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Population dynamical consequences of gregariousness in a size-structured consumer-resource interaction.
Tobias van Kooten1, Lennart Persson, André M de Roos
1Department of Ecology and Environmental Science, Umeå University, Sweden. tobias.v.kooten@emg.umu.se
Journal of Theoretical Biology
|January 24, 2007
Summary
Group living in animals increases competition and life-history variation. Reduced gregariousness synchronizes consumer life-histories, reduces habitat heterogeneity, and leads to predictable population cycles.
Area of Science:
- Ecology
- Population Dynamics
- Behavioral Ecology
Background:
- Many animal species exhibit group living, which can intensify intra-group competition.
- Variation in competition intensity within groups may drive life-history variability among groups.
- Existing models of physiologically structured populations typically predict single generation cycles driven by competition.
Purpose of the Study:
- To investigate how gregariousness (group living tendency) affects population dynamics.
- To understand the interplay between group living, resource availability, and life-history variation.
- To explore the impact of habitat heterogeneity and individual life-history variability on population dynamics.
Main Methods:
- A size-structured consumer population with limited mobility was modeled in a spatially explicit environment.
- Gregariousness of the consumer population was systematically varied.
- The effects on population dynamics were analyzed through resource dynamics and consumer life-history traits.
Main Results:
- High gregariousness resulted in significant spatial resource variation and highly variable individual life-histories, leading to stochastic population dynamics.
- Reduced gregariousness led to synchronized consumer life-histories, decreased habitat heterogeneity, and the emergence of single generation cycles.
- These findings suggest a strong link between group living, resource dynamics, and population-level predictability.
Conclusions:
- Group living, through its influence on resource competition and life-history synchrony, significantly shapes population dynamics.
- Habitat heterogeneity and life-history variability are key mediators of population dynamics in group-living species.
- Population dynamical feedbacks are crucial for understanding the ecological significance of group living in nature.
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