| subspecies delineation amid phenotypic, geographic and genetic discordance in a songbird. | understanding the processes that drive divergence within and among species is a long-standing goal in evolutionary biology. traditional approaches to assessing differentiation rely on phenotypes to identify intra- and interspecific variation, but many species express subtle morphological gradients in which boundaries among forms are unclear. this intraspecific variation may be driven by differential adaptation to local conditions and may thereby reflect the evolutionary potential within a specie ... | 2017 | 28100017 |
| high-resolution tide projections reveal extinction threshold in response to sea-level rise. | sea-level rise will affect coastal species worldwide, but models that aim to predict these effects are typically based on simple measures of sea level that do not capture its inherent complexity, especially variation over timescales shorter than 1 year. coastal species might be most affected, however, by floods that exceed a critical threshold. the frequency and duration of such floods may be more important to population dynamics than mean measures of sea level. in particular, the potential for ... | 2017 | 27684043 |
| seasonal fecundity is not related to geographic position across a species' global range despite a central peak in abundance. | the range of a species is determined by the balance of its demographic rates across space. population growth rates are widely hypothesized to be greatest at the geographic center of the species range, but indirect empirical support for this pattern using abundance as a proxy has been mixed, and demographic rates are rarely quantified on a large spatial scale. therefore, the texture of how demographic rates of a species vary over its range remains an open question. we quantified seasonal fecundit ... | 2017 | 27718065 |
| novel microsatellite markers for the saltmarsh sharp-tailed sparrow, ammodramus caudacutus (aves: passeriformes). | we have developed eight high-quality microsatellite dna loci for the saltmarsh sharp-tailed sparrow and one additional locus with evidence of null alleles. in a sample of 250-350 individuals, the average number of alleles per locus was 14.7 and average observed heterozygosity was 0.80. these loci were tested in three additional species of emberizid sparrows, indicating that more than half of the loci could be useful in other sparrows. | 2008 | 21585730 |
| mercury concentrations in tidal marsh sparrows and their use as bioindicators in delaware bay, usa. | mercury (hg) contamination from industrial sources is pervasive throughout north america and is recognized by the us environmental protection agency as a health hazard for wildlife and humans. avian species are commonly used as bioindicators of hg because they are sensitive to contaminants in the environment and are relatively easy to sample. however, it is important to select the appropriate avian species to use as a bioindicator, which should be directly related to the project objectives. in t ... | 2010 | 20135218 |
| mercury in breeding saltmarsh sparrows (ammodramus caudacutus caudacutus). | environmental mercury exposure of birds through atmospheric deposition and watershed point-source contamination is an issue of increasing concern globally. the saltmarsh sparrow (ammodramus caudacutus) is of high conservation concern throughout its range and the potential threat of mercury exposure adds to other anthropogenic stressors, including sea level rise. to assess methylmercury exposure we sampled blood of the northern nominal subspecies of saltmarsh sparrows (a. c. caudacutus) nesting i ... | 2011 | 21792662 |
| understanding associations between nitrogen and carbon isotopes and mercury in three ammodramus sparrows. | we analyzed nitrogen and carbon stable isotope ratios and mercury (hg) in breast feathers from three species of closely related sparrows, saltmarsh, seaside, and nelson's sparrows (ammodramus caudacutus, a. maritimus, and a. nelsoni, respectively), to assess if trophic position and food web structure influence hg exposure in these species. sparrows were captured during the non-breeding season from 2006 to 2008 in north carolina salt marshes near wrightsville beach, new hanover county. generalize ... | 2012 | 22285218 |
| cerebellar abnormalities typical of methylmercury poisoning in a fledged saltmarsh sparrow, ammodramus caudacutus. | a fledged, 12-15 day-old saltmarsh sparrow, ammodramus caudacutus, was collected from an accidental kill on cinder island, long island, ny, usa. the sparrow was assessed for feather mercury levels and the brain analyzed for cerebellar abnormalities by microscopic examination. in humans, fetal minamata disease is caused by maternal ingestion of mercury. it is characterized by disrupted and disordered cerebellar neuronal migration in the fetus or infant. results from this sparrow show cerebellar a ... | 2013 | 23478946 |
