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At least 541 records · Page 30Linked to original sources
USGS1983

Reduced fecundity in small populations of the rare plant Gentianopsis ciliate (Gentianaceae)

Habitat destruction is the main cause for the biodiversity crisis. Surviving populations are often fragmented, i.e., small and isolated from each other. Reproduction of plants in small populations is often reduced, and this has been attributed to inbreeding depression, reduced attractiveness for pollinators, and reduced habitat quality in small populations. Here we present data on the effects of fragmentation on the rare, self-compatible perennial herb Gentianopsis ciliata (Gentianaceae), a species with very small and presumably well-dispersed seeds. We studied the relationship between population size, plant size, and the number of flowers produced in 63 populations from 1996-1998. In one of the years, leaf and flower size and the number of seeds produced per fruit was studied in a subset of 25 populations. Plant size, flower size, and the number of seeds per fruit and per plant increased with population size, whereas leaf length and the number of flowers per plant did not. The effects of population size on reproduction and on flower size remained significant if the effects were adjusted for differences in plant size, indicating that they could not be explained by differences in habitat quality. The strongly reduced reproduction in small populations may be due to pollination limitation, while the reduced flower size could indicate genetic effects.

American Birds↗
USGS1984

Contaminants in wood stork eggs and their effects on reproduction, Florida, 1982

One egg was removed from five Wood Stork (Mycteria americana) nests at each of eight colonies in central and northern Florida in 1982. DDE and mercury were present in all eggs with concentrations ranging up to 9.4 and 0.73 ppm wet weight, respectively. PCBs occurred in 25 eggs with a high value of 3.5 ppm. No other organochlorine compounds occurred in more than 307. of the eggs. Contaminant concentrations were remarkably similar among colonies. DDE was negatively correlated with eggshell thickness (r=-0.48 P < 0.01). Eggshell thickness averaged 4.2% less than for eggs collected before 1947. Contaminants showed no significant link to hatching or fledging success. However, eggs from nests with less than 100 percent hatching success showed a tendency toward higher DDE and PCB concentrations (P= 0.09 and 0.12, respectively).

American Birds↗
USGS2006

Comparative dynamics of avian communities across edges and interiors of North American ecoregions

Aim Based on a priori hypotheses, we developed predictions about how avian communities might differ at the edges vs. interiors of ecoregions. Specifically, we predicted lower species richness and greater local turnover and extinction probabilities for regional edges. We tested these predictions using North American Breeding Bird Survey (BBS) data across nine ecoregions over a 20-year time period. Location Data from 2238 BBS routes within nine ecoregions of the United States were used. Methods The estimation methods used accounted for species detection probabilities < 1. Parameter estimates for species richness, local turnover and extinction probabilities were obtained using the program COMDYN. We examined the difference in community-level parameters estimated from within exterior edges (the habitat interface between ecoregions), interior edges (the habitat interface between two bird conservation regions within the same ecoregion) and interior (habitat excluding interfaces). General linear models were constructed to examine sources of variation in community parameters for five ecoregions (containing all three habitat types) and all nine ecoregions (containing two habitat types). Results Analyses provided evidence that interior habitats and interior edges had on average higher bird species richness than exterior edges, providing some evidence of reduced species richness near habitat edges. Lower average extinction probabilities and turnover rates in interior habitats (five-region analysis) provided some support for our predictions about these quantities. However, analyses directed at all three response variables, i.e. species richness, local turnover, and local extinction probability, provided evidence of an interaction between habitat and region, indicating that the relationships did not hold in all regions. Main conclusions The overall predictions of lower species richness, higher local turnover and extinction probabilities in regional edge habitats, as opposed to interior habitats, were generally supported. However, these predicted tendencies did not hold in all regions.

Journal of Biogeography↗
USGS2006

Population trajectory of burrowing owls (Athene cunicularia) in eastern Washington

Anecdotal evidence suggests that burrowing owls have declined in Washington. The Washington Department of Fish and Wildlife is currently conducting a status review for burrowing owls which will help determine whether they should be listed as threatened or endangered in the state. To provide insights into the current status of burrowing owls (Athene cunicularia), we analyzed data from the North American Breeding Bird Survey using two analytical approaches to determine their current population trajectory in eastern Washington. We used a one-sample t-test to examine whether trend estimates across all BBS routes in Washington differed from zero. We also used a mixed model analysis to estimate the rate of decline in number of burrowing owls detected between 1968 and 2005. The slope in number of burrowing owls detected was negative for 12 of the 16 BBS routes in Washington that have detected burrowing owls. Numbers of breeding burrowing owls detected in eastern Washington declined at a rate of 1.5% annually. We suggest that all BBS routes that have detected burrowing owls in past years in eastern Washington be surveyed annually and additional surveys conducted to track population trends of burrowing owls at finer spatial scales in eastern Washington. In the meantime, land management and regulatory agencies should ensure that publicly managed areas with breeding burrowing owls are not degraded and should implement education and outreach programs to promote protection of privately owned areas with breeding owls.

