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At least 127 records · Page 7Linked to original sources

USGS analysis of the Australian UNCLOS submission

In November 2004, the Government of Australia made a submission to the Commission on the Limits of the Continental Shelf (CLCS) for 10 extended continental shelf (ECS) regions, utilizing Article-76 of the United Nations Convention on the Law of the Sea (UNCLOS). With information provided in the Australian Executive Summary, the USGS examined the 10 regions of the submission from geological, morphological, and resource perspectives. By their own request, the Australians asked that CLCS take no action on the Australian-Antarctic Territory. The major limitation in this analysis is that no bathymetric soundings or detailed hydrographic profiles were provided in the Australian Executive Summary that might show why the Foot of the Slope (FOS) was chosen or where the 2,500-m contour is located. This represents a major limitation because more than half of the 4,205 boundary points utilize the bathymetric formula line and more than one-third of them utilize the bathymetric constraint line. CLCS decisions on the components of this submission may set a precedent for how ECSs are treated in future submissions. Some of the key decisions will cover (a) how a 'natural prolongation' of a continental margin is determined, particularly if a bathymetric saddle that appears to determine the prolongation is in deep water and is well outside of the 200-nm limit (Exmouth Plateau), (b) defining to what extent that plateaus, rises, caps, banks and spurs that are formed of oceanic crust and from oceanic processes can be considered to be 'natural prolongations' (Kerguelen Plateau), (c) to what degree UNCLOS recognizes reefs and uninhabited micro-islands (specifically, rocks and/or sand shoals) as islands that can have an EEZ (Middleton and Elizabeth Reefs north of Lord Howe Island), and (d) how the Foot of the Slope (FOS) is chosen (Great Australian Bight). The submission contains situations that are relevant to potential future U.S. submissions and are potentially analogous to certain features of the US margins. The Australian margin has significant geological and morphological variety, similar to the US margin and gives a good idea of the complexity of issues related to the U.S. margin. Decisions about basins and ridges in the Lord Howe Rise and Three Kings Ridge regions will likely bear on the status of ridges in the Arctic, such as Lomonosov Ridge. The Naturaliste Plateau and the South Tasman Rise appear to have parallels with the Chukchi Plateau in the Arctic and the Blake Plateau off the southeastern U.S. The ECS on Macquarie Island/Ridge may determine how boundaries along ridges such as the Mariannas are treated.

Open-File Report

Winter and spring diet of the orangebelly darter, Etheostoma radiosum, among tributaries of the Lower Mountain Fork River

Little is known about prey use by the orangebelly darter, Etheostoma radiosum , and what is known has been described from relatively large river systems. We examined prey use by orangebelly darters from first- and second-order tributaries in the Lower Mountain Fork River of southeastern Oklahoma. Adult darters ( n = 141) were captured from five tributaries in 2015, and stomach contents were examined to determine prey use. Aquatic isopods were the most frequently consumed organism. This differs notably from previous reports that insects, primarily dipterans, were the predominant prey for the species.

Oklahoma

Spring and winter records of the eastern pipistrelle (Perimyotis subflavus) in southeastern New Mexico

Eastern pipistrelles ( Perimyotis subflavus ) were first documented from South Dakota, western Texas, and New Mexico during recent years, suggesting that the distribution of this species is expanding westward across central parts of North America. In New Mexico, only 2 records of P. subflavus previously were known—one from summer and one from autumn. Here we report on 3 new records of P. subflavus from southeastern New Mexico, including the first 2 records from winter and the first record from spring. One individual in winter was observed hibernating in a cave in Chaves County. Our records and previous ones from autumn and summer suggest that this species is resident throughout the year in New Mexico.

New Mexico

Distribution of the white-ankled mouse (Peromyscus pectoralis) in New Mexico

The white-ankled mouse (Peromyscus pectoralis) was previously known only from Carlsbad Caverns National Park and nearby areas in extreme southeastern New Mexico. I discovered 15 new localities for P. pectoralis, which extend its distribution 225 km north-northwest. This new distribution does not represent a recent northward expansion of P. pectoralis in New Mexico but reflects the lack of mammalian surveys in the region and misidentification of museum specimens from past surveys. At present, the distribution of P. pectoralis in New Mexico includes the Guadalupe Mountains and lowland habitats between the Sacramento Mountains and Pecos River.

