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Q44 - Regional vs Local Drivers of Species Diversity

Theoretical 1 Real exam question - full text reproduced under IBO's CC BY-NC-SA 4.0 license
Ecology

Regional species diversity in ecosystems usually increases with primary productivity while local species diversity does not show any defined relation with primary productivity. It suggests that different processes have distinctive influence on species diversity at regional and local scale. Figure illustrates four hypothesized mechanisms and their influence on alpha-diversity (mean local diversity) and beta-diversity (diversity in species composition between local sites). (HNDD: Interspecific negative population density dependence. CNDD: Intraspecific negative population density dependence.).

Figure 1. Figure 1.

Using the information and data, determine which of the statements are true or which are false.

A. Predators or pathogens specific to the dominant species will decrease alpha-diversity.
B. Increasing CNDD has a homogenizing effect on community composition among sites.
C. Regions with weak HNDD are expected to have higher degree of community differentiation.
D. Environmental perturbation acts in a fashion similar to effect of increasing CNDD on alpha and beta diversity.
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Question reproduced from IBO 2018, Theoretical Paper 1, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)