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At least 1,783 records · Page 99Linked to original sources
USGS2000

Ecology and demographics of Pacific sand lance, Ammodytes hexapterus Pallas, in Lower Cook Inlet, Alaska

Distinct sand lance populations occur within the relatively small geographic area of Lower Cook Inlet, Alaska. Marked meso-scale differences in abundance, growth, and mortality exist as a consequence of differing oceanographic regimes. Growth rate within populations (between years) was positively correlated with temperature. However, this did not extend to inter-population comparisons where differing growth rates were better correlated to marine productivity. Most sand lance reached maturity in their second year. Field observations and indices of maturity, gonad development, and ova-size distribution all indicated that sand lance spawn once each year. Sand lance spawned intertidally in late September and October on fine gravel/sandy beaches. Embryos developed over 67 days through periods of intertidal exposure and sub-freezing air temperatures. Mean dry-weight energy value of sand lance cycles seasonally, peaking in spring and early summer (20.91 kJg -1 for males, 21.08 kJg -1 for females), and subsequently declining by about 25% during late summer and fall (15.91 kJg -1 for males, 15.74 kJg -1 for females). Sand lance enter the winter with close to their minimum whole body energy content. Dry weight energy densities of juveniles increased from a minimum 16.67 kJg -1 to a maximum of 19.68 kJg -1 and are higher than adults in late summer.

Alaska↗
USGS1993

Ecology and population status of Northern Fulmars ( Fulmarus glacialis ) of the North Pacific

I n the North Pacific, the breeding distribution of Northern Fulmars ( Fulmarus glacialis ) includes about equal numbers of very large colonies (50,000-500,000 individuals) and relatively small ones (5-5,000 individuals). The almost complete segregation of light and dark colour phases between adjacent colonies in the Bering Sea and Sea of Okhotsk suggests there is little gene flow among the major colonies. Annual productivity averaged 0.42 chicks per breeding pair in 10 years at one colony in the Gulf of Alaska; adult survival was 0.97 per year over five years at the same location. There is no clear indication of population change at either of two large colonies studied, but several small colonies in the western Aleutians and northern Gulf of Alaska have increased since the mid-1970s. Fulmars appear to have low vulnerability to oil pollution and drifting gill nets, but they are relatively heavy consumers of plastic debris. Introduced predators probably reduced fulmar populations in the past. Population monitoring is recommended for one or more of the large Pacific colonies and several of the smaller ones. Small colonies may provide early indications of changing population status.

Conference Paper↗
USGS1993

Status and ecology of kittiwakes ( Rissa tridactyla and R. brevirostris ) in the North Pacific

Black-legged Kittiwakes ( Rissa tridactyla ) are widely distributed in the subarctic North Pacific and adjacent seas, with a total breeding population of about 2.6 million individuals. Red-legged Kittiwakes ( R. brevirostris ) breed in four locations, and at least 95% of their estimated world population of 230,000 birds nest on one island (St. George, Pribilof Islands). Compared to Black-legged Kittiwakes in Britain, both species in Alaska have exhibited poor productivity since at least the mid-1970s. The situation worsened during the 1980s, with recent (1985-1989) estimates of annual productivity averaging 0.19 young per nest. The frequency of "colony failures" (<0.1 young per nest) exceeded 50% in Alaska between 1985 and 1989. Low productivity has involved, to varying degrees, the failure of many birds to lay eggs, reduced clutch sizes, low hatching success, and poor chick survival. There is evidence of population declines in some colonies of Black-legged Kittiwakes, but other colonies appear to be stable or increasing. High adult survival may account for the relative stability of Black-legged Kittiwakes, but widespread declines are anticipated unless productivity improves. The evidence suggests that poor productivity results from low surface availability of key prey species.

