of New and Old Wold savannah origins. New Phytologist (2014) 204: 4–6
A focus genus for my research on diversification in tropical rain forests over the past decade has been Inga (Leguminosae), which is species-rich (300 spp.), widely distributed, 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 (http://www.pnas.org/content/114/10/2645.abstract)
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 a BBSRC Syntax grant. Our work addresses how plant defences against herbivores have evolved and how have they influenced species radiations in the tropics. These projects also 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. We are taking these next-generation DNA sequencing methods in an applied context to pinpoint Inga species useful in agroforestry systems, in a new BBSRC GRCF project.
Tropical dry forest, Mantaro valley, Peru
Niche evolution of South American trees and its application to conservation
At RBGE I led a NERC Standard Grant in partnership with ecologists at the University of Leeds that takes advantage of tree inventories (many by RBGE scientists), covering more than 1000 sites in three major biomes in South America: rain forests, dry forests and savannas. We are investigating how many times lineages of trees have switched between the different biomes, which will deliver important knowledge for future studies of evolutionary diversification and especially conservation. 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.
DRYFLOR project workshop and fieldwork, Salta, Argentina, February 2014
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)
Rosalía Piñeiro (UK/Spain)
Rosalía is a BBSRC-funded postdoc working on a Global Challenges Research Fund project that aims to improve agroforestry systems in Brazil based on the legume genus Inga
Peter Moonlight (UK)
Peter is a postdoc working on the dry forests of NE Brazil via the "Nordeste" project
Julia Weintritt (Poland/UK)
DRYFLOR project network co-ordinator
James Nicholls (Australia/UK)
James was an NSF Dimensions of Biodiversity funded postdoc working on phylogenetics of Inga and it herbivores who is now back home in his native Australia working at CSIRO
Danilo Neves (Brazil)
Danilo was a recent NERC-funded postdoc who worked on niche evolution of South American trees. He has recently won a professorship at the prestigious Universidade Federal de Minas Gerais in Belo Horizonte - well done Danilo!
Karina Banda Rodriguez (Colombia)
Recent PhD student and DRYFLOR project partner for Colombia. Karina’s 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 is now a postdoc at the University of Leeds based in Peru.
Flávia Fonseca Pezzini (Brazil)
Current PhD student: Biogeography and systematics of Ceiba in neotropical dry forests
Pedro Miranda (Brazil)
Pedro is a PhD student co-supervised with Kyle Dexter (U Edinburgh) who works on the nature and definition of biomes in tropical Latin America
Jess Rickenback (UK)
Jess is a PhD student at the University of Edinburgh and RBGE studying the biogeography and ecology of high rainfall savannas
Vanessa Rezende (Brazil)
Recent 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.
Anne Bruneau (Canada)
Professor at the University of Montreal and Director of Science at Montreal Botanical Garden. On sabbatical at RBGE from July to December 2015, she led work resulting a a new classification for the legume family published by the Legume Phylogeny Working Group
University of Exeter and Royal Botanic Garden Edinburgh
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.
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.