USGS Science⌕ Search

SEARCH · USGS Science

Results for “Plants”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 919 records · Page 51Linked to original sources
USGS2022

INHABIT: A web-based decision support tool for invasive plant species habitat visualization and assessment across the contiguous United States

Narrowing the communication and knowledge gap between producers and users of scientific data is a longstanding problem in ecological conservation and land management. Decision support tools (DSTs), including websites or interactive web applications, provide platforms that can help bridge this gap. DSTs can most effectively disseminate and translate research results when producers and users collaboratively and iteratively design content and features. One data resource seldom incorporated into DSTs are species distribution models (SDMs), which can produce spatial predictions of habitat suitability. Outputs from SDMs can inform management decisions, but their complexity and inaccessibility can limit their use by resource managers or policy makers. To overcome these limitations, we present the Invasive Species Habitat Tool (INHABIT), a novel, web-based DST built with R Shiny to display spatial predictions and tabular summaries of habitat suitability from SDMs for invasive plants across the contiguous United States. INHABIT provides actionable science to support the prevention and management of invasive species. Two case studies demonstrate the important role of end user feedback in confirming INHABIT’s credibility, utility, and relevance.

PLoSOne↗
USGS1982

Effects of an aquatic plant and suspended clay on the activity of fish toxicants

Rotenone, antimycin, permethrin, pydrin, and Salicylanilide I were tested for their toxicities against fathead minnows ( Pimephales promelas ) in the presence of Canadian waterweed ( Elodea canadensis ) or suspended clay. The plants had little effect on the activity of rotenone and antimycin but substantially reduced the activity of permethrin and pydrin (synthetic pyrethroids). Bentonite severely inhibited the activity of all chemicals tested. Salicylanilide I was affected least and pydrin most (27 times as much pydrin was required when I g/liter of bentonite was present in 96-hour tests). The efficacy of the registered fish toxicants rotenone and antimycin is probably not significantly affected by vegetation under field conditions, but is greatly reduced by suspended bentonite clay.

North American Journal of Fisheries Management↗
USGS1984

First evidence of successful natural reproduction by planted lake trout in Lake Huron

Twenty-two lake trout (Salvelinus namaycush) swim-up fry, 24-27 mm long, were captured with emergent fry traps and a tow net in northwestern Lake Huron on a small nearshore reef off Alpena, Michigan, between May 10 and June 1, 1982. These catches represent the first evidence of successful production of swim-up fry by planted, hatchery-reared lake trout in Lake Huron since the lake trout rehabilitation program began in 1973.

North American Journal of Fisheries Management↗
USGS2003

Flood flows, leaf breakdown, and plant-available nitrogen on a dryland river floodplain

We tested the hypothesis that decomposition in flood-inundated patches of riparian tree leaf litter results in higher plant-available nitrogen in underlying, nutrient-poor alluvium. We used leafpacks ( n = 56) containing cottonwood ( Populus deltoides ssp. wislizenii ) leaf litter to mimic natural accumulations of leaves in an experiment conducted on the Yampa River floodplain in semi-arid northwestern Colorado, USA. One-half of the leafpacks were set on the sandy alluvial surface, and one-half were buried 5 cm below the surface. The presence of NO 3 − and NH 4 + presumed to result from a leafpack's submergence during the predictable spring flood pulse was assessed using an ion-exchange resin bag (IER) placed beneath each leafpack and at control locations. Leafpacks and IERs were collected one week after flood peak (71 days total exposure) at half the stations; the remainder were collected three weeks later (93 days exposure). A multi-peaked spring flood with above-average maximum discharge inundated leafpacks for total time periods ranging from 133 to 577 hours. Litter lost from 43 to 68 percent of its initial organic matter (OM) content. Organic matter loss increased with total time inundated and total time of exposure on the floodplain. Burial retarded OM loss if the total time inundated was relatively long, and substrate texture (sand vs. silt) affected OM loss in a complex manner through interactions with total time inundated and total time of exposure. No pulse of N attributable to leaf breakdown was detected in the IERs, and leafpack litter showed no net change in the mass of nitrogen present. Patterns of leafpack and IER nitrogen levels suggested that litter removed N from floodwater and thereby reduced N availability in underlying sediment. Immobilization of floodwater-N by litter and N mineralization outside the flood period may be important components of N flux in semi-arid and arid floodplain environments.

