"changes in population size" is a correct and usable phrase.
You can use it when you are referring to the fluctuations in the size of a population over a certain period of time. For example: "A number of factors, such as natural disasters and epidemic diseases, can lead to drastic changes in population size."
Human populations have undergone major changes in population size in the past 100,000 years, including recent rapid growth.
Abundance indices are widely used to study changes in population size in wildlife management.
The changes in population size of carabid beetles inhabiting an ancient woodland were analysed in a long-term investigation covering a period of nine years (1994 2002).
We used the robust asymmetrical before-after-control-impact (BACI) design to evaluate changes in population size for fishery target species four years after designation.
Moreover, we used Bayesian skyline plots, tests of neutrality and mismatch distributions to assess the potential changes in population size through time.
Instead, methods relying on allele frequency must be used – which are vulnerable to the fact that frequency patterns produced by selection can also be produced by demographic processes such as changes in population size and genetic drift.
Yet, the two latter forces are the most important ones when inferring population history as they reflect changes in population size and migration patterns during different phases of history.
Rapid changes in population size during past glacial cycles have been related to processes of strong genetic drift (Knowles and Richards 2005).
However, these models explained population dynamics during the years in which data were collected; observed changes in population size during the data-collection period were strongly positively correlated with population growth rate.
In this work, we carried out simulations with WMN-GA system to see effect of changes in population size and number of generations for node placement problem in WMNs.
The increase in numbers of incidents post World War II could suggest there is a worsening volcanic safety record, but alternatively this may reflect improved reporting and changes in population size and distribution.
