Patterns of mouflon (Ovis gmelini) survival under moderate environmental conditions: effects of sex, age, and epizootics

1997 ◽  
Vol 75 (11) ◽  
pp. 1867-1875 ◽  
Author(s):  
N. Cransac ◽  
A. J. M. Hewison ◽  
M. L. Maublanc ◽  
J. M. Gaillard ◽  
J. M. Cugnasse
Keyword(s):  
Sexual Selection ◽  
Environmental Conditions ◽  
Resource Limitation ◽  
Density Dependent ◽  
Annual Survival ◽  
Survival Probabilities ◽  
Capture Recapture ◽  
Stochastic Events ◽  
The Impact ◽  
Dimorphic Species

We estimated survival probabilities over a 9-year period for an introduced population of Mediterranean mouflon (Ovis gmelini), applying capture – recapture models to resighting data from individually marked animals. Survival was high and constant among lambs, yearling males, and adults of both sexes, and we were unable to detect senescence among old animals. Survival of female yearlings varied widely among years. No difference in survival probabilities between the sexes was detected, indicating that the survival costs of sexual selection were low in this dimorphic species. We suggest that these results may be explained by a lack of limiting conditions on this study site. An outbreak of keratoconjunctivitis during the rut of 1993 caused a marked fall in annual survival for both sexes. Among males, this decline was constant for all ages (approximately 23%), but for females the impact of the disease varied in relation to age, with young ewes particularly affected. Otherwise, the population appears to be stable and we hypothesise that the removal of animals for export and through hunting, together with stochastic events such as periodic epizootics, maintains mouflon numbers at a level where the influence of density-dependent resource limitation on survival is limited.

scholarly journals Annual survival probabilities of anadromous Arctic Char remain high and stable despite inter-annual differences in sea ice melt date

2021 ◽  
Author(s):  
Isabeau Caza-Allard ◽  
Marc J. Mazerolle ◽  
Les N Harris ◽  
Brendan Malley ◽  
Ross F. Tallman ◽  
...  
Keyword(s):  
Sea Ice ◽  
Survival Probability ◽  
Interannual Variation ◽  
Salvelinus Alpinus ◽  
Ice Cover ◽  
Arctic Char ◽  
Annual Survival ◽  
Survival Probabilities ◽  
Ice Melt ◽  
The Impact

Throughout their range, anadromous Arctic Char (Salvelinus alpinus) support commercial, recreational, and subsistence fisheries that are important economically, socially, and culturally yet drivers of interannual variation in survival in this species, however, remain poorly understood. Here, we aimed to quantify the impact of environmental and biological parameters on the survival probability of anadromous Arctic Char near the community of Cambridge Bay, Nunavut. To do so, we tracked 183 Arctic Char tagged with acoustic transmitters and used capture-mark-recapture methods to estimate survival probabilities over six years. Annual survival probabilities for individuals was high, varying between 0.79 and 0.88, whereas recapture probabilities varied between 0.64 and 0.90. Interannual variation in survival probability was low and neither the environmental (air temperature, sea ice cover) nor biological (sex) variables influenced survival probability. These estimates suggest that annual survival probability is high for anadromous adult Arctic Char in the Cambridge Bay area, despite clear differences in the ice cover melt date among years. These results further our understanding of the demographic parameters of Arctic Char in the region, which will be important for future assessments of the sustainability of commercial fisheries as well as for predicting population responses to a rapidly changing Arctic.

scholarly journals Morphological Variations of Wild Populations of Brycon dentex (Characidae, Teleostei) in the Guayas Hydrographic Basin (Ecuador). The Impact of Fishing Policies and Environmental Conditions

Animals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1901
Author(s):  
Ana Gonzalez-Martinez ◽  
Carmen De-Pablos-Heredero ◽  
Martin González ◽  
Jorge Rodriguez ◽  
Cecilio Barba ◽  
...  
Keyword(s):  
Discriminant Analysis ◽  
Environmental Conditions ◽  
Anthropogenic Activity ◽  
Freshwater Species ◽  
Fishing Pressure ◽  
Wild Populations ◽  
Morphometric Variation ◽  
Morphological Variations ◽  
Body Development ◽  
The Impact

The Guayas, located in Ecuador, is the largest basin in the Pacific Ocean and has an inventory of 123 native freshwater species. Most of these are endemic species that are threatened or at-risk due to anthropogenic activity and the modification, fragmentation, and destruction of habitats. The aim of this study was to determine the morphometric variation in three wild populations of Brycon dentex in the Guayas basin rivers and their connections to fishing management and environmental conditions. A total of 200 mature fish were captured, and 26 morphometric parameters were measured. The fishing policies (Hypothesis 1) and environmental conditions (Hypothesis 2) were considered fixed factors and were validated by t-tests. The morphological variation among the three populations (Hypothesis 3) was validated through a discriminant analysis. Fishing policies and resource management were found to generate morphological differences associated with body development. In addition, the environmental conditions were found to influence the size and structure of Brycon dentex populations. The analyzed populations were discriminated by the generated morphometric models, which differentiated Cluster 1 (Quevedo and Mocache rivers) with high fishing pressure from Cluster 2 (Pintado river) with medium–low fishing pressure. Morphometric differentiation by discriminant analysis is a direct and economic methodology that can be applied as an indicator of diversity maintenance.

