scholarly journals Forestry Practices in Québec and Ontario in Relation to Moose Population Dynamics

1988 ◽  
Vol 64 (3) ◽  
pp. 246-250 ◽  
Author(s):  
Michel Crête
Keyword(s):  
Population Dynamics ◽  
Forest Fires ◽  
Carrying Capacity ◽  
Timber Harvest ◽  
Deciduous Species ◽  
Potential Threat ◽  
Management Units ◽  
Forestry Practices ◽  
Moose Population ◽  
Role Management

Abundant forage, particularly twigs of deciduous species, represents the key element of K carrying capacity for moose. Forest fires previously created such quality habitat, while timber harvest should now play a comparable role. Management units for moose habitat should cover 40-50 km2. Hunting and predation represent the regulating factors of most moose populations in Québec and Ontario, so that habitat is only lightly used. This situation poses difficulties in evaluating the role played by forestry practices on population dynamics; however the logging of a new area, which creates accessibility and removes much cover, greatly exposes moose to hunting until regrowth again provides a visual screen. Moreover, the increasing use of herbicide in forestry, to eliminate deciduous species, represents a potential threat for moose habitat.

Population Dynamics of Limnetic Cladocera in a Beaver Pond

1975 ◽  
Vol 32 (3) ◽  
pp. 341-346 ◽  
Author(s):  
Judith K. Kwik ◽  
John C. H. Carter
Keyword(s):  
Population Dynamics ◽  
Embryonic Development ◽  
Carrying Capacity ◽  
Sampling Errors ◽  
Beaver Pond ◽  
Bosmina Longirostris ◽  
Georgian Bay ◽  
Development Times ◽  
Different Temperatures ◽  
Ceriodaphnia Quadrangula

In a small, shallow, predation free beaver pond near Georgian Bay, Ontario Ceriodaphnia quadrangula was monacmic and Daphnia ambigua and Bosmina longirostris triacmic. Each species peaked and declined rapidly, presumably overshooting the carrying capacity of a food limited environment. Embryonic development times of each species at different temperatures was determined in the laboratory and fitted with Bĕlahrádek’s function. Calculated instantaneous rates of birth and death were normal for D. ambigua and C. quadrangula but too low to account for the rapid fluctuations in numbers of B. longirostris, suggesting occasional gross sampling errors. Bosmina longirostris may periodically abandon the limnoplankton for a benthic existence thus avoiding capture.

scholarly journals Hierarchical modelling of temperature and habitat size effects on population dynamics of North Atlantic cod

2010 ◽  
Vol 67 (5) ◽  
pp. 833-855 ◽  
Author(s):  
Irene Mantzouni ◽  
Helle Sørensen ◽  
Robert B. O'Hara ◽  
Brian R. MacKenzie
Keyword(s):  
Population Dynamics ◽  
North Atlantic ◽  
Carrying Capacity ◽  
Size Effects ◽  
Atlantic Cod ◽  
Ecosystem Approach ◽  
Reproductive Rate ◽  
Model Parameters ◽  
Habitat Size ◽  
Hierarchical Modelling

Abstract Mantzouni, I., Sørensen, H., O'Hara, R. B., and MacKenzie, B. R. 2010. Hierarchical modelling of temperature and habitat size effects on population dynamics of North Atlantic cod. – ICES Journal of Marine Science, 67: 833–855. Understanding how temperature affects cod (Gadus morhua) ecology is important for forecasting how populations will develop as climate changes in future. The effects of spawning-season temperature and habitat size on cod recruitment dynamics have been investigated across the North Atlantic. Ricker and Beverton and Holt stock–recruitment (SR) models were extended by applying hierarchical methods, mixed-effects models, and Bayesian inference to incorporate the influence of these ecosystem factors on model parameters representing cod maximum reproductive rate and carrying capacity. We identified the pattern of temperature effects on cod productivity at the species level and estimated SR model parameters with increased precision. Temperature impacts vary geographically, being positive in areas where temperatures are <5°C, and negative for higher temperatures. Using the relationship derived, it is possible to predict expected changes in population-specific reproductive rates and carrying capacities resulting from temperature increases. Further, carrying capacity covaries with available habitat size, explaining at least half its variability across stocks. These patterns improve our understanding of environmental impacts on key population parameters, which is required for an ecosystem approach to cod management, particularly under ocean-warming scenarios.

scholarly journals A 25-years population dynamics of sika deer in Kyushu Island, Japan: Estimation using vector autoregressive spatiotemporal model and evaluation of a large-scale management