Colorado↗
USGS1997

Soil, plant, and structural considerations for surface barriers in arid environments: Application of results from studies in the Mojave Desert near Beatty, Nevada

The suitability of a waste-burial site depends on hydrologic processes that can affect the near-surface water balance. In addition, the loss of burial trench integrity by erosion and subsidence of trench covers may increase the likelihood of infiltration and percolation, thereby reducing the effectiveness of the site in isolating waste. Although the main components of the water balance may be defined, direct measurements can be difficult, and actual data for specific locations are seldom available. A prevalent assumption is that little or no precipitation will percolate to buried wastes at an arid site. Thick unsaturated zones, which are common to arid regions, are thought to slow water movement and minimize the risk of waste migration to the underlying water table. Thus, reliance is commonly placed on the natural system to isolate contaminants at waste-burial sites in the arid West. Few data are available to test assumptions about the natural soil-water flow systems at arid sites, and even less is known about how the natural processes are altered by construction of a waste-burial facility. The lack of data is the result of technical complexity of hydraulic characterization of the dry, stony soils, and insufficient field studies that account for the extreme temporal and spatial variations in precipitation, soils, and plants in arid regions. In 1976, the U.S. Geological Survey (USGS) began a long-term study at a waste site in the Mojave Desert. This paper summarizes the findings of ongoing investigations done under natural-site and waste-burial conditions, and discusses how this information may be applied to the design of surface barriers for waste sites in arid environments. The waste-burial site is in one of the most arid parts of the United States and is about 40 km northeast of Death Valley, near Beatty, Nev. (Figure 1). Precipitation averaged 108 mm/yr during 1981-1992. The water table is 85-115 m below land surface (Fischer, 1992). Sediments are largely alluvial and fluvial deposits (Nichols, 1987). Vegetation is sparse; creosote bush is the dominant species. The waste facility has been used for burial of low-level radioactive waste (1962-1992) and hazardous chemical waste (1970 to present). Burial-trench construction includes excavation of native soil, emplacement of waste, and backfilling with previously stockpiled soil. Only the most recently closed hazardous-waste trench (1991) incorporates a plastic liner in the cover. The surfaces of completed burial trenches and perimeter areas are kept free of vegetation.

Nevada↗
USGS2024

Review of the life history and conservation of federally endangered plant species of the Lower Rio Grande Valley, Texas, U.S.A.

This review aims to summarize information critical to the conservation of the federally listed endangered species of South Texas, which occur along the border of Texas and Mexico. This paper describes the characteristics, habitat, population status, distribution, life history, threats, and restoration of endangered plant species of the Lower Rio Grande Valley, Texas, which includes Cameron, Willacy, Hildago, and Starr County. Seven federally listed species are considered including Ambrosia cheiranthifolia, Asclepias prostrata, Astrophytum asterias, Ayenia limitaris, Manihot walkerae, Lesquerella thamnophila (syn. Physaria thamnophila), and Thymophylla tephroleuca. An eighth species, Physostegia correllii is under consideration for federal listing by the U.S. Fish and Wildlife Service. This paper assembles information on the background, biological status, major threats, and conservation to aid managers and the scientific community in restoring and managing these species.

Texas↗
USGS2001

The importance of competition in regulating plant species abundance along a salinity gradient

Current theories differ in their predictions concerning the effects of interspecific interactions on species growth and distribution along environmental gradients. In this study, we examined the influence of competition on species composition across a salinity gradient. This work involved three common fresh and brackish marsh species. The three species, Spartina patens, Sagittaria lancifolia, and Panicum hemitomon, differ in salt tolerances but are commonly found in overlapping zones across coastal marsh gradients in the southeastern United States. Plants were grown in a greenhouse under four salinity treatments (0, 2, 4, and 8 g/kg), in monocultures and in three‐species mixtures. Data from the monocultures and mixtures were used to examine the importance of competition in regulating community composition and species' growth. Results for individual species were significantly different when grown in monoculture vs. the three‐species mixture. While with increasing salinity community dominance shifted toward the most salt‐tolerant species, Spartina patens, competition was found to alter community composition equally over all salinities. However, the responses of individual species demonstrated a very different pattern; the relative importance of competition in influencing individual growth differed substantially depending on the salinity tolerances of species. These results support the contention that, as abiotic stress increases, competition becomes less of a limiting factor in regulating the abundance of a species. However, the role of competition at the community level is the sum of the individual species' responses and may or may not vary with the level of abiotic stress.

Ecology↗
USGS2010

Do competitors modulate rare plant response to precipitation change?

