Cadmium in beavers translocated from the Elbe river to the rhine/meuse estuary, and the possible effect on population growth rate

1994 ◽  
Vol 27 (2) ◽  
Author(s):  
B.A. Nolet ◽  
V.A.A. Dijkstra ◽  
D. Heidecke
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Population Growth Rate ◽  
Elbe River ◽  
The Elbe River

scholarly journals Biological scaling in green algae: the role of cell size and geometry

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Helena Bestová ◽  
Jules Segrestin ◽  
Klaus von Schwartzenberg ◽  
Pavel Škaloud ◽  
Thomas Lenormand ◽  
...  
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Population Growth Rate ◽  
Internal Diffusion ◽  
Scaling Exponent ◽  
Power Scaling ◽  
Nutrient Distribution ◽  
Metabolic Scaling ◽  
Key Factor ◽  
Size And Morphology

AbstractThe Metabolic Scaling Theory (MST), hypothesizes limitations of resource-transport networks in organisms and predicts their optimization into fractal-like structures. As a result, the relationship between population growth rate and body size should follow a cross-species universal quarter-power scaling. However, the universality of metabolic scaling has been challenged, particularly across transitions from bacteria to protists to multicellulars. The population growth rate of unicellulars should be constrained by external diffusion, ruling nutrient uptake, and internal diffusion, operating nutrient distribution. Both constraints intensify with increasing size possibly leading to shifting in the scaling exponent. We focused on unicellular algae Micrasterias. Large size and fractal-like morphology make this species a transitional group between unicellular and multicellular organisms in the evolution of allometry. We tested MST predictions using measurements of growth rate, size, and morphology-related traits. We showed that growth scaling of Micrasterias follows MST predictions, reflecting constraints by internal diffusion transport. Cell fractality and density decrease led to a proportional increase in surface area with body mass relaxing external constraints. Complex allometric optimization enables to maintain quarter-power scaling of population growth rate even with a large unicellular plan. Overall, our findings support fractality as a key factor in the evolution of biological scaling.

Lessons from a century of conservation translocations

2021 ◽  
Author(s):  
Shane D Morris ◽  
Katherine E. Moseby ◽  
Barry W. Brook ◽  
Christopher N. Johnson
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Population Growth Rate ◽  
Historical Context ◽  
Extrinsic Factors ◽  
Global Database ◽  
Terrestrial Vertebrates ◽  
Failure Classification ◽  
High Population Growth ◽  
Number Of Individuals

Translocation—moving individuals for release in different locations—is among the most important conservation interventions for increasing or re-establishing populations of threatened species. However, translocations often fail. To improve their effectiveness, we need to understand the features that distinguish successful from failed translocations. Here, we assembled and analysed a global database of translocations of terrestrial vertebrates (n=514) to assess the effects of various design features and extrinsic factors on success. We analysed outcomes using standardized metrics i.e. a categorical success/failure classification, and population growth rate. Probability of categorical success and population growth rate increased with the total number of individuals released but with diminishing returns above about 20-50 individuals. There has been no increase in numbers released per translocation over time. Positive outcomes—reported success and high population growth—were less likely for translocation in Oceania, possibly because invasive species are a major threat in this region and are difficult to control at translocation sites. Increased rates of categorical reported success and population growth were found for Europe and North America, suggesting the key role of historical context in positive translocation outcomes. Categorical success has increased throughout the 20th century, but that increase may have plateaued at about 75% since about 1990. Our results suggest there is potential for further increase in the success of conservation translocations. This could be best achieved by greater investment in individual projects, as indicated by total number of animals released.

scholarly journals Knowledge attitude and practice of contraception in Barabanki district of Uttar Pradesh: how far are we from meeting the unmet needs of contraception

2019 ◽  
Vol 8 (12) ◽  
pp. 4775
Author(s):  
Neha Thakur ◽  
Nahid Zia Khan ◽  
Narendra Rai
Keyword(s):  
Growth Rate ◽  
Family Planning ◽  
Population Growth ◽  
Population Growth Rate ◽  
Unmet Needs ◽  
Uttar Pradesh ◽  
Common Source ◽  
High Fertility ◽  
Barrier Method ◽  
College Hospital

Background: Barabanki one of the most populous districts of Uttar Pradesh with population growth rate being much higher than the national population growth rate. The objective of this study was to gain the knowledge about awareness and contraceptive practices in married women residing in Barabanki. To identify socio-demographic factors associated with unmet needs for contraceptionand also to ascertain the participation of husband in family planning.Methods: A cross sectional study was conducted in outpatient department of Obstetrics Gynecology and Department of Pediatrics in Medical college hospital in Barabanki. 144 females were enrolled in the study during the study period of one year. They were interviewed on the basis of a pre-structured proforma. Data obtained was then analyzed.Results: A total 144 women in the age group 18-45 years participated in the study of which 53% had knowledge of contraception. More than two thirds were not using any form of contraception. The most common method of contraception was barrier method followed by Depot medroxy progesterone acetate. Copper T was least used mode of contraception. The most common source of knowledge regarding contraception was from electronic media followed by friends and family. The most common reason behind the absence of contraception was lack of knowledge of contraception and husband disapproval.Conclusions: Poor knowledge of contraception led to decreased usage of contraceptive measures. Husband participation is virtually absent in family planning leading to high fertility. In order to make our family planning programs successful we must incorporate media for wider coverage to increase awareness and husbands for better implementation.

scholarly journals Beyond demographic buffering: Context dependence in demographic strategies across animals

2021 ◽  
Author(s):  
Omar Lenzi ◽  
Arpat Ozgul ◽  
Roberto Salguero-Gomez ◽  
Maria Paniw
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Temporal Variation ◽  
Population Growth Rate ◽  
Natural Populations ◽  
Environmental Context ◽  
Context Dependence ◽  
Vital Rate ◽  
Rate Variation ◽  
Vital Rates

Temporal variation in vital rates (e.g., survival, reproduction) can decrease the long-term mean performance of a population. Species are therefore expected to evolve demographic strategies that counteract the negative effects of vital rate variation on the population growth rate. One key strategy, demographic buffering, is reflected in a low temporal variation in vital rates critical to population dynamics. However, comparative studies in plants have found little evidence for demographic buffering, and little is known about the prevalence of buffering in animal populations. Here, we used vital rate estimates from 31 natural populations of 29 animal species to assess the prevalence of demographic buffering. We modeled the degree of demographic buffering using a standard measure of correlation between the standard deviation of vital rates and the sensitivity of the population growth rate to changes in such vital rates across populations. We also accounted for the effects of life-history traits, i.e., age at first reproduction and spread of reproduction across the life cycle, on these correlation measures. We found no strong or consistent evidence of demographic buffering across the study populations. Instead, key vital rates could vary substantially depending on the specific environmental context populations experience. We suggest that it is time to look beyond concepts of demographic buffering when studying natural populations towards a stronger focus on the environmental context-dependence of vital-rate variation.

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