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Positive feedback of consumer population density on resource supply
T S Bianchi1, C G Jones, M Shachak
1the Institute of Ecosystem Studies, The New York Botanical Garden, Millbrook, NY 12545, USA.
Trends in Ecology & Evolution
|January 14, 2011
Summary
Animal populations can benefit from increased resources at higher densities, leading to better individual fitness. These positive density-dependent feedbacks can explain social behavior and higher population levels.
Area of Science:
- Ecology
- Population Dynamics
- Behavioral Ecology
Background:
- Recent research indicates positive density-dependent feedbacks between animal populations and their resources.
- These feedbacks enhance individual fitness at high population densities.
- Such phenomena are observed in diverse organisms lacking strong social structures.
Purpose of the Study:
- To investigate the mechanisms and implications of positive density-dependent feedbacks in animal populations.
- To explore how these feedbacks influence population dynamics and individual fitness.
- To provide a resource-based explanation for the evolution of social behavior.
Main Methods:
- Experimental manipulation of resource availability.
- Experimental manipulation of animal population density.
- Analysis of correlations between resource abundance and population density in natural settings.
Main Results:
- Positive feedbacks were detected through experimental manipulations, not just correlations.
- These feedbacks can lead to increased equilibrium population densities.
- They alter the conditions under which intraspecific competition becomes apparent.
Conclusions:
- Positive density-dependent feedbacks play a significant role in regulating animal populations.
- These feedbacks offer a resource-driven explanation for the evolution of gregariousness.
- Understanding these mechanisms is crucial for predicting population dynamics and social evolution.
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