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USGS2019

Water velocity regulates macro-consumer herbivory on the benthic macrophyte Podostemum ceratophyllum Michx.

1) Macrophytes influence aquatic ecosystems by increasing habitat complexity and providing trophic resources for aquatic fauna. While herbivory on freshwater macrophytes is widely documented in lakes, low-velocity riverine habitats, the influence of herbivory on macrophytes in higher-velocity habitats has rarely been examined. 2) We investigated the hypothesis that high water velocity can reduce consumption rates of the submerged macrophyte, Podostemum ceratophyllum, an angiosperm which grows attached to stable substrates in high water-velocity riverine habitats throughout eastern North America. 3) We estimated grazing-pressure by conducting short-term (up to 77-d) transplant and consumer-exclosure experiments, and quantified changes in Podostemum stem length when the plant was eposed to low (<0.5 m s-1) and higher velocities in two Piedmont rivers in Georgia (USA). Podostemum transplanted into low-velocity habitats rapidly lost stem length unless macro-consumers were excluded from accessing the plant. In contrast, Podostemum tranplanted into high-velocity habitats showed little change or gained stem length. 4) We estimated that 85% (67 – 98%; 95% credible interval) of the daily stem growth (0.026 cm cm-1 day-1) in Podostemum was consumed during a 77-d paired consumer-access versus exclosure experiment conducted in mean water velocities of 0.35-0.5 m s-1. We also found a positive relation (R2 = 0.58) between Podostemum biomass and water velocity (ranging between ~0.1 -1.4 m s-1) in benthic samples collected over a two-month period. 5) We conclude that high water velocity reduces herbivory on Podostemum, and that water velocity can thus control the acural of benthic plant biomass and the movement of plant-derived materials through benthic food webs. Our research has implications for estimating resource storage and flux in lotic food webs and illuminates a mechanism by which flow regulation and management may affect basal resources in rivers.

Georgia↗

USGS2020

Multiple mechanisms determine the effect of warming on plant litter decomposition in a dryland

In drylands, where soil fertility is typically low, plant litter decomposition provides particularly critical carbon and nitrogen inputs into soil. Although climate change is projected to increase the already large global extent of drylands, it is unknown how warmer temperatures will affect core ecosystem processes, such as plant litter decomposition, in these systems. To address this key unknown, we conducted a litterbag study in a long-term dryland warming experiment in southeastern Utah, USA. Unexpectedly, we did not find an overall effect of warming on leaf litter mass loss over time. Instead, our results indicated both positive and negative effects of warming on mass loss which offset one another. In particular, our findings suggested that a warming-induced degradation of biological soil crusts (soil surface community of mosses, lichens, and/or cyanobacteria that live in drylands worldwide) increased soil-litter mixing, thereby accelerating decomposition. Results also suggested that warming-induced decreases in litter moisture slowed decomposition. In addition to assessing mass loss, we found that warming lowered the carbon-to-nitrogen ratio of the decomposing litter. These results showed that warming did not alter the total litter mass-loss rates in this ecosystem, but that decomposition patterns were affected through more nuanced changes to both the biological and physical environment of dryland soils.

Utah↗

USGS1999

Habitat invasibility and dominance by alien annual plants in the western Mojave Desert

Patterns of habitat invasibility and alien dominance, respectively measured as species richness and biomass of alien annual plants, were evaluated in association with four habitat factors at the Desert Tortoise Research Natural Area (DTNA) in the western Mojave Desert, USA. Habitat factors varied in levels of disturbance outside (high) and inside (low) the DTNA, and in levels of soil nutrients in washlet (high) and hummock (low) topographic positions, in Larrea -north (high), Larrea -south (medium), and interspace (low) microhabitats near creosote bushes ( Larrea tridentata ), and during 1995 when rainfall was 207% (high) and 1994 when rainfall was 52% (low) of the long-term average. Dominant alien plants included the annual grasses Bromus rubens , Bromus trinii , and Schismus spp., and the forb Erodium cicutarium . Species richness and dominance of alien annual plants were slightly higher where disturbance was high, and much higher where soil nutrients were high. B. rubens and B. trinii were most dominant in washlets and in the Larrea -north microhabitats during both years. These two species evolved in mesic ecosystems, and appeared to be particularly limited by soil nutrients at this site. Schismus spp. and E. cicutarium were also most dominant in washlets, but their dominance varied between interspaces in 1994 and the Larrea -south microhabitat in 1995. Monitoring to detect the invasion of new annual plants should focus on regions of high rainfall and nitrogen deposition and on washes and beneath-canopy microhabitats. The ecological range of each alien species should be evaluated separately, because their evolutionary origins may greatly affect their patterns of invasion and dominance in the Mojave Desert.