Ecologists increasingly suspect that climate change will directly impact species physiology, demography, and phenology, but also indirectly affect these measures via changes to the surrounding community. Unfortunately, few studies examine both the direct and indirect pathways of impact. Doing so is important because altered competitive pressures can reduce or magnify the direct responses of a focal species to climate change. Here, we examine the effects of changing rainfall on three rare annual plant species in the presence and absence of competition on the California Channel Islands. We used rain-out shelters and hand watering to exclude and augment early, late, and season-long rainfall, spanning the wide range of precipitation change forecast for the region. In the absence of competition, droughts reduced the population growth rates of two of three focal annuals, while increased rainfall was only sometimes beneficial, As compared to the focal species, the dominant competitors were more sensitive to the precipitation treatments, benefiting from increased season-long precipitation and harmed by droughts. Importantly, the response of two of three competitors to the precipitation treatments tended to be positively correlated with those of the focal annuals. Although this leads to the expectation that increased competition will counter the direct benefits of favorable conditions, such indirect effects of precipitation change proved weak to nonexistent in our experiment. Competitors had little influence on the precipitation response of two focal species, due to their low sensitivity to competition and highly variable precipitation responses. Competition did affect how our third focal species responded to precipitation change, but this effect only approached significance, and whether it truly resulted from competitor response to precipitation change was unclear. Our work suggests that even when competitors respond to climate change, these responses may have little effect on the focal species. Ultimately, the strength of the indirect effect depends on how strongly climate change alters competition, and how sensitive focal species are to changes in competition. ?? 2010 by the Ecological Society of America.

Ecology↗
USGS2011

Seasonal timing of first rain storms affects rare plant population dynamics

A major challenge in forecasting the ecological consequences of climate change is understanding the relative importance of changes to mean conditions vs. changes to discrete climatic events, such as storms, frosts, or droughts. Here we show that the first major storm of the growing season strongly influences the population dynamics of three rare and endangered annual plant species in a coastal California (USA) ecosystem. In a field experiment we used moisture barriers and water addition to manipulate the timing and temperature associated with first major rains of the season. The three focal species showed two- to fivefold variation in per capita population growth rates between the different storm treatments, comparable to variation found in a prior experiment imposing eightfold differences in season-long precipitation. Variation in germination was a major demographic driver of how two of three species responded to the first rains. For one of these species, the timing of the storm was the most critical determinant of its germination, while the other showed enhanced germination with colder storm temperatures. The role of temperature was further supported by laboratory trials showing enhanced germination in cooler treatments. Our work suggests that, because of species-specific cues for demographic transitions such as germination, changes to discrete climate events may be as, if not more, important than changes to season-long variables.

Ecology↗
USGS2009

Reproductive health of bass in the potomac, USA, drainage: Part 1. exploring the effects of proximity to wastewater treatment plant discharge

Intersex (specifically, testicular oocytes) has been observed in male smallmouth bass (SMB; Micropterus dolomieu ) and other centrarchids in the South Branch of the Potomac River, USA, and forks of the Shenandoah River, USA, during the past five years. This condition often is associated with exposure to estrogenic endocrine‐disrupting chemicals in some fish species, but such chemicals and their sources have yet to be identified in the Potomac. In an attempt to better understand the plausible causes of this condition, we investigated the reproductive health of bass sampled up‐ and downstream of wastewater treatment plant (WWTP) effluent point sources on the Potomac River in Maryland, USA. Smallmouth bass were sampled from the Conococheague Creek and the Monocacy River, and largemouth bass (LMB; Micropterus salmoides ) were collected near the Blue Plains WWTP on the mainstem of the Potomac River. Chemical analyses of compounds captured in passive samplers at these locations also were conducted. A high prevalence of intersex (82–100%) was identified in male SMB at all sites regardless of collection area. A lower prevalence of intersex (23%) was identified in male LMB collected at the Blue Plains site. When up‐ and downstream fish were compared, significant differences were noted only in fish from the Conococheague. Differences included condition factor, gonadosomatic index, plasma vitellogenin concentration, and estrogen to testosterone ratio. In general, chemicals associated with waste‐water effluent, storm‐water runoff, and agriculture were more prevalent at the downstream sampling sites. An exception was atrazine and its associated metabolites, which were present in greater concentrations at the upstream sites. It appears that proximity to effluent from WWTPs may influence the reproductive health of bass in the Potomac watershed, but inputs from other sources likely contribute to the widespread, high incidence of testicular oocytes.

