Book review of "A most remarkable creature: The hidden life and epic journey of the world’s smartest birds of prey"
No abstract available.
Journal of Field Ornithology↗
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Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.
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The American black bear (Ursus americanus) as an apex predator: Investigating the ecological role of the world’s most abundant large carnivore
Introduction American black bears ( Ursus americanus ) have been documented to have top-down effects, both consumptive (through predation) and nonconsumptive (through fear effects). However, their behavioural and dietary adaptability has led to uncertainty about the conditions under which these may occur. Objectives We aimed to (1) investigate when, where, and how often black bears influence lower trophic levels, and (2) critically assess the experimental design of such studies to determine trends and biases. Methods We conducted a systematic literature search and used linear mixed-effects models to assess the relationships among prey age class, the presence of other large carnivores, and the percentage of ungulate mortality due to black bears. We also summarised the measured effects of black bears on other carnivores and the results of any experimental studies. Results We found a strong negative relationship between puma presence and the percentage of ungulate mortality due to black bears, but only in areas with at least one other large carnivore (e.g., wolves). Among 16 studies of black bears' impacts on other carnivores, most documented negative behavioural effects. While only 5% of studies had strong experimental design, bear removal consistently increased juvenile ungulate survival. Discussion and Synthesis Our findings highlight black bears' strong top-down effects, resembling or exceeding those of other large carnivores. These effects were greatest when no other large carnivores were present, but as highly effective kleptoparasites, black bears can alter the feeding habits of other large carnivores. Thus, we argue that ‘apex’ is a conditional state, not a species-wide status.
Mammal Review↗
Developed and potential water power of the United States and other countries of the world
No abstract available.
Science↗
Mechanisms controlling world water chemistry: Evaporation-crystallization process
No abstract available.
Science↗
Pervasive shifts in forest dynamics in a changing world
Forest dynamics arise from the interplay of environmental drivers and disturbances with the demographic processes of recruitment, growth, and mortality, subsequently driving biomass and species composition. However, forest disturbances and subsequent recovery are shifting with global changes in climate and land use, altering these dynamics. Changes in environmental drivers, land use, and disturbance regimes are forcing forests toward younger, shorter stands. Rising carbon dioxide, acclimation, adaptation, and migration can influence these impacts. Recent developments in Earth system models support increasingly realistic simulations of vegetation dynamics. In parallel, emerging remote sensing datasets promise qualitatively new and more abundant data on the underlying processes and consequences for vegetation structure. When combined, these advances hold promise for improving the scientific understanding of changes in vegetation demographics and disturbances.
Science↗
Military use of geologists in World War II
No abstract available.
Geological Society of America Bulletin↗
Overcoming the momentum of anachronism: American geologic mapping in a twenty-first-century world
The practice of geologic mapping is undergoing conceptual and methodological transformation. Profound changes in digital technology in the past 10 yr have potential to impact all aspects of geologic mapping. The future of geologic mapping as a relevant scientific enterprise depends on widespread adoption of new technology and ideas about the collection, meaning, and utility of geologic map data. It is critical that the geologic community redefine the primary elements of the traditional paper geologic map and improve the integration of the practice of making maps in the field and office with the new ways to record, manage, share, and visualize their underlying data. A modern digital geologic mapping model will enhance scientific discovery, meet elevated expectations of modern geologic map users, and accommodate inevitable future changes in technology.
GSA Special Papers↗
Military geology unit of the U.S. Geological Survey during World War II
On June 24, 1942, the temporary Military Geology Unit of the U.S. Geological Survey was formalized after the U.S. Army Corps of Engineers requested them to prepare terrain intelligence studies to meet wartime priorities. The entire Military Geology Unit wartime roster was 114 professionals, including 88 geologists, 11 soil scientists, and 15 other specialists; 14 were women. Assisting staff (illustrators, typists, photographers, and others) totaled 43. The unit produced 313 studies, including 140 major terrain folios, 42 other major special reports, and 131 minor studies. These reports contain about 5,000 maps, 4,000 photographs and figures, 2,500 large tables, and 140 terrain diagrams. Most products were designed in the beginning for general strategic planning in Washington and later for detailed strategic planning overseas; they utilized graphics and nontechnical, telegraphic-style tabular texts. The Military Geology Unit's principal effort was the preparation of the terrain folios titled Strategic Engineering Studies. They varied somewhat in content and format, but the key components usually were introduction, terrain appreciation, rivers, road and airfield construction, construction materials, and water resources. The folios, produced at an average rate of about one per week and at an average cost of $2,500, were compiled from scientific journals, books, maps, and photographs available in the Washington area by a team of 3 to 8 scientists; 8 to 12 teams might be working concurrently. MGU personnel took great pride in never having missed a delivery deadline.