California↗

USGS2013

Biodiversity losses and conservation trade-offs: Assessing future urban growth scenarios for a North American trade corridor

The Sonoran Desert and Apache Highlands ecoregions of North America are areas of exceptionally high plant and vertebrate biodiversity. However, much of the vertebrate biodiversity is supported by only a few vegetation types with limited distributions, some of which are increasingly threatened by changing land uses. We assessed the impacts of two future urban growth scenarios on biodiversity in a binational watershed in Arizona, USA and Sonora, Mexico. We quantified and mapped terrestrial vertebrate species richness using Wildlife Habitat Relation models and validated the results with data from National Park Service biological inventories. Future urban growth, based on historical trends, was projected to the year 2050 for 1) a “Current Trends” scenario and, 2) a “Megalopolis” scenario that represented a transnational growth corridor with open-space conservation attributes. Based on Current Trends, 45% of existing riparian woodland (267 of 451species), and 34% of semi-desert grasslands (215 of 451 species) will be lost, whereas, in the Megalopolis scenario, these types would decline by 44% and 24% respectively. Outcomes of the two models suggest a trade-off at the taxonomic class level: Current Trends would reduce and fragment mammal and herpetofauna habitat, while Megalopolis would result in loss of avian-rich riparian habitat.

International Journal of Biodiversity Science, Eco↗

USGS2015

Marshes to mudflats—Effects of sea-level rise on tidal marshes along a latitudinal gradient in the Pacific Northwest

Summary In the Pacific Northwest, coastal wetlands support a wealth of ecosystem services including habitat provision for wildlife and fisheries and flood protection. The tidal marshes, mudflats, and shallow bays of coastal estuaries link marine, freshwater, and terrestrial habitats, and provide economic and recreational benefits to local communities. Climate change effects such as sea-level rise are altering these habitats, but we know little about how these areas will change over the next 50–100 years. Our study examined the effects of sea-level rise on nine tidal marshes in Washington and Oregon between 2012 and 2015, with the goal of providing scientific data to support future coastal planning and conservation. We compiled physical and biological data, including coastal topography, tidal inundation, vegetation structure, as well as recent and historical sediment accretion rates, to assess and model how sea-level rise may alter these ecosystems in the future. Multiple factors, including initial elevation, marsh productivity, sediment availability, and rates of sea-level rise, affected marsh persistence. Under a low sea-level rise scenario, all marshes remained vegetated with little change in the present configuration of communities of marsh plants or gradually increased proportions of middle-, high-, or transition-elevation zones of marsh vegetation. However, at most sites, mid sea-level rise projections led to loss of habitat of middle and high marshes and a gain of low marshes. Under a high sea-level rise scenario, marshes at most sites eventually converted to intertidal mudflats. Two sites (Grays Harbor and Willapa) seemed to have the most resilience to a high rate of rise in sea-level, persisting as low marsh until at least 2110. Our main model finding is that most tidal marsh study sites are resilient to sea-level rise over the next 50–70 years, but that sea-level rise will eventually outpace marsh accretion and drown most habitats of high and middle marshes by 2110.