Southwestern Naturalist

White-tailed deer (Odocoileus virginianus) predation on grassland songbird nestlings

White-tailed deer ( Odocoileus virginianus ) were videotaped depredating four songbird nests in grassland habitats in southeastern and northcentral North Dakota, 1996–1999. Deer ate two Savannah sparrow ( Passerculus sandwichensis ), two grasshopper sparrow ( Ammodramus savannarum ), one clay-colored sparrow ( Spizella pallida ), one red-winged blackbird ( Agelaius phoeniceus ) and three brown-headed cowbird ( Molothrus ater ) nestlings. Deer removed nestlings quickly (5–19 sec/nest) at night (22:00 to 05:17 Central Daylight Time) and left no evidence of predation. Although probably opportunistic, deer predations clearly were deliberate and likely are more common than generally believed.

North Dakota

Southwestern bats and their external bacteria

Bat species diversity within the United States is greatest in the Southwest, with approximately 30 species present. At least 16 of these bat species hibernate and are susceptible to white-nose syndrome (WNS), which is caused by the fungus Pseudogymnoascus destructans . Since 2006, millions of bats from 35 U.S. states and 7 Canadian provinces have died from WNS. In previous studies of external surfaces of bats sampled from southwestern states, Actinobacteria were detected that were shown to have antifungal properties against P. destructans in laboratory testing. These studies motivated us to expand our research to sites that represent possible gateways for P. destructans to enter the Southwest so that we could establish a baseline of bat microbiota before the arrival of WNS. We surveyed for the presence of bats and their external microbiota at 3 national parks and monuments located in southeastern Colorado and northeastern New Mexico. Our results document new occurrence records of bat species and their external bacteria at each sampling location. Additionally, we provide insight on the composition of bat external microbiota in the absence of P. destructans , while revealing information about the Streptomyces and other possible native defenses of bats against P. destructans at a gateway into the Southwest.

Western North American Naturalist

Survival of female white-cheeked pintails during brood rearing in Puerto Rico

Anas bahamensis (White-cheeked Pintail) is widely distributed across the Caribbean islands and South America. The species is classified as threatened in Puerto Rico and a species of least concern across most of its range. Little demographic data exist for the species, particularly during the breeding season. During 2000-2002, we radiomarked 31 incubating females at the Humacao Nature Reserve (Humacao) in southeastern Puerto Rico and estimated daily and interval survival rates of females during brood rearing. Only one of 31 birds died; the average ± 95% CI daily survival rate of pintails was 0.998 ± 0.989-0.999 for all years, and interval survival was 0.913 ± 0.527-0.987 for a 60-day brood-rearing period. High survival of females suggests their mortality during brood rearing does not influence White-cheeked Pintail populations at Humacao, but further studies of reproductive and annual ecology are needed.

Puerto Rico

Small-scale variation in trap placement affects arthropod capture rates on sticky traps in riparian woodlands

Arthropods are important prey for many avian taxa, particularly during the breeding season. Many studies have used sticky traps to estimate relative abundance of arthropods as avian prey, but we know little about the potential biases associated with sticky traps. We evaluated the effect of small-scale variation in trap placement on the biomass of arthropods caught on sticky traps in six riparian woodlands in southeastern Arizona. We detected differences in arthropod biomass between two height categories (1 and 4 m off the ground) for three insect orders and between two sampling locations (0 and 10 m from the center of the stream bed) for two insect orders. These differences indicate that placement of sticky traps affects arthropod capture rates and, hence, small variation in trap placement can bias investigators' ability to document spatial and temporal differences in arthropod abundance. Investigators who use sticky traps to make comparisons of arthropod abundance need to ensure that placement is consistent over time or across treatments to ensure that comparisons are not biased.

