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At least 739 records · Page 41Linked to original sources
USGS2022

Five years of monitoring a bio-engineered living shoreline: Comparison of oyster population development by reef technology.

The Living Shoreline Demonstration Project (PO-148) used five bio-engineered reef technologies (Reef Balls in two configurations; Figure 1) acting as breakwaters to protect vulnerable shorelines. While the primary goal is to attenuate wave energy, the sustainability and success of these products as “living” shorelines are based on their ability to enhance oyster habitat, enabling the reef to maintain elevation within the rapidly changing environment (i.e., sea level rise, subsidence). This report documents the recruitment, survival, and growth of the living components of the reef – oysters and other encrusting organisms (e.g. mussels, barnacles). This final technical report provides data from five years of monitoring (November 2017 – December 2021) of reefs located along the western side of Eloi Bay in Pontchartrain Basin (Figure 2). Monitoring goals included assessment of (1) annual oyster densities and population dynamics on the reefs, (2) annual density and diversity of other encrusting organisms, and (3) comparisons of outcomes by reef technology, exposure, and water quality. Detailed information on technologies used, construction design, as-built elevations are available in Coast & Harbor Engineering (2016) Design Memorandum dated March 25, 2016, submitted to Louisiana Coastal Protection and Restoration Authority.

Louisiana↗
USGS1991

Seed germination and life history syndromes in the California chaparral

Syndromes are life history responses that are correlated to environmental regimes and are shared by a group of species (Stebbins, 1974). In the California chaparral there are two syndromes contrasted by the timing of seedling recruitment relative to wildfires. One syndrome, here called the fire-recruiter or refractory seed syndrome, includes species (both resprouting and non-resprouting) which share the feature that the timing of seedling establishment is specialized to the first rainy season after fire. Included are woody, suffrutescent and annual life forms but no geophytes have this syndrome. These species are linked by the characteristic that their seeds have a dormancy which is readily broken by environmental stimuli such as intense heat shock or chemicals leached from charred wood. Such seeds are referred to as “refractory” and dormancy, in some cases, is due to seed coat impermeability (such seeds are commonly called hardseeded), but in other cases the mechanism is unknown. Seeds of some may require cold stratification and/or light in addition to fire related stimuli. In the absence of fire related cues, a portion or all of a species’ seed pool remains dormant. Most have locally dispersed seeds that persist in the soil seed bank until the site burns. Dispersal of propagules is largely during spring and summer which facilitates the avoidance of flowering and fruiting during the summer and fall drought. Within a life form (e.g., shrub, suffrutescent, etc.), the seeds of these species have less mass than those of species with non-refractory seeds and this possibly reflects the environmental favorableness of the postfire environment for seedling establishment. Regardless of when fire occurs, germination is normally delayed until late winter or early spring. In the absence of fire, or other disturbance, opportunities for population expansion are largely lacking for species with this syndrome. The other syndrome, here called the fire-resister or non-refractory seed syndrome, includes species that are resilient to frequent fires (mostly by vegetative resprouting), but require fire-free periods for recruiting new seedlings. Included are shrubs, subshrubs, suffrutescents, lianas, geophytes and annuals. All are linked by the characteristic that their seeds germinate in the absence of cues related to wildfires. In many cases no form of seed dormancy is present and the seeds germinate soon after dispersal; consequently these species do not accumulate a persistent seed bank. Germination and seedling establishment is independent of fire and thus opportunities for population expansion are also independent of fire. The demographic pattern of seedling recruitment varies with the life form. For shrubs, seedling recruitment may be restricted to sites free of fire for periods of a hundred years or more. Recruitment appears to require relatively mesic conditions and this may account for the patchy distribution of these species within the matrix of relatively arid sites. Finding such sites has selected for propagules specialized for wind or animal dispersal; the majority are bird dispersed. These shrub species all disperse fruits in fall and winter and this may have been selected to take advantage of migratory birds as well as to time dispersal to the winter rains typical of the mediterranean-climate. Germination typically occurs within several weeks of the first fall or winter rains. Maturation of flowers and fruits during the summer and fall drought may account for the distribution of these species on more mesic sites. Seed mass of these species is large and this may have been selected to provide an advantage to seedlings establishing under the canopy of this dense shrub community.