Environmental Toxicology and Chemistry↗
USGS2009

Hydrologic characterization of desert soils with varying degrees of pedogenesis: 1. field experiments evaluating plant-relevant soil water behavior

To assess the eff ect of pedogenesis on the soil moisture dynamics infl uencing the character and quality of ecological habitat, we conducted infi ltration and redistribution experiments on three alluvial deposits in the Mojave National Preserve: (i) recently deposited active wash sediments, (ii) a soil of early Holocene age, and (iii) a highly developed soil of late Pleistocene age. At each, we ponded water in a 1-m-diameter infi ltration ring for 2.3 h and monitored soil water content and matric pressure during and atier infi ltration, using probes and electrical resistivity imaging (ERI). Infi ltration and downward fl ow rates were greater in younger material, favoring deep-rooted species. Deep-rooted species tend to colonize the margins of washes, where they are unaff ected by sediment transport that inhibits colonization. The ERI results support important generalizations, for example that shallower than 0.5 m, infi ltrated water persists longer in highly developed soil, favoring shallow-rooted species. Soil moisture data for the two youngest soils suggested that saturation overshoot, which may have signifi cant but unexplored hydroecologic and pedogenic eff ects, occurred at the horizontally advancing weting front. Spatial heterogeneity of soil properties generally increased with pedogenic development. Evidence suggested that some early-stage developmental processes may promote uniformity; the intermediate- age soil appeared to have the least heterogeneity in terms of textural variation with depth, and also the least anisotropy. Lateral heterogeneity was pronounced in older soil, having a multitude of eff ects on the distribution and retention of soil water, and may facilitate certain water-conserving strategies of plants over what would be possible in a laterally homogeneous soil. ?? Soil Science Society of America.

California↗
USGS1977

Interactions of nutrients, plant growth and herbivory in a mangrove ecosystem

The effect of nutrient enrichment of red mangroves ( Rhizophora mangle ) was studied by comparing two mangrove—covered islands in the Indian River at Ft. Pierce, Florida, USA, one (high nutrient) with and one (low nutrient) without a breeding colony of pelicans and egrets. Repeated measurements taken on > 100 tagged branches in each area revealed higher growth rates at the high nutrient site. Trees at the high nutrient site showed greater additions of (1) leaves; (2) reproductive parts; (3) new lateral branches; and (4) larger increments to existing stems. Growth in the fertilized stand also began earlier in the year and had a second maximum not shared by the low nutrient area. Both leaves and fruits at the high nutrient site were richer in nitrogen. More striking than the effects on plant growth, however, was the proportionately much greater stimulation of herbivory by insects in response to nutrient enrichment. Larvae of the five lepidopteran species that we observed feeding on buds or leaves were either more abundant or only present in the high nutrient area, as was the scolytid beetle that infested seedlings before they dropped from the parent tree. This difference in herbivory between sites disappeared when the birds seasonally migrated away from their nesting areas at the high nutrient site. This observation and the demonstration that the mangrove skipper Phocides pigmalion attains a higher growth efficiency on high nutrient leaves are both consistent with the hypothesis that increased nutritive value of vegetation (correlated with the increased concentration of nitrogen) is responsible for the 4x greater losses to herbivores in the high nutrient. Implications for environmental management and in more complex communities are discussed.

Florida↗
USGS2007

Aquatic Communities and Selected Water Chemistry in St. Vrain Creek near the City of Longmont, Colorado, Wastewater-Treatment Plant, 2005 and 2006

In 2005, the U.S. Geological Survey and the City of Longmont, Colo., began a study to document chemical characteristics of St. Vrain Creek that had previously been unavailable either due to high cost of analysis or lack of analytical capability. Stream samples were collected at seven sites on St. Vrain Creek during the spring of 2005 and 2006 for analysis of wastewater compounds. A Lagrangian-sampling design was followed during each sampling event, and time-of-travel studies were conducted just prior to each sampling event to determine appropriate sampling times for the synoptic. In addition, semipermeable membrane devices, passive samplers that concentrate hydrophobic organic chemicals, were installed at six sites during the spring of 2005 and 2006 for approximately 4 weeks. After retrieval, contaminant residues concentrated in the semipermeable membrane devices were recovered and used in a toxicity assay that provided a screen for aryl hydrocarbon receptor type compounds, including polycyclic aromatic hydrocarbons, polychlorinated biphenyls, dioxins, and furans. In addition, the U.S. Geological Survey summarized information on macroinvertebrate and fish communities known from St. Vrain Creek dating back to the early 1900s in order to assess their utility in evaluating wastewater-treatment plant upgrades and habitat improvement projects. Unfortunately, because of inconsistencies in data collection these data cannot be used as intended; however, they are useful for understanding to some degree gross patterns in fish species distribution, but less so for macroinvertebrates.

