scholarly journals Cascading effects of freshwater salinization on plankton communities in the Sierra Nevada

Author(s):  
Emma R. Moffett ◽  
Henry K. Baker ◽  
Christine C. Bonadonna ◽  
Jonathan B. Shurin ◽  
Celia C. Symons
2018 ◽  
Vol 374 (1764) ◽  
pp. 20180012 ◽  
Author(s):  
William D. Hintz ◽  
Devin K. Jones ◽  
Rick A. Relyea

Recent discoveries have documented evolutionary responses to freshwater salinization. We investigated if evolutionary responses to salinization exhibit life-history trade-offs or if they can mitigate ecological impacts such as cascading effects through mechanisms of tolerance and cross-tolerance. We conducted an outdoor mesocosm experiment using populations ofDaphnia pulex—a ubiquitous algal grazer—that were either naive or had previously experienced selection to become more tolerant to sodium chloride (NaCl). During the initial phase of population growth, we discovered that evolved tolerance comes at the cost of slower population growth in the absence of salt. We found evolvedDaphniapopulations maintained a tolerance to NaCl approximately 30 generations after the initial discovery. Evolved tolerance to NaCl also conferred cross-tolerance to a high concentration of CaCl2(3559 µS cm−1) and a moderate concentration of MgCl2(967 µS cm−1). A higher concentration of MgCl2(2188 µS cm−1) overwhelmed the cross-tolerance and killed allDaphnia. Tolerance to NaCl did not mitigate NaCl-induced cascades leading to phytoplankton blooms, but cross-tolerance at moderate concentrations of MgCl2and high concentrations of CaCl2mitigated such cascading effects caused by these two salts. These discoveries highlight the important interplay between ecology and evolution in understanding the full impacts of freshwater salinization.This article is part of the theme issue ‘Salt in freshwaters: causes, ecological consequences and future prospects’.


Author(s):  
Elizabeth Cortés Castillo ◽  
Julián Andrés López Isaza
Keyword(s):  

Author(s):  
Ernesto Hernández-Romero ◽  
Reyna Rojano-Hernández ◽  
Ricardo Mendoza-Robles ◽  
José. I. Cortés- Flores ◽  
Antonio N. Turrent-Fernández

En la Sierra Nevada de Puebla, México, los huertos de durazno (Prunus persica L.) presentan problemas de producción relacionados con alta incidencia de plagas (incluye enfermedades), nutrición deficiente e inadecuado manejo de poda, que acentúan el problema de floración precoz en la mayoría de las variedades mejoradas.


2007 ◽  
Vol 343 ◽  
pp. 77-85 ◽  
Author(s):  
JI Sonnenholzner ◽  
LB Ladah ◽  
KD Lafferty

2017 ◽  
Vol 94 (3) ◽  
pp. 37-61
Author(s):  
Douglas R. Littlefield

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.


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