| development of diagnostic microsatellite markers from whole-genome sequences of ammodramus sparrows for assessing admixture in a hybrid zone. | studies of hybridization and introgression and, in particular, the identification of admixed individuals in natural populations benefit from the use of diagnostic genetic markers that reliably differentiate pure species from each other and their hybrid forms. such diagnostic markers are often infrequent in the genomes of closely related species, and genomewide data facilitate their discovery. we used whole-genome data from illumina hiseqs2000 sequencing of two recently diverged (600,000 years) a ... | 2015 | 26078861 |
| differential introgression and the maintenance of species boundaries in an advanced generation avian hybrid zone. | evolutionary processes, including selection and differential fitness, shape the introgression of genetic material across a hybrid zone, resulting in the exchange of some genes but not others. differential introgression of molecular or phenotypic markers can thus provide insight into factors contributing to reproductive isolation. we characterized patterns of genetic variation across a hybrid zone between two tidal marsh birds, saltmarsh (ammodramus caudacutus) and nelson's (a. nelsoni) sparrows ... | 2016 | 27000833 |
| genotype-environment associations support a mosaic hybrid zone between two tidal marsh birds. | local environmental features can shape hybrid zone dynamics when hybrids are bounded by ecotones or when patchily distributed habitat types lead to a corresponding mosaic of genotypes. we investigated the role of marsh-level characteristics in shaping a hybrid zone between two recently diverged avian taxa - saltmarsh (ammodramus caudacutus) and nelson's (a. nelsoni) sparrows. these species occupy different niches where allopatric, with caudacutus restricted to coastal marshes and nelsoni found i ... | 2016 | 26811792 |
| a climate change adaptation strategy for management of coastal marsh systems. | sea level rise is causing shoreline erosion, increased coastal flooding, and marsh vulnerability to the impact of storms. coastal marshes provide flood abatement, carbon and nutrient sequestration, water quality maintenance, and habitat for fish, shellfish, and wildlife, including species of concern, such as the saltmarsh sparrow (ammodramus caudacutus). we present a climate change adaptation strategy (ccas) adopted by scientific, management, and policy stakeholders for managing coastal marshes ... | 2017 | 30271313 |
| predictors of specialist avifaunal decline in coastal marshes. | coastal marshes are one of the world's most productive ecosystems. consequently, they have been heavily used by humans for centuries, resulting in ecosystem loss. direct human modifications such as road crossings and ditches and climatic stressors such as sea-level rise and extreme storm events have the potential to further degrade the quantity and quality of marsh along coastlines. we used an 18-year marsh-bird database to generate population trends for 5 avian species (rallus crepitans, tringa ... | 2017 | 27542096 |
| factors that influence vital rates of seaside and saltmarsh sparrows in coastal new jersey, usa. | as saltmarsh habitat continues to disappear, understanding the factors that influence saltmarsh breeding bird population dynamics is an important step for the conservation of these declining species. using five years (2011 - 2015) of demographic data, we evaluated and compared seaside (ammodramus maritimus) and saltmarsh (a. caudacutus) sparrow apparent adult survival and nest survival at the edwin b. forsythe national wildlife refuge, new jersey, usa. we determined the effect of site management ... | 2017 | 29479129 |
| long-term monitoring of mercury in adult saltmarsh sparrows breeding in maine, massachusetts and new york, usa 2000-2017. | here we report on the results of a long-term study of mercury exposure in a songbird species, the saltmarsh sparrow (ammodramus caudacutus). we measured total mercury concentrations in blood (n = 840) and feathers (n = 560) of adult saltmarsh sparrows at six locations between 2000 and 2017: rachel carson national wildlife refuge (rcnwr) in wells, maine; scarborough marsh state wildlife management area in scarborough, maine; parker river national wildlife refuge on plum island, massachusetts; pin ... | 2020 | 32124146 |