California, Oregon, Washington↗

USGS2005

Effects of rain gardens on the quality of water in the Minneapolis-St. Paul metropolitan area of Minnesota, 2002-04

Rain gardens are a popular method of managing runoff while attempting to provide aesthetic and environmental benefits. Five rain-garden sites in the Minneapolis – Saint Paul metropolitan area of Minnesota were instrumented to evaluate the effects of this water-management system on surface and subsurface water quality. Most of these sites were in suburban locations and frequently in newer developments. Because of this they were affected by changing hydrology during the course of this study. Less-than-normal precipitation during much of the study may have resulted in samples that may not be representative of normal conditions. However, the resulting data indicate that properly designed rain gardens enhance infiltration and can reduce concentrations of dissolved ions relative to background conditions. The runoff events in one rain garden and several runoff events in the other rain gardens produced no sampled overflow during this study because the gardens captured all of the inflow, which subsequently infiltrated beneath the land surface, evaporated, or transpired through garden vegetation. Where measured, overflow had reduced concentrations of suspended solids and most nutrient species associated with particulate material, as compared to inflow. Many of these materials settle to the bottom of the rain garden, and some nutrients may be assimilated by the plant community. Site design, including capacity relative to drainage area and soil permeability, is an important consideration in the efficiency of rain-garden operation. Vegetation type likely affects the infiltration capacity, nutrient uptake, and evapotranspiration of a rain garden and probably the resulting water quality. The long-term efficiency of rain gardens is difficult to determine from the results of this study because most are still evolving and maturing in relation to their hydrologic, biologic, and chemical setting. Many resource managers have questioned what long-term maintenance will be needed to keep rain gardens operating effectively. Additional or continued studies could address many of these concerns.

Minnesota↗

USGS2014

Spatiotemporal variations in estrogenicity, hormones, and endocrine-disrupting compounds in influents and effluents of selected wastewater-treatment plants and receiving streams in New York, 2008-09

Endocrine-disrupting compounds (EDCs) in wastewater effluents have been linked to changes in sex ratios, intersex (in males), behavioral modifications, and developmental abnormalities in aquatic organisms. Yet efforts to identify and regulate specific EDCs in complex mixtures are problematic because little is known about the estrogen activity (estrogenicity) levels of many common and emerging contaminants. The potential effects of EDCs on the water quality and health of biota in streams of the New York City water supply is especially worrisome because more than 150 wastewater-treatment plants (WWTPs) are permitted to discharge effluents into surface waters and groundwaters of watersheds that provide potable water to more than 9 million people. In 2008, the U.S. Geological Survey (USGS), the New York State Department of Environmental Conservation (NYSDEC), New York State Department of Health (NYSDOH), and New York City Department of Environmental Protection (NYCDEP) began a pilot study to increase the understanding of estrogenicity and EDCs in effluents and receiving streams mainly in southeastern New York. The primary goals of this study were to document and assess the spatial and temporal variability of estrogenicity levels; the effectiveness of various treatment-plant types to remove estrogenicity; the concentrations of hormones, EDCs, and pharmaceuticals, personal care products (PPCPs); and the relations between estrogenicity and concentrations of hormones, EDCs, and PPCPs. The levels of estrogenicity and selected hormones, non-hormone EDCs, and PPCPs were characterized in samples collected seasonally in effluents from 7 WWTPs, once or twice in effluents from 34 WWTPs, and once in influents to 6 WWTPs. Estrogenicity was quantified, as estradiol equivalents, using both the biological e-screen assay and a chemical model. Results generally show that (1) estrogenicity levels in effluents varied spatially and seasonally, (2) a wide range of known and unknown EDCs were present in both WWTP effluents and receiving streams, (3) some effluents may be important sources of estrogenicity in weakly diluted streams, (4) measured levels of biological estrogenicity were often higher than estimated levels of chemical estrogenicity, and (5) the type of treatment had a large effect on the removal efficacy, and consequently, the estrogenicity levels observed in treated effluents.

New York↗

USGS2025

A comprehensive assessment of membrane bioreactor contaminant removal efficacy through analytical chemistry, fish exposures, and microbiome characterization

