Colonial, more widely distributed and less abundant bird species undergo wider population fluctuations independent of their population trend

Colonial, more widely distributed and less abundant bird species undergo wider population fluctuations independent of their population trend

Understanding temporal variability in population size is important for conservation biology because wide population fluctuations increase the risk of extinction. Previous studies suggested that certain ecological, demographic, life-history and genetic characteristics of species might be related to the degree of their population fluctuations. We checked whether that was the case in a large sampl...

Field observations on population fluctuations of chicory aphids 1970

When less is more: positive population-level effects of mortality.

Experimental and theoretical studies show that mortality imposed on a population can counter-intuitively increase the density of a specific life-history stage or total population density. Understanding positive population-level effects of mortality is advancing, illuminating implications for population, community, and applied ecology. Reconciling theory and data, we found that the mathematical ...

The trend of population aging and planning of health services for the elderly: A review study

Background & Aim: Ageing represents the accumulation of changes in a human being over time, and it is synonymous with the beginning of the age of 65.The purpose of this paper is to provide a picture of the growth of the elderly population in the world and planning and policies to provide health services to this category of the population. Methods: This study was conducted to review. There were...

Population Trend and Public Health in Japan **

The "population problem" is the most fundamental of the problems which confront the world today. In recently developing countries, the mortality rate was lowered after the war owing to the marked improvement of public health. The fertility rate remained uncontrolled at an extremely high level in these same countries. Furthermore, even in countries which now have high mortality, public health ac...