Two transects reveal remarkable variation in gene flow on opposite ends of a European toad hybrid zone

Microbial BiotechnologyAnimal science

Electromagnetic constraints on a melt region beneath the central Mariana back-arc spreading ridge

Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 13 (2012): Q10017, doi:10.1029/2012GC004326.An electrical resistivity profile across the central Mariana subduction system shows high resistivity in the upper mantle beneath the back-arc spreading ridge where melt might be expected to exist. Although seismic data are equivocal on the extent of a possible melt region, the question arises as to why a 2-D magnetotelluric (MT) survey apparently failed to image any melt. We have run forward models and inversions that test possible 3-D melt geometries that are consistent with the MT data and results of other studies from the region, and that we use to place upper bounds on the possible extent of 3-D melt region beneath the spreading center. Our study suggests that the largest melt region that was not directly imaged by the 2-D MT data, but that is compatible with the observations as well as the likely effects of melt focusing, has a 3-D shape on a ridge-segment scale focused toward the spreading center and a resistivity of 100 Ω-m that corresponds to ∼0.1–∼1% interconnected silicate melt embedded in a background resistivity of ∼500 Ω-m. In contrast to the superfast spreading southern East Pacific Rise, the 3-D melt region suggests that buoyant mantle upwelling on a ridge-segment scale is the dominant process beneath the slow-spreading central Mariana back-arc. A final test considers whether the inability to image a 3-D melt region was a result of the 2-D survey geometry. The result reveals that the 2-D transect completed is useful to elucidate a broad range of 3-D melt bodies.TM and NS are supported by the scientific program of “TAIGA” (Trans-crustal Advection and In situ reaction of Global sub-seafloor Aquifer)” sponsored by the MEXT of Japan, and are also supported by the JSPS for Grant-In-Aid for Scientific Research (21244070). Participation in the Marianas experiment by RLE and ADC was supported by NSF grant OCE0405641.2013-04-2

Landscape and Conservation Genetics of Amphibians and Reptiles in California

Examining patterns of diversity at fine and global spatial scales is an important component of to inferring underlying evolutionary mechanisms, understanding species distributional patterns, and informing conservation. Globally, amphibians and reptiles are among the fastest declining taxonomic groups, and now more than ever, it is necessary to quantify diversity and its spatial drivers in order to most effectively conserve species. In this dissertation, I examine the population, landscape, and conservation genomics of several species along a continuum of endangerment, from highly endangered and on the brink of extinction to widespread and abundant. Throughout, I use large-scale molecular data sets coupled with spatial analyses to examine spatial genetic diversity in these varied species. My goals were to contribute to our understanding of how genetic diversity is distributed across a multitude of landscapes and to provide genetic context for the conservation of these species. In Chapters 1 and 2, I examined how genetic diversity is spread across the limited ranges of two ecologically disparate species, California tiger salamanders, Ambystoma californiense, in Santa Barbara County, and the Panamint alligator lizard, Elgaria panamintina, found only in the isolated desert mountain ranges of eastern California, and found surprising parallels. In both, I found populations with exceedingly low levels of genetic diversity and genetic effective population sizes. For tiger salamanders, genetic diversity and divergence is strongly correlated with the number of suitable breeding habitats in regional neighborhoods and presence of natural vernal pools, while divergence across the range of E. panamintina is primarily mediated by geographic distance. In both cases, our findings have important implications for how management and mitigation efforts may more effectively assist the recovery and/or protection of these groups. In Chapter 3, I examined the drivers of spatial genetic structure in the widespread southern alligator lizard, Elgaria multicarinata. I found that patterns of genetic isolation are driven primarily by geographic distances, but that regional ecological niches have also diverged. Collectively, my work demonstrates the utility of integrating genetic and spatial analyses across spatial scales to help elucidate how genetic diversity is distributed across variable landscapes

Landscape and Conservation Genetics of Amphibians and Reptiles in California

Examining patterns of diversity at fine and global spatial scales is an important component of to inferring underlying evolutionary mechanisms, understanding species distributional patterns, and informing conservation. Globally, amphibians and reptiles are among the fastest declining taxonomic groups, and now more than ever, it is necessary to quantify diversity and its spatial drivers in order to most effectively conserve species. In this dissertation, I examine the population, landscape, and conservation genomics of several species along a continuum of endangerment, from highly endangered and on the brink of extinction to widespread and abundant. Throughout, I use large-scale molecular data sets coupled with spatial analyses to examine spatial genetic diversity in these varied species. My goals were to contribute to our understanding of how genetic diversity is distributed across a multitude of landscapes and to provide genetic context for the conservation of these species. In Chapters 1 and 2, I examined how genetic diversity is spread across the limited ranges of two ecologically disparate species, California tiger salamanders, Ambystoma californiense, in Santa Barbara County, and the Panamint alligator lizard, Elgaria panamintina, found only in the isolated desert mountain ranges of eastern California, and found surprising parallels. In both, I found populations with exceedingly low levels of genetic diversity and genetic effective population sizes. For tiger salamanders, genetic diversity and divergence is strongly correlated with the number of suitable breeding habitats in regional neighborhoods and presence of natural vernal pools, while divergence across the range of E. panamintina is primarily mediated by geographic distance. In both cases, our findings have important implications for how management and mitigation efforts may more effectively assist the recovery and/or protection of these groups. In Chapter 3, I examined the drivers of spatial genetic structure in the widespread southern alligator lizard, Elgaria multicarinata. I found that patterns of genetic isolation are driven primarily by geographic distances, but that regional ecological niches have also diverged. Collectively, my work demonstrates the utility of integrating genetic and spatial analyses across spatial scales to help elucidate how genetic diversity is distributed across variable landscapes

Dreams and Dream Interpretation of the Diegueño Indians of Southern California

While not precisely 'lost,' the paper presented in this installment of Lost and Found appears to be little cited in the literature, and it certainly deserves wider scholarly recognition than it has received so far. Although the theoretical framework employed by the authors now seems somewhat dated, the interesting ethnographic data they present shed new light on significant but rather sparsely documented aspects of indigenous Kumeyaay medical beliefs and practices. The paper was originally published in the Psychoanalytic Quarterly [Vol. 5, pp. 195-225,1936]; it has been reformatted slightly for presentation here