Treated municipal wastewater effluent is an important pathway for Contaminants of Emerging Concern (CEC) to enter aquatic ecosystems. As the aging wastewater infrastructure in many industrialized countries requires upgrades or replacement, assessing new treatment technologies in the context of CEC effects may provide additional support for science-based resource management. Here, we used three lines of evidence, analytical chemistry, fish exposure experiments, and fish and water microbiome analysis, to assess the effectiveness of membrane bioreactor treatment (MBR) to replace traditional activated sludge treatment. To do this, we sampled a municipal wastewater treatment plant with a split wastewater stream, a portion of which was treated with an MBR and another via an oxidation ditch (OXI). The OXI and MBR treatments substantially reduced most measured CECs compared to the primary effluent (PRI). Only pesticides and some pharmaceuticals were recalcitrant to both secondary treatment methods. While ammonia toxicity of PRI prevented its inclusion in fish exposure experiments, exposure of fish with waters from the OXI or MBR treated wastewater produced only subtle biological differences with no adverse apical outcomes. These findings were consistent with low chemically derived exposure: activity ratios for OXI and MBR. Microbiome analysis of fish and wastewater highlighted the significant reduction of microbial abundance and diversity in the MBR treatment compared to all other treatments. The comparable removal efficacy of CECs in MBR makes it an attractive alternative to traditional OXI, especially when MBR may eliminate the need for tertiary treatment for wastewater disinfection.

Environmental Toxicology and Chemistry↗

USGS1996

Physical, chemical, and biological data for four wetland habitats in Canaan Valley, West Virginia

This report contains data collected during 1992 as part of a project designed to identify microenvironmental factors affecting rates of denitrification in wetlands in Canaan Valley, West Virginia. Four wetland habitats were selected for the study--a moss-lichen wetland, a persistent emergent wetland, a scrub-shrub wetland, and a riverine wetland. Physical, chemical, and biological characteristics of each habitat were determined by field measurements and laboratory analyses. Samples were collected in March, June, August, and October. Sediment pH, temperature, and oxidation-reduction potential were measured in the field. Sediment samples were analyzed for concentrations of calcium, sodium, magnesium, potassium, nitrate and nitrite, ammonia, ammonia plus organic nitrogen, phosphorus, inorganic carbon, and total carbon. The most probable number of denitrifying bacteria was determined by a multiple-tube test. The dominant plant species were identified by plant-community analysis. The moss-lichen wetland was characterized by low pH (3.4 to 5.0) and small populations of denitrifying bacteria (70 to 400 per gram of wet soil). The scrub-shrub wetland was also acidic (pH 4.0 to 5.0), but supported larger numbers of denitrifying bacteria (510 to 11,000 per gram of wet soil). The number of denitrifying bacteria in the persistent emergent wetland exceeded 1,000,000 per gram of wet soil in early summer and pH in this habitat was higher (5.1 to 6.6) than in the bogs. Riverine wetland pH ranged from 5.4 to 6.9, and the number of denitrifying bacteria ranged from 200 to 11,000 per gram of wet soil.

Open-File Report↗

USGS1996

Reconnaissance investigation of water quality, bottom sediment, and biota associated with irrigation drainage in the Vermejo Project area and the Maxwell National Wildlife Refuge, Colfax County, northeastern New Mexico, 1993

