scholarly journals Long-term ecological changes in the densely populated rural landscapes of China

Author(s):  
Erie C. Ellis
Science ◽  
2013 ◽  
Vol 341 (6150) ◽  
pp. 1085-1089 ◽  
Author(s):  
H. D. Graven ◽  
R. F. Keeling ◽  
S. C. Piper ◽  
P. K. Patra ◽  
B. B. Stephens ◽  
...  

Seasonal variations of atmospheric carbon dioxide (CO2) in the Northern Hemisphere have increased since the 1950s, but sparse observations have prevented a clear assessment of the patterns of long-term change and the underlying mechanisms. We compare recent aircraft-based observations of CO2 above the North Pacific and Arctic Oceans to earlier data from 1958 to 1961 and find that the seasonal amplitude at altitudes of 3 to 6 km increased by 50% for 45° to 90°N but by less than 25% for 10° to 45°N. An increase of 30 to 60% in the seasonal exchange of CO2 by northern extratropical land ecosystems, focused on boreal forests, is implicated, substantially more than simulated by current land ecosystem models. The observations appear to signal large ecological changes in northern forests and a major shift in the global carbon cycle.


1996 ◽  
Vol 32 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Adriana Cociasu ◽  
Liliana Dorogan ◽  
Christoph Humborg ◽  
Luci Popa

Author(s):  
Adson da S. G. Ferreira ◽  
Henrique C. M. P. da Silva ◽  
Hélio O. S. Rodrigues ◽  
Marileide Silva ◽  
Eden C. de Albuquerque Junior

ABSTRACT The intensive use of pesticides to control pests in agriculture has exposed the environment and humans to a variety of risks. Among the crops with higher consumption of these compounds there is the sugarcane, developed in regions bordered by large watersheds. In this work, the occurrence of pesticides in the water of Ipojuca River was investigated in a 50 km range of its eastern portion, in a region noted for intense agroindustrial activity, especially by sugarcane cultivation, in the state of Pernambuco. Among fungicides, herbicides, insecticides and carbamates, 238 pesticides were investigated in the Ipojuca River using the technique of liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The study, conducted in the months of May, June, October and November 2012, detected the presence of Diuron and Ametryn herbicide residues in 100% of the water samples at concentrations from 0.01 to 1.4 μg L-1. The detection of these herbicides, even at residual concentrations, can lead to perceptible ecological changes in the long term, such as the reduction of the biological potential of animal and plant species.


1971 ◽  
Vol 177 (1048) ◽  
pp. 307-320 ◽  

Many pollutants, even when present in the water in concentrations well below lethal levels, may cause marked changes in the physiology and behaviour of fish. The work reported deals mainly with salmonids. The responses to insecticides are particularly interesting. Of fundamental interest is the suggestion that DDT seems to act by interfering with the normal thermal acclimation mechanism(s), probably within the central nervous system. The results are not without practical significance. Some responses, including those induced by heavy metal ions from mining wastes, may cause long-term ecological changes of consequence.


Abstract.—Spiny dogfish <em>Squalus acanthias </em>are an abundant and commercially important species of fish off both the Atlantic and Pacific coasts of North America. They are opportunistic feeders and have a varied diet that can include many fish species, especially small forage fish such as herring, capelin, and sand lance as well as crustaceans, worms, euphausiids, gelatinous zooplankton, and cephalopods. The purpose of our present study is to investigate the utility of the second dorsal spine in providing multiyear information on the feeding habits of dogfish using stable isotope (C and N) analysis. The outer dentine and enamel layers of a spine from three dogfish (caught off the coast of British Columbia) were analyzed to obtain their stable nitrogen and carbon isotope composition (δ<sup>15</sup>N and δ<sup>13</sup>C, respectively). Each sample had annuli from multiple years, allowing possible seasonal migrations to be averaged over samples. The δ<sup>15</sup>N ranged from a low of 11.6‰ to a high of 14.9‰ over the three spines and δ<sup>13</sup>C ranged from –11.5‰ to –18.4‰. The variable isotopic signatures along the spine indicate that the method may be used to assess ecological changes. Stable isotope measurements of dogfish spines could be a valuable means of determining long-term changes in habitat usage and feeding ecology.


Author(s):  
John Bintliff

The Classical world witnessed many forms of physical landscape change due to long-term and short-term geological and climatological processes. There have also been alterations to the land surface resulting from an interaction between human impact and these natural factors. Cyclical changes in land use, agricultural technology, economy, and politics have continually transformed the rural landscapes of the Mediterranean and the wider Classical world and their mapping, in turn, can shed light on fundamental aspects of ancient society that are not always documented in Classical texts.


2021 ◽  
Vol 750 ◽  
pp. 142254
Author(s):  
Yu-Jia Lin ◽  
Lotfi Rabaoui ◽  
Abdullajid Usama Basali ◽  
Maclopez Lopez ◽  
Reynaldo Lindo ◽  
...  

2019 ◽  
Vol 20 ◽  
pp. e00697 ◽  
Author(s):  
David S. Green ◽  
Elise F. Zipkin ◽  
Darren C. Incorvaia ◽  
Kay E. Holekamp

2020 ◽  
Vol 727 ◽  
pp. 138519
Author(s):  
Carmen Pérez-Martínez ◽  
Kathleen M. Rühland ◽  
John P. Smol ◽  
Vivienne J. Jones ◽  
José M. Conde-Porcuna

2014 ◽  
Vol 102 ◽  
pp. 559-571 ◽  
Author(s):  
Jongseong Ryu ◽  
Jungho Nam ◽  
Jinsoon Park ◽  
Bong-Oh Kwon ◽  
Jung-Ho Lee ◽  
...  

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