Facts Concerning Natural Breeding Area of Beet Leafhopper (Eutettix Tenella Baker) in San Joaquin Valley of California

1922 ◽  
Vol 15 (6) ◽  
pp. 411-420 ◽  
Author(s):  
Henry H. P. Severin ◽  
Almon J. Basinger
Keyword(s):  
San Joaquin Valley ◽  
Breeding Area ◽  
Beet Leafhopper ◽  
Natural Breeding

scholarly journals Survival and Habitat use of Mallard (Anas Platyrhynchos) Broods in the San Joaquin Valley, California

The Auk ◽  
2007 ◽  
Vol 124 (4) ◽  
pp. 1305-1316 ◽  
Author(s):  
Michael P. Chouinard ◽  
Todd W. Arnold
Keyword(s):  
Anas Platyrhynchos ◽  
Central Valley ◽  
San Joaquin Valley ◽  
Hatching Date ◽  
Moist Soil ◽  
Breeding Area ◽  
Seasonal Wetlands ◽  
Factors Affecting ◽  
Duckling Survival ◽  
Soil Units

Abstract The Central Valley of California is an important breeding area for Mallards (Anas platyrhynchos), but estimating recruitment rates for this population has been hampered by lack of data on duckling survival. To gain a better understanding of factors affecting brood and duckling survival, we radiomarked 56 brood hens and 112 ducklings (two per brood) on two actively managed wetland complexes in the San Joaquin Valley during 1996-1997. Total brood mortality was extensive, affecting 27 of 53 broods (51%). Survival of individual ducklings from hatching until 30 days of age was 24.8% (95% confidence interval: 0.178–0.335), with most mortality resulting from predation during the first 12 days of life. Survival differed between years and study areas but was unaffected by hatching date. Broods preferred reverse-cycle seasonal wetlands to more permanent wetlands throughout their first 30 days of life, and ducklings also had higher 2- to 30-day survival probabilities in reverse-cycle wetlands (x̄ ± SE = 0.755 ± 0.095) than in semipermanent-permanent wetlands (0.189 ± 0.056) or moist-soil units (0.173 ± 0.067). We recommend that waterfowl managers in the Central Valley provide reverse-cycle seasonal wetlands during the broodrearing period to enhance survival of locally breeding Mallards. Supervivencia y Uso de Hábitat por Nidadas de Anas platyrhynchos en el Valle de San Joaquín, California

Temporal patterns in the acoustic presence of baleen whale species in a presumed breeding area off Namibia

2019 ◽  
Vol 620 ◽  
pp. 201-214 ◽  
Author(s):  
K Thomisch ◽  
O Boebel ◽  
J Bachmann ◽  
D Filun ◽  
S Neumann ◽  
...  
Keyword(s):  
Temporal Patterns ◽  
Baleen Whale ◽  
Breeding Area

Transportation and the Environment

2017 ◽  
Vol 94 (3) ◽  
pp. 37-61
Author(s):  
Douglas R. Littlefield
Keyword(s):  
Nineteenth Century ◽  
San Francisco ◽  
Sierra Nevada ◽  
Mississippi River ◽  
San Joaquin Valley ◽  
Eastern United States ◽  
Major Health ◽  
San Joaquin River ◽  
Natural Wetlands ◽  
Prevailing View

Some histories of California describe nineteenth-century efforts to reclaim the extensive swamplands and shallow lakes in the southern part of California's San Joaquin Valley – then the largest natural wetlands habitat west of the Mississippi River – as a herculean venture to tame a boggy wilderness and turn the region into an agricultural paradise. Yet an 1850s proposition for draining those marshes and lakes primarily was a scheme to improve the state's transportation. Swampland reclamation was a secondary goal. Transport around the time of statehood in 1850 was severely lacking in California. Only a handful of steamboats plied a few of the state's larger rivers, and compared to the eastern United States, roads and railroads were nearly non-existent. Few of these modes of transportation reached into the isolated San Joaquin Valley. As a result, in 1857 the California legislature granted an exclusive franchise to the Tulare Canal and Land Company (sometimes known as the Montgomery franchise, after two of the firm's founders). The company's purpose was to connect navigable canals from the southern San Joaquin Valley to the San Joaquin River, which entered from the Sierra Nevada about half way up the valley. That stream, in turn, joined with San Francisco Bay, and thus the canals would open the entire San Joaquin Valley to world-wide commerce. In exchange for building the canals, the Montgomery franchise could collect tolls for twenty years and sell half the drained swamplands (the other half was to be sold by the state). Land sales were contingent upon the Montgomery franchise reclaiming the marshes. Wetlands in the mid-nineteenth century were not viewed as they are today as fragile wildlife habitats but instead as impediments to advancing American ideals and homesteads across the continent. Moreover, marshy areas were seen as major health menaces, with the prevailing view being that swampy regions’ air carried infectious diseases.

ANALYSIS OF ACCUMULATION AND DISTRIBUTION OF LEAD IN THE SYSTEM WATER-BOTTOM SEDIMENTS IN THE BACH DANG ESTUARY (VIETNAM)

2017 ◽  
pp. 62-66
Author(s):  
Truong Van Tuan ◽  
Irina Vladimirovna Volkova
Keyword(s):  
Bottom Sediment ◽  
Bottom Sediments ◽  
Water Samples ◽  
Suspended Solids ◽  
Natural Habitat ◽  
Bottom Layer ◽  
Sediment Samples ◽  
Natural Breeding ◽  
System Water ◽  
Water Bottom

Research was held in the estuary of the river Bach Dang (Dongbay community, Rakhtay district, Hai Phong, Vietnam) in June, 2012 - May, 2013. Concentration of lead was studied in water, suspended solids and bottom sediment. Clam beach (natural breeding environment of Meretrix lyrata ) was inspected regularly, every month. Water samples were taken 6 times from the bottom layer 10 cm down the bottom, once per 3 hours in each of 12 investigated zones. Bottom sediment samples were taken at the depth 2 cm. The findings show that lead accumulates mainly in suspended solids (23.3 mg/kg) and in bottom sediment (14.31 mg/kg), in water it is in small quantities (0.003 mg/kg). Analysis of bottom sediment samples taken in different places showed that they have even leadcontent, lead is distributed uniformly, localization of contaminations is not found. The results obtained can be assumed as the basis for investigating lead accumulation and its excretion by clam Meretrix lyrata organisms in the natural habitat.

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