Recapitulation: Population Size and Population Changes

1991 ◽  
pp. 149-153
Author(s):  
Krystyna Falińska
Keyword(s):  
Population Size ◽  
Population Changes

scholarly journals The Dynamics of Changes in the Amphibian (Amphibia) Population Size in the Masurian Landscape Park Monitoring Results of Spring Migration Monitoring from the Years 2011–2019

2020 ◽  
Vol 31 (4) ◽  
pp. 8-16
Author(s):  
Wojciech Gotkiewicz ◽  
Krzysztof Wittbrodt ◽  
Ewa Dragańska
Keyword(s):  
Population Size ◽  
Biological Diversity ◽  
Iucn Red List ◽  
Red List ◽  
Spring Migration ◽  
Clear Correlation ◽  
Population Changes ◽  
Amphibian Species ◽  
Research Activities ◽  
Dynamics Of Population

Abstract The study presents the results of nine-year-long monitoring of the population size of amphibians (Amphibia) as one of the indicator communities used to assess the biological diversity level. The study was conducted in the Masurian Landscape Park located in Warmińsko-MazurskieVoivodeship. The obtained results demonstrated that 13 out of the 18 domestic amphibian species occurred in the area selected for research activities, including the species entered in the IUCN Red List. No clear correlation was found between the dynamics of population changes and the environmental, primarily climatic, determinants.

Multiple Scotlands

2018 ◽  
Author(s):  
Michael Anderson ◽  
Corinne Roughley
Keyword(s):  
Population Size ◽  
Rural Areas ◽  
Large Scale ◽  
Minimum Size ◽  
Agricultural Activity ◽  
Population Changes ◽  
Remote Areas ◽  
Urbanized Areas ◽  
Agrarian Systems ◽  
Over Time

The parish database shows major variations in trends and timings of population changes in less urbanized areas of Scotland. Even within parishes, people increasingly concentrated into larger villages and towns at the expense of more remote areas. The critical minimum size for settlements increased over time, but depended on distance from other larger places and on whether a locality became more than just a centre for agricultural activity. Mining and factory industry were key sources of growth even in many rural areas but caused major legacy problems as they collapsed. Fishing and its related activities increasingly concentrated on a small number of large centres. Transport hubs, administrative and school infrastructure, and large-scale retail facilities were dependent on, but also supported, population size. Agrarian systems varied widely across Scotland and each produced its own pattern of population sex ratios, migration, and change.

Ten years of the resource-based habitat paradigm: the biotope-habitat issue and implications for conserving butterfly diversity

2014 ◽  
Vol 2 (8) ◽  
pp. 1 ◽  
Author(s):  
Roger L. H. Dennis ◽  
Leonardo Dapporto ◽  
John W. Dover
Keyword(s):  
Population Size ◽  
Basic Problem ◽  
Population Distribution ◽  
Range Size ◽  
Population Status ◽  
Population Changes ◽  
Butterfly Diversity ◽  
The Status ◽  
Species Evolution ◽  
Habitat Parameters

The widely used term ‘habitat’ underlies all aspects of a species’ (and community’s) population size, consequently population changes, distribution and range size and changes; ultimately, habitat parameters determine the status of species, whether thriving or threatened with extinction. Habitat parameters also lie at the root of species’ evolution (speciation) involving cycles of resource specialism/generalism. A basic problem is that habitat has long been treated as synonymous with biotope. But, the two variable terms habitat and biotope describe very different phenomena and we make a case for clarity in the use of the term ‘habitat’, especially when the focus is conserving biodiversity. In this review, in reference to butterflies, we distinguish habitat from biotope as a real, grounded resources-based and conditions-based entity, and explain how usage of the terms greatly affects our perception of population status, and of population, distribution, range and speciation processes, central to conserving biodiversity.

scholarly journals The hitch-hiking effect of a favourable gene

1974 ◽  
Vol 23 (1) ◽  
pp. 23-35 ◽  
Author(s):  
John Maynard Smith ◽  
John Haigh
Keyword(s):  
Population Size ◽  
Large Population ◽  
Natural Populations ◽  
Population Changes ◽  
Average Heterozygosity ◽  
Gene Frequencies ◽  
Total Size ◽  
Long Run ◽  
Selective Substitution ◽  
Aggregate Effect