2021 ◽  
Author(s):  
Kei Suzuki ◽  
Yasumitsu Kuwano ◽  
Yuki Kanamori ◽  
Yohei Kawauchi ◽  
Yoshihiko Uchimura ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Density Dependence ◽  
Large Scale ◽  
Sika Deer ◽  
High Density ◽  
Management Units ◽  
Vector Autoregressive ◽  
Kyushu Island ◽  
Core Areas ◽  
Scale Management

Regional management of large herbivore populations is known to be effective in reducing local economic damages and conserving local endemic plants. However, herbivores often move across management areas, and the effect of population management on a large spatial scale is poorly understood, even though it is necessary to use a large-scale approach across multiple management units to implement appropriate management. In this study, to better understand large-scale management and improve management efficiency, we evaluated effects of large-scale management of a sika deer (Cervus nippon) population on Kyushu Island (approximately 36,750 km2) in Japan. We estimated the population dynamics and spatial distributions of the deer and evaluated the effects of harvests, density dependence, and climatic conditions on the population dynamics both across Kyushu Island and in smaller prefectural management units. Fecal pellet count surveys conducted from 1995 to 2019 and results from a vector autoregressive spatio-temporal model showed relatively stable population dynamics and four high-density core areas. No increasing or decreasing trends were observed in the population dynamics, even though harvesting increased annually until it reached about 110,000 in 2014, indicating that harvesting was not related to the population dynamics. In addition, although no effects of density dependence were confirmed, maximum snow depth during winter decreased deer density at the management unit scale. Harvesting represents a major source of mortality in the Kyushu Island population because of the absence of predators. Although, approximately 110,000 sika deer were harvested annually after 2014, it is surprising that the effect of harvesting on population dynamics was not significant. A main cause of no reduction of the population was that the population used to determine the harvest number was underestimated. In addition, it was indicated that multi-management units need to manage the core areas because the high-density core areas were located across a few management units. This study highlights the difficulties involved with wide-area management of large herbivores and points out the importance of accurate stock assessment, reduction of the risk of management failure, and cooperation among management units. Our research is an important contribution to the study of the effects of large-scale harvesting in a large geographic area.

Population Dynamics of Daphnia galeata mendotae as Modified by Chronic Cadmium Stress

1978 ◽  
Vol 35 (4) ◽  
pp. 461-469 ◽  
Author(s):  
J. S. Marshall
Keyword(s):  
Population Dynamics ◽  
Carrying Capacity ◽  
Brood Size ◽  
Lake Michigan ◽  
Cadmium Stress ◽  
Whole Body ◽  
Average Weight ◽  
Daphnia Galeata ◽  
Female Ratio ◽  
Daphnia Galeata Mendotae

Forty populations of Daphnia galeata mendotae were maintained for 22 wk (or until they became extinct) in a medium consisting of filtered Lake Michigan water to which Chlamydomonas reinhardi and different concentrations of a mixture of labelled (109Cd) plus stable CdCl2 were added 24 h before use. The medium was changed daily Monday through Fridays. Weekly determinations were made of total numbers, average individual dry weight, mean brood size, egg–female ratio, aborted eggs and embryos, and average whole-body 109Cd content. Chronic cadmium stress reduced the populations' average numbers and biomass, while it increased the populations' turnover rates, temporal variability, probability of extinction, and proportion of ovigerous females. For individuals there was increased prenatal mortality, reduced life expectancy, increased average weight, and increased brood size. Due to compensatory increases in the proportion of ovigerous females and mean brood size, the cadmium sensitivity of population attributes was considerably less than that of the most sensitive individual attribute, prenatal mortality. A linear relationship between population carrying capacity (relative mean numbers) and added cadmium concentration indicated that the effective concentration for a 50% reduction of carrying capacity (EC50) is 7.7 μg Cd/L and that for a 1% reduction (EC1) is 0.15 μg Cd/L. An increase of 0.15 μg Cd/L in Lake Michigan itself, barring synergistic interaction with other factors in the lake, would probably not have a detectable effect on the population dynamics of D. galeata mendotae. Key words: zooplankton dynamics, stress ecology, Daphnia galeata mendotae, cadmium, heavy metals, toxic substances, Laurentian Great Lakes