The Southwestern Naturalist

Impact of zebra and quagga mussels (Dreissena spp.) on freshwater unionids (Bivalvia: Unionidae) in the Detroit River of the Great Lakes

To assess the impact of zebra and quagga mussel ( Dreissena spp.) infestation on unionids, unionids (Bivalvia: Unionidae) were sampled in the Detroit River in 1982–1983, before mussels invaded the river, and in 1992 and 1994, after mussels invaded the river. Live unionids at four stations along the southeastern shore accounted for 97% (20 species) of all shells collected in 1982–1983, whereas live unionids accounted for only 10% (13 species) in 1992. A similar decline in live unionids occurred at nine stations along the northwestern shore, except the decline occurred over the three sampling periods: in 1982–83, 84% (22 species) were live; in 1992, 65% (26 species) were live; and, in 1994, only 3% (13 species) were live. The difference in time to near-total mortality of unionids along the southeastern and northwestern shores is attributed to differences in the time of invasion and abundance of zebra mussel veligers in distinct water masses emanating from Lake St. Clair located immediately upstream of the Detroit River. Although individuals of all species of all unionid subfamilies declined between 1982 and 1992/1994, members of the subfamilies Anodontinae and Lampsilinae declined more than Ambleminae. Between 1986 and 1992/1994, five Anodontinae, three Lampsilinae and 0 Ambleminae species have been extirpated from the river due to dreissenid mussel infestation. Numbers of individuals of commonly found species declined more than numbers of individuals of uncommonly found species. However, the number of uncommon species declined 47% (17 to 9) along both the southeastern and northwestern shores, whereas common species remained the same (3 species) along the southeastern shore and declined only 40% (5 to 3 species) along the northwestern shore. This study, and others, suggest that high mortality of unionids can occur between 4 and 6 yr after initial invasion by dreissenids or up to 8 yr depending on water current patterns. Infestation-induced mortality of unionids in the Detroit River is similar to that observed at a few locations in other rivers, but is higher over a larger area than that measured in other rivers to date, probably because the Detroit River was the first to be colonized by dreissenid mussels in North America.

Michigan, Ontario

Associations of wintering birds with habitat in semidesert and plains grasslands in Arizona

We studied associations with winter habitat for seven species of birds, one species-group (eastern and western meadowlarks combined), and total sparrows at seven sites in the semidesert and plains grasslands of southeastern Arizona from 1999–2001, sampling with mist-nets and survey-transects. We measured structure and composition of vegetation, assessing vegetative differences among sites, and modeled associations between indices of avian abundance and six vegetative variables using generalized linear models. For all vegetative variables, there were significant differences among sites. Numbers of northern harriers ( Circus cyaneus ) were positively associated with total number of sparrows. Indices of abundance for individual species of birds were statistically correlated with various measures of structure and composition of vegetation. In particular, grasshopper ( Ammodramus savannarum ) and vesper ( Pooecetes gramineus ) sparrows were negatively associated with amount of bare ground; horned larks ( Eremophila alpestris ) were negatively associated with vertical grass density; Baird's sparrows ( A. bairdii ) were negatively associated with shrub density; meadowlarks ( Sturnella magna and S. neglecta combined) were positively associated with native grass. Our results suggest that these species would benefit from management of habitat that affects the vegetative characteristics associated with their abundance.

Arizona

Modeling aboveground biomass of Tamarix ramosissima in the Arkansas River Basin of Southeastern Colorado, USA

Predictive models of aboveground biomass of nonnative Tamarix ramosissima of various sizes were developed using destructive sampling techniques on 50 individuals and four 100-m2 plots. Each sample was measured for average height (m) of stems and canopy area (m2) prior to cutting, drying, and weighing. Five competing regression models (P < 0.05) were developed to estimate aboveground biomass of T. ramosissima using average height and/or canopy area measurements and were evaluated using Akaike's Information Criterion corrected for small sample size (AICc). Our best model (AICc = -148.69, ??AICc = 0) successfully predicted T. ramosissima aboveground biomass (R2 = 0.97) and used average height and canopy area as predictors. Our 2nd-best model, using the same predictors, was also successful in predicting aboveground biomass (R2 = 0.97, AICc = -131.71, ??AICc = 16.98). A 3rd model demonstrated high correlation between only aboveground biomass and canopy area (R2 = 0.95), while 2 additional models found high correlations between aboveground biomass and average height measurements only (R2 = 0.90 and 0.70, respectively). These models illustrate how simple field measurements, such as height and canopy area, can be used in allometric relationships to accurately predict aboveground biomass of T. ramosissima. Although a correction factor may be necessary for predictions at larger scales, the models presented will prove useful for many research and management initiatives.

