Biogeography of biodiversity hotspots

Hotspots of biodiversity are areas where exceptional concentrations of endemics are undergoing exceptional loss of habitat (Myers et al. 2000). Most of the formally 34 identified biodiversity hotspots are located in tropical regions of developing countries that currently experience great threats to biodiversity and have scarce conservation resources.

We have developed collaborative networks to conduct biogeographic studies in biodiversity hotspots around the world. Study areas include formally identified hotspots (e.g. Wallacea, Sundaland, Cerrado) and other areas of exceptionally high species richness and/or renowned for their contribution to the development of evolutionary theory (e.g. Amazonia, Galapagos, Gulf of California). Our studies typically involve biogeographic and phylogeographic reconstructions using multiple codistributed species and populations. These studies have so far changed the general notion about patterns and tempo of evolution in some of these areas, provided insights about the relative roles of ecological and vicariant factors as drivers of diversification, and contributed to taxonomic and conservation efforts in these important regions (some examples below).   

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Research projects

 Comparative Biogeography of Lepidoptera in Wallacea
Wallacea is a biodiversity hotspot located between the Oriental and Australian regions that has been central to the development of evolutionary theory. Nonetheless, this zone is poorly known from biogeographical and molecular evolutionary perspectives. This project represents the first comparative molecular phylogenetic and biogeographic analysis of organisms co-occurring in the region: three widespread butterfly genera, CharaxesCethosia and Delias, each with numerous species with restricted distribution useful for biogeographical analysis. Phylogenetic divergences in each group appear consistent with morphological diversification and support ancient speciation events in Wallacea. So far we have reported on well-supported phylogenies for each group (see publication list) and are currently preparing a biogeographic redefinition of Wallacea based on the comparative dataset and inferred geological evolution of a palaeo micro-continent. Patterns and processes depicted in this study provide a useful framework for illuminating future studies on evolution and conservation of Wallacea’s historically isolated biodiversity. Team members and collaborators: C Muller and L Beheregaray (Macquarie and Flinders); N Wahlberg (University of Turku, Finland).

– Biogeography of Elasmobranchs from the Gulf of California, a Marine Hotspot
This project aims to understand historical and ecological factors that have influenced biogeographic history in co-distributed elasmobranchs from the Gulf of California (Mexico), a marine biodiversity hotspot. The fascinating Gulf of California (also known as the Sea of Cortez) ranks amongst the five most productive and biodiverse marine ecosystems in the world, and supports significant fisheries and tourism activities that are key to the national economy. Our study groups include sharks and rays of RhinobatosSquatinaMustelus and Rhizoprionodon. The project makes use of both nuclear and mtDNA data to assess phylogenetic relationships, phylogeography and seascape genetics in co-distributed samples. Team members and collaborators: J Sandoval-Castillo and L Beheregaray (Flinders), Oscar Sosa-Nishizaki (Center of Scientific Research of Ensenada, Mexico).

– Biogeography of Cerrado Herpetofauna – Origins, Evolution and conservation
The Cerrado (central Brazil) is one of the 34 global biodiversity hotspots for conservation. It is a savanna-like landscape with a complex and diverse vegetation structure that originally covered around 2 million km2. Much of the Cerrado is poorly sampled and only a few biogeographic and phylogeographic studies were conducted in the region. We are investigating biogeographic history of four co-distributed lizard species from the Cerrado using a combination of nuclear and mitochondrial DNA sequences. The species to be included are Gymnodactylus amarali (Phyllodactylidae), Micrablepharus atticolus (Gymnophtalmidae), Tropidurus itambere (Tropiduridae) and Anolis chrysolepis (Polychrotidae). Team members: Fabricius Domingos and Luciano Beheregaray (Flinders) and Guarino Colli (University of Brasília, Brazil).

– Biogeography of Amazonian Fishes
The Amazon Basin is the hottest in the world in fish diversity. We are sudying evolution and biogeography of co-distributed Amazonian fishes sampled over the last ten years along the basin’s four major rivers (Amazonas, Negro, Tapajos and Madeira). We have produced several papers that pioneered the combination of population genomics with large-scale phylogeographic datasets to understand evolution in Amazonia. We have reported on an extensive number of cryptic species in Amazonian fishes and on speciation events caused by Andean neotectonics or divergent natural selection. Team members and collaborators: L Beheregaray, G Cooke, M Sistrom, M Piggott and S Corrigan (Macquarie), N Chao (UFAM, Brazil), G Caccone (Yale).

– Biogeography of Galapagos Giant Tortoises
The Galapagos Islands contain some of the world’s most remarkable biological radiations and offer an exceptional natural laboratory to study evolution. These isolated islands have provided opportunities for rapid colonization and speciation and have a geological record that can be used to estimate the chronology of biogeographic and evolutionary events. This project (based at Yale at headed by Gisella Caccone and Jeff Powell), uses a combination of molecular, morphological and field-based approaches to understand the evolutionary history and inform the conservation management of the iconic radiation of Galapagos giant tortoises. Key findings include the effects of a prehistoric volcanic eruption in population demography and evolution, a biogeographic reconstruction of a complex adaptive radiation associated with oceanography and volcanism, the implications of island colonization and diversification for conservation of endangered species and the rediscovery of extinct species using genetic data from extant and extinct populations. Team members include: G Caccone and J Powell (Yale), L Beheregaray (Flinders), C Ciofi (Univ of Florence), M Russello (UBC), N Poulakakis (Univ of Crete), J Gibbs (Univ of New York at Syracuse).

