Meningeal Worm in White-Tailed Deer in Northwestern Ontario and Moose Population Densities

1973 ◽  
Vol 37 (3) ◽  
pp. 327 ◽  
Author(s):  
Barry P. Saunders
Keyword(s):  
Population Densities ◽  
Northwestern Ontario ◽  
Moose Population

Depression of belowground respiration rates at simulated high moose population densities in boreal forests

Ecology ◽  
2009 ◽  
Vol 90 (10) ◽  
pp. 2724-2733 ◽  
Author(s):  
Inga-Lill Persson ◽  
Mats B. Nilsson ◽  
John Pastor ◽  
Tobias Eriksson ◽  
Roger Bergström ◽  
...  
Keyword(s):  
Boreal Forests ◽  
Population Densities ◽  
Respiration Rates ◽  
Belowground Respiration ◽  
Moose Population

MONITORING SPRUCE BUDWORM POPULATION DENSITY WITH SEX PHEROMONE TRAPS

1988 ◽  
Vol 120 (2) ◽  
pp. 175-183 ◽  
Author(s):  
C.J. Sanders
Keyword(s):  
Sex Pheromone ◽  
Population Density ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Pheromone Traps ◽  
Cooperative Research ◽  
Population Densities ◽  
Larval Population ◽  
Northwestern Ontario ◽  
Sex Pheromone Traps

AbstractAnnual catches of male spruce budworm (Choristoneura fumiferana [Clem.]) in sex pheromone traps over a 21-year period in northwestern Ontario were well correlated with larval population densities in each subsequent year (r2 = 81%). On the basis of the criterion of 3 successive years of increasing catches or a threshold of 50 moths per trap, warning of extensive defoliation could have been given 6 years in advance. In 18 plots in northwestern Ontario and 35 plots distributed throughout the province, coefficients of determination (r2) between catch and population density in the same generation ranged from 40 to 74% in 1982 and 1983, but fell below 23% in 1984 when population densities in many plots were high. Coefficients of determination between catch and population densities in the following generation (eggs or larvae) ranged from 41 to 62%. On the basis of several years of cooperative research, sex pheromone traps are now in operational use in eastern North America for monitoring spruce budworm populations.

scholarly journals MITE (ACARINA) POPULATIONS IN RING-BILLED GULL NESTS

1974 ◽  
Vol 106 (3) ◽  
pp. 319-327 ◽  
Author(s):  
R. Freitag ◽  
J. P. Ryder ◽  
P. Wanson
Keyword(s):  
Lake Superior ◽  
Egg Laying ◽  
Mite Population ◽  
Breeding Cycle ◽  
Nest Density ◽  
Population Densities ◽  
Egg Hatching ◽  
Northwestern Ontario ◽  
Larus Delawarensis ◽  
Nest Initiation

AbstractMites collected from 69 Larus delawarensis Ord nests on Granite Island, Lake Superior, northwestern Ontario, during the summers of 1972 and 1973 showed phenological relationships with the breeding cycle of the gulls. The populations of five selected mite genera varied in relation to nest initiation, egg laying, and egg hatching periods of the gulls. Moisture within the nests significantly affected mite population densities, whereas nest density did not.

Effects of Seed Treatments and a Soil-applied Nematicide on Corn Yields and Nematode Population Densities

2013 ◽  
Author(s):  
Gregory L. Tylka ◽  
Mychele Batista da Silva ◽  
Joel L. DeJong ◽  
Joshua L. Sievers ◽  
Ryan Rusk
Keyword(s):  
Nematode Population ◽  
Seed Treatments ◽  
Population Densities

scholarly journals Landscape heterogeneity buffers biodiversity of simulated meta-food-webs under global change through rescue and drainage effects

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Remo Ryser ◽  
Myriam R. Hirt ◽  
Johanna Häussler ◽  
Dominique Gravel ◽  
Ulrich Brose
Keyword(s):  
Habitat Fragmentation ◽  
Food Web ◽  
Food Webs ◽  
Landscape Heterogeneity ◽  
Landscape Connectivity ◽  
Biodiversity Loss ◽  
Mechanistic Explanation ◽  
Population Densities ◽  
Rescue Effect ◽  
Drainage Effect

AbstractHabitat fragmentation and eutrophication have strong impacts on biodiversity. Metacommunity research demonstrated that reduction in landscape connectivity may cause biodiversity loss in fragmented landscapes. Food-web research addressed how eutrophication can cause local biodiversity declines. However, there is very limited understanding of their cumulative impacts as they could amplify or cancel each other. Our simulations of meta-food-webs show that dispersal and trophic processes interact through two complementary mechanisms. First, the ‘rescue effect’ maintains local biodiversity by rapid recolonization after a local crash in population densities. Second, the ‘drainage effect’ stabilizes biodiversity by preventing overshooting of population densities on eutrophic patches. In complex food webs on large spatial networks of habitat patches, these effects yield systematically higher biodiversity in heterogeneous than in homogeneous landscapes. Our meta-food-web approach reveals a strong interaction between habitat fragmentation and eutrophication and provides a mechanistic explanation of how landscape heterogeneity promotes biodiversity.

scholarly journals The role of bacterial urease activity on the uniformity of carbonate precipitation profiles of bio-treated coarse sand specimens

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Charalampos Konstantinou ◽  
Yuze Wang ◽  
Giovanna Biscontin ◽  
Kenichi Soga
Keyword(s):  
Calcium Carbonate ◽  
Calcium Chloride ◽  
Urease Activity ◽  
Coarse Sand ◽  
Carbonate Precipitation ◽  
Population Densities ◽  
Carbonate Cements ◽  
Microbially Induced Carbonate Precipitation

AbstractProtocols for microbially induced carbonate precipitation (MICP) have been extensively studied in the literature to optimise the process with regard to the amount of injected chemicals, the ratio of urea to calcium chloride, the method of injection and injection intervals, and the population of the bacteria, usually using fine- to medium-grained poorly graded sands. This study assesses the effect of varying urease activities, which have not been studied systematically, and population densities of the bacteria on the uniformity of cementation in very coarse sands (considered poor candidates for treatment). A procedure for producing bacteria with the desired urease activities was developed and qPCR tests were conducted to measure the counts of the RNA of the Ure-C genes. Sand biocementaton experiments followed, showing that slower rates of MICP reactions promote more effective and uniform cementation. Lowering urease activity, in particular, results in progressively more uniformly cemented samples and it is proven to be effective enough when its value is less than 10 mmol/L/h. The work presented highlights the importance of urease activity in controlling the quality and quantity of calcium carbonate cements.

Sign in / Sign up

Export Citation Format

Share Document