Western North American Naturalist

Pleistocene porcupine (Erethizontidae) records in arid southwestern North America and comparisons with the modern distribution of Erethizon dorsatum in southern California and Arizona

he North American porcupine ( Erethizon dorsatum ) is widely distributed throughout many ecosystems on the continent from northern Mexico to the Arctic Ocean, except for the southeastern portion of the United States. Habi­tats include the arid Desert Southwest region where modern records are generally sparse. The paleogeographic range in the Desert Southwest is not unlike the modern distribution of Erethizon , with some exceptions. Although there are early Pleistocene records of Erethizon for southern California, no late Pleistocene records (Rancholabrean North American Land Mammal Age [NALMA]) are known for Imperial, Inyo, Riverside, or San Bernardino Counties in southern California or in Mexico. This is surprising given late-Pleistocene records in Arizona, Nevada, and New Mexico and modern records from southern California and Mexico. Pleistocene habitats for porcupines were similar to those occupied today, just at different elevations due to differing climates. Modern preferred habitats in the Desert Southwest include conifer-clad high-elevation areas and associated pinyon pine / juniper belts, and occasionally riparian corridors in desert environments. The overall rarity of porcupines today in arid parts of the Desert Southwest is likely due to the combination of increasing aridity in the region during the Holocene, past persecution by humans, and increasing predator populations.

Arizona, California

Abundance, distribution, and population trends of the iconic Hawaiian Honeycreeper, the ʻIʻiwi (Vestiaria coccinea) throughout the Hawaiian Islands

Naturalists in the 1800s described the ʻIʻiwi (Vestiaria coccinea) as one of the most abundant forest birds, detected in forested areas from sea level to tree line across all the major Hawaiian Islands. However, in the late 1800s, ʻIʻiwi began to disappear from low elevation forests, and by the mid-1900s, the species was largely absent from low- and mid-elevation areas. Today, ʻIʻiwi are restricted to high-elevation forests on the islands of Hawaiʻi, east Maui, and Kauaʻi, with a few birds apparently persisting on Oʻahu, Molokaʻi, and west Maui. ʻIʻiwi are highly vulnerable to introduced disease, and the prevalence of avian malaria in low and mid-elevations is believed to be the cause of ʻIʻiwi being restricted to high elevations where temperatures are too cold for the development of the disease and its mosquito vector. With global warming, it is feared that the disease will move quickly into the high-elevation forests where the last ʻIʻiwi reside, threatening their viability. The U.S. Fish and Wildlife Service was petitioned to list the ʻIʻiwi as an Endangered Species in 2010, and this report provides a comprehensive review of the abundance, distribution, and trends using historical survey data as well as the most recently available survey information (up to 2012). We estimate the total population size of ‘I‘iwi at 550,972–659,864 (mean = 605,418) individuals. Of these, 90 percent are on the island of Hawaiʻi, followed by east Maui (about 10 percent), with less than 1 percent on Kauaʻi. ʻIʻiwi population trends vary across the islands. ʻIʻiwi population in Kauaʻi has experienced sharp declines, with a projected trend of 92 percent decline over a 25 year period based on the 2000–2012 surveys. On East Maui, the northeastern region has experienced declines (34 percent over a 25 year period), while the southeastern region has been stable to moderately increasing. On the island of Hawaiʻi, population trends are mixed. On the windward side, populations are largely declining, although the northern section (Hakalau Forest) has stable populations. On the leeward side, results suggest a strongly increasing population, with estimates of as much as a 147 percent increase over a 25 year period from the Puʻu Waʻawaʻa region. However, it is unclear how much these results from the leeward side of Hawaiʻi show a population trend contrary to population trends in all other areas or are an artifact of a sparsely sampled area. Trends by elevation suggest a large decrease in numbers of ʻIʻiwi at elevations below 1,200 meters on Kauaʻi and northeast Maui. Low elevation ʻIʻiwi populations also appear to have decreased in other regions, although low-elevation areas are not surveyed as often as other areas because of their lack of native forest birds. An exception to this pattern was the lower portions of the Hakalau Forest National Wildlife Refuge Kona Unit in the central leeward part of the island of Hawaiʻi, where populations appeared stable at the lower elevations. Based on the most recent surveys (up to 2012), approximately 50 percent of ʻIʻiwi live in a narrow, 500-meter band at elevations of 1,200–1,700 meters, suggesting that ʻIʻiwi are vulnerable to future shifts in climate.

