Intra‐ and interspecific density‐dependent dispersal in an aquatic prey–predator system

Abstract

Summary1. Dispersal intensity is a key process for the persistence of prey-predator metacommunities. Consequently, knowledge of the ecological mechanisms of dispersal is fundamental to understanding the dynamics of these communities. Dispersal is often considered to occur at a constant per capita rate; however, some experiments demonstrated that dispersal may be a function of local species density. 2. Here we use aquatic experimental microcosms under controlled conditions to explore intra-and interspecific density-dependent dispersal in two protists, a prey Tetrahymena pyriformis and its predator Dileptus sp. 3. We observed intraspecific density-dependent dispersal for the prey and interspecific density-dependent dispersal for both the prey and the predator. Decreased prey density lead to an increase in predator dispersal, while prey dispersal increased with predator density. 4. Additional experiments suggest that the prey is able to detect its predator through chemical cues and to modify its dispersal behaviour accordingly. 5. Density-dependent dispersal suggests that regional processes depend on local community dynamics. We discuss the potential consequences of density-dependent dispersal on metacommunity dynamics and stability.

The effect of predator avoidance and travel time delay on the stability of predator-prey metacommunities

“…Predator-prey models based on demographic processes typically assume instantaneous and density-independent movement (Jansen 2001) on the same time scale as demographics. In contrast, predator avoidance or foraging behavior can trigger densitydependent movement on much faster timescales (Abdllaoui et al 2007;Hauzy et al 2007). In particular, the time to movement from a patch can be comparable to travel time between patches.…”

Influences of migrations from local competitive pressures on populations between patches

“…As a matter of fact, more and more researchers find that the dispersal rates of populations should be affected by many other factors such as the qualities and quantities of foods, the pressures from competitors and the predation risks of enemies. For example, Hauzy et al [7] observed that the dispersal of prey is influenced by its own density and predators' density, and the dispersal rate of predators is affected by prey's density. de Roos et al [6] and Persson et al [14] studied flexible behaviors in size-structured populations by assuming that the movement rate out of a patch is purely a function of fitness of individuals within that patch.…”

Population-level consequences of heterospecific density-dependent movements in predator–prey systems

“…In the majority of cases (Hassell 1971;Bernstein 1984;Kratz 1996;Maeda et al 1998;Zemek and Nachman 1998;Diehl et al 2000;French and Travis 2001;Hauzy et al 2007;Ohara and Takabayashi 2012), were the strength of the observed density dependence within the range for which our covariance approximation is accurate.…”