ASSESSING ENVIRONMENTAL IMPACTS DURING NATURAL DISASTER: THE DEVELOPMENT OF A RAPID ENVIRONMENTAL ASSESSMENT METHODOLOGY

2002 ◽  
Vol 04 (04) ◽  
pp. 475-492 ◽  
Author(s):  
CHARLES KELLY
Keyword(s):  
Environmental Impact ◽  
Impact Assessment ◽  
Environmental Impact Assessment ◽  
Environmental Conditions ◽  
Environmental Damage ◽  
Assessment Procedure ◽  
Disaster Victims ◽  
Wide Range ◽  
Negative Impacts ◽  
The Impact

The linkages between disaster and environmental damage are recognized as important to predicting, preventing and mitigating the impact of disasters. Environmental Impact Assessment (EIA) procedures are well developed for non-ndisaster situations. However, they are conceptually and operationally inappropriate for use in disaster conditions, particularly in the first 120 days after the disaster has begun. The paper provides a conceptual overview of the requirements for an environmental impact assessment procedure appropriate for disaster conditions. These requirements are captured in guidelines for a Rapid Environmental Impact Assessment (REA) for use in disasters. The REA guides the collection and assessment of a wide range of factors which can indicate: (1) the negative impacts of a disaster on the environment, (2) the impacts of environmental conditions on the magnitude of a disaster and, (3) the positive or negative impacts of relief efforts on environmental conditions. The REA also provides a foundation for recovery program EIAs, thus improving the overall post disaster recovery process. The REA is designed primarily for relief cadres, but is also expected to be usable as an assessment tool with disaster victims. The paper discusses the field testing of the REA under actual disaster conditions.

PREDATION BY CALOSOMA SYCOPHANTA L. (COLEOPTERA: CARABIDAE): EVIDENCE FOR A LARGE IMPACT ON GYPSY MOTH, LYMANTRIA DISPAR L. (LEPIDOPTERA: LYMANTRIIDAE), PUPAE

1985 ◽  
Vol 117 (9) ◽  
pp. 1117-1126 ◽  
Author(s):  
Ronald M. Weseloh
Keyword(s):  
Gypsy Moth ◽  
Lymantria Dispar ◽  
Ground Level ◽  
Mortality Factor ◽  
Substantial Impact ◽  
Entire Study ◽  
Dispersal Potential ◽  
Capture Recapture ◽  
The Impact ◽  
Entire Study Area

AbstractThe impact of predation by Calosoma sycophanta L. on an increasing prey population was assessed by recapturing marked adult beetles, periodically observing tagged gypsy moth pupae, and examining gypsy moth pupal remains in different microhabitats. Adult beetles dispersed in random directions but many tended to remain near the trap at which they were originally caught, suggesting a low dispersal potential. About 75% of the adult beetles present in the plot on one day were still present the next day. Capture–recapture estimates suggested that there were at most about 250 male beetles and half as many females/ha in the plot. Calosoma larvae destroyed 70% of tagged gypsy moth pupae under burlap bands on tree trunks near ground level, which was much more than any other mortality factor. Although this percentage was the same when mortality was assessed by looking at pupal remains within 5 m of the ground on tree trunks, pupae higher in trees and on leaves were not attacked as frequently. On average, about 40% of the pupae present in the entire study area were destroyed by Calosoma larvae. Each female beetle in the site would have had to produce about 30 progeny to have this effect. These data suggest that a relatively low number of adult beetles can have a substantial impact on gypsy moth populations.

scholarly journals Ozone damage, detoxification and the role of isoprenoids – new impetus for integrated models

2016 ◽  
Vol 43 (4) ◽  
pp. 324 ◽  
Author(s):  
Supriya Tiwari ◽  
Rüdiger Grote ◽  
Galina Churkina ◽  
Tim Butler
Keyword(s):  
Stomatal Conductance ◽  
Environmental Conditions ◽  
Economic Losses ◽  
Plant Responses ◽  
Damage Scenarios ◽  
Biochemical Processes ◽  
Wide Range ◽  
Defence Responses ◽  
High Concentrations ◽  
The Impact

High concentrations of ozone (O3) can have significant impacts on the health and productivity of agricultural and forest ecosystems, leading to significant economic losses. In order to estimate this impact under a wide range of environmental conditions, the mechanisms of O3 impacts on physiological and biochemical processes have been intensively investigated. This includes the impact on stomatal conductance, the formation of reactive oxygen species and their effects on enzymes and membranes, as well as several induced and constitutive defence responses. This review summarises these processes, discusses their importance for O3 damage scenarios and assesses to which degree this knowledge is currently used in ecosystem models which are applied for impact analyses. We found that even in highly sophisticated models, feedbacks affecting regulation, detoxification capacity and vulnerability are generally not considered. This implies that O3 inflicted alterations in carbon and water balances cannot be sufficiently well described to cover immediate plant responses under changing environmental conditions. Therefore, we suggest conceptual models that link the depicted feedbacks to available process-based descriptions of stomatal conductance, photosynthesis and isoprenoid formation, particularly the linkage to isoprenoid models opens up new options for describing biosphere-atmosphere interactions.