Data Series↗
USGS2004

Overview--Development of a geodatabase and conceptual model of the hydrogeologic units beneath Air Force Plant 4 and Naval Air Station-Joint Reserve Base Carswell Field, Fort Worth, Texas

Air Force Plant 4 (AFP4) and adjacent Naval Air Station-Joint Reserve Base Carswell Field (NAS–JRB) at Fort Worth, Tex., constitute a contractor-owned, government-operated facility that has been in operation since 1942. Contaminants from the 3,600-acre facility, primarily volatile organic compounds (VOCs) and metals, have entered the ground-water-flow system through leakage from waste-disposal sites and from manufacturing processes. Environmental data collected at AFP4 and NAS–JRB during 1993–2002 created the need for consolidation of the data into a comprehensive temporal and spatial geodatabase. The U.S. Geological Survey (USGS), in cooperation with the U.S. Air Force Aeronautical Systems Center Environmental Management Directorate, developed a comprehensive geodatabase of temporal and spatial environmental data associated with the hydrogeologic units beneath the facility. A three-dimensional conceptual model of the hydrogeologic units integrally linked to the geodatabase was designed concurrently. Three hydrogeologic units—from land surface downward, the alluvial aquifer, the GoodlandWalnut confining unit, and the Paluxy aquifer—compose the subsurface of interest at AFP4 and NAS–JRB. The alluvial aquifer consists primarily of clay and silt with sand and gravel channel deposits that might be interconnected or interfingered. The Goodland-Walnut confining unit directly underlies the alluvial aquifer and consists of limestone, marl, shale, and clay. The Paluxy aquifer is composed of dense mudstone and fine- to coarse-grained sandstone

Texas↗
USGS2015

Contaminant removal by wastewater treatment plants in the Stillaguamish River Basin, Washington

Human activities in most areas of the developed world typically release nutrients, pharmaceuticals, personal care products, pesticides, and other contaminants into the environment, many of which reach freshwater ecosystems. In urbanized areas, wastewater treatment plants (WWTPs) are critical facilities for collecting and reducing the amounts of wastewater contaminants (WWCs) that ultimately discharge to rivers, coastal areas, and groundwater. Most WWTPs use multiple methods to remove contaminants from wastewater. These include physical methods to remove solid materials (primary treatment), biological and chemical methods to remove most organic matter (secondary treatment), advanced methods to reduce the concentrations of various contaminants such as nitrogen, phosphorus and (or) synthetic organic compounds (tertiary treatment), and disinfection prior to discharge (Metcalf and Eddy, Inc., 1979). This study examined the extent to which 114 organic WWCs were removed by each of three WWTPs, prior to discharge to freshwater and marine ecosystems, in a rapidly developing area in northwestern Washington State. Removal percentages for each WWC were estimated by comparing the concentrations measured in the WWTP influents with those measured in the effluents. The investigation was carried out in the 700-mi 2 Stillaguamish River Basin, the fifth largest watershed that discharges to Puget Sound (fig. 1).

Washington↗
USGS2003

Near field receiving water monitoring of trace metals in clams (Macoma balthica) and sediments near the Palo Alto water quality control plant in south San Francisco Bay, California: 2002

This report presents trace element concentrations analyzed on samples of fine-grained sediments and clams (Macoma balthica) collected from a mudflat one kilometer south of the discharge of the Palo Alto Regional Water Quality Control Plant in South San Francisco Bay. This report serves as a continuation of the Near Field Receiving Water Monitoring Study, which was started in 1994. The data for 2002, herein, are interpreted within that context. Metal concentrations in both sediments and clam tissue samples have been within the range of values produced by seasonal variability. However, copper and zinc, display continued decreases. Copper in sediment was observed to drop below the ERL (Effects Range-Low) concentration for the third consecutive year and zinc concentrations never exceeded the ERL. Yearly average concentrations of copper, zinc and silver in Macoma balthica for 2002 are some of the lowest recorded since monitoring began in 1975. Mercury and selenium concentrations in sediments and clams at Palo Alto were similar concentrations observed elsewhere in the San Francisco Bay.

California↗