Based on findings of limited studies during 1989-92, a reconnaissance investigation was conducted in 1993 to assess the effects of the Vermejo Irrigation Project on water quality in the area of the project, including the Maxwell National Wildlife Refuge. This project was part of a U.S. Department of the Interior National Irrigation Water-Quality Program to determine whether irrigation drainage has caused or has the potential to cause significant harmful effects on human health, fish, and wildlife and whether irrigation drainage may adversely affect the suitability of water for other beneficial uses. For this study, samples of water, sediment, and biota were collected from 16 sites in and around the Vermejo Irrigation Project prior to, during the latter part of, and after the 1993 irrigation season (April, August-September, and November, respectively). No inorganic constituents exceeded U.S. Environmental Protection Agency drinking-water standards. The State of New Mexico standard of 750 micrograms per liter for boron in irrigation water was exceeded at three sites (five samples), though none exceeded the livestock water standard of 5,000 micrograms per liter. Selenium concentrations exceeded the State of New Mexico chronic standard of 2 micrograms per liter for wildlife and fisheries water in at least eight samples from five sites. Bottom-sediment samples were collected and analyzed for trace elements and compared to concentrations of trace elements in soils of the Western United States. Concentrations of three trace elements at eight sites exceeded the upper values of the expected 95-percent ranges for Western U.S. soils. These included molybdenum at one site, selenium at seven sites, and uranium at four sites. Cadmium and copper concentrations exceeded the National Contaminant Biomonitoring Program 85th percentile in fish from six sites. Average concentrations of selenium in adult brine flies (33.7 μ g/g dry weight) were elevated above concentrations in other invertebrates. Concentrations of other elements were below their respective toxicity levels. Plants, invertebrates, fish, and fish fillets were collected and analyzed. These analyses were compared to diagnostic criteria and to each other to determine the extent of bioaccumulation of trace elements. Plants contained larger dry weight concentrations of aluminum, arsenic, boron, chromium, iron, lead, magnesium, manganese, nickel, and vanadium than invertebrates and fish. Adult brine flies, gathered from playas, contained larger geometric mean dry weight concentrations of boron, magnesium, and selenium than other invertebrates. Of all samples collected, the largest mercury concentrations were found in fish fillets, although these concentrations were below levels of concern. Mercury and selenium bioaccumulation was evident in various habitats of the study area. Biological samples from Natural playa, an endemic wetland, and Half playa, a playa that receives additional water through seepage and irrigation delivery canals, generally had elevated concentrations of boron, iron, magnesium, and selenium than samples from reservoir and river sites. Selenium concentrations were lowest in biota from the two reservoir sites, although a wetland immediately downstream from the dam impounding Lake No. 13 (created by seepage from the reservoir) had elevated concentrations of selenium in biota. The geometric mean selenium concentration of whole-fish samples, except those from Lakes No. 13 and No. 14, exceeded the 5- μ g/g dry weight selenium concentration that demarcates the approximate lower limit of the threshold range of concentrations that have freen associated with adverse effects on piscine reproduction. Biota collected on and in the area around Maxwell National Wildlife Refuge contained concentrations of selenium that are in the lower range of threshold values that have been associated (dietarily) with risks of avian reproductive abnormalities. Bottom-sediment samples from two sites downstream from the irrigation project were collected and analyzed for 23 organic compounds (principally organochlorine pesticide residues). Three compounds were detected at the two sites: DDD was found at 0.2 microgram per kilogram, DDE was detected at 0.1 microgram per kilogram at both sites, and chlordane was detected at 1 microgram per kilogram. None of the 28 whole-fish and fillet samples analyzed for PCB and organochlorine pesticide residues contained any of the 23 organic compounds tested for at concentrations higher than the analytical reporting limit (less than 0.01 μ g/g wet weight). Concentrations of inorganic analytes were generally within established guidelines or expected concentrations for water, sediment, and biota. lirigation-return flows were found to be unrelated to adverse effects in biota.

New Mexico↗

USGS2022

High abundance of a single taxon (amphipods) predicts aquatic macrophyte biodiversity in prairie wetlands

Conservation programs often aim to protect the abundance of individual species and biodiversity simultaneously. We quantified relations between amphipod densities and aquatic macrophyte (large plants and algae) diversity to test a hypothesis that biodiversity can support high abundance of a single taxonomic group. Amphipods ( Gammarus lacustris and Hyalella azteca ) are key forage for waterfowl and are declining in the Prairie Pothole Region of North America. We sampled a large gradient of amphipod densities (0–7050 amphipods/m 3 ) in 49 semi-permanent wetlands, and 50% of the study wetlands had high amphipod densities (> 500 amphipods/m 3 ). Generalized linear models revealed G. lacustris and H. azteca densities increased exponentially with macrophyte diversity indices. Further, H. azteca densities were greatest at moderate levels of submersed vegetation biomass. Community analyses showed both amphipod species were positively associated with diverse macrophyte assemblages and negatively associated with high coverage of cattails ( Typha spp.), a taxon that creates monotypic stands, as well as bladderwort ( Utricularia spp.), a carnivorous plant. Our results indicate that amphipods could be used as an umbrella species for protecting diverse macrophyte communities in semi-permanent and permanent wetlands of North America’s Prairie Pothole Region.