Botanical Review↗
USGS2006

Mercury in water and biomass of microbial communities in hot springs of Yellowstone National Park, USA

Ultra-clean sampling methods and approaches typically used in pristine environments were applied to quantify concentrations of Hg species in water and microbial biomass from hot springs of Yellowstone National Park, features that are geologically enriched with Hg. Microbial populations of chemically-diverse hot springs were also characterized using modern methods in molecular biology as the initial step toward ongoing work linking Hg speciation with microbial processes. Molecular methods (amplification of environmental DNA using 16S rDNA primers, cloning, denatured gradient gel electrophoresis (DGGE) screening of clone libraries, and sequencing of representative clones) were used to examine the dominant members of microbial communities in hot springs. Total Hg (THg), monomethylated Hg (MeHg), pH, temperature, and other parameters influential to Hg speciation and microbial ecology are reported for hot springs water and associated microbial mats.

Applied Geochemistry↗
USGS2008

A multi-model framework for simulating wildlife population response to land-use and climate change

Reliable assessments of how human activities will affect wildlife populations are essential for making scientifically defensible resource management decisions. A principle challenge of predicting effects of proposed management, development, or conservation actions is the need to incorporate multiple biotic and abiotic factors, including land-use and climate change, that interact to affect wildlife habitat and populations through time. Here we demonstrate how models of land-use, climate change, and other dynamic factors can be integrated into a coherent framework for predicting wildlife population trends. Our framework starts with land-use and climate change models developed for a region of interest. Vegetation changes through time under alternative future scenarios are predicted using an individual-based plant community model. These predictions are combined with spatially explicit animal habitat models to map changes in the distribution and quality of wildlife habitat expected under the various scenarios. Animal population responses to habitat changes and other factors are then projected using a flexible, individual-based animal population model. As an example application, we simulated animal population trends under three future land-use scenarios and four climate change scenarios in the Cascade Range of western Oregon. We chose two birds with contrasting habitat preferences for our simulations: winter wrens (Troglodytes troglodytes), which are most abundant in mature conifer forests, and song sparrows (Melospiza melodia), which prefer more open, shrubby habitats. We used climate and land-use predictions from previously published studies, as well as previously published predictions of vegetation responses using FORCLIM, an individual-based forest dynamics simulator. Vegetation predictions were integrated with other factors in PATCH, a spatially explicit, individual-based animal population simulator. Through incorporating effects of landscape history and limited dispersal, our framework predicted population changes that typically exceeded those expected based on changes in mean habitat suitability alone. Although land-use had greater impacts on habitat quality than did climate change in our simulations, we found that small changes in vital rates resulting from climate change or other stressors can have large consequences for population trajectories. The ability to integrate bottom-up demographic processes like these with top-down constraints imposed by climate and land-use in a dynamic modeling environment is a key advantage of our approach. The resulting framework should allow researchers to synthesize existing empirical evidence, and to explore complex interactions that are difficult or impossible to capture through piecemeal modeling approaches. ?? 2008 Elsevier B.V.

Ecological Modelling↗
USGS2026

Rethinking seed selection based on climate matching during restoration: Geography, soils and climate explain species-specific mortality

Implicit in the construction of seed transfer zones (STZs) are the assumptions that plant populations are adapted to their home climates and that transferring native seed across climate gradients risks maladaptation and poor performance. However, plants are adapted to multiple aspects of their environments that are often excluded from STZ development. Here, we used models integrating geographic distance, climate distance and soil metrics to predict plant mortality in an experimental garden for three restoration-relevant species in the southwestern United States: Bouteloua curtipendula , Heterotheca villosa and Sporobolus cryptandrus . Overall, climate distance explained mortality better than geographic distance, but increasing climate distance was not consistently associated with higher mortality. In contrast, mortality always increased with geographic distance. Species responded idiosyncratically to environmental gradients such as soil texture and pH, indicating that incorporating site-specific variables beyond climate can improve predictions of survival. Finally, seed sources of H. villosa from hotter, drier climates exhibited improved survival during abnormally hot, dry conditions at the experimental site, whereas no consistent pattern emerged for the two grass species. Collectively, our results suggest that seeding strategies extending beyond climate matching alone may better support restoration outcomes when species-specific guidance is unavailable.

