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Page Share Cite Suggested Citation: Techniques for the Study of Primate Population Ecology. The National Academies Press. In this chapter the relationships between some of these variables are discussed in light of their influence in determining population size in relation to environmental factors.
Often, however, population size is expressed as a density, which is defined as the number of animals per unit area. Density is often converted to biomass by multiplying the number of individuals in the population by their average weight.
Accurate Determinants of Population Density and Growth estimates of biomass should take into account differences in the numbers of animals of different body sizes or ages in the popula- tion.
The weight of inert gut contents may be subtracted in estimates of mean weights. The biomass of a species roughly represents the amount of resources or energy that it extracts from an environment. Since species vary in body size, such interspecific comparisons based on numbers alone would be inadequate.
It is desirable to express den- sities in terms of biomass because it provides some measure of the importance or impact that a species has on an environment relative to other species. Comparisons of biomass can be made between different age classes within the same population e. Different methods for estimating densities and their correspon- ding biomasses are in use.
The following definitions are useful: Crude density refers to the number of animals within a defined geographic area without regard to the suitability of the area for supporting the species in question.
Estimates of crude density are useful only for reporting numbers of animals in a defined area, such as a game reserve or census plot. The area itself may encom- pass a diversity of habitats, some of which are totally unsuitable for the species in question.
Ecological density refers to the number of animals per unit area of suitable habitat. Estimates of ecological density may be higher than those of crude density if the latter incorporates areas not in- habited by the species of interest.
UsuaHy this requires a long-term intensive survey of a relatively small area of land. Eisenberg reviewed density estimates for neotropical primates made by 24 different authors. For meaningful com- parisons he found it useful to separate density estimates according to the method of data collection.
For example, for each of the following species the first and second values from each pair of den- sity estimates are based on the home range method and on a less intensive survey method, respectively: In each case the estimate of ecological density based on the home range method was greater than that based on a broader, less- intensive survey method.
Probably the latter method involves the risks of underestimating the number of animals occupying a large area and of incorporating habitats of variable suitability.Mark C. Foley () used Russian People’s longitudinal survey for studying determinants of unemployment in early studying relationship among economic growth, trade, foreigh direct investment(FDI) and unemployment in Taiwan.
The PG represent population growth, FDI is for Foreign Direct Investment and INR. Determinants of human population growth determinants, population density also presents a signiﬁcant factor for the levels and trends of human birth rates.
population growth rates, the speed of LDC fertility decline will . Finally, we will also analyse trends in population growth, their determinants and consequences. OBJECTIVES After studying this lesson, you will be able to: technology but the patterns of population distribution all over the world continues to reflect the influence of varied physical factors.
(i). Video: Population Change from Aging, Death, and Migration Fertility, mortality and migration are principal determinants of how a population can change, and they are at the very core of demographic.
This article throws light upon the top four determinants of population growth. The determinants are: 1. Fertility 2. Mortality 3. Life expectancy 4. Migration. Population Growth Determinant # 1.
Fertility: Fertility — occurrence of birth per year — is one of the most important indicators of population growth. Measures & Determinants of Human Fertility Basics Chapter Exam Instructions Choose your answers to the questions and click 'Next' to see the next set of questions.