Conservation Biology↗

USGS2014

Biochar application to hardrock mine tailings: Soil quality, microbial activity, and toxic element sorption

Waste rock piles from historic mining activities remain unvegetated as a result of metal toxicity and high acidity. Biochar has been proposed as a low-cost remediation strategy to increase soil pH and reduce leaching of toxic elements, and improve plant establishment. In this laboratory column study, biochar made from beetle-killed pine wood was assessed for utility as a soil amendment by mixing soil material from two mine sites collected near Silverton, Colorado, USA with four application rates of biochar (0%, 10%, 20%, 30% vol:vol). Columns were leached seven times over 65 days and leachate pH and concentration of toxic elements and base cations were measured at each leaching. Nutrient availability and soil physical and biological parameters were determined following the incubation period. We investigated the hypotheses that biochar incorporation into acidic mine materials will (1) reduce toxic element concentrations in leaching solution, (2) improve soil parameters (i.e. increase nutrient and water holding capacity and pH, and decrease compaction), and (3) increase microbial populations and activity. Biochar directly increased soil pH (from 3.33 to 3.63 and from 4.07 to 4.77 in the two materials) and organic matter content, and decreased bulk density and extractable salt content in both mine materials, and increased nitrate availability in one material. No changes in microbial population or activity were detected in either mine material upon biochar application. In leachate solution, biochar increased base cations from both materials and reduced the concentrations of Al, Cd, Cu, Pb, and Zn in leachate solution from one material. However, in the material with greater toxic element content, biochar did not reduce concentrations of any measured dissolved toxic elements in leachate and resulted in a potentially detrimental release of Cd and Zn into solution at concentrations above that of the pure mine material. The length of time of effectiveness and specific sorption by biochar is variable by element and the toxic element concentration and acidity of the initial mine material.

Applied Geochemistry↗

USGS2016

Large herbivores surf waves of green-up during spring

The green wave hypothesis (GWH) states that migrating animals should track or ‘surf’ high-quality forage at the leading edge of spring green-up. To index such high-quality forage, recent work proposed the instantaneous rate of green-up (IRG), i.e. rate of change in the normalized difference vegetation index over time. Despite this important advancement, no study has tested the assumption that herbivores select habitat patches at peak IRG. We evaluated this assumption using step selection functions parametrized with movement data during the green-up period from two populations each of bighorn sheep, mule deer, elk, moose and bison, totalling 463 individuals monitored 1–3 years from 2004 to 2014. Accounting for variables that typically influence habitat selection for each species, we found seven of 10 populations selected patches exhibiting high IRG—supporting the GWH. Nonetheless, large herbivores selected for the leading edge, trailing edge and crest of the IRG wave, indicating that other mechanisms (e.g. ruminant physiology) or measurement error inherent with satellite data affect selection for IRG. Our evaluation indicates that IRG is a useful tool for linking herbivore movement with plant phenology, paving the way for significant advancements in understanding how animals track resource quality that varies both spatially and temporally.

Proceedings of the Royal Society B: Biological Sci↗

USGS2017

Monitoring Hawaiian biodiversity: Pilot study to assess changes to forest birds and their habitat

Biological diversity, or biodiversity, is the variety and abundance of species in a defined area, and is one of the oldest and most basic descriptions of biological communities. Understanding how populations and communities are structured and change over space and time in response to internal and external forces is a management priority. Effective management practices and conservation strategies depend on our understanding of the relationship between changes in biodiversity and ecological drivers such as invasive species, land use and climate change. To demonstrate how changes in biodiversity may be monitored over a large (400 km2) tract of native forest habitat, we compared bird and plant community composition and structure in an upper montane region of Hawai‘i Island originally surveyed in 1977 as part of the Hawai‘i Forest Bird Survey (Scott et al. 1986) with a comprehensive sample of the same region in 2015. Our findings suggest that across a region spanning an elevation range of 600 to 2,000 m considerable changes occurred in the plant and bird communities between 1977 and 2015. Endemic and indigenous plants species richness (i.e., total number of species) decreased dramatically in the low and middle elevations below an invasive weed front, whereas naturalized plant species richness did not change between the two periods at any elevation. Endemic bird abundance decreased and two species were lost in the lower elevations (< 1,100 m) between 1977 and 2015, while naturalized bird abundance and the numbers of species increased in the same area. In addition to changes in community composition, the structure of the forest showed evidence of changes in dominant and sub-dominant tree canopy cover, shrub and herbaceous cover, dominant tree canopy height, and matted fern cover. Biodiversity monitoring helps to define specific conservation targets and to measure progress towards reaching those targets. It is difficult to ascribe causative factors to a change in biodiversity without directly manipulating the environment. Forest habitat in a variety of settings (i.e., islands and regions with differing land-use histories and elevation ranges), however, can provide opportunities to evaluate the influence of ecological drivers. Declines in native bird biodiversity in low-elevation areas may be attributed to invasive species as land use and climate conditions have remained relatively similar over the 40-year period. Thus, the shift from an endemic-naturalized co-dominated community in 1977 to one dominated by naturalized, alien birds in 2015, and reduction in native bird abundance over that period, may reflect increasing dominance by naturalized plants within this forested area. Inferences drawn from analyses of region-wide surveys, especially with replicate datasets, will facilitate the identification of broad-scale changes in biodiversity, and provide a needed current datum in Hawaiian plant and bird biodiversity monitoring.

