Perennial Pepperweed (Lepidium latifolium): Properties of Invaded Tidal Marshes

2010 ◽  
Vol 3 (2) ◽  
pp. 130-138 ◽  
Author(s):  
Laura K. Reynolds ◽  
Katharyn E. Boyer
Keyword(s):  
United States ◽  
San Francisco ◽  
Soil Characteristics ◽  
San Francisco Estuary ◽  
Western United States ◽  
Tidal Marshes ◽  
Lepidium Latifolium ◽  
Sarcocornia Pacifica ◽  
Structural And Functional Properties ◽  
Wetland Habitats

AbstractLepidium latifolium (perennial pepperweed) is recognized as a threat to wetland habitats throughout much of the western United States, but its role in tidal marshes has not been explored. Over three seasons in three regions of San Francisco Estuary (Suisun, San Pablo, and South San Francisco bays), we characterized locations in tidal marshes where monotypic stands of L. latifolium are replacing the native Sarcocornia pacifica (pickleweed). Soils within L. latifolium stands had significantly lower moisture, salinity, organic matter, and carbon : nitrogen (C : N) and higher pH than in adjacent S. pacifica stands at similar elevation and distance from channels. In addition, L. latifolium canopies were 2 to 3 times taller, thus increasing light reaching soils, and tended to support different insect/spider assemblages (sampled only at the Suisun site). Patterns were generally consistent across the three sites, although less pronounced for some measures at the South Bay site. Overall, these data suggest that L. latifolium invasion of tidal marshes is leading to modification of both structural and functional properties, several of which might further facilitate spread of the invader; however, additional study is needed to determine cause vs. effect for several soil characteristics.

Horizontal particle velocity and its relation to magnitude in the Western United States

1979 ◽  
Vol 69 (6) ◽  
pp. 2037-2061
Author(s):  
A. F. Espinosa
Keyword(s):  
United States ◽  
Data Base ◽  
San Francisco ◽  
Seismic Waves ◽  
Scaling Law ◽  
Direct Determination ◽  
Strong Motion ◽  
Western United States ◽  
Short Period ◽  
Horizontal Particle

abstract A magnitude (ML) scaling law has been derived from the strong-motion data base of the San Fernando earthquake of February 9, 1971, and the results have been compared with other strong-motion recordings obtained from 62 earthquakes in the Western United States. The relationship derived is ML = 3.21 + 1.35 log10Δ + log10v. An excellent agreement was obtained between the determined ML values in this study and those evaluated by Kanamori and Jennings (1978). This scaling law is applicable to the collected data from 63 earthquakes whose local magnitudes range from about 4.0 to 7.2, recorded at epicentral distances between about 5 to 300 km, and with short-period seismic waves in the range of 0.2 to 3.0 sec. The Long Beach earthquake of 1933, with an ML = 6.3 (PAS) and an ML = 6.43 ± 0.36 as determined by Kanamori and Jennings is in agreement with an ML = 6.49 ± 0.32 obtained in this study. The Imperial Valley earthquake of 1940, with an ML = 6.5 (PAS), compares well with an ML = 6.5 as determined in this study. The Kern County earthquake of 1952, with an ML = 7.2 (BRK), is in fairly good agreement with the ML = 7.0 ± 0.2 obtained in this investigation. This value is significantly lower than the commonly quoted 7.7 value for this event. The San Francisco earthquake of 1957, with an ML = 5.3 (BRK), agrees very well with an ML = 5.3 ± 0.1 as determined in this study. The Parkfield earthquake of 1966 has an ML = 5.8 ± 0.3, which is consistent with the 5.6 (PAS). The procedure developed here is applied to the data base obtained from the Western United States strong-motion recordings. The procedure allows the evaluation of ML for moderate and larger earthquakes from the first integration of the strong-motion accelerograms and allows the direct determination of ML from the scaled amplitudes in a rapid, economical, and accurate manner. It also has allowed for the extension of the trend of the attenuation curve for horizontal particle velocities at distances less than 5 km for different size events.

Germination of Seeds of Perennial Pepperweed (Lepidium latifolium)

Weed Science ◽  
1986 ◽  
Vol 34 (2) ◽  
pp. 252-255 ◽  
Author(s):  
Gerald K. Miller ◽  
James A. Young ◽  
Raymond A. Evans
Keyword(s):  
United States ◽  
Constant Temperature ◽  
Western United States ◽  
Lepidium Latifolium ◽  
Temperature Regimes ◽  
Riparian Habitats ◽  
Alternating Temperature