SummaryWhen a selectively favourable gene substitution occurs in a population, changes in gene frequencies will occur at closely linked loci. In the case of a neutral polymorphism, average heterozygosity will be reduced to an extent which varies with distance from the substituted locus. The aggregate effect of substitution on neutral polymorphism is estimated; in populations of total size 106 or more (and perhaps of 104 or more), this effect will be more important than that of random fixation. This may explain why the extent of polymorphism in natural populations does not vary as much as one would expect from a consideration of the equilibrium between mutation and random fixation in populations of different sizes. For a selectively maintained polymorphism at a linked locus, this process will only be important in the long run if it leads to complete fixation. If the selective coefficients at the linked locus are small compared to those at the substituted locus, it is shown that the probability of complete fixation at the linked locus is approximately exp (− Nc), where c is the recombinant fraction and N the population size. It follows that in a large population a selective substitution can occur in a cistron without eliminating a selectively maintained polymorphism in the same cistron.

scholarly journals Long-term and large-scale multispecies dataset tracking population changes of common European breeding birds

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Vojtěch Brlík ◽  
Eva Šilarová ◽  
Jana Škorpilová ◽  
Hany Alonso ◽  
Marc Anton ◽  
...  
Keyword(s):  
Population Size ◽  
Large Scale ◽  
Breeding Birds ◽  
Population Changes ◽  
Size Change ◽  
Relative Population ◽  
Bird Monitoring ◽  
Population Size Change ◽  
Country Specific

AbstractAround fifteen thousand fieldworkers annually count breeding birds using standardized protocols in 28 European countries. The observations are collected by using country-specific and standardized protocols, validated, summarized and finally used for the production of continent-wide annual and long-term indices of population size changes of 170 species. Here, we present the database and provide a detailed summary of the methodology used for fieldwork and calculation of the relative population size change estimates. We also provide a brief overview of how the data are used in research, conservation and policy. We believe this unique database, based on decades of bird monitoring alongside the comprehensive summary of its methodology, will facilitate and encourage further use of the Pan-European Common Bird Monitoring Scheme results.

scholarly journals Modeling the decline of the Porcupine Caribou Herd, 1989-1998: the importance of survival vs. recruitment

Rangifer ◽  
2003 ◽  
Vol 23 (5) ◽  
pp. 123
Author(s):  
Stephen M. Arthur ◽  
Kenneth R. Whitten ◽  
Francis J. Mauer ◽  
Dorothy Cooley
Keyword(s):  
Population Growth ◽  
Population Size ◽  
Rangifer Tarandus ◽  
Deterministic Model ◽  
Survival Rates ◽  
Adult Survival ◽  
Population Changes ◽  
Temporary Reduction

The Porcupine caribou (Rangifer tarandus granti) herd increased from approximately 100 000 animals during the 1970s to 178 000 in 1989, then declined to 129 000 by 1998. Our objective was to model the dynamics of this herd and investigate the potential that lower calf recruitment, as was observed during 1991-1993, produced the observed population changes. A deterministic model was prepared using estimates of birth and survival rates that reproduced the pattern of population growth from 1971-1989. Then, parameters were changed to simulate effects of lower calf recruitment and adult survival. Reducing recruitment for 3 years caused an immediate reduction in population size, but the population began to recover in 5-6 years. Even a dramatic temporary reduction in recruitment did not explain the continuing decline after 1995. In contrast, a slight but persistent reduction in adult survival caused a decline that closely followed the observed pattern. This suggests that survival of adults, and perhaps calves, has declined since the late 1980s.

Reduction of spermatogonia and testosterone in rat testes flown on space lab-3

1986 ◽  
Vol 44 ◽  
pp. 248-249
Author(s):  
Delbert E. Philpott ◽  
W. Sapp ◽  
C. Williams ◽  
T. Fast ◽  
J. Stevenson ◽  
...  
Keyword(s):  
Social Interaction ◽  
Social Status ◽  
Population Size ◽  
Physiological Response ◽  
Social Rank ◽  
Reproductive Function ◽  
Testicular Development ◽  
Organ Weights ◽  
Reproductive Maturation ◽  
Metabolic Activities

Space Lab 3 (SL-3) was flown on Shuttle Challenger providing an opportunity to measure the effect of spaceflight on rat testes. Cannon developed the idea that organisms react to unfavorable conditions with highly integrated metabolic activities. Selye summarized the manifestations of physiological response to nonspecific stress and he pointed out that atrophy of the gonads always occurred. Many papers have been published showing the effects of social interaction, crowding, peck order and confinement. Flickinger showed delayed testicular development in subordinate roosters influenced by group numbers, social rank and social status. Christian reported increasing population size in mice resulted in adrenal hypertrophy, inhibition of reproductive maturation and loss of reproductive function in adults. Sex organ weights also declined. Two male dogs were flown on Cosmos 110 for 22 days. Fedorova reported an increase of 30 to 70% atypical spermatozoa consisting of tail curling and/or the absence of a tail.

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