Models of population divergence have mostly been developed and validated for temperate zones or rainforests, and their generality to other habitats is largely unexplored. This project will use a rigorous statistical hypothesis-generating and molecular-testing framework to investigate the diversification processes of three diverse groups of lizards widely distributed across the eastern-central South American ?dry diagonal? biomes, which are species-rich but historically neglected. The main goals are (1) to use modeling to predict stability areas across past climatic fluctuations, (2) based on the stability surface, to generate and test genetic predictions for expected diversification histories using multiple genetic markers and integrative analytical approaches, and (3) to use a model-based comparative approach to test for spatial and temporal co-divergence in the three lizards groups.
Diversification studies can help elucidate how species and genetic diversity originated and have been maintained, which are essential parameters to endorse conservation decisions. The project focuses on a sub-continental scale that enhances opportunity for international collaboration. The genetic results will reveal new species, and the resources generated (specimens, tissues, sequences, and palaeo models) will be available to the community on public databases so they can be compared to other biomes and taxa.
Major Goals: This award supported the PhD project of Brazilian student Fernanda Werneck, which centered on the open biomes forming the "dry diagonal" that extend along a southwest-northeast axis south of the Amazon Basin. These include Caatinga, Cerrado, and Chaco that are characterized by large numbers of unique poorly known species that are threatened by rapid habitat loss. This project addressed the following: (1) How many Quaternary refugia existed over the past 120,000 yrs, and where were they? (2) Refugia identified by paleo-distribution modeling provided genetic predictions for the phylogeographic histories of three lizard species co-distributed across this region: stable refugial areas should have population genetic "signatures" of high variability/deep genealogies indicative of long-term persistence, whereas lower genetic variability/shallow genealogies would characterize younger populations that have recently dispersed out of the refugia. (3) This "historic Quaternary climate stability" hypothesis was then contrasted with the "ancient divergence" hypothesis derived from patterns of plant endemism and time-calibrated phylogenies of other taxa, using multi-locus phylogeographic methods for the gecko Phyllopezus pollicaris (for which the largest number of samples was available over the broadest geographic area). (4) Work continues on two other lizard species broadly co-distributed with P. pollicaris and each with other, Micrablepharus maximiliani and Vanzosaura rubricauda, for a comparative phylogeographic study of spatial & temporal co-divergence among these three. Major Accomplishments/Dissemination of Results: Dr. Werneck published a review of dry diagonal biogeography (Werneck 2011; Quaternary Science Review), completed fieldwork in 2011-12, and amassed almost 400 tissues of P. pollicaris from 68 localities representing most of the dry diagonal region, including refugial and non-refugial areas to test the phylogeographic predictions. Sequences were collected for two mitochondrial and 11 nuclear genes, and the same strategy was used for 258 individuals/45 localities for M. maximiliani, and 161 individuals/34 localities for V. rubricauda. Dr. Werneck’s remaining thesis chapters included paleo-distributional modeling studies of the Caatinga (Werneck et al 2011; Global Ecology & Biogeography) and the Cerrado (Werneck et al 2012; Jour. of Biogeography) biomes, the phylogeographic study of P. pollicaris (Werneck et al. 2012; Evolution), and a collaborative phylogenetic study of the genus Phyllopezus (Gamble et al. 2012, Molecular Phylogenetics & Evolution). Her studies show that most speciation in P. pollicaris complex occurred in the Miocene, with Pleistocene climate fluctuations having little influence. Tests of three alternative speciation hypotheses suggest two rounds of allopatric and then ecological/sympatric speciation, with the distributions of the three clades derived from these events largely coinciding with the Chaco, Cerrado, and Caatinga formations. At least genetic groups likely represent new species, a result with strong implications for alpha taxonomy, biodiversity assessments, and conservation planning. Dr. Werneck defended her dissertation in June/2012, and was awarded the PhD in August/2012. Dr. Werneck returned to Brazil to a post-doc at the University of Brasilia (UnB; Sept. 2012 – Oct. 2013), where she taught classes and prepared for analyses the sequences collected for the two other lizard taxa. In November 2013 she was hired as a Researcher at Instituto Nacional de Pesquisas da Amazônia (INPA), in Manaus. INPA (www.inpa.gov.br/index.php) is the leading Brazilian research institution with a primary focus on Amazonian biodiversity and global Tropical Biology; she was hired as the vice-curator of the Reptile-Amphibian Collections that house 35,000+ specimens. BROADER OUTCOMES: Since 2011 Dr. Werneck attended seven workshops (US, Brazil, and Portugal), contributed eight oral/poster presentations, co-authored 7 non-thesis papers, and an invited book chapter (historical biogeography of the dry diagonal biota). While at BYU she mentored Sites’ Peruvian PhD student C. Aguilar in all aspects of DNA extraction/amplification/sequencing/basic phylogenetic analyses. She recently co-taught a ‘Statistical Phylogeography’ workshop with three colleagues at the Centro Nacional Patagonico (CENPAT-CONICET) in Puerto Madryn, Argentina (May-2014), and since returning to Brazil, she has taught graduate courses in: Phylogenetic Systematics, Reptile Biology, Evolutionary Biology, Community Ecology, and Ecology and Evolution, at UnB, INPA, & the Federal Univ. of Amazonas. She currently mentors 2 undergraduates (1 at UnB and 1 at INPA), 5 MS (1 UnB, 1 Museu Paraense Emilio Goeldi, and 3 at INPA), and co-advises 1 UnB PhD student. She is now analyzing data for the comparative phylogeographic study of the 3 lizard species she studied, but she can now also include frog species for which her students are collecting data, thereby increasing the generality of this study. Dr. Werneck’s ‘biodiversity prediction’ approach contributed to broader knowledge of whether ‘historic climate stability’ or ‘ancient divergence’ are more important explanations of Neotropical diversity, and her results (explicit georeferenced diversification models) are open to further testing either by non-molecular data (species occurrence, endemism data) or by molecular studies of other dry diagonal taxa. Her papers have been cited and several researchers have requested her paleo-models and stability surfaces for use in their own studies; these include: Pinheiro et al. 2013 (Evolution), and Turchetto-Zolet et al. 2013 (Molecular Ecology).