Book chapter↗
Costs of living for juvenile Chinook salmon ( Oncorhynchus tshawytscha ) in an increasingly warming and invaded world
Rapid environmental change in freshwater ecosystems has created a need to understand the interactive effects of multiple stressors, with temperature and invasive predators identified as key threats to imperiled fish species. We tested the separate and interactive effects of water temperature and predation by non-native smallmouth bass ( Micropterus dolomieu ) on the lethal (mortality) and sublethal (behavior, physiology, and growth) effects for juvenile Chinook salmon ( Oncorhynchus tshawytscha ) in seminatural stream channel experiments. Over 48 h trials, there was no difference in direct predation with warmer temperatures, but significant interactive effects on sublethal responses of juvenile salmon. Warmer temperatures resulted in significantly stronger and more variable antipredator responses (surface shoaling and swimming activity), while physiological indicators (plasma glucose, plasma cortisol) suggested suppression of physiological mechanisms in response to the combined stressors. These patterns corresponded with additive negative growth in predation, temperature, and combined treatments. Our results suggest that chronic increases in temperature may not increase direct predation over short periods, but can result in significant sublethal costs with negative implications for long-term development, disease resistance, and subsequent size-selective mortality of Pacific salmon.
Canadian Journal of Fisheries and Aquatic Sciences↗
Computational sustainability: Computing for a better world and a sustainable future
Computational sustainability aims to develop computational methods to help solve environmental, economic, and societal problems and thereby facilitate a path towards a sustainable future. Sustainability problems are unique in scale, impact, complexity, and richness, offering challenges but also opportunities for the advancement of the state of the art of computing and information science.
Communications of the ACM↗
The state of the world’s mangrove forests: Past, present, and future
Intertidal mangrove forests are a dynamic ecosystem experiencing rapid changes in extent and habitat quality over geological history, today and into the future. Climate and sea level have drastically altered mangrove distribution since their appearance in the geological record ∼75 million years ago (Mya), through to the Holocene. In contrast, contemporary mangrove dynamics are driven primarily by anthropogenic threats, including pollution, overextraction, and conversion to aquaculture and agriculture. Deforestation rates have declined in the past decade, but the future of mangroves is uncertain; new deforestation frontiers are opening, particularly in Southeast Asia and West Africa, despite international conservation policies and ambitious global targets for rehabilitation. In addition, geological and climatic processes such as sea-level rise that were important over geological history will continue to influence global mangrove distribution in the future. Recommendations are given to reframe mangrove conservation, with a view to improving the state of mangroves in the future.
Annual Review of Environment and Resources↗
Onset of snowmelt and streamflow in 2004 in the Western Unites States: How shading may affect spring streamflow timing in a warmer world
Historic streamflow records show that the onset of snowfed streamflow in the western United States has shifted earlier over the past 50 yr, and March 2004 was one of the earliest onsets on record. Record high temperatures occurred throughout the western United States during the second week of March, and U.S. Geological Survey (USGS) stream gauges throughout the area recorded early onsets of streamflow at this time. However, a set of nested subbasins in Yosemite National Park, California, told a more complicated story. In spite of high air temperatures, many streams draining high-elevation basins did not start flowing until later in the spring. Temperatures during early March 2004 were as high as temperatures in late March 2002, when streams at all of the monitored Yosemite basins began flowing at the same time. However, the March 2004 onset occurred before the spring equinox, when the sun was lower in the sky. Thus, shading and solar radiation differences played a much more important role in 2004, leading to differences in streamflow timing. These results suggest that as temperatures warm and spring melt shifts earlier in the season, topographic effects will play an even more important role than at present in determining snowmelt timing. ?? 2006 American Meteorological Society.
Journal of Hydrometeorology↗
Integrated geophysical imaging of a concealed mineral deposit: a case study of the world-class Pebble porphyry deposit in southwestern Alaska
We combined aeromagnetic, induced polarization, magnetotelluric, and gravity surveys as well as drillhole geologic, alteration, magnetic susceptibility, and density data for exploration and characterization of the Cu-Au-Mo Pebble porphyry deposit. This undeveloped deposit is almost completely concealed by postmineralization sedimentary and volcanic rocks, presenting an exploration challenge. Individual geophysical methods primarily assist regional characterization. Positive chargeability and conductivity anomalies are observed over a broad region surrounding the deposit, likely representing sulfide minerals that accumulated during multiple stages of hydrothermal alteration. The mineralized area occupies only a small part of the chargeability anomaly because sulfide precipitation was not unique to the deposit, and mafic rocks also exhibit strong chargeability. Conductivity anomalies similarly reflect widespread sulfides as well as water-saturated glacial sediments. Mineralogical and magnetic susceptibility data indicate magnetite destruction primarily within the Cu-Au-Mo mineralized area. The magnetic field does not show a corresponding anomaly low but the analytic signal does in areas where the deposit is not covered by postmineralization igneous rocks. The analytic signal shows similar lows over sedimentary rocks outside of the mineralized area, however, and cannot uniquely distinguish the deposit. We find that the intersection of positive chargeability anomalies with analytic signal lows, indicating elevated sulfide concentrations but low magnetite at shallow depths, roughly delineates the deposit where it is covered only by glacial sediments. Neither chargeability highs nor analytic signal lows are present where the deposit is covered by several hundred meters of sedimentary and volcanic rocks, but a 3D resistivity model derived from magnetotelluric data shows a corresponding zone of higher conductivity. Gravity data highlight geologic features within the deposit, including shallow diorite sills that locally contain higher-grade mineralization. The results thus show ways in which an integrated survey approach might be used to distinguish zones of potentially economic mineralization.
