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This research investigates the mechanisms underlying species tolerance of extreme environments, focusing on pika (genus Ochotona). There are 30 pika species, each occupying a unique elevational range between 0 - 6400 m with the highest concentration of species diversity in the Himalayas and Tibetan Plateau region. Limited oxygen at high elevation critically stresses aerobic metabolism; however, little is known about how pikas are capable of tolerating the extreme hypoxia of their high-elevation habitat. Additionally, climate change is causing many pika populations to shift their ranges even higher in elevation.
Bats have been identified as the reservoirs for a number of emerging infectious diseases but most of these pathogens have coevolved with their hosts for long periods of time without causing issue. We are seeking to understand the potential sources, sinks and pathways of zoonotic infection in a countryside landscape that is home to one of the most diverse bat faunas in the world by examining bats and livestock as well as surveying human behavior.
We take an interdisciplinary approach to reconstruct recent extinctions in the Caribbean across the past 15,000 years, and leverage these data towards guiding conservation planning in the region under a changing climate and growing human population. Techniques include genomics, stable isotopes, radiocarbon dating, and morphometrics.
Costa Rica is home to one of the richest, most ecologically diverse bat faunas in the world and is also subject to widespread habitat conversion like many developing nations. We seek to understand how bat ecology and deforestation affect infections in bats as well as how ecologically diverse bats may have evolved to deal with their infections.
Species are shifting their ranges due to climate change, many moving to cooler and higher locations. However, with elevation increase comes oxygen decline, potentially limiting a species’ ability to track its environment depending on what mechanisms it has available to compensate for hypoxic stress. Pikas (Family Ochotonidae), cold-specialist small mammal species, are already undergoing elevational range shifts. We collected RNA samples from one population of Ochotona roylei in the western Himalaya at three sites – 3,600, 4,000, and 5,000 meters – and found no evidence of significant population genetic structure, nor any loci under positive selection between sites. However, out of over 10,000 expressed transcripts, 26 were significantly up-regulated at the 5,000 m site and were significantly enriched for pathways consistent with physiological compensation for limited oxygen. These results suggest that differences in gene expression alone may enable hypoxia tolerance on this local scale, indicating elevational flexibility that may facilitate successful range shifts in response to climate change.
Anthropogenic pressures (e.g. poaching) have tremendously reduced the black rhinoceros (Diceros bicornis) distribution and population size. While conservation efforts have been effective, doubling the population size over 20 years from a low of 2,400 individuals, the species remains critically endangered and populations must be actively protected from poaching. We are sequencing hundreds of low coverage genomes from one of the largest collections of rhino tissue samples collected to date in Africa to 1) determine parentage for offspring and evaluate the effect of management actions (e.g. dehornings, translocations) on reproductive success and breeding patterns and 2) determine relevant genetic characteristics of each population. Our results will be directly applicable to the genetic and demographic management of free-ranging populations and especially to the planning of rhino re-introduction projects.
ELIZABETH A. HADLY<br/>PROFESSOR, DEPARTMENT OF BIOLOGY <br/>DEPARTMENT OF GEOLOGICAL SCIENCES, BY COURTESY<br/><br/>Professor Hadly uses a combined field and laboratory approach to examine how ecological perturbations link or decouple levels of biological organization, because understanding the links among ecosystems, species, populations and genes is central to understanding how organisms exist, evolve and become extinct. She addresses problems in organismal biology from both evolutionary and ecological perspectives, primarily using extant species. One of the unique aspects of her overall approach is the focus on the decadal to millennial time scale, a scale that is little studied, although it is a scale that is integral to understanding links between ecology and evolution, and increasingly important to understand the impacts of the Anthropocene.