Estimating California mussel (Mytilus californianus) size from hinge fragments: a methodological application in historical ecology

2015 ◽  
Vol 58 ◽  
pp. 167-174 ◽  
Author(s):  
Breana Campbell ◽  
Todd J. Braje
2021 ◽  
Vol 13 (2) ◽  
pp. 817
Author(s):  
Ove Eriksson ◽  
Matilda Arnell ◽  
Karl-Johan Lindholm

Infield systems originated during the early Iron Age and existed until the 19th century, although passing many transitions and changes. The core features of infield systems were enclosed infields with hay-meadows and crop fields, and unenclosed outland mainly used for livestock grazing. We examine the transitions and changes of domesticated landscapes with infield systems using the framework of human niche construction, focusing on reciprocal causation affecting change in both culture and environment. A first major transition occurred during the early Middle Ages, as a combined effect of a growing elite society and an increased availability of iron promoted expansion of villages with partly communal infields. A second major transition occurred during the 18th and 19th centuries, due to a then recognized inefficiency of agricultural production, leading to land reforms. In outlands, there was a continuous expansion of management throughout the whole period. Even though external factors had significant impacts as well, human niche construction affected a range of cultural and environmental features regarding the management and structure of domesticated landscapes with infield systems. Thus, niche construction theory is a useful framework for understanding the historical ecology of infield systems.


Author(s):  
R. Norman Kelley ◽  
Michael J. Smith-Ashwood ◽  
Derek V. Ellis

Determining the duration and timing of spermatogenesis in Mytilus californianus Conrad became key questions in our study of carcinogen-mutagen indices in the marine environment. We had postulated that the murine sperm deformation assay of Bruce, Furrer & Wyrobek (1974) should have marine analogues, and we assayed a number of marine invertebrates sampled near potentially carcinogenic waste flows, and by γ-ray dose-response experiments. Our field results demonstrated some deformation but only at a very low level (less than 5 % in Mytilus edulis L.). Development of a γ-ray doseresponse (90–900 rads) procedure for M. californianus by radium needle inserted through a drilled hole closed with a plastic plug, and subsequent biopsy of gonadal tissue at measured distances from the site of irradiation, did not show deformations from a pilot test in June 1979. If a viable dose-response procedure was to be developed it was necessary to establish seasonal reproductive timing so that specimens could be collected or cultured to maximize spermatogenesis and hence response potential, and also to establish the duration of spermatogenesis so that response measures via a gonadal tissue extraction could be appropriately timed.


2017 ◽  
Vol 104 (5) ◽  
pp. 645-648 ◽  
Author(s):  
Erin Beller ◽  
Loren McClenachan ◽  
Andrew Trant ◽  
Eric W. Sanderson ◽  
Jeanine Rhemtulla ◽  
...  
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