Density dependence in group dynamics of a highly social mongoose, Suricata suricatta

• Published in: The Journal of animal ecology Vol. 81; no. 3; pp. 628 - 639
• Main Authors: Bateman, Andrew W., Ozgul, Arpat, Coulson, Tim, Clutton-Brock, Tim H.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing 01.05.2012; Blackwell Publishing Ltd; Blackwell
• Subjects: Animal and plant ecology; Animal behavior; Animal ecology; Animal, plant and microbial ecology; Animals; Behavior, Animal; Behavior, Animal - physiology; Beverton–Holt model; Biological and medical sciences; Conspecifics; Data processing; demographic decomposition; Demography; Density; Density dependence; Ecological modeling; Ecosystem; Emigration; Environmental conditions; environmental effects; environmental factors; Female; Fundamental and applied biological sciences. Psychology; General aspects; Group dynamics; Group size; Herpestes; Herpestidae; Herpestidae - physiology; Male; Mammalia; Modeling; Models, Biological; Mortality; Parametric models; physiology; Population Density; Population dynamics; Rain; Rainfall; Ricker model; Social Behavior; social structure; Subpopulations; Suricata suricatta; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Wildfowl; Fissipedia; Carnivora; Demography; Beverton-Holt model; Decomposition; environmental effects; demographic decomposition; Vertebrata; Mammalia; Ricker model; Dynamics; Density dependence; Models; Herpestes ichneumon
• ISSN: 0021-8790; 1365-2656; 1365-2656
• DOI: 10.1111/j.1365-2656.2011.01934.x

1. For social species, the link between individual behaviour and population dynamics is mediated by group-level demography. 2. Populations of obligate cooperative breeders are structured into social groups, which may be subject to inverse density dependence (Allee effects) that result from a dependence on conspecific helpers, but evidence for population-wide Allee effects is rare. 3. We use field data from a long-term study of cooperative meerkats (Suricata suricatta; Schreber, 1776) -a species for which local Allee effects are not reflected in population-level dynamics -to empirically model interannual group dynamics. 4. Using phenomenological population models, modified to incorporate environmental conditions and potential Allee effects, we first investigate overall patterns of group dynamics and find support only for conventional density dependence that increases after years of low rainfall. 5. To explain the observed patterns, we examine specific demographic rates and assess their contributions to overall group dynamics. Although per-capita meerkat mortality is subject to a component Allee effect, it contributes relatively little to observed variation in group dynamics, and other (conventionally density dependent) demographic rates -especially emigration -govern group dynamics. 6. Our findings highlight the need to consider demographic processes and density dependence in subpopulations before drawing conclusions about how behaviour affects population processes in socially complex systems.