Chapter 4 - Absolute population estimates by sampling a unit of habitat: air, plants, plant products and vertebrate hosts.

This chapter describes the techniques that may be used for sampling animals from the air, from plants and from vertebrate hosts. This is one of four approaches to the absolute population estimate; the other three methods being (i) distance or nearest neighbour, (ii) mark-recapture and (iii) removal trapping . In this approach the habitat is sampled together with the animals it contains. Hence two separate measurements have to be made: the total number of animals in the unit of the habitat sampled and the total number of these units in the whole habitat of the population being studied. The second may involve the use of the techniques of the botanist, forester, surveyor or hydrologist and cannot be considered in detail here. The first concerns the extraction of animals from the samples and sometimes the taking of samples; this and the next two chapters will be concerned mainly with these problems in five habitats, two biotic (plants and vertebrate hosts) and three physical (air, soil and water).

4.1. Sampling from the air 4.1.1. Sampling apparatus 4.1.2. Rotary and other traps 4.1.3. Comparison and efficiencies of the different types of suction traps 4.1.4. Conversion of catch to aerial density 4.1.5. Conversion of density to total aerial population 4.2. Sampling from plants 4.2.1. Assessing the plant 4.2.2. Determining the numbers of invertebrates 4.2.3. Special sampling problems with animals in plant material 4.3. Sampling from vertebrate hosts 4.3.1. Sampling from living hosts 4.3.2. Sampling from dead hosts 4.3.3. Sampling from vertebrate homes