Northwest Science↗
USGS2008

Atlantic Flyway review: Region IV Piedmont-Coastal Plain, Fall 2007: Patuxent powerline right-of-way (390-0764)

This station operates at the Patuxent Research Refuge in a powerline right-of-way that bisects an upland deciduous forest. This area has been used for this purpose since 1980, except in the years 2004-2006. Twenty-six nets are arrayed along approximately one-half mile that runs generally on an east-west orientation. The habitat is marked by dense 4-6 foot high shrub foliage with very few trees of any height. Trees are purposely kept to a minimum within the right-of-way to avoid arcing with the powerlines. We operated seven days in August and November and 14 days in September and October for a total of 42 days, generally on a M/W I F schedule. Nets were opened · by 25-30 minutes before sunrise, and closed about 3.5 hours later. Weather did not have a significant impact on our operations. We did have a few mornings in late October when some nets were frozen, delaying their opening. Only once (13 Nov) did rain necessitate closing nets early.

Maryland↗
USGS1990

Fluorian garnets from the host rocks of the Skaergaard intrusion: implications for metamorphic fluid composition

Zoned, silica-deficient, calcic garnets containing up to 5 mol% F substitution for O formed during contact metamorphism of basalts by the Skaergaard intrusion in East Greenland. Fluorian calcic garnets occur as a retrograde alteration of prograde wollastonite and clinopyroxene that fills vesicles and vugs in lavas 30-70 m from the intrusion. The F content of garnet is extremely sensitive to minor changes in fluid composition. The calculations show that a decrease in pH or an increase in log aF- of 0.3 at constant pressure and temperature will decrease the F concentration in garnet from 5 to 0 mol%. The results of this study show that fluorian hydrous grandites provide a mineralogical record of the activities of F species in coexisting metamorphic and hydrothermal fluids. -from Authors

American Mineralogist↗
USGS2004

Sequence stratigraphy of the Kingak Shale (Jurassic-Lower Cretaceous), National Petroleum Reserve in Alaska

Beaufortian strata (Jurassic-Lower Cretaceous) in the National Petroleum Reserve in Alaska (NPRA) are a focus of exploration since the 1994 discovery of the nearby Alpine oil field (>400 MMBO). These strata include the Kingak Shale, a succession of depositional sequences influenced by rift opening of the Arctic Ocean Basin. Interpretation of sequence stratigraphy and depositional facies from a regional two-dimensional seismic grid and well data allows the definition of four sequence sets that each displays unique stratal geometries and thickness trends across NPRA. A Lower to Middle Jurassic sequence set includes numerous transgressive-regressive sequences that collectively built a clastic shelf in north-central NPRA. Along the south-facing, lobate shelf margin, condensed shales in transgressive systems tracts downlap and coalesce into a basinal condensed section that is likely an important hydrocarbon source rock. An Oxfordian-Kimmeridgian sequence set, deposited during pulses of uplift on the Barrow arch, includes multiple transgressive-regressive sequences that locally contain well-winnowed, shoreface sandstones at the base of transgressive systems tracts. These shoreface sandstones and overlying shales, deposited during maximum flooding, form stratigraphic traps that are the main objective of exploration in the Alpine play in NPRA. A Valanginian sequence set includes at least two transgressive-regressive sequences that display relatively distal characteristics, suggesting high relative sea level. An important exception is the presence of a basal transgressive systems tract that locally contains shoreface sandstones of reservoir quality. A Hauterivian sequence set includes two transgressive-regressive sequences that constitute a shelf-margin wedge developed as the result of tectonic uplift along the Barrow arch during rift opening of the Arctic Ocean Basin. This sequence set displays stratal geometries suggesting incision and synsedimentary collapse of the shelf margin.

