Prospecting and dispersal: their eco-evolutionary dynamics and implications for population patterns

Dispersal is not a blind process, and evidence is accumulating that individual dispersal strategies are informed in most, if not all, organisms. The acquisition and use of information are traits that may evolve across space and time as a function of the balance between costs and benefits of informed dispersal. If information is available, individuals can potentially use it in making better decisions, thereby increasing their fitness. However, prospecting for and using information probably entail costs that may constrain the evolution of informed dispersal, potentially with population-level consequences. By using individual-based, spatially explicit simulations, we detected clear coevolutionary dynamics between prospecting and dispersal movement strategies that differed in sign and magnitude depending on their respective costs. More specifically, we found that informed dispersal strategies evolve when the costs of information acquisition during prospecting are low but only if there are mortality costs associated with dispersal movements. That is, selection favours informed dispersal strategies when the acquisition and use processes themselves were not too expensive. When non-informed dispersal strategies evolve, they do so jointly with the evolution of long dispersal distance because this maximizes the sampling area. In some cases, selection produces dispersal rules different from those that would be ‘optimal’ (i.e. the best possible population performance—in our context quantitatively measured as population density and patch occupancy—among all possible individual movement rules) for the population. That is, on the one hand, informed dispersal strategies led to population performance below its highest possible level. On the other hand, un- and poorly informed individuals nearly optimized population performance, both in terms of density and patch occupancy.     

Gillespie eco‐evolutionary models (GEMs) reveal the role of heritable trait variation in eco‐evolutionary dynamics

Heritable trait variation is a central and necessary ingredient of evolution. Trait variation also directly affects ecological processes, generating a clear link between evolutionary and ecological dynamics. Despite the changes in variation that occur through selection, drift, mutation, and recombination, current eco‐evolutionary models usually fail to track how variation changes through time. Moreover