Hawai'i

Estimating ages of Utah chubs by use of pectoral fin rays, otoliths, and scales

Utah chub Gila atraria is native to the Upper Snake River system in Wyoming and Idaho and to the Lake Bonneville Basin in Utah and southeastern Idaho. However, the Utah chub has been introduced into many other waterbodies in the western United States, where it competes with ecologically and economically important species. The objectives of this study were to evaluate between-reader precision and reader confidence in age estimates obtained from pectoral fin rays, lapilli (otoliths), asterisci (otoliths), and scales for Utah chubs collected from Henrys Lake, Idaho. Lapilli have been previously shown to provide accurate age estimates for Utah chubs; therefore, we sought to compare age estimates from fin rays, asterisci, and scales to those from lapilli. The between-reader coefficient of variation (CV) in age estimates was lowest and the percent of exact reader agreement (PA-0) was highest for pectoral fin rays (CV = 4.7, PA-0 = 74%), followed by scales (CV = 10.3, PA-0 = 52.3%), lapilli (CV = 11.6, PA-0 = 48.2%), and asterisci (CV = 13.0, PA-0 = 41.7%). Consensus age estimates from pectoral fin rays showed high concordance with consensus age estimates from lapilli. Our results indicate that pectoral fin rays provide the most precise age estimates for Utah chub. Pectoral fin rays are easily collected and processed and also provide age estimates without requiring fish sacrifice.

Western North American Naturalist

Floral Composition of Pollen Collected from a Rusty Patched Bumble Bee (Bombus affinis, Cresson) Nest in Southeastern Minnesota

Understanding the forage diets of imperiled bumble bees can improve conservation planning and habitat restoration efforts. In this study, we describe the taxonomic composition of bee-collected pollen from 2 Rusty Patched Bumble Bee ( Bombus affinis , Cresson) nests located in southeastern Minnesota. This is the first published reporting of pollen collected from active B. affinis nests. We also compared pollen identification via traditional palynological light microscopy with genetic identification via ITS metabarcoding. Among the 49 pollen samples analyzed, we detected 41 and 56 distinct taxa via light microscopy and metabarcoding, respectively. Furthermore, 27 of 47 total genera overlapped between the 2 methods. Bittersweet Nightshade ( Solanum dulcamara , Linnaeus) was the most detected species for both metabarcoding and microscopy identification for pollen prevalence. Pollen volume from the microscopy data showed that Lesser Burdock ( Arctium minus , Bernhardi), Alfalfa ( Medicago sativa , Linnaeus), Bittersweet Nightshade ( Solanum dulcamara , Linnaeus), Plumeless Thistle ( Carduus acanthoides , Linnaeus), and Red Clover ( Trifolium pratense , Linnaeus) together comprised more than half of the total volume of pollen. Light microscopy and metabarcoding revealed compositionally distinct plant communities when analyzed at the species level. Methodological concordance improved when analyzing pollen data at genus level, but both methods still reveal marginally distinct groupings. Our study highlights specific plant taxa that are important components of B. affinis pollen diets and provides actionable research for conservation efforts in urban systems. Our study also supports that B. affinis is a generalist forager and will collect pollen from a variety of native and non-native host plants.