Alaska↗
USGS1982

The short-tailed Albatross, Diomedea albatrus , its status, distribution and natural history

The Short-tailed Albatross (Diomedea albatrus ) is presently an Endangered Species that was formerly abundant in the North Pacific. Owing to the activities of feather hunters operating on the albatross's nesting grounds for a 50-year period in the late 19th and early 20th centuries, the species was almost reduced to extinction. The Short-tailed Albatross is the largest of the three species of Diomedea that breed in the North Pacific (Table 1) and when mature is the only albatross in the North Pacific with a white back .

American Birds↗
USGS2009

Sexing California Clapper Rails using morphological measurements

California Clapper Rails (Rallus longirostris obsoletus) have monomorphic plumage, a trait that makes identification of sex difficult without extensive behavioral observation or genetic testing. Using 31 Clapper Rails (22 females, 9 males), caught in south San Francisco Bay, CA, and using easily measurable morphological characteristics, we developed a discriminant function to distinguish sex. We then validated this function on 33 additional rails. Seven morphological measurements were considered, resulting in three which were selected in the discriminate function: culmen length, tarsometatarsus length, and flat wing length. We had no classification errors for the development or testing datasets either with resubstitution or cross-validation procedures. Male California Clapper Rails were 6-22% larger than females for individual morphological traits, and the largest difference was in body mass. Variables in our discriminant function closely match variables developed for sexing Clapper Rails of Gulf Coast populations. However, a universal discriminant function to sex all Clapper Rail subspecies is not likely because of large and inconsistent differences in morphological traits among subspecies.

North American Bird Bander↗
USGS2016

Dynamic distributions and population declines of Golden-winged Warblers

With an estimated breeding population in 2010 of 383,000 pairs, the Golden-winged Warbler ( Vermivora chrysoptera ) is among the most vulnerable and steeply declining of North American passerines. This species also has exhibited among the most dynamic breeding distributions, with populations expanding and then contracting over the past 150 years in response to regional habitat changes, interactions with closely related Blue-winged Warblers ( V. cyanoptera ), and possibly climate change. Since 1966, the rangewide population has declined by >70% (-2.3% per year; latest North American Breeding Bird Survey data), with much steeper declines in the Appalachian Mountains bird conservation region (-8.3% per year, 98% overall decline). Despite apparently stable or increasing populations in the northwestern part of the range (Minnesota, Manitoba), population estimates for Golden-winged Warbler have continued to decline by 18% from the decade of the 1990s to the 2000s. Population modeling predicts a further decline to roughly 37,000 individuals by 2100, with the species likely to persist only in Manitoba, Minnesota, and possibly Ontario. To delineate the present-day distribution and to identify population concentrations that could serve as conservation focus areas, we compiled rangewide survey data collected in 2000-2006 in 21 states and 3 Canadian provinces, as part of the Golden-winged Warbler Atlas Project (GOWAP), supplemented by state and provincial Breeding Bird Atlas data and more recent observations in eBird. Based on >8,000 GOWAP surveys for Golden-winged and Blue-winged warblers and their hybrids, we mapped occurrence of phenotypically pure and mixed populations in a roughly 0.5-degree grid across the species’ ranges. Hybrids and mixed Golden-winged-Blue-winged populations occurred in a relatively narrow zone across Minnesota, Wisconsin, Michigan, southern Ontario, and northern New York. Phenotypically pure Golden-winged Warbler populations occurred north of this hybrid zone, but the future of northern populations in the Great Lakes states and Canada (where >80% of the species occurs at present) is highly uncertain because of continued northward expansion of Blue-winged Warblers and hybridization. A second, now-disjunct band of Golden-winged Warbler populations exists in the Appalachian Mountains from southeastern New York to northern Georgia, surrounded at lower elevations by Blue-winged Warblers. Important concentrations of Golden-winged Warblers persist in the Allegheny Mountains region of West Virginia, the Cumberland Mountains in Tennessee, Blue Ridge Mountains of western North Carolina, Allegheny Plateau and Pocono Mountains in Pennsylvania, and in the Hudson Highlands of southern New York. These high-elevation Appalachian populations have escaped contact with Blue-winged Warblers until very recently and represent important refugia for conservation and management; other Appalachian populations are rapidly declining. In addition, based on historical records and standardized surveys across the wintering grounds, we identified three regions of concentration: highlands and Caribbean slopes from Guatemala and Belize to northwestern Nicaragua; middle elevations (both slopes) in Costa Rica and western Panama; and in an arc of the northern Andes from central Colombia to northern Venezuela. It is possible that the winter range has been shifting towards the northwest in recent decades, paralleling shifts in the breeding distribution. Future conservation efforts for Golden-winged Warbler need to include close monitoring of the dynamic phenotypic and genetic distributional shifts, and may need to consider the “winged warbler” complex together as a highly adaptable evolutionary unit.