Approximation of K carrying capacity for moose in eastern Quebec

1989 ◽  
Vol 67 (2) ◽  
pp. 373-380 ◽  
Author(s):  
Michel Crête
Keyword(s):  
Carrying Capacity ◽  
Consumption Rate ◽  
Balsam Fir ◽  
Annual Production ◽  
Eastern North America ◽  
Forage Production ◽  
Deciduous Species ◽  
Block Boundary ◽  
Positive Linear Relationship ◽  
Annual Summer

Estimation of moose density ranged between 18 and 20 animals/10 km2 in a 120-km2 boreal area of eastern Quebec that has been excluded from hunting for many decades. Moose were sedentary; 81% of telemetry locations of 12 adults (6 of each sex) that were captured in the area were within the block boundary. Use of winter forage was low for balsam fir, but variable and relatively high (29%) for deciduous twigs. When pooling the present results with comparable studies done elsewhere in Quebec, a significant positive linear relationship was found between percent deciduous browse removal and moose density. Annual summer and winter forage production of deciduous species was low in the study area in comparison with other areas in Quebec; however, the situation was the reverse for balsam fir. The K carrying capacity was estimated to exceed 20 moose/10 km2 when considering actual density in the study area. The same conclusion was reached by comparing forage consumption rate by moose for the whole winter and the annual production of 14 kg∙ha−1 of deciduous twigs. Daily forage needs versus annual production led to an unrealistic estimate of the K carrying capacity when also taking into account the annual production of balsam fir. Prime moose habitats in eastern North America probably possess comparable or higher K carrying capacities.

Using salvage logging and tolerance to risk to reduce the impact of forest fires on timber supply calculations

2015 ◽  
Vol 45 (4) ◽  
pp. 480-486 ◽  
Author(s):  
A. Leduc ◽  
P.Y. Bernier ◽  
N. Mansuy ◽  
F. Raulier ◽  
S. Gauthier ◽  
...  
Keyword(s):  
Forest Fires ◽  
Timber Harvest ◽  
Mitigation Measures ◽  
Class Structure ◽  
Forest Age ◽  
Timber Supply ◽  
Salvage Logging ◽  
Age Class ◽  
Burn Rate ◽  
The Impact

It is acknowledged that natural forest fires cannot and even should not be eliminated from the North American boreal forest. Forest fires produce immediate losses of wood volume, disrupt the conversion of the actual forest age structure into a target structure, and prevent planned timber supply (PTS) levels from being achieved. In this paper, we explore the extent to which periodic shortfalls in available timber under various burn rates can be mitigated through salvage logging and the tolerance of forest managers to a given level of shortfall, both as a function of forest age class structure. Simulations are done using both a deterministic and a stochastic representation of burn rate over time. Results show that the frequency of shortfall events can be reduced by salvage logging and by the introduction of measures that generate a tolerance to shortfall and that this mitigation potential is influenced by initial forest age class structure and burn rate. Results also show that even a 100% rate of salvage logging cannot fully compensate for timber losses to fire and eliminate fire-induced timber shortfalls. Furthermore, interannual burn rate variability reduces the efficiency of both mitigation measures. As the PTS is never realized under fire risk, the real cost of opting for different PTS scenarios should be estimated not from the difference in PTS but rather from the more realistic difference in realized timber harvest.

Echinococcus granulosus (Cestoda: Taeniidae) infections and moose – wolf population dynamics in southwestern Quebec

1989 ◽  
Vol 67 (1) ◽  
pp. 216-219 ◽  
Author(s):  
François Messier ◽  
Manfred E. Rau ◽  
Marilyn A. McNeill
Keyword(s):  
Population Dynamics ◽  
Echinococcus Granulosus ◽  
Definitive Host ◽  
Total Weight ◽  
Regulatory Effect ◽  
Wolf Population ◽  
Use Of Space ◽  
Wolf Predation ◽  
Aggregated Distribution ◽  
Moose Population

The prevalence, mean number, and mean total weight of Echinococcus granulosus cysts in the lungs of moose increased with moose density in southwestern Quebec. Such responses in the level of infection were documented in areas of 0.17, 0.23, and 0.37 moose/km2. The increase of E. granulosus infection in moose was attributed to higher densities of wolves, the definitive host of this parasite, as well as an accompanying increase in the rate of wolf predation upon moose. The aggregated distribution of this parasite within the moose population is considered to reflect the highly heterogeneous use of space by wolves and the consequent aggregated distribution of parasite eggs within the environment. A possible regulatory effect of E. granulosus infections on moose numbers is discussed.

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