Waterbird assemblages in the Aspen Parkland of western Canada: the influence of fishes, invertebrates, and the environment on species composition

2007 ◽  
Vol 6 (2) ◽  
pp. 53-65 ◽  
Author(s):  
Caroline E. MCPARLAND ◽  
Cynthia A. PASZKOWSKI
2003 ◽  
Vol 33 (12) ◽  
pp. 2509-2513 ◽  
Author(s):  
Brian W Benscoter ◽  
R Kelman Wieder

Fire directly releases carbon (C) to the atmosphere through combustion of biomass. An estimated 1470 ± 59 km2 of peatland burns annually in boreal, western Canada, releasing 4.7 ± 0.6 Tg C to the atmosphere via direct combustion. We quantified within-site variation in organic matter lost via combustion in a bog peatland in association with the 116 000-ha Chisholm, Alberta, fire in 2001. We hypothesized that for peatlands with considerable small-scale microtopography (bogs and treed fens), hummocks will burn less than hollows. We found that hollows exhibit more combustion than hummocks, releasing nearly twice as much C to the atmosphere. Our results suggest that spatial variability in species composition and site hydrology within a landform and across a landscape could contribute to considerable spatial variation in the amounts of C released via combustion during peatland fire, although the magnitude of this variation may be dependent on fire severity.


1993 ◽  
Vol 73 (4) ◽  
pp. 749-763 ◽  
Author(s):  
D. H. McCartney

The Aspen Parkland of western Canada constitutes a major portion of the agricultural areas of Manitoba, Saskatchewan and Alberta, with 86% of the forage production and 66% of the beef cattle herd. Although some areas still exist in the natural state, most of the Parkland has been cleared of aspen (Populus tremuloides Michx.) for farming. Introduced pasture species have been seeded, and bromegrass (Bromus inermis L.) and alfalfa (Medicago spp.) have been found to be the most productive. The addition of nitrogen and phosphorus fertilizer has been shown to nearly triple forage production in the presence of adequate moisture and favorable temperatures. Straight nitrogen has resulted in a reduction of the proportion of alfalfa in a mixed sward. The severity and time of grazing have a marked effect on pasture productivity. Bush pastures can be renovated by using selective herbicides, fire and controlled grazing to manage woody brush regrowth or by sod seeding of alfalfa in the depleted stands. Spring-seeded winter cereals can be grazed throughout the growing season or as part of a grazing rotation with perennial forages by extending the grazing season in the fall. Key words: Aspen Parkland, pasture, forage, research, review


1962 ◽  
Vol 94 (5) ◽  
pp. 555-560 ◽  
Author(s):  
J.R. Vockeroth ◽  
W.R.M. Mason ◽  
R.H. Wigmore ◽  
W.J. Brown ◽  
J.A. Downes ◽  
...  

1971 ◽  
Vol 28 (3) ◽  
pp. 311-321 ◽  
Author(s):  
R. Stewart Anderson

Investigations of crustacean plankton communities in 146 alpine and subalpine waters in some western Canadian national parks and environs showed that species composition varied little from year to year and that there was a mean of 2.93 species per community Diaptomus arcticus occurred in 60% of the communities. More cladoceran species than copepod species were found, but there were usually more copepod than cladoceran species in a community. Many of the species found in subalpine waters did not occur in alpine waters, where they were probably limited more by physical factors — such as temperature and morphometry — and the presence of large predators than by altitude. Except for anostracans, few species seemed to be restricted to either lakes or ponds in the study area. Congeneric occurrences of large cladocerans or nonpredaceous diaptomid copepods were uncommon, as were co-occurrences of large cladocerans and nonpredaceous diaptomids.


1990 ◽  
Vol 64 (4) ◽  
pp. 614-628 ◽  
Author(s):  
Jed Day

The Upper Devonian (Frasnian) conodont fauna of the Lime Creek Formation of north-central Iowa is dominated by species of Polygnathus. Patterns of species composition and abundance are consistent with the Polygnathus biofacies described from the Frasnian of the Northwest Territories of western Canada. Consequently, the standard Frasnian conodont zones, defined on sequences developed in the Palmatolepis biofacies, are not applicable to the Lime Creek sequence. The Lime Creek conodont sequence correlates with Zones 4, 5 and Faunal Interval 7 of the Frasnian conodont sequence in the Alberta Rockies and with similar sequences in the southwestern United States. The Pb elements of Palmatolepis semichatovae Ovnatanova and Ancyrognathus? deformis (Anderson) are described and illustrated for the first time.In the Lime Creek Formation of north-central Iowa, brachiopods of the lowermost part of the Nervostrophia thomasi Zone of Day (1989a) occur in Zone 4, brachiopods of most of the N. thomasi, Douvillina arcuata, and Cyrtospirifer whitneyi Zones span conodont Zone 5, and the Elita inconsueta and Iowatrypa owenensis Zones occur in Faunal Interval 7. Species of the ammonoid Manticoceras and of the gastropods Floyda, Turbonopsis, and Westerna are restricted to Faunal Interval 7. Species of the calcareous foraminifer Nanicella first occur in Zone 5, and are joined by species of Multiseptida high in Zone 5.


2008 ◽  
Vol 88 (1) ◽  
pp. 19-28 ◽  
Author(s):  
D. H. McCartney ◽  
H. A. Lardner ◽  
F. C. Stevenson

Annual ryegrass or Italian ryegrass (Lolium multiflorum) can be used to improve pasture productivity through extension of the grazing season in the Aspen parkland of western Canada. A study conducted at Agriculture and Agri Food Canada Melfort, SK. and Lacombe, AB, showed that weaned calves could successfully graze Italian ryegrass late into the fall as part of the overall backgrounding system. Spring-seeded annual Italian ryegrass produced between 4300 and 6700 kg total dry matter per hectare across all sites and had an average crude protein content of 184 g kg-1 and in vitro DM digestibility of 640 g kg-1. Spring calves were early weaned in late August or conventionally weaned in October and backgrounded on Italian ryegrass pasture or a silage-based ration in drylot pens. The cost of growing Italian ryegrass was $339 ha-1 resulting in a grazing cost per day of $0.31–$0.68 depending upon the number of grazing days per ha. There were no differences in performance of animals backgrounded on Italian ryegrass pasture compared with those backgrounded in the feedlot. The total cost per head for backgrounding early-weaned calves on Italian ryegrass and finished in a feedlot was $398 compared with $429 for early-weaned calves backgrounded and finished in a feedlot, while conventionally weaned calves backgrounded and finished in a feedlot cost $418. Backgrounding calves on Italian ryegrass pasture reduced the number of days in the feedlot along with the associated cost of yardage and stored feed. Backgrounding calves in a feedlot had a yardage charge of $0.40 or higher, which added a cost in addition to stored feed costs of the ration. Backgrounding calves on extended season grazing of Italian ryegrass reduced health problems due to elimination of mixing animals in feedlot pens, less need for stored feed including storage and feeding losses and less labour to feed the cattle and haul manure in the spring. Backgrounding calves on high-quality fall pasture was more economical than backgrounding in a feedlot system. Key words: Background, steer, pasture, economics


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