Arizona, Colorado, New Mexico, Utah↗
USGS1996

Variations in the reproductive cycle of Dreissena polymorpha in Europe, Russia, and North America

The reproductive cycle of the zebra mussel { Dreissena polymorpha ) is highly variable throughout its range in Europe, Russia , and North America. The environmental factors influencing this variation are poorly understood, but successful reproduction is occurring in areas where it was initially believed that adult zebra mussels could not survive (i.e., southern United States). The differences in mussel reproduction occurring from site-to-site make it difficult to predict timing of specific events, such as the start of larval production, that are important in initiating containment or control procedures. For example, the amount of time required for a fertilized egg to develop into a juvenile mussel can be as short as 8 days, or as long as 240 days. Release of gametes by adults can be a highly synchronized event, focused over a 1–2 week period, or it can be completely non-synchronized, occurring throughout the year. Zebra mussels in some localities start spawning at water temperatures of 12–13°C, but do not start until water temperatures reaches 22°C at other sites. While some of this variability in reproductive behavior stems from mussel adaptation to local conditions, part is due to difficulties in sampling these events. It is difficult to determine reproductive success of a specific population because of the problems in separating locally produced larvae from larvae drifting in from other areas. Further research is needed not only on the relationship between reproduction and environment at the community level, but also on the variability in response of individual mussels.

American Zoologist↗
USGS2012

Long-distance swimming by polar bears (Ursus maritimus) of the southern Beaufort Sea during years of extensive open water

Polar bears ( Ursus maritimus Phipps, 1774) depend on sea ice for catching marine mammal prey. Recent sea-ice declines have been linked to reductions in body condition, survival, and population size. Reduced foraging opportunity is hypothesized to be the primary cause of sea-ice-linked declines, but the costs of travel through a deteriorated sea-ice environment also may be a factor. We used movement data from 52 adult female polar bears wearing Global Positioning System (GPS) collars, including some with dependent young, to document long-distance swimming (>50 km) by polar bears in the southern Beaufort and Chukchi seas. During 6 years (2004-2009), we identified 50 long-distance swims by 20 bears. Swim duration and distance ranged from 0.7 to 9.7 days (mean = 3.4 days) and 53.7 to 687.1 km (mean = 154.2 km), respectively. Frequency of swimming appeared to increase over the course of the study. We show that adult female polar bears and their cubs are capable of swimming long distances during periods when extensive areas of open water are present. However, long-distance swimming appears to have higher energetic demands than moving over sea ice. Our observations suggest long-distance swimming is a behavioral response to declining summer sea-ice conditions.

Canadian Journal of Zoology↗
USGS2013

Experimental reintroduction reveals novel life-history variation in Laysan Ducks ( Anas laysanensis )

Subfossil remains indicate that the Laysan Duck ( Anas laysanensis ) formerly occurred throughout the Hawaiian archipelago, but for more than 150 years it has been confined to a single, small atoll in the northwestern chain, Laysan Island. In 2004–2005, 42 ducks were reintroduced from Laysan to Midway Atoll, where they exhibited variation in life history never observed on Laysan. On Laysan, females have never been observed to breed successfully at age 1 year and few attempt it, whereas on Midway, females routinely raised young at <1 year of age. Mean (± SD) clutch size on Midway (7.0 ± 1.1, n = 41) was larger than the maximum clutch size of six eggs observed on Laysan. On Midway, renesting following nest failure (0.55 probability, n = 27) and double brooding (0.50, n = 54) were routine, and two instances of triple brooding were observed, whereas on Laysan, renesting and double brooding are rare (0.05 probability for both during our study; n = 21 and 19, respectively) and triple brooding has never been observed. Other novel life history on Midway included early cessation of parental care to renest. Altered life history on Midway is likely related to better feeding conditions and low population density compared with Laysan. An especially intriguing possibility is that the phenotypic plasticity observed represents exposure of hidden reaction norms evolved when the species inhabited a range of environments, but several alternative explanations exist. Future reintroductions of this species may provide opportunities to test hypotheses about mechanisms underlying phenotypic plasticity.

