Long-term c i  / c a response of trees in western North America to atmospheric CO 2 concentration derived from carbon isotope chronologies

Oecologia ◽  
1998 ◽  
Vol 117 (1-2) ◽  
pp. 19-25 ◽  
Author(s):  
Xiahong Feng
Keyword(s):  
North America ◽  
Carbon Isotope ◽  
Western North America

scholarly journals Carbon isotope and magnetic polarity evidence for non-depositional events within the Cambrian-Ordovician Boundary section near Dayangcha, Jilin Province, China

1993 ◽  
Vol 130 (4) ◽  
pp. 443-452 ◽  
Author(s):  
R. L. Ripperdan ◽  
M. Magaritz ◽  
J. L. Kirschvink
Keyword(s):  
North America ◽  
Sea Level ◽  
Carbon Isotope ◽  
Magnetic Polarity ◽  
Jilin Province ◽  
Western North America ◽  
Sea Level Changes ◽  
Stratotype Section ◽  
Black Mountain

AbstractCarbon isotope and magnetic polarity stratigraphic results from the Cambrian-Ordovician Boundary section at Xiaoyangqiao, near Dayangcha, Jilin Province, China, in comparison to a contemporaneous section at Black Mountain, Australia, indicate strata equivalent to major portions of the Australian sequence are either absent or are restricted to highly condensed intervals. These intervals are correlative with regressive sea level events identified in Australia and western North America, suggesting regional or eustatic sea level changes strongly influenced deposition of the Xiaoyangqiao sequence. These results also suggest the Xiaoyangqiao section is unfavourable as the site of the Cambrian-Ordovician Boundary Global Stratotype Section and Point.

Long-Term Trends of Chickadee Populations in Western North America

The Condor ◽  
1991 ◽  
Vol 93 (1) ◽  
pp. 130-137 ◽  
Author(s):  
Leonard A. Brennan ◽  
Michael L. Morrison
Keyword(s):  
North America ◽  
Western North America ◽  
Long Term Trends

scholarly journals Stable or seral? Fire-driven alternative states in aspen forests of western North America

2019 ◽  
Vol 15 (6) ◽  
pp. 20190011 ◽  
Author(s):  
Jesse L. Morris ◽  
R. Justin DeRose ◽  
Thomas Brussel ◽  
Simon Brewer ◽  
Andrea Brunelle ◽  
...  
Keyword(s):  
North America ◽  
Fire History ◽  
Biological Diversity ◽  
Disturbance Ecology ◽  
Western North America ◽  
Alternative States ◽  
Sediment Record ◽  
Subalpine Fir ◽  
Critical Transitions

As important centres for biological diversity, aspen forests are essential to the function and aesthetics of montane ecosystems in western North America. Aspen stands are maintained by a nuanced relationship with wildfire, although in recent decades aspen mortality has increased. The need to understand the baseline environmental conditions that favour aspen is clear; however, long-term fire history reconstructions are rare due to the scarcity of natural archives in dry montane settings. Here, we analyse a high-resolution lake sediment record from southwestern, Utah, USA to quantify the compositional and burning conditions that promote stable (or seral) aspen forests. Our results show that aspen presence is negatively correlated with subalpine fir and that severe fires tend to promote persistent and diverse aspen ecosystems over centennial timescales. This information improves our understanding of aspen disturbance ecology and identifies the circumstances where critical transitions in montane forests may occur.

LONG-TERM DECLINES AND DECADAL PATTERNS IN POPULATION TRENDS OF SONGBIRDS IN WESTERN NORTH AMERICA, 1979–1999

The Condor ◽  
10.1650/7131 ◽  
2003 ◽  
Vol 105 (4) ◽  
pp. 737 ◽  
Author(s):  
Grant Ballard ◽  
Geoffrey R. Geupel ◽  
Nadav Nur ◽  
Thomas Gardali
Keyword(s):  
North America ◽  
Population Trends ◽  
Western North America
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