Perennial pepperweed (Lepidium latifoliumL. # LEPLA) is a serious weed of meadows and riparian habitats in the intermountain area of the western United States. Germination of seeds of this species was tested at 55 constant- and alternating-temperature regimes. No significant differences were found in mean germination at a range of temperatures varying from 0 to 40 C for seedlots collected at the same site in different years or at different locations in the same year. Optimum germination not significantly (P = 0.01) lower than the maximum observed occurred most frequently at 5/40 C (5 C for 16 h and 40 C for 8 h), and 10/40 and 15/40 C. Germination was enhanced by alternating regimes with low night temperatures (0, 2, or 5 C) and high day temperatures (35 and 40 C), in comparison with more moderate constant-temperature regimes.

scholarly journals The contribution of marine organics to the air quality of the western United States

2010 ◽  
Vol 10 (15) ◽  
pp. 7415-7423 ◽  
Author(s):  
B. Gantt ◽  
N. Meskhidze ◽  
A. G. Carlton
Keyword(s):  
United States ◽  
Air Quality ◽  
San Francisco ◽  
Atmospheric Chemistry ◽  
Environmental Protection Agency ◽  
Regional Scale ◽  
The United States ◽  
Coastal Areas ◽  
Western United States ◽  
The Us

Abstract. The contribution of marine organic emissions to the air quality in coastal areas of the western United States is studied using the latest version of the US Environmental Protection Agency (EPA) regional-scale Community Multiscale Air Quality (CMAQv4.7) modeling system. Emissions of marine isoprene, monoterpenes, and primary organic matter (POM) from the ocean are implemented into the model to provide a comprehensive view of the connection between ocean biology and atmospheric chemistry and air pollution. Model simulations show that marine organics can increase the concentration of PM2.5 by 0.1–0.3 μg m−3 (up to 5%) in some coastal cities such as San Francisco, CA. This increase in the PM2.5 concentration is primarily attributed to the POM emissions, with small contributions from the marine isoprene and monoterpenes. When marine organic emissions are included, organic carbon (OC) concentrations over the remote ocean are increased by up to 50% (25% in coastal areas), values consistent with recent observational findings. This study is the first to quantify the air quality impacts from marine POM and monoterpenes for the United States, and it highlights the need for inclusion of marine organic emissions in air quality models.

scholarly journals First Record of the Large-Scale Loach Paramisgurnus dabryanus (Cobitidae) in the United States

2018 ◽  
Vol 9 (1) ◽  
pp. 246-254 ◽  
Author(s):  
Joseph E. Kirsch ◽  
Richard F. Feeney ◽  
Alisha Goodbla ◽  
Christopher Hart ◽  
Zachary J. Jackson ◽  
...  
Keyword(s):  
United States ◽  
San Francisco ◽  
Large Scale ◽  
Fish Communities ◽  
The United States ◽  
San Francisco Estuary ◽  
Bifurcation Structure ◽  
Paramisgurnus Dabryanus ◽  
San Joaquin River ◽  
The U.S

Abstract Exotic species have been implicated as a major threat to native freshwater fish communities in the Unites States. The San Francisco Estuary watershed has been recognized as one of the most invaded systems where exotics often dominate the fish community. On October 6, 2014, members of the U.S. Fish and Wildlife Service detected a previously unknown exotic fish in a disconnected pool immediately upstream from the Chowchilla Bifurcation Structure in the San Joaquin River, a major tributary of the San Francisco Estuary. A member of the U.S. Fish and Wildlife Service initially identified the fish as an Oriental Weatherfish Misgurnus anguillicaudatus using external morphological characteristics. We conducted additional fish sampling near the Chowchilla Bifurcation Structure in November 2014 and collected a total of six additional specimens in disconnected pool habitats. Unexpectedly, genetic and meristic techniques revealed that these specimens were Large-Scale Loach Paramisgurnus dabryanus. To our knowledge this is the first confirmed occurrence of Large-Scale Loach in the United States and the suspected pathway of introduction is release from aquaria. Very little is known about the population in the San Joaquin River. We recommend further evaluation of the ecology, distribution, and abundance of Large-Scale Loach to better understand their potential impact on the fish communities of the San Joaquin River and the likelihood of establishment throughout the United States.

scholarly journals Salt Marsh Claviceps purpurea in Native and Invaded Spartina Marshes in Northern California

Plant Disease ◽  
2007 ◽  
Vol 91 (4) ◽  
pp. 380-386 ◽  
Author(s):  
A. J. Fisher ◽  
J. M. DiTomaso ◽  
T. R. Gordon ◽  
B. J. Aegerter ◽  
D. R. Ayres
Keyword(s):  
United States ◽  
Salt Marsh ◽  
San Francisco ◽  
Atlantic Coast ◽  
The United States ◽  
San Francisco Estuary ◽  
Claviceps Purpurea ◽  
Northern California ◽  
Native Plant ◽  
Worldwide Distribution