Hawai'i↗
USGS1995

Desert tortoises in the Mojave and Colorado deserts

The desert tortoise ( Gopherus agassizii ) is a widespread species of the southwestern United States and Mexico. Within the United States, desert tortoises live in the Mojave, Colorado, and Sonoran deserts of southeastern California, southern Nevada, southwestern Utah, and western Arizona (Fig. 1). A substantial portion of the habitat is on lands administered by the U.S. Department of the Interior. The U.S. government treats the desert tortoise as an indicator or umbrella species to measure the health and well-being of the ecosystems it inhabits. The tortoise functions well as an indicator because it is long-lived, takes 12-20 years to reach reproductive maturity, and is sensitive to changes in the environment. In 1990 the U.S. Fish and Wildlife Service listed the species as threatened in the northern and western parts of its geographic range (Fig. 1) because of widespread population declines and overall habitat loss, deterioration, and fragmentation. Because some populations exhibit significant genetic, morphologic (see glossary), and behavioral differences, the Desert Tortoise Recovery Team identified six distinctive population segments (Fig. 1) for critical habitat protection and long-term conservation within the Mojave and Colorado deserts (e.g., Lamb et al. 1989; USFWS 1994). The population segments are representative of distinctive climatic, floristic, and geographic regions.

Arizona, California, Nevada, Utah↗
USGS1993

Coupled effects of vertical mixing and benthic grazing on phytoplankton populations in shallow, turbid estuaries

Coastal ocean waters tend to have very different patterns of phytoplankton biomass variability from the open ocean, and the connections between physical variability and phytoplankton bloom dynamics are less well established for these shallow systems. Predictions of biological responses to physical variability in these environments is inherently difficult because the recurrent seasonal patterns of mixing are complicated by aperiodic fluctuations in river discharge and the high-frequency components of tidal variability. We might expect, then, less predictable and more complex bloom dynamics in these shallow coastal systems compared with the open ocean. Given this complex and dynamic physical environment, can we develop a quantitative framework to define the physical regimes necessary for bloom inception, and can we identify the important mechanisms of physical-biological coupling that lead to the initiation and termination of blooms in estuaries and shallow coastal waters? Numerical modeling provides one approach to address these questions. Here we present results of simulation experiments with a refined version of Cloern's (1991) model in which mixing processes are treated more realistically to reflect the dynamic nature of turbulence generation in estuaries. We investigated several simple models for the turbulent mixing coefficient. We found that the addition of diurnal tidal variation to Cloern's model greatly reduces biomass growth indicating that variations of mixing on the time scale of hours are crucial. Furthermore, we found that for conditions representative of South San Francisco Bay, numerical simulations only allowed for bloom development when the water column was stratified and when minimal mixing was prescribed in the upper layer. Stratification, however, itself is not sufficient to ensure that a bloom will develop: minimal wind stirring is a further prerequisite to bloom development in shallow turbid estuaries with abundant populations of benthic suspension feeders.

Journal of Marine Research↗
USGS2002

Mechanisms of impact and potential recovery of nearshore vertebrate predators following the 1989 Exxon Valdez oil spill