scholarly journals Transgenerational effects modulate density-dependent prophylactic resistance to viral infection in a lepidopteran pest

2015 ◽  
Vol 11 (3) ◽  
pp. 20150012 ◽  
Author(s):  
Kenneth Wilson ◽  
Robert I. Graham
Keyword(s):  
Disease Resistance ◽  
Survival Rates ◽  
Post Challenge ◽  
Transgenerational Effects ◽  
Density Dependent ◽  
Offspring Fitness ◽  
Rearing Density ◽  
Lepidopteran Pest ◽  
The Impact ◽  
Resistance To Viral Infection

There is an increasing appreciation of the importance of transgenerational effects on offspring fitness, including in relation to immune function and disease resistance. Here, we assess the impact of parental rearing density on offspring resistance to viral challenge in an insect species expressing density-dependent prophylaxis (DDP); i.e. the adaptive increase in resistance or tolerance to pathogen infection in response to crowding. We quantified survival rates in larvae of the cotton leafworm ( Spodoptera littoralis ) from either gregarious- or solitary-reared parents following challenge with the baculovirus S. littoralis nucleopolyhedrovirus. Larvae from both the parental and offspring generations exhibited DDP, with gregarious-reared larvae having higher survival rates post-challenge than solitary-reared larvae. Within each of these categories, however, survival following infection was lower in those larvae from gregarious-reared parents than those from solitary-reared, consistent with a transgenerational cost of DDP immune upregulation. This observation demonstrates that crowding influences lepidopteran disease resistance over multiple generations, with potential implications for the dynamics of host–pathogen interactions.

Architecting Fail-Safe Supply Networks

2016 ◽  
Author(s):  
Shabnam Rezapour ◽  
Ramakrishnan S. Srinivasan ◽  
Jeffrey Tew ◽  
Janet K. Allen ◽  
Farrokh Mistree
Keyword(s):  
Service Level ◽  
Level Of Service ◽  
Supply Network ◽  
Flow Dynamic ◽  
Supply Networks ◽  
Uncertainty Sources ◽  
High Magnitude ◽  
Stochastic Events ◽  
Fail Safe ◽  
The Impact

A fail-safe network is one that mitigates the impact of different uncertainty sources and provides the most profitable level of service. This is achieved by having 1) a structurally fail-safe topology against rare but high magnitude stochastic events called disruptions and 2) an operationally fail-safe flow dynamic against frequent but low magnitude stochastic events called variations. A structurally fail-safe network should be robust and resilient against disruptions. Robustness and resilience respectively determine how well and how quickly disruptions are handled by the SN. Flow planning must be reliable in an operationally fail-safe supply network against variations to provide the most profitable service level to customers. We formulate the problem of designing/redesigning fail-safe supply networks as a compromise Decision Support Problem. We analyze the correlations among robustness, resilience, and profit for supply networks and propose a method for supply network managers to use when they need to find a compromise among robustness, resilience, and profit.

scholarly journals The Impact of Changing Environmental Conditions on the Retention of Heavy Metals Adsorbed by Pine Bark

2017 ◽  
pp. 278-284
Author(s):  
Oleksandr Khokhotva
Keyword(s):  
Heavy Metals ◽  
Environmental Conditions ◽  
Metal Removal ◽  
High Capacity ◽  
Pine Bark ◽  
Urea Solution ◽  
Metal Leaching ◽  
Total Efficiency ◽  
Runoff Water ◽  
The Impact

Landfills are widely used for the disposal of households' and industrial waste. Liquid landfill effluents contain heavy metals, are toxic to humans and ecosystems and have to be efficiently treated. One treatment option that is becoming popular is the reactive filter technology. The total efficiency of metal removal by a filter media greatly depends not only on adsorption itself, but also on the metal leaching from the adsorbent. The last parameter, in turn, may be dependant on changing environmental conditions since filters are usually located on open air and flow of contaminated water (landfill leachate, runoff water) has the intermittent nature. A filter material may dry, become frozen or stay wet, depending on a season. Previously adsorbed metals can leach from an adsorbent at the next flash of water, coming to water treatment facilities. Among others, pine bark has shown a high capacity to adsorb heavy metals from landfill leachates. In this study, pine bark has been pre-treated with urea-solution in order to increase its stability and adsorption properties. Within leaching experiments using either non-treated or pre-treated bark samples no significant influence of the changing environmental conditions on the extent of metal leaching was observed, though in most cases, metal leaching from wet bark samples exposed to freezing was somewhat higher. Zn leaching was the highest and Cu leaching the lowest for both NTB and UTB samples. The metal leaching from non-treated bark was several-fold higher compared to urea-treated bark. Possible mechanisms of barkurea interactions and reasons for enhanced metals adsorption by urea-modified bark are discussed.

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