Conference Paper↗
USGS2009

Zoogeography, conservation, and ecology of crayfishes within the Cheat River basin of the Upper Monongehela River drainage, West Virginia

During summer 2008, we studied the geographic distribution and conservation status of crayfishes within the Cheat River basin of the upper Monongahela River drainage. Stream sites (n = 73) were selected with a probabilistic sampling design, whereas one reservoir (Cheat Lake) and seven terrestrial sites for burrowing crayfishes were selected non-randomly. Stream crayfishes were seined or hand-collected following standardized protocols, and physical habitat and physiochemical water quality parameters were recorded at each site. Cambarus b. bartonii , C. carinirostris , and Orconectes obscurus were initially documented within the Cheat River basin in 1956. Surveys conducted in the late 1980s documented the presence of C. carinirostris , C. dubius , C. monongalensis , and O. obscurus . Our data on crayfish distributions from 2008 are consistent with those of the late 1980s. Survey data from 1956, however, indicated depauperate populations of Cambarus throughout the basin during a time period of basin-wide habitat and water quality degradation. Currently, C. carinirostris is abundant throughout the Cheat River system, except in areas with low pH and elevated conductivity. Orconectes obscurus populations within the Cheat River basin are stable and occur primarily in higher stream orders. Future astacological efforts in the Cheat River basin, however, are needed to define the distribution of the basins two burrowing species, C. dubius and C. monongalensis .

West Vigninia↗
USGS2017

Developing multi-model ensemble projections of ecologically relevant climate variables for Puerto Rico and the US Caribbean

The global increases in surface air temperature are the most widespread and direct consequence of anthropogenic climate change. However, while 21st century temperatures are projected to increase in the Caribbean, the low variability and high average temperatures suggest that impacts on ecosystems and water resources are more likely through changes to the availability, timing, and pattern of moisture. The lack of local-scale climate model information that can resolve the complex topography and small scale climate features hinders the development of robust adaptation strategies. The goal of this project was to develop a suite of local-scale climate projections using dynamic downscaling to aid the development of adaptation strategies in Puerto Rico and the U.S. Virgin Islands (USVI). This project began by engaging the ecologists, hydrologists, and conservation biologists in the region to determine the most valuable types of information to aid research and decision making. The final product provides projections of future climate at a 2km horizontal resolution based on three global climate models and two regional climate models for a scenario with high greenhouse gas emissions. Results from the projections suggest that for Puerto Rico, annual temperature would increase between 1°C and 1.3°C by mid-century with larger temperature increases located in the interior portion of the island. Precipitation totals decrease for much of the island with island average decline between 12% and 19%, with some potentially large localized decreases exceeding 30%. The projected changes for the USVI are dominated by the surrounding ocean environment. The resulting projections will be provided to stakeholders in the region via the USGS and the CLCC.

Puerto Rico↗
USGS2016

Ecology and conservation of Lesser Prairie-Chickens

Lesser Prairie-Chickens have experienced substantial declines in terms of population and the extent of area that they occupy. While they are an elusive species, making it difficult at times to monitor them, current evidence indicates that they have been persistently decreasing in number since the Dust Bowl of the 1930s dramatically affected their core range. In May of 2014, the United States Fish and Wildlife Service listed Lesser Prairie-Chickens as a threatened species, granting them federal protection under the Endangered Species Act, which included a special rule recognizing significant conservation planning efforts made by state and federal wildlife agencies within the geographical range of the species. Although the listing was vacated by judicial ruling in September 2015, concern for persistence of the species persists. These actions illustrate the uncertain legal status and future conservation challenges for Lesser Prairie-Chickens.

Book↗
USGS2015

Regulating services as measures of ecological resilience on DoD lands

Knowledge of the capacity and flow of ecosystem services can help DoD land managers make decisions that enhance cost-effectiveness, minimize environmental damage, and maximize resources available for military missions. We demonstrated a methodology to quantify and map selected regulating services (RS), which helps land managers envision tradeoffs. Our objectives were to 1) estimate current capacity of and demand for selected RS within DoD lands, 2) examine the effects of future DoD land management and climate changes on the capacity and flow of these RS, and 3) project how land-use and climate changes in nearby lands affect future demand for RS. Our approach incorporates widely accepted models and equations, remote sensing, GIS analysis, and stakeholder involvement. Required data include land cover/use, soil type, precipitation, and air temperature. We integrated data into the a) Surface Curve Number Method and b) Revised Universal Soil Loss Equation to estimate capacity of sediment, nitrogen (N) and surface-water regulation. Capacities and flows of RS vary greatly across landscapes and are likely to vary as climate changes or development occurs. Analyses of RS capacity and flow can help managers and planners prioritize actions in the context of best management practices and compatible use buffers. Staff surveys indicated that our approach was informative and easy to use. Implementation may be most limited by on-installation personnel time.

Report↗