Michael Harvey, Ph.D. - US grants

The project will address the controversy surrounding the impact of base level change on channel response, on the magnitude of the upstream influence, on the nature of valley-filled deposits associated with base-level rise, and on the nature and distribution of sedimentary deposits on shelves of different slopes, by a series of experimental studies in large flumes and in a rainfall-erosion facility. The objectives are to determine: a) the effect of base- level change on meandering and braided streams; b) the effect of the rate and magnitude of base-level change; c) the effect of subaqueous slopes on channel response; d) for different magnitudes of base-level changes, the upstream progression of erosion and deposition for valleys of different slopes and widths; and e) the long-term effect of grade-control structures on valley morphology, channel stability, and sediment yield. The results will be applied to erosion control measures that can reduce sediment yields and stabilize actively eroding steeplands for long periods of time.

The production of species diversity is of fundamental interest, but the factors that cause diversification are poorly understood. Diversification is known to occur at different rates depending on the species or group of species involved, and comparative study of this variation can reveal the processes that promote diversity. Comparative phylogeography is the study of diversification at the population level within different species, and it allows us to observe differences in diversification at the point where speciation occurs. The goals of this study are to use comparative phylogeography and novel methods of generating data to detect differences in diversification across species, and to analyze the factors that promote faster diversification in some species than in others. Phylogeography will be compared across sixteen Amazonian bird species with similar distributions. A new set of genetic markers scattered across the genome will be used to generate data from 24 individuals of each species. These genetic sequences will be extracted from museum tissue samples using a new method of enriching genomic DNA for sequences of interest, and then sequenced on a next-generation sequencing instrument. New analytical tools for testing models will allow us to measure the processes that are most important in driving the diversification of a given species. The massive amount of data generated by this method will allow for analysis of more complex models than could ever be analyzed previously, giving us new insight into the processes promoting species diversity.

This project provides research opportunities for undergraduate students in Louisiana and the geographic scope of the project fosters inter-institutional and international collaborations. The research provides a test of next-generation sequencing methods and a new genomic marker set, and our results will aid in the application of these methods to other study systems. New biogeographic and geographic genetic data from our work support conservation efforts in the Amazon. All specimens, audio recordings, and observational data from our fieldwork and genetic data from our lab work are deposited in publicly accessible collection and databases. We consider these resources invaluable for current and future, pure and applied research on Amazonian birds and other systems.

An international team of researchers from the University of Texas at Arlington, the Indonesian Institute of Sciences, Broward College, and 15 other institutions in 11 countries, will fill in a massive gap in global biodiversity awareness through a large scale inventory of reptiles (snakes, lizards, crocodiles and turtles) and amphibians (frogs and caecilians) from the Javan and Sumatran montane forests of Indonesia. As of today, the biodiversity of these tropical montane highlands is very poorly known. Previous work hints that these areas may be some of the most species rich on earth, and may contain vast numbers of endemic species with restricted ranges.

These species represent the largest number of vertebrate animals yet to be discovered and described by scientists.The survey will likely discover hundreds of new species from this poorly known area of the world and will result in educational and research partnerships between Indonesia and the USA. As a benefit to the scientific community, the project will produce modern specimen repositories and web-based resources for identification and conservation management, and for genetic and biodiversity work.

The Neotropical region includes Central and South America and the Caribbean and contains the highest diversity of birds of any region on the planet. Roughly one in three birds in the Neotropics is from a group called the suboscine passerines. The suboscines are diverse in form and function and are an important component of the bird life in habitats ranging from tropical rainforests to alpine grasslands and rocky coastlines. The origins of this diversity – the tempo and mode of species formation – have been studied through prior NSF-funded work. However, this work did not contain sufficient sampling to capture the most recent and ongoing speciation events. These recent speciation events are the most critical for evolutionary research because they tell us about where and why new species are forming currently. High-resolution sampling also provides the information necessary to identify new species and revise species classification. In this project, the investigators are completely sampling suboscine diversity, obtaining new vouchered samples and adding genomic data from 1,548 missing populations in order to resolve the species limits in the group and provide a comprehensive framework for research on diversification. This work integrates a concerted program for recruiting and retaining underrepresented students in biodiversity science in three underserved geographic areas: Appalachian Tennessee, Louisiana, and majority Hispanic communities in west Texas. It involves a new program on avian diversity at the K–12 level, development of a dedicated module on biodiversity genetics for undergraduate Genetics students, and support for graduate and post-graduate researchers to conduct research.

The unifying principle of this project is that a completely sampled phylogeny of all suboscine evolutionary units is needed to provide the foundation for systematic revision as well as improved capacity for research on speciation and evolution in the group. The researchers are leveraging the well-sampled suboscine passerine radiation (1,323 currently recognized species, plus 1,875 subspecies) to complete two primary aims. First, they are using field work, existing genomic resources, and historical DNA approaches to obtain genomic data from all 1,548 unsampled taxa, including all subspecies, in the group and estimate a complete, time-calibrated phylogeny. Second, they are using this phylogeny to conduct a re-assessment and revision of suboscine systematics at the genus, species, and subspecies levels within a hypothesis-testing framework. Because the phylogeny contains information on all lineage divergences in suboscines even those between the youngest taxa, it provides an invaluable resource for researchers interested in detailed diversification dynamics, modes of speciation, avian evolution at a range of timescales, molecular evolution, and species concepts and delimitation. The new specimens, genetic samples, and genomic data being obtained are also invaluable. Together, this work and its results are providing a high-resolution picture of how diversity has evolved in a species-rich tropical group that contributes to one of the major biodiversity hotspots on the planet.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.