Studies in Avian Biology↗
USGS1977

Atlantic Flyway review: Region V: Laurel, Prince Georges County, MD

Robbins Nest is located on the fall line one-half mile below Rocky Gorge Reservoir. During the fall migration, about 8 nets are run on the upper part of the 3 acres (edge of the lawn, the garden, under the Virginia Pines, and the upper edge of the mature oak woods that drop 80 feet to the Patuxent River). Foul weather on weekends, combined with commitments away from home, severely restricted this season's operation. August banding was limited to the weekend of the 23-24th. In September, all-day netting was conducted on the 6-7th and 20-21st, and this was supplemented with before- and after-work banding on 16 other days. October banding also was limited to 4 whole days and parts of 16 others.

Maryland↗
USGS2018

Post-spring migration colony-site prospecting by Roseate Terns (Sterna dougallii)

We recorded banded Roseate Terns (Sterna dougallii) and unbanded individuals mated to banded individuals in May and the first third of June in 2001 and 2002 to quantify post spring migration prospecting by this species at Falkner Island, Connecticut, USA. In 2001, more than one quarter: 34/125 (27.2%) of those observed by 19 May and 38/150 (25.3%) of those observed by 25 May did not remain at this colony site and went elsewhere to attempt breeding. In 2002, fewer terns were observed by 19 May, but an even higher percentage: 11/28 (39.3%) of those seen by 19 May and 58/151 (38.4%) of those seen by 25 May did not stay and nest. Our results demonstrate that a substantial proportion of the earliest arriving individuals at this site are prospecting and gathering information about local conditions before making a decision about going elsewhere to nest.

North American Bird Bander↗
USGS2019

Handbook to the partners in flight population estimates database, version 3.0

This document describes the content of Version 3.0 of the Partners in Flight (PIF) Population Estimates Database, which provides population estimates for breeding USA/Canada landbirds at several geographic scales following the Partners in Flight approach described initially in Rich et al. (2004) and by Rosenberg and Blancher (2005) and most recently refined by Stanton et al. (2019). The Handbook also provides details about how the estimates were derived, information on limitations and caveats, a guide to using the estimates, and future desired directions for improving the estimates. This version of the database is intended as a companion to the Partners in Flight Landbird Conservation Plan: 2016 Revision for Canada and Continental United States (Rosenberg et al. 2016), although estimates for most species included in the database have been updated from those used in the 2016 Plan. Most of the estimates in the database are based on North American Breeding Bird Survey (BBS) data for landbirds from the decade 2006–2015. The information in this 2019 Version of the Handbook, for Version 3.0 of the database, describes all changes that have been made to the database since 2007 (Version 1.0, cf. Blancher et al. 2007)—including the additions documented in the Handbook for Version 2.0 (Blancher et al. 2013)—and therefore serves as a single source document describing the current database. Version 3.0 of the database addresses some of the recommendations suggested by Thogmartin et al. (2006) but does not yet fully address other limitations noted by Thogmartin et al. (2006), Blancher et al. (2007), Thogmartin (2010), Matsuoka et al. (2012), and Twedt (2015). By far, the most substantial change to the database comprises the incorporation of quantitative uncertainty bounds around population estimates for most species (see Stanton et al. 2019 for details). PIF Science anticipates that future versions of the database will occur in stages: first, improving elements of the basic PIF approach (e.g., incorporating more recent BBS data, updating Time of Day Adjustments, and refining Pair Adjustments); next, addressing additional concerns inherent in the PIF approach (e.g., replacing average maximum detection distance bins with research-derived species-specific effective detection radii); and later, perhaps replacing the sample-based PIF approach with a spatially-explicit, model-based (pixel-based) approach that more deliberately incorporates habitat and road biases and the proportion of birds available but not detected by current sampling methodology. This current Version 3.1 of the Handbook updates citations in the Literature Cited and incorporates relatively minor improvements in text clarity over the previous 3.0 version. The content of the Population Estimates Database itself remains the same except for changes to the global and USA/Canada estimates for Northern Bobwhite and Black Vulture.

Partners in Flight Technical Publication↗