Hawaii↗

USGS2021

The importance of forests in bumble bee biology and conservation

Declines of many bumble bee species have raised concerns because of their importance as pollinators and potential harbingers of declines among other insect taxa. At present, bumble bee conservation is predominantly focused on midsummer flower restoration in open habitats. However, a growing body of evidence suggests that forests may play an important role in bumble bee life history. Compared with open habitats, forests and woody edges provide food resources during phenologically distinct periods, are often preferred nesting and overwintering habitats, and can offer favorable abiotic conditions in a changing climate. Future research efforts are needed in order to anticipate how ongoing changes in forests, such as overbrowsing by deer, plant invasions, and shifting canopy demographics, affect the suitability of these habitats for bumble bees. Forested habitats are increasingly appreciated in the life cycles of many bumble bees, and they deserve greater attention from those who wish to understand bumble bee populations and aid in their conservation.

BioScience↗

USGS2014

Water-quality and biological conditions in selected tributaries of the Lower Boise River, southwestern Idaho, water years 2009-12

Water-quality conditions were studied in selected tributaries of the lower Boise River during water years 2009–12, including Fivemile and Tenmile Creeks in 2009, Indian Creek in 2010, and Mason Creek in 2011 and 2012. Biological samples, including periphyton biomass and chlorophyll-a, benthic macroinvertebrates, and fish were collected in Mason Creek in October 2011. Synoptic water-quality sampling events were timed to coincide with the beginning and middle of the irrigation season as well as the non-irrigation season, and showed that land uses and irrigation practices affect water quality in the selected tributaries. Large increases in nutrient and sediment concentrations and loads occurred over relatively short stream reaches and affected nutrient and sediment concentrations downstream of those reaches. Escherichia coli (E. coli) values increased in study reaches adjacent to pastured lands or wastewater treatment plants, but increased E. coli values at upstream locations did not necessarily affect E. coli values at downstream locations. A spatial loading analysis identified source areas for nutrients, sediment, and E. coli , and might be useful in selecting locations for water-quality improvement projects. Effluent from wastewater treatment plants increased nutrient loads in specific reaches in Fivemile and Indian Creeks. Increased suspended-sediment loads were associated with increased discharge from irrigation returns in each of the studied tributaries. Samples collected during or shortly after storms showed that surface runoff, particularly during the winter, may be an important source of nutrients in tributary watersheds with substantial agricultural land use. Concentrations of total phosphorus, suspended sediment, and E. coli exceeded regulatory water-quality targets or trigger levels at one or more monitoring sites in each tributary studied, and exceedences occurred during irrigation season more often than during non-irrigation season. As with water-quality sampling results, bottom-sediment samples analyzed for contaminants of emerging concern indicated that adjacent land uses can affect in-stream conditions. Contaminants of emerging concern were detected in four categories: urban compounds, industrial compounds, fecal steroids, and personal care products. Compounds in one or more of the four contaminant categories were detected at higher concentrations in upstream sites than in downstream sites in the tributaries and in the lower Boise River. High concentrations of compounds in upstream locations indicated that adjacent land use might be an important factor in contributing contaminants of emerging concern to the lower Boise River watershed. Expanded monitoring at Mason Creek near the mouth included a streamgage, a continuous water-quality monitor, and monthly water-quality sample collection. Data collected during expanded monitoring efforts at Mason Creek near the mouth provided information to develop and compare water-quality models. Regression models were developed using turbidity, discharge, and seasonality as surrogates to estimate concentrations of water-quality constituents. Daily streamflow also was used in a load model to estimate daily loads of water-quality constituents. Surrogate regression models may be useful for long-term monitoring and generally performed better than other models to estimate concentrations and loads of total phosphorus, total nitrogen, and suspended sediment in Mason Creek. Biological sampling results from Mason Creek showed low periphyton biomass and chlorophyll-a concentrations compared to those historically measured in the Boise River near Parma, Idaho, during October and November. The most abundant invertebrate found in Mason Creek was the highly tolerant and invasive New Zealand mudsnail ( Potamopyrgus antipodarum ). The presence of small rainbow trout (90 millimeters) may indicate salmonid spawning in Mason Creek. The rangeland-fish-index score of 58 for Mason Creek is comparable to rangeland-fish-index scores calculated for the Boise River near Middleton, indicating intermediate biotic condition.

