SEE-U 2000: Atlantic Forest - Module 4:Exercise 4

Exercise Contents:

• | Your Questions
• | Background
• | Your Assignment
• | Methodology
• | Objectives
• | Key Skills
• | Timetable
• | Materials Needed

Exercise Contents:
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# Atlantic Forest ## Exercise 4: Population Size in Habitats of Different Area Module 4: Growth and Competition: Population and Metapopulation Dynamics
Printer format ### Your Questions Does population size change in response to changes in habitat? ### Background The study of the population size, structure and dynamics is fundamental for understanding how to conserve and manage any species. In many tropical ecosystems populations are relatively small, especially for insects, except under special conditions. There are several problems associated with small populations and a discussion of these can be found in your text (Wilson and Perlman). Estimating population size requires counting the number of individuals present in a certain area, or population density. The method of obtaining this data will of course vary with the particular species being studied. For plant species, the usual method is through placement of quadrats and measuring and counting all the individuals inside the quadrats. For sessile animals, this method also works well. However, for many animals the usual technique for estimating population size is by capture and recapturing individuals. To study population dynamics, aside from collection of data on the number of individuals, other data required are the population structure, rates of population growth, mortality and recruitment. With these data it is possible to construct models, using matrixes, to predict future trends in population density. In this lab we will look at population size of species in relation to the size of their local habitat and build a simple model of population growth. ### Your Assignment Estimate population size for species in habitat patches of different sizes Build a simple population growth model ### Methodology Task A—Select sampling areas Using maps, select areas of similar habitat, but with different total area Select the species to use for data collection Task B—Estimate population size Collect data on population size, either quadrat sampling or capture and re-capture Task C—Data analysis Data entry into computer Calculate population size estimates Compare population size among sites sampled Task D—Study population growth Build a model of population growth for the studied species (with Stella) ### Objectives Estimate the population size of several species Introduce basic concepts of population structure and dynamics Introduce population sampling techniques Introduce a modeling technique (Stella) ### Key Skills Learn methods for estimation of population size Become familiar with population dynamics models Use of a modeling program (Stella) ### Timetable Total time—2 days Morning—Day 1 Select species to sample Select sampling areas Begin data collection Afternoon—Day 1 Continue data collection Study population dynamics model Morning—Day 2 Terminate data collection, if necessary Data entry and analysis Build a population growth model Afternoon—Day 2 Data entry and analysis, if needed Work on population growth model Write up activity and discussion ### Materials Needed Local maps Field notebook and writing equipment Tape measures (50 m) Compass and GPS Material for establishing quadrats (stakes, string, flagging) Collection or observation equipment for studied species Equipment for marking captured individuals