Minnesota

Avian community responses to management of vegetation and water levels in restored wetlands at the Humacao Nature Reserve, Puerto Rico

Coastal wetlands of the Caribbean have been greatly reduced in area and quality, and information on wildlife responses to management is lacking. We applied wetland management practices (disking, control of water levels) in a site historically disturbed by Saccharum spp. (sugarcane) cultivation at the Humacao Nature Reserve, southeastern Puerto Rico, and evaluated avian community response. We conducted weekly bird surveys and nest searches on disked and non-disked plots within recently constructed impoundments. The avian community shifted from 16 upland dominated species pre-restoration, to 67 wetland-dependent species at the end of our study (2001–2002). Ordination analysis indicated avian guild use of plots varied with environmental variables. Bird species diversity was not influenced by treatment, month, or salinity levels but was influenced by water depth and vegetation cover. Bird abundance was influenced by water depth, but not by treatment, month, salinity or vegetation cover. Furthermore, water depths of 0.10–0.20 m and salinity of ≤15 ppt promoted habitat conditions suitable for a diverse wetland avian community. We located 268 nests of 8 wetland bird species and observed adults with young of various other waterbirds, including species of conservation concern such as Dendrocygna arborea (West Indian Whistling Duck) and Porzana flaviventer (Yellow-breasted Crake). Bird community responses suggest that management practices (i.e., soil disturbance and control of water levels) can improve wetland biodiversity in abandoned sugarcane fields of Puerto Rico. Moreover, these practices may benefit wetland biodiversity in other Caribbean islands with a similar history of land use and habitat degradation.

Humacao Nature Reserve

A putative hybrid swarm within Oonopsis foliosa (Asteraceae: Astereae)

Oo??nopsis foliosa var. foliosa and var. monocephala are endemic to short-grass steppe of southeastern Colorado and until recently were considered geographically disjunct. The only known qualitative feature separating these 2 varieties is floral head type; var. foliosa has radiate heads, whereas var. monocephala heads are discoid. Sympatry between these varieties is restricted to a small area in which a range of parental types and intermediate head morphologies is observed. We used distribution mapping, morphometric analyses, chromosome cytology, and pollen stainability to characterize the sympatric zone. Morphometrics confirms that the only discrete difference between var. foliosa and var. monocephala is radiate versus discoid heads, respectively. The outer florets of putative hybrid individuals ranged from conspicuously elongated yet radially symmetric disc-floret corollas, to elongated radially asymmetric bilabiate- or deeply cleft corollas, to stunted ray florets with appendages remnant of corolla lobes. Chromosome cytology of pollen mother cells from both putative parental varieties and a series of intermediate morphological types collected at the sympatric zone reveal evidence of translocation heterozygosity. Pollen stainability shows no significant differences in viability between the parental varieties and putative hybrids. The restricted distribution of putative hybrids to a narrow zone of sympatry between the parental types and the presence of meiotic chromosome-pairing anomalies in these intermediate plants are consistent with a hybrid origin. The high stainability of putative-hybrid pollen adds to a growing body of evidence that hybrids are not universally unfit.

Western North American Naturalist

Effects of exotic grasses on soil seed banks in Southeastern Arizona grasslands

At the Appleton-Whittell Research Ranch, an ungrazed grassland preserve in southeastern Arizona, soil seed banks were sampled in June, August, and October 2002 and June 2003. Wildfire had previously burned 90% of the research ranch in May 2002. Seed density and species richness in burned native grassland (2 plots) were compared to those in burned exotic grassland (2 plots). Averaged over 4 sample dates, seed densities were as follows: burned native grassland, 591 ± 243.1 seeds ·m −2 and 784 ± 334.9 seeds ·m −2 ; burned exotic grassland, 501 ± 198.9 seeds ·m −2 and 196 ± 123.8 seeds ·m −2 . Species richness in the seed bank, also averaged over 4 sample dates, was as follows: burned native grassland, 16.3 ± 1.7 species ·m −2 and 19.5 ± 1.0 species ·m −2 ; burned exotic grassland, 12.0 ± 3.4 species ·m −2 and 11.06 ± 2.5 species ·m −2 . The seed bank of burned exotic grassland contained significantly fewer seeds and species than that of burned native grassland. In addition, the seed bank in burned exotic grassland comprised mainly exotic grasses, whereas annual and perennial herbs, most of them native, dominated the seed bank of burned native grassland. Of the 50 species detected in soil samples, only 20 had a persistent seed bank, and only 1 of these was a native perennial bunchgrass. The preponderance of transient species means that eradication of exotic grasses must be followed by reseeding of native grasses and herbs, perhaps repeatedly, if native grassland is to replace exotic grassland.

Arizona