Select Publications

– Beheregaray LB, Ciofi C, Geist D, Gibbs J, Caccone G, Powell JR (2003) Genes record a prehistoric volcano eruption in the Galápagos. Science 302, 75.

– Beheregaray LB, Ciofi C, Caccone G, Gibbs J, Powell JR (2003) Genetic divergence, phylogeography and conservation units of giant tortoises from Santa Cruz and Pinzón, Galápagos Islands. Conservation Genetics 4, 31-46.

– Beheregaray LB, Havill N, Gibbs J, Fritts T, Powell JR, Caccone G (2004) Giant tortoises are not so slow: rapid diversification and biogeographic consensus in the Galápagos. Proceedings of the National Academy of Sciences USA 101, 6514-6519.

– Ciofi C, Wilson GA, Beheregaray LB, C Marquez, J Gibbs, W Tapia, H Snell, Caccone G, Gibbs J, Powell JR (2006) Phylogeographic history and gene flow among giant Galápagos tortoises on southern Isabela island. Genetics 172, 1727-1744.

– Beheregaray LB, Caccone A (2007) Cryptic biodiversity in a changing world. Journal of Biology 6, 1-5.

– Russello MA, Beheregaray LB, Gibbs J, Fritts T, Havill N, Powell JR, Caccone A (2007) Lonesome George is not alone among Galápagos tortoises. Current Biology 17, R317-R318.

– Beheregaray LB (2008) Twenty years of Phylogeography: the state of the field and the challenges for the Southern Hemisphere. Molecular Ecology 17, 3754-3774.

– Poulakakis N, Glaberman S, Michael R, Beheregaray LB, Ciofi C, Powell JR, Caccone A (2008) Historical DNA analysis reveals living descendants of an extinct species of Galapagos Tortoise. Proceedings of the National Academy of Sciences USA 105, 15464-.

– Cooke GM, Chao NL & Beheregaray LB (2009) Phylogeography of a flooded forest specialist fish from central Amazonia based on intron DNA: the cardinal tetra Paracheirodon axelrodiFreshwater Biology 54, 1216-1232.

– Corrigan S, Beheregaray LB (2009) A recent shark radiation: molecular phylogeny, biogeography and speciation of wobbegong sharks (Orectolobidae). Molecular Phylogenetics and Evolution 52, 205-216.

– Sistrom MJ, Chao NL, Beheregaray LB (2009) Population history of the Amazonian one-lined pencilfish based on intron DNA data.  Journal of Zoology 278, 287–298.

– Teske PR, Beheregaray LB (2009) Evolution of seahorses’ upright posture was linked to Oligocene seagrass expansion. Biology Letters 5, 521-523.

– Faulks LK, Gilligan DM, Beheregaray LB (2010) Clarifying an ambiguous evolutionary history: range-wide phylogeography of an Australian freshwater fish, Golden Perch (Macquaria ambigua). Journal of Biogeography 37, 1329–1340.

– Faulks LK, Gilligan DM, Beheregaray LB (2010) Evolution and maintenance of divergent lineages in an endangered freshwater fish, Macquaria australasicaConservation Genetics 11, 921–934.

– Müller CJ, Beheregaray LB (2010) Paleo-Island affinities revisited: Biogeography and systematics of the genus Cethosia (Lepidoptera: Nymphalidae). Molecular Phylogenetics and Evolution 57, 314-326.

– Müller CJ, Wahlberg N, Beheregaray LB (2010) ‘After Africa’ – The Evolutionary History and Systematics of the genus Charaxes Ochsenheimer (Lepidoptera: Nymphalidae: Charaxinae) in the Indo-Pacific Region. Biological Journal of the Linnean Society 100, 457–481.

– Piggott M, Chao NL, Beheregaray LB (2011) Three fishes in one: cryptic species in an Amazonian floodplain forest specialist. Biological Journal of the Linnean Society 102, 391–403.

– Cooke G, Chao NL, Beheregaray LB (2012) Biogeographic history of the croaker genus Plagioscion (Sciaenidae): marine incursions, cryptic species and ecological diversification in Amazonia. Journal of Biogeography 39, 724-738.

– Cooke GM, Chao NL, Beheregaray LB (2012) Divergent natural selection with gene flow along major environmental gradients in Amazonia: Insights from genome scans, population genetics and phylogeography of the characin fish Triportheus albusMolecular Ecology  21, 2410–2427.

– Cooke GM, Chao NL, Beheregaray LB (2012) Natural selection in the water: freshwater invasion and adaptation by water colour in the Amazonian pufferfish. Journal of Evolutionary Biology 25, 1305-1320.

– Cooke GM, Chao NL, Beheregaray LB (2012) Five cryptic species in the Amazonian catfish Centromochlus existimatus identified based on biogeographic predictions and genetic data. PLoS ONE 7(11): e48800

– Cooke GM, Landguth EL, Beheregaray LB (2014) Riverscape genetics identifies replicated ecological divergence across an Amazonian ecotone. Evolution 68, 1947-1960.

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