Geology topics

Gregory B. Pauly

Publications and source records attributed to Gregory B. Pauly.

3 recordsLinked to original sources

USGS2022

Natural and anthropogenic landscape factors shape functional connectivity of an ecological specialist in urban Southern California

Identifying how natural (i.e., unaltered by human activity) and anthropogenic landscape variables influence contemporary functional connectivity in terrestrial organisms can elucidate the genetic consequences of environmental change. We examine population genetic structure and functional connectivity among populations of a declining species, the Blainville's horned lizard ( Phrynosoma blainvillii ), in the urbanized landscape of the Greater Los Angeles Area in Southern California, USA. Using single nucleotide polymorphism data, we assessed genetic structure among populations occurring at the interface of two abutting evolutionary lineages, and at a fine scale among habitat fragments within the heavily urbanized area. Based on the ecology of P. blainvillii , we predicted which environmental variables influence population structure and gene flow and used gravity models to distinguish among hypotheses to best explain population connectivity. Our results show evidence of admixture between two evolutionary lineages and strong population genetic structure across small habitat fragments. We also show that topography, microclimate, and soil and vegetation types are important predictors of functional connectivity, and that anthropogenic disturbance, including recent fire history and urban development, are key factors impacting contemporary population dynamics. Examining how natural and anthropogenic sources of landscape variation affect contemporary population genetics is critical to understanding how to best manage sensitive species in a rapidly changing landscape.

California↗

USGS2022

Hidden in plain sight: Detecting invasive species when they are morphologically similar to native species

Early detection and rapid response (EDRR) can help mitigate and control invasive species outbreaks early on but its success is dependent on accurate identification of invasive species. We evaluated a novel outbreak in San Diego County, California of the Sonoran Spotted Whiptail ( Aspidoscelis sonorae ) in order to confirm their spread as well as quantify how to better detect and potentially manage this invasive species in California. We found that A. sonorae went undetected for over two years due to its morphological similarity to native whiptails and that it has spread rapidly since they were first observed. There are two species of native California whiptails with which A. sonorae can be confused locally, the Orange-throated Whiptail ( Aspidoscelis hyperythrus ), and to a lesser extent the Tiger Whiptail ( Aspidoscelis tigris ). We review key diagnostic features to distinguish A. sonorae from native California whiptails. We also discuss how to efficiently use widely available community science tools to rapidly assess a novel invasive species outbreak and outline suggestions to help manage cryptic invasive species.

California↗

USGS2004

Species boundaries, phylogeography, and conservation genetics of the red-legged frog ( Rana aurora/draytonii ) complex

The red-legged frog, Rana aurora , has been recognized as both a single, polytypic species and as two distinct species since its original description 150 years ago. It is currently recognized as one species with two geographically contiguous subspecies, aurora and draytonii ; the latter is protected under the US Endangered Species Act. We present the results of a survey of 50 populations of red-legged frogs from across their range plus four outgroup species for variation in a phylogenetically informative, ∼400 base pairs (bp) fragment of the mitochondrial cytochrome b gene. Our mtDNA analysis points to several major results. (1) In accord with several other lines of independent evidence, aurora and draytonii are each diagnosably distinct, evolutionary lineages; the mtDNA data indicate that they do not constitute a monophyletic group, but rather that aurora and R. cascadae from the Pacific northwest are sister taxa; (2) the range of the draytonii mtDNA clade extends about 100 km further north in coastal California than was previously suspected, and corresponds closely with the range limits or phylogeographical breaks of several codistributed taxa; (3) a narrow zone of overlap exists in southern Mendocino County between aurora and draytonii haplotypes, rather than a broad intergradation zone; and (4) the critically endangered population of draytonii in Riverside County, CA forms a distinct clade with frogs from Baja California, Mexico. The currently available evidence favours recognition of aurora and draytonii as separate species with a narrow zone of overlap in northern California.

Molecular Ecology↗