scholarly journals Identification and community profiling of Vaccinium membranaceum root-associated fungi over an elevation gradient in BC's eastern rocky mountains.

2009 ◽  
Author(s):  
Monika A. Gorzelak
2007 ◽  
Vol 41 (8) ◽  
pp. 2723-2729 ◽  
Author(s):  
Marc J. Demers ◽  
Erin N. Kelly ◽  
Jules M. Blais ◽  
Frances R. Pick ◽  
Vincent L. St. Louis ◽  
...  

Author(s):  
Alisha A. Shah ◽  
H. Arthur Woods ◽  
Justin C. Havird ◽  
Andrea C. Encalada ◽  
Alexander S. Flecker ◽  
...  

AbstractA fundamental gap in climate change vulnerability research is an understanding of the relative thermal sensitivity of ectotherms. Aquatic insects are vital to stream ecosystem function and biodiversity but insufficiently studied with respect to their thermal physiology. With global temperatures rising at an unprecedented rate, it is imperative that we know how aquatic insects respond to increasing temperature and whether these responses vary among taxa, latitudes, and elevations. We evaluated the thermal sensitivity of standard metabolic rate in stream-dwelling baetid mayflies and perlid stoneflies across a ~2,000 m elevation gradient in the temperate Rocky Mountains in Colorado, U.S.A., and the tropical Andes in Napo, Ecuador. We used temperature-controlled water baths and microrespirometry to estimate changes in oxygen consumption. Tropical mayflies generally exhibited greater thermal sensitivity in metabolism compared to temperate mayflies; tropical mayfly metabolic rates increased more rapidly with temperature and the insects more frequently exhibited behavioral signs of thermal stress. By contrast, temperate and tropical stoneflies did not clearly differ. Varied responses to temperature among baetid mayflies and perlid stoneflies may reflect differences in evolutionary history or ecological roles as herbivores and predators, respectively. Our results show that there is physiological variation across elevations and species and that low elevation tropical mayflies may be especially imperiled by climate warming. Given such variation among species, broad generalizations about the vulnerability of tropical ectotherms should be made more cautiously.


1986 ◽  
Vol 16 (2) ◽  
pp. 315-320 ◽  
Author(s):  
M. J. Mitchell ◽  
M. B. David ◽  
D. G. Maynard ◽  
S. A. Telang

Sulfur constituents of soils and streams were measured in the Marmot Basin watershed of the Rocky Mountains (Alberta). Total S in the soils ranged from 2.5 to 49.8 μmol/g dry mass; carbon-bonded S and ester sulfate were the dominant S constituents (67–86 and 5–32% of total S, respectively), with sulfate ranging from 0.1 to 8.1% of total S. Organic S was 12–21% of total S in stream waters. High concentrations of sulfate (93–355 μmol/L), Ca (763–1075 μmol/L), Mg (387–765 μmol/L), and C (1930–4160 μmol/L) in streams were due to mineral weathering. Atmospheric inputs of S at Marmot Creek were much less important than in forest ecosystems subject to acidic deposition. A tentative budget demonstrated the importance of weathering and organic S in this watershed. Analysis of one tributary (Middle Creek) along an elevation gradient indicated that a portion of the sulfate was retained within the terrestrial portion of the ecosystem in organic forms. The dynamics of these organic S constituents exert a major influence on S flux in some forest ecosystems as a result of their role in mineralization and immobilization processes.


1992 ◽  
Vol 70 (5) ◽  
pp. 886-890 ◽  
Author(s):  
Michael A. Bozek ◽  
Wayne A. Hubert

We assessed the relation of three measures of habitat to the distribution of four species of Salmonidae, cutthroat trout (Oncorhynchus clarki), brook trout (Salvelinus fontinalis), brown trout (Salmo trutta), and rainbow trout (Oncorhynchus mykiss), in streams of the central Rocky Mountains. We examined whether single measures of three habitat dimensions (climate, stream energy, and stream size) could account for current distribution patterns of four resident trout species in Wyoming. The three habitat dimensions were represented by three habitat variables: elevation, channel gradient, and wetted stream width. Considerable overlap in the ranges of elevation, gradient, and wetted width was observed among reaches where the four species were found, but differences in the mean values of these habitat features were observed among species. Using discriminant analysis, we categorized the presence and absence of individual species in stream reaches by the three habitat variables. We successfully predicted the presence of brook trout (87%), cutthroat trout (59%), brown trout (50%), and rainbow trout (39%) in streams, but the absence of each species was predicted more successfully (rainbow trout (94%), brown trout (94%), cutthroat trout (90%), and brook trout (57%)). The three habitat features were useful in describing the segregation of trout species in streams of the central Rocky Mountains.


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