The 1989 spill of some 42 million L of crude oil into Prince William Sound, Alaska, represents not only the largest tanker spill in United States history, but the world’s largest spill in northern waters. Acute effects have been studied extensively. However, efforts to quantify the spill’s long-term chronic effects and develop defensible restoration measures have been plagued by varying levels of scientific uncertainty. That such uncertainty exists is not unexpected. The spill occurred in Prince William Sound’s highly variable physical setting typified by its complex oceanography and fjord-like geomorphology. Additionally, uncertainty was driven by the scarcity of precise pre-spill population estimates and spotty life-history information for most species. The research reported herein in, structured in eight primary papers and 27 supporting papers (appendices), documents the state of recovery and assessments of continuing constraints to population recovery for four vertebrate predators (sea otter Enhydra lutris , harlequin duck Histrionicus histrionicus , river otter Lontra canadensis , and pigeon guillemot Cepphus columba ) whose recovery status remained uncertain some 5 years after the Exxon Valdez oil spill. These species are used in a collective weight of evidence approach to better understand the process of coastal community recovery. Each species is examined for the strength of information it brings in health, population, and trophic metrics to support or reject the hypothesis of continuing oil effects in the nearshore system versus the alternatives that food constraints or demographic bottlenecks limit these focal species. While data for individual species contain various levels of uncertainty, scientific confidence is developed in the following picture when examined across species, metric, and hypothesis: Within the nearshore coastal environment, sporadic releases of residual oil are occurring, and benthic species, primarily invertebrates, are being exposed in a temporally and spatially patchy manner sufficient to transport oil up through the food chain. Thus, for the two invertebrate-feeders, sea otter and harlequin duck, evidence exists over several lines of investigation to suggest that local-scale populations continue to be constrained not by food availability or natural demographic processes, but by increased levels of mortality coincident with continued exposure to residual oil. Conversely, weight of evidence suggests that only limited direct oil-related effects are being transferred through the fish trophic pathway. Sufficient evidence suggests recovery is occurring in river otter populations, while the lack of recovery in pigeon guillemot may be attributed to food limitations (both natural and indirectly related to the spill) and/or slow demographic response to initial acute mortalities. Individual lines of investigation often contained uncertainty, but the collective weight of evidence presented in this multipaper volume indicates lack of full recovery of the nearshore ecosystem from the Exxon Valdez oil spill nearly a decade following the event. Integrated, multispecies approaches can allow sufficient weight of evidence to develop despite inherent system variability or data limitations and, thus, facilitate both better societal understanding of such pollution events and development of appropriate restoration responses.

Alaska↗
USGS1981

Historical evidence for discrete stocks of lake trout ( Salvelinus namaycush ) in Lake Michigan

Although few biological data exist on the now extinct native lake trout, Salvelinus namaycush , of Lake Michigan, historical records and interviews with former commercial fishermen strongly suggest that this once widespread resource was composed of a number of discrete spawning populations or stocks. A natural division of the resource into distinct stocks is consistent with the size of Lake Michigan and its varied physiography. The native trout may have undergone subtle genetic changes over the millennia, although we cannot determine whether the physical and behavioral differences represented different genotypes or only temporary effects of the local environment. Because of physiographic similarities among the upper Great Lakes and probable interchanges of lake trout during the last glacial period, we recommend that progeny of extant wild stocks, particularly from Lake Superior, are genetically most suitable for recolonizing Lake Michigan. Moreover, the hatchery-held parents of such fish should be infused periodically with genes of the wild or feral donor populations. Despite the sound historical basis for these recommendations, we also recognize that sufficiently high stocking rates coupled with a reduction of heavy exploitation may be even more important than heritability in obtaining self-sustaining populations.

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS2026

Navigating uncertainty and competing objectives: Spring chinook salmon recovery in the upper Willamette river

Globally, anadromous fish populations are threatened with extinction due to multiple factors, including river impoundments that block migration, widespread alteration of physical habitat, temperature, and flow regimes, commercial and recreational harvest, changes in biological communities, and long-term climate trends. In this synthesis, we describe how physical and biological factors, policy and law, and public resource allocation affect management of spring-run Chinook Salmon ( Oncorhynchus tshawytscha ) in the Upper Willamette River (UWR), Oregon, USA. Efforts to restore salmon populations often involve trade-offs, for example, water management decisions must account for flood control, agricultural and municipal water use, and management of other species. UWR Chinook Salmon recovery efforts are also governed by multiple laws, policies, and action agencies that in some cases have incongruent objectives. Competing and conflicting objectives, combined with uncertainty regarding the outcomes of proposed management actions, create significant challenges for decision makers. Resource limitations, regulatory constraints, and incongruent objectives have created challenges for managers in the UWR, but opportunities exist for improved adaptive management and collaboration, which could build trust and engagement among stakeholders and ultimately support the successful implementation of decision tools. A suite of decision support tools that have been used in the Willamette River basin and elsewhere across the range of Pacific salmon have the potential to enhance decision processes. These tools can be effective when decision makers and stakeholders commit to long-term, collaborative utilization of the tools for decision making, and when available resources and regulatory environments are conducive to implementation and adaptive refinement of both the decision-support tools and management plans. The general biological and institutional principles discussed for UWR Chinook Salmon in this work apply more generally to populations of anadromous fishes across their range, especially to populations in highly regulated river systems.