Alaska↗
Remote sensing of global croplands for food security: Way forward
This book opens a new pathway for global mapping that is focused on a specific land use theme, such as irrigated or rain-fed croplands and classes within these themes. Since croplands use most of the water consumed by humans, specific knowledge of irrigated and rain-fed croplands will be critical for precise estimates of water use. At present and in the coming decades, irrigated and rain-fed cropland area mapping is crucial for food security studies. Throughout this book, various subjects pertaining to global croplands are discussed comprehensively.
Book chapter↗
The rise and fall of infectious disease in a warmer world
Now-outdated estimates proposed that climate change should have increased the number of people at risk of malaria, yet malaria and several other infectious diseases have declined. Although some diseases have increased as the climate has warmed, evidence for widespread climate-driven disease expansion has not materialized, despite increased research attention. Biological responses to warming depend on the non-linear relationships between physiological performance and temperature, called the thermal response curve. This leads performance to rise and fall with temperature. Under climate change, host species and their associated parasites face extinction if they cannot either thermoregulate or adapt by shifting phenology or geographic range. Climate change might also affect disease transmission through increases or decreases in host susceptibility and infective stage (and vector) production, longevity, and pathology. Many other factors drive disease transmission, especially economics, and some change in time along with temperature, making it hard to distinguish whether temperature drives disease or just correlates with disease drivers. Although it is difficult to predict how climate change will affect infectious disease, an ecological approach can help meet the challenge.
F1000 Research↗
Regional contingencies in the relationship between aboveground Bbomass and litter in the world’s grasslands
Based on regional-scale studies, aboveground production and litter decomposition are thought to positively covary, because they are driven by shared biotic and climatic factors. Until now we have been unable to test whether production and decomposition are generally coupled across climatically dissimilar regions, because we lacked replicated data collected within a single vegetation type across multiple regions, obfuscating the drivers and generality of the association between production and decomposition. Furthermore, our understanding of the relationships between production and decomposition rests heavily on separate meta-analyses of each response, because no studies have simultaneously measured production and the accumulation or decomposition of litter using consistent methods at globally relevant scales. Here, we use a multi-country grassland dataset collected using a standardized protocol to show that live plant biomass (an estimate of aboveground net primary production) and litter disappearance (represented by mass loss of aboveground litter) do not strongly covary. Live biomass and litter disappearance varied at different spatial scales. There was substantial variation in live biomass among continents, sites and plots whereas among continent differences accounted for most of the variation in litter disappearance rates. Although there were strong associations among aboveground biomass, litter disappearance and climatic factors in some regions (e.g. U.S. Great Plains), these relationships were inconsistent within and among the regions represented by this study. These results highlight the importance of replication among regions and continents when characterizing the correlations between ecosystem processes and interpreting their global-scale implications for carbon flux. We must exercise caution in parameterizing litter decomposition and aboveground production in future regional and global carbon models as their relationship is complex.
PLoS ONE↗
Woodland dynamics at the northern range periphery: A challenge for protected area management in a changing world
Managers of protected natural areas increasingly are confronted with novel ecological conditions and conflicting objectives to preserve the past while fostering resilience for an uncertain future. This dilemma may be pronounced at range peripheries where rates of change are accelerated and ongoing invasions often are perceived as threats to local ecosystems. We provide an example from City of Rocks National Reserve (CIRO) in southern Idaho, positioned at the northern range periphery of pinyon-juniper (P-J) woodland. Reserve managers are concerned about P-J woodland encroachment into adjacent sagebrush steppe, but the rates and biophysical variability of encroachment are not well documented and management options are not well understood. We quantified the rate and extent of woodland change between 1950 and 2009 based on a random sample of aerial photo interpretation plots distributed across biophysical gradients. Our study revealed that woodland cover remained at approximately 20% of the study area over the 59-year period. In the absence of disturbance, P-J woodlands exhibited the highest rate of increase among vegetation types at 0.37% yr −1 . Overall, late-successional P-J stands increased in area by over 100% through the process of densification (infilling). However, wildfires during the period resulted in a net decrease of woody evergreen vegetation, particularly among early and mid-successional P-J stands. Elevated wildfire risk associated with expanding novel annual grasslands and drought is likely to continue to be a fundamental driver of change in CIRO woodlands. Because P-J woodlands contribute to regional biodiversity and may contract at trailing edges with global warming, CIRO may become important to P-J woodland conservation in the future. Our study provides a widely applicable toolset for assessing woodland ecotone dynamics that can help managers reconcile the competing demands to maintain historical fidelity and contribute meaningfully to the U.S. protected area network in a future with novel, no-analog ecosystems.
Idaho↗