Idaho↗

USGS2019

Improving ecological restoration to curb biotic invasion - A practical guide

Common practices for invasive species control and management include physical, chemical, and biological approaches. The first two approaches have clear limitations and may lead to unintended (negative) consequences, unless carefully planned and implemented. For example, physical removal rarely completely eradicates the targeted invasive species and can cause disturbances that facilitate new invasions by nonnative species from nearby habitats. Chemical treatments can harm native, and especially rare, species through unanticipated side effects. Biological methods may be classified as biocontrol and the ecological approach. Similar to physical and chemical methods, biocontrol also has limitations and sometimes leads to unintended consequences. Therefore, a relatively safer and more practical choice may be the ecological approach, which has two major components: (1) restoration of native species and (2) biomass manipulation of the restored community, such as selective grazing or prescribed burning (to achieve and maintain viable population sizes). Restoration requires well-planned and implemented planting designs that consider alpha-, beta-, and gamma-diversity and the abundance of native and invasive component species at local, landscape, and regional levels. Given the extensive destruction or degradation of natural habitats around the world, restoration could be most effective for enhancing ecosystem resilience and resistance to biotic invasions. At the same time, ecosystems in human-dominated landscapes, especially those newly restored, require close monitoring and careful intervention (e.g., through biomass manipulation), especially when successional trajectories are not moving as intended. Biomass management frequently uses prescribed burning, grazing, harvesting, and thinning to maintain overall ecosystem health and sustainability. Thus, the resulting optimal, balanced, and relatively stable ecological conditions could more effectively limit the spread and establishment of invasive species. Here we review the literature (especially within the last decade) on ecological approaches that involve biodiversity, biomass, and productivity, three key community/ecosystem variables that reciprocally influence one another. We focus on the common and most feasible ecological practices that can aid in resisting new invasions and/or suppressing the dominance of existing invasive species. We contend that, because of the strong influences from neighboring areas (i.e., as exotic species pools), local restoration and management efforts in the future need to consider the regional context and projected climate changes.

Invasive Plant Science and Management↗

USGS2010

Limits on the adaptability of coastal marshes to rising sea level

Assumptions of a static landscape inspire predictions that about half of the world's coastal wetlands will submerge during this century in response to sea-level acceleration. In contrast, we use simulations from five numerical models to quantify the conditions under which ecogeomorphic feedbacks allow coastal wetlands to adapt to projected changes in sea level. In contrast to previous sea-level assessments, we find that non-linear feedbacks among inundation, plant growth, organic matter accretion, and sediment deposition, allow marshes to survive conservative projections of sea-level rise where suspended sediment concentrations are greater than ~20 mg/L. Under scenarios of more rapid sea-level rise (e.g., those that include ice sheet melting), marshes will likely submerge near the end of the 21st century. Our results emphasize that in areas of rapid geomorphic change, predicting the response of ecosystems to climate change requires consideration of the ability of biological processes to modify their physical environment.

Geophysical Research Letters↗