Oregon↗
USGS2022

Depth drives growth dynamics of dreissenid mussels in Lake Ontario

Understanding dreissenid mussel population dynamics and their impacts on lake ecosystems requires quantifying individual growth across a range of habitats. Most dreissenid mussel growth rates have been estimated in nutrient rich or nearshore environments, but mussels have continued to expand into deep, cold, low-nutrient habitats of the Great Lakes. We measured annual quagga mussel ( Dreissena rostriformis bugensis) growth at 15 m, 45 m, and 90 m in Lake Ontario using caged mussels near Oswego, New York, USA from June 2018 to May 2019. Quagga mussel growth (starting size 12 mm) was greatest at 15 m (mean shell length increase = 10.2 mm), and was lower at 45 m (5.9 mm) and 90 m (0.7 mm). Caged mussels were obtained from near the 90-m site and those reared at 15 and 45 m developed thicker shells than those that were caged at 90 m. We observed relatively high colonization by quagga and, to a lesser degree, zebra mussels ( Dreissena polymorpha ) at 15 m, very few colonizers at 45 m, and none at 90 m. Higher growth potential, but low natural mussel densities observed at 15 m and 45 m suggest factors other than growth limit dreissenid abundance at these depths. The relatively slow dreissenid growth rates observed in offshore habitats are consistent with the gradual abundance increases documented in these zones across the Great Lakes and suggest new mussels that become established in these habitats may contribute to ecosystem effects for decades.

New York↗
USGS2017

New zircon (U-Th)/He and U/Pb eruption age for the Rockland tephra, western USA

Eruption ages of a number of prominent Quaternary volcanic deposits remain inaccurately and/or imprecisely constrained, despite their importance as regional stratigraphic markers in paleo-environment reconstruction and as evidence of climate-altering eruptions. Accurately dating volcanic deposits presents challenging analytical considerations, including poor radiogenic yield, scarcity of datable minerals, and contamination of crystal populations by magma, eruption, and transport processes. One prominent example is the Rockland tephra, which erupted from the Lassen Volcanic Center in the southern Cascade arc. Despite a range in published eruption ages from 0.40 to 0.63 Ma, the Rockland tephra is extensively used as a marker bed across the western United States. To more accurately and precisely constrain the age of the Rockland tephra-producing eruption, we report U/Pb crystallization dates from the outermost ∼2 μm of zircon crystal faces (surfaces) using secondary ion mass spectrometry (SIMS). Our new weighted mean 238 U/ 206 Pb age for Rockland tephra zircon surfaces is 0.598 ± 0.013 Ma (2σ) and MSWD = 1.11 (mean square weighted deviation). As an independent test of the accuracy of this age, we obtained new (U-Th)/He dates from individual zircon grains from the Rockland tephra, which yielded a weighted mean age of 0.599 ± 0.012 Ma (2σ, MSWD = 5.13). We also obtained a (U-Th)/He age of 0.628 ± 0.014 Ma (MSWD = 1.19) for the Lava Creek Tuff member B, which was analyzed as a secondary standard to test the accuracy of the (U-Th)/He technique for Quaternary tephras, and to evaluate assumptions made in the model-age calculation. Concordance of new U/Pb and (U-Th)/He zircon ages reinforces the accuracy of our preferred Rockland tephra eruption age, and confirms that zircon surface dates sample zircon growth up to the time of eruption. We demonstrate the broad applicability of coupled U/Pb zircon-surface and single-grain zircon (U-Th)/He geochronology to accurate dating of Quaternary tephra, and highlight the challenges and opportunities of this technique.

