Geology topics

Kim T Scribner

Publications and source records attributed to Kim T Scribner.

4 recordsLinked to original sources

USGS2024

A phylogeographical study of the discontinuously distributed Harlequin Duck (Histrionicus histrionicus)

Species distributions are often indicative of historical biogeographical events and contemporary spatial biodiversity patterns. The Harlequin Duck Histrionicus histrionicus is a sea duck of conservation concern that has a disjunct distribution, with discrete portions of its range associated with northern Pacific and Atlantic Ocean basins. Movement data indicate migratory connectivity within regions of each ocean basin but not cross-continent dispersal, suggesting that genetic structuring could exist at multiple spatial scales. Little is known regarding the impacts of past vicariance events on the species phylogeographical structure and historical demography, or rates of gene flow at different spatial scales. We used data from microsatellite loci and mitochondrial DNA (mtDNA) sequences to quantify levels of genetic diversity within, and the extent of spatial genetic differentiation among locations sampled at multiple spatial scales across the species range. Samples were collected at nonbreeding locations, which represent groupings appropriate for characterizing genetically differentiated subgroups at regional and continental scales. Collectively, genetic data and coalescence modelling suggested that individuals colonized regions currently occupied within both ocean basins in the Holocene from a single refuge in the Atlantic. Further, it seems likely there was secondary contact with lineages derived from populations in Asia, based on the shallow species-wide mtDNA phylogeny and high incidence of recently derived private mtDNA haplotypes. Estimates of inter-location variance in microsatellite allele and mtDNA haplotype frequency were moderate and significant between western (Pacific – North America) and eastern (Atlantic – North America, Greenland and Iceland) ocean basins and among sampling groups within each ocean basin. Genetic differentiation among sampling groups was particularly evident at the species distributional margins in the Atlantic (Iceland) and the Pacific (Shemya Island) Ocean basins. Coalescent modelling results suggest that contemporary spatial genetic patterns in the species arose through the combined influences of secondary contact, shared ancestry and gene flow after the last glacial maxima.

Ibis↗

USGS2023

Evaluating the utility of effective breeding size estimates for monitoring sea lamprey spawning abundance

Sea lamprey ( Petromyzon marinus ) is an invasive species that is a significant source of mortality for populations of valued fish species across the North American Great Lakes. Large annual control programs are needed to reduce the species' impacts; however, the number of successfully spawning adults cannot currently be accurately assessed. In this study, effective breeding size ( N b ) and the minimum number of spawning adults ( N s ) were estimated for larval cohorts from 17 tributaries across all five Great Lakes using single nucleotide polymorphisms (SNP) genotyped via RAD-capture sequencing. Reconstructed larval pedigrees showed substantial variability in the size and number of full- and half-sibling groups, N b (<1–367), and N s (5–545) among streams. Generalized linear models examining the effects of stream environmental characteristics and aspects of sampling regimes on N b and N s estimates identified sample size, the number of sampling sites, and drainage area as important factors predicting N b and N s . Correlations between N b , N s , and capture–mark–recapture estimates of adult census size ( N c ) increased when streams with small sample sizes ( n < 50) were removed. Results collectively indicate that parameters estimated from genetic data can provide valuable information on spawning adults in a river system, especially if sampling regimes are standardized and physical stream covariates are included.

Ecology and Evolution↗

USGS2021

Pedigree accumulation analysis: Combining methods from community ecology and population genetics for breeding adult estimation

Estimates of the number of successfully breeding adults ( N S ) in a population can predict levels of recruitment. However, assessments of N S are often difficult to obtain because encounters with adults are limited due to life-history characteristics, low abundance or other constraints associated with access to critical habitats. Alternatively, efforts to sample individuals at earlier ontogenetic stages can be more tractable, resulting in more comprehensive samples. To estimate N S , we describe, evaluate and apply two nonparametric species richness estimators to information associated with genetic pedigree reconstruction. Simulations compared bias and precision associated with Chao and Jackknife methods when estimating N S . We also evaluated N S estimation sensitivity to two sources of variation associated with species reproductive ecology (variance in reproductive success and sex ratio skew) and genetic pedigree assignment error. Finally, the application of our novel method was demonstrated in two different species and systems (Chinook Salmon in Oregon, USA and Lake Sturgeon in Michigan, USA). We found unbiased N S estimates were generated across a broad range of offspring sample sizes using the Chao method. Empirical results corroborated simulation-based expectations and highlighted applications where parents and offspring are sampled, and when only offspring are sampled. When offspring sample sizes are adequate and pedigree reconstruction errors are low, the combination of established methods from community ecology and genetic pedigree reconstruction provides an accurate alternative method to estimate N S that can facilitate population assessments.

Methods in Ecology and Evolution↗

USGS2021

Coalescent methods reconstruct contributions of natural colonization and stocking to origins of Michigan inland Cisco (Coregonus artedi)

Fish population structure in previously glaciated regions is often influenced by natural colonization processes and human-mediated dispersal, including fish stocking. Endemic populations are of conservation interest because they may contain rare and unique genetic variation. While coregonines are native to certain Michigan inland lakes, some were stocked with fish from Great Lakes sources, calling into question the origin of extant populations. While most stocking targeted lake whitefish ( Coregonus clupeaformis ), cisco ( C. artedi ) were also stocked from the Great Lakes to inland waterbodies. We used population genetic data (microsatellite genotypes and mitochondrial (mt)DNA sequences), coalescent modeling, and approximate Bayesian computation to investigate the origins of 12 inland Michigan cisco populations. The spatial distribution of mtDNA haplotypes suggests Michigan is an introgression zone for two ancestral cisco lineages associated with separate glacial refugia. Low levels of genetic diversity and high levels of genetic divergence were observed for populations located well inland of the Great Lakes relative to populations occupying waterbodies near the Great Lakes. Estimates of recent Great Lakes gene flow ranged from 27 to 48% for populations near the Great Lakes shoreline but were substantially lower (under 8%) for populations further inland. Inland lakes with elevated recent gene flow estimates may have been recipients of stocked coregonine fry, including cisco. Low levels of genetic diversity paired with a high likelihood of endemism as indicated by strong genetic divergence and low Great Lakes population inputs suggest the analyzed cisco populations occupying southern Michigan kettle lakes are of elevated conservation interest.

Michigan↗