The fungal pathogen Claviceps purpurea (subgroup G3) has a worldwide distribution on salt marsh Spartina spp. In Northern California (United States), native Spartina foliosa sustains high rates of infection by G3 C. purpurea in marshes north of the San Francisco Estuary. Invasive populations of S. alterniflora and S. alterniflora × foliosa hybrids are virtually disease free in the same estuary, although S. alterniflora is host to G3 C. purpurea in its native range (Atlantic Coast of the United States). Greenhouse inoculation experiments showed no differences in susceptibility among S. foliosa, S. alterniflora, and Spartina hybrids. Under field conditions, S. foliosa sustained a higher incidence of disease in coastal marshes than in marshes within the bay. This geographic effect may be attributable to environmental differences between the coast and the bay proper, with the former being more conducive to infection by C. purpurea. Seed set of S. foliosa spikelets was 40 to 70% lower on infected than on uninfected inflorescences, but seed germination was not affected. The C. purpurea epidemic on S. foliosa on the coast north of the San Francisco Estuary further reduces the meager competitive ability of this declining native plant species.

scholarly journals Spatial Heterogeneity in Prey Availability, Feeding Success, and Dietary Selectivity for the Threatened Longfin Smelt

2022 ◽  
Author(s):  
Arthur Barros ◽  
James A. Hobbs ◽  
Malte Willmes ◽  
Christina M. Parker ◽  
Micah Bisson ◽  
...  
Keyword(s):  
San Francisco ◽  
Prey Availability ◽  
Prey Selection ◽  
Open Water ◽  
Tidal Marshes ◽  
Diet Shift ◽  
Fish Length ◽  
Feeding Success ◽  
Wetland Habitats ◽  
Longfin Smelt

AbstractFood availability is a key determinant of the nursery value of a given habitat for larval and juvenile fishes. Growth, survival, and recruitment success are often inter-correlated and influenced by prey availability and associated feeding success. This is likely true for the threatened population of Longfin Smelt (Spirinchus thaleichthys) in the San Francisco Estuary (SFE) which has collapsed in recent decades along with its preferred prey. In years with high precipitation and freshwater outflow, larval Longfin Smelt are found in shallow wetland habitats throughout the SFE, but variation in the availability of food and feeding success in these habitats remains unexplored. To examine spatial variation in the trophic value of different rearing habitats, we quantified variation in prey availability, feeding success, and prey selection for larval and juvenile Longfin Smelt captured in restored tidal marshes, sloughs, and open-water habitats in the northern and southern SFE. Prey abundance varied spatially, with densities approximately tenfold greater in southern sloughs and restored tidal ponds relative to northern and open-water habitats. Feeding success of larval Longfin Smelt was positively correlated with both fish length and prey density. Larval Longfin Smelt fed selectively on the copepod Eurytemora affinis, with larger individuals (> 25 mm total length) exhibiting an ontogenetic diet shift to larger mysid shrimps. Our results suggest that wetland habitats across the SFE vary greatly in their trophic value, with previously unexplored habitats exhibiting the highest densities of prey and the highest foraging success for larval Longfin Smelt.

scholarly journals Climate regime and soil storage capacity interact to effect evapotranspiration in western United States mountain catchments

2014 ◽  
Vol 11 (2) ◽  
pp. 2277-2319 ◽  
Author(s):  
E. S. Garcia ◽  
C. L. Tague
Keyword(s):  
United States ◽  
Soil Water ◽  
Soil Characteristics ◽  
Water Holding Capacity ◽  
Western United States ◽  
Total Biomass ◽  
Soil Water Holding Capacity ◽  
Climate Controls ◽  
Climatic Drivers ◽  
Water Holding

Abstract. In the winter-wet, summer-dry forests of the western United States (US), total annual evapotranspiration (ET) is largely a function of three separate but interacting properties: (1) climate, especially magnitude of precipitation, its partitioning into rain or snow, and snowmelt timing; (2) soil characteristics, including soil water holding capacity and rates of drainage; and (3) the total biomass where larger, more abundant vegetation is directly proportional to greater ET. Understanding how these controls influence ET in Mediterranean mountain environments is complicated by shifts between water and energy limitations both within the year and between years. We use a physically based process model to evaluate the strength of climate controls and soil properties in predicting ET in three snow-dominated, mountainous catchments in the western US. As we expect, statistical analysis shows that annual precipitation is a primary control of annual ET across all catchments. However, secondary climate controls vary across catchments. Further, the sensitivity of annual ET to precipitation and other climatic controls varies with soil characteristics. In the drier, more snow-dominated catchments ET is also controlled by spring temperature through its influence on the timing of snowmelt and the synchronicity between seasonal water availability and demand. In wetter catchments that receive a large fraction of winter precipitation as rainfall, the sensitivity to ET is also strongly influenced by soil water holding capacity. We show that in all catchments, soil characteristics affect the sensitivity of annual ET to climatic drivers. Estimates of annual ET become more sensitive to climatic drivers at low soil water holding capacities in the catchments with the stronger decoupling between precipitation and growing season demands.

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