Quaternary Science Reviews↗
USGS2016

Investigating dynamic sources of pharmaceuticals: Demographic and seasonal use are more important than down-the-drain disposal in wastewater effluent in a University City setting

Pharmaceutical pollution in surface waters poses risks to human and ecosystem health. Wastewater treatment facilities are primary sources of pharmaceutical pollutants, but little is known about the factors that affect drugs entering the wastewater stream. This paper investigates the effects of student pharmaceutical use and disposal behaviors and an annual demographic shift on pharmaceutical pollution in a university town. We sampled wastewater effluent during a ten-day annual spring student move-out period at the University of Vermont. We then interpreted these data in light of survey results that investigated pharmaceutical purchasing, use, and disposal practices among the university student population. Surveys indicated that the majority of student respondents purchased pharmaceuticals in the previous year. Many students reported having leftover drugs, though only a small portion disposed of them, mainly in the trash. We detected 51 pharmaceuticals in 80% or more of the wastewater effluent samples collected over the ten-day sampling period. Several increased in concentration after students left the area. Concentrations of caffeine and nicotine decreased weakly. Drug disposal among this university student population does not appear to be a major source of pharmaceuticals in wastewater. Increases in pharmaceutical concentration after the students left campus can be tied to an increase in the seasonal use of allergy medications directly related to pollen, as well as a demographic shift to a year-round older population, which supports national data that older people use larger volumes and different types of pharmaceuticals than the younger student population.

Vermont↗
USGS2026

Growth form and lifespan of herbaceous species mediate the role of traits in short-term drought response

Increased climate variability is expected to intensify short-term drought events. Plants have evolved stress tolerance strategies involving trade-offs in resource conservation, mycorrhizal collaboration and plant size, yet how these strategies promote drought resistance across different herbaceous plant groups remains unknown. Leveraging 63 globally distributed grassland and shrubland sites from the International Drought Experiment, we identified plant traits linked to drought resistance in 661 populations of 421 species after 1 year of extreme drought. We assessed how traits, site precipitation and drought severity affected cover change across growth forms and lifespans, and how trait–environment interactions influenced drought resistance. Across all species, leaf N (an acquisitive trait) was associated with drought resistance, whereas in forbs, drought resistance was also associated with a conservative root trait and plant size. In addition, interactions among traits mediated drought resistance; root traits predicted performance only in concert with other traits. Environmental variables influenced trait effects on drought resistance, notably for annuals in wetter sites, suggesting that drought-escape strategies in annuals may be advantageous only under mild stress. Our study highlights variability in traits that predict drought resistance across herbaceous plant groups, emphasizing the importance of species context, environmental stress and the selection of traits in research and management.

Nature Ecology and Evolution↗
USGS2012

Evidence of local adaptation in westslope cutthroat trout

An understanding of the process of local adaptation would allow managers to better protect and conserve species. Many salmonids are in need of such efforts, and because they often persist in differing, isolated environments, they are useful organisms for studying local adaptation. In addition, the temperature sensitivity of salmonids provides a likely target for natural selection. We studied thermal adaptation in four wild populations and one hatchery stock of westslope cutthroat trout Oncorhynchus clarkii lewisi . The mean summer temperatures of source streams ranged from 6.7°C to 11.2°C. Embryos were collected from the wild, and embryonic development, embryonic survival, and juvenile growth were determined. A significant relationship between median embryonic survival and source stream temperature was detected. Based on a rank test, populations from colder streams had a greater decline in median embryonic survival at warm temperatures than populations from warmer streams. Embryonic development and juvenile growth did not appear to be influenced by source. These findings suggest that populations are thermally adapted to their source streams and this should be considered by managers. However, further study is necessary to sort out the potential confounding factors, whether genetic or epigenetic.

Transactions of the American Fisheries Society↗