Effects of individual condition and habitat quality on natal dispersal behaviour in a small rodent

Abstract

5Norsk Polarinstitutt, Seabird ecology and management, Polarmiljøsenteret, 9296 Tromsø, Norway Summary 1. Individuals should benefit from settling in high-quality habitats, but dispersers born under favourable conditions have a better physical condition and should therefore be more successful at settling in high-quality habitats. 2. We tested these predictions with root voles (Microtus oeconomus) by a manipulation of individual condition through litter-size enlargement and reduction during lactation combined with a manipulation of habitat quality through degradation of the vegetation cover. We accurately monitored movements of 149 juveniles during a settlement and breeding period of 3 months. 3. The litter size treatment had long-lasting effects on body size, life-history traits and home range size, but did not influence dispersal behaviour. 4. Different stages of dispersal were influenced by habitat quality. In low-quality patches, females dispersed earlier, spent more time prospecting their environment before settling, and settlers had a smaller adult body size than in high-quality patches. Preference and competition for high-quality patches is likely adaptive as it increased fitness both in terms of survival and reproduction. 5. We found no interactive effect of individual condition and habitat quality on natal dispersal and habitat selection. 6. These findings suggest that immediate conditions are more important determinants of dispersal decisions than conditions experienced early in life.

Effects of rearing conditions on natal dispersal processes in a long‐lived predator bird

“…In fact, several studies of mammals and birds have shown that parents cannot fully compensate for the increased energetic requirement of an enlarged brood (Monaghan, 2008; Rémy et al., 2011). Bonelli’s eagles usually lay one or two eggs (Real, 1991), so females have to face a trade‐off between forming one or two eggs at the time of egg formation.…”

“…An individual’s internal state can provide information on the fitness potential of its environment, thereby affecting its decision to stay or leave its natal area (Clobert et al., 2012). In other words, the costs and benefits of natal dispersal are influenced by the internal state of individuals and by environmental conditions experienced both in the natal area and in future breeding sites (Acker et al., 2018; Bonte et al., 2012; Bowler & Benton, 2005; Clobert et al., 2009; del Mar Delgado, Penteriani, Revilla, & Nams, 2010; Rémy, Le Galliard, Gundersen, Steen, & Andreassen, 2011). Thus, both modeling and empirical studies indicate that natal dispersal behavior often represents a plastic‐, phenotype‐, and condition‐dependent strategy (Bonte et al., 2012; Clobert et al., 2012; Rémy et al., 2011).…”

“…In addition, an understanding of the impact of rearing conditions may be highly useful in management and conservation, yet the potential consequences for future survival of offspring reared under poor environmental conditions are usually ignored. Conditions during early life vary owing to differences in parental and environmental quality (Sergio et al., 2009; Van De Pol, Bruinzeel, Heg, Van Der Jeugd, & Verhulst, 2006), and a large body of evidence exists to show that favorable rearing conditions are beneficial for individuals, particularly in short‐term effects such as increased juvenile survival (Rémy et al., 2011; Rödel et al., 2009). In this sense, Green and Cockburn (2001) and Sergio et al.…”

“…Less is known about the mid‐ and long‐term effects of rearing conditions on long‐lived species (Szostek & Becker, 2015), which include the complex set of processes that, together, conform natal dispersal, such as the probability of surviving until recruitment, that is, the entry of prebreeding birds into the breeding portion of the population (Green & Cockburn, 2001; Hernández‐Matías et al., 2010), the age at which individuals recruit (Acker et al., 2018; Grande et al., 2009; Hernández‐Matías, Real, Pradel, Ravayrol, Vincent‐Martin, 2011; Kokko & Sutherland, 1998), and the distance from the place of birth to the recruitment site, the so‐called natal dispersal distance (NDD) (Rémy et al., 2011; Stamps, 2006). This gap in our knowledge is understandable given that effects of rearing conditions are less pronounced during middle and late life stages (Van De Pol et al., 2006).…”

Comparing permeability of matrix cover types for the marsh rice rat (Oryzomys palustris)

“…Resistance can be measured as an individual's reluctance to cross a boundary, the physical cost of the movement, or increased mortality risk (Zeller et al 2012). Resistance can result from the perceived level of risk to entering the matrix (Fahrig 2007), the quality of the habitat being dispersed from (Roe et al 2009), or the social pressures pushing individuals to disperse (Remy et al 2011). By quantifying the resistance of landcover types in the matrix, researchers can predict the direction of dispersal in the landscape and estimate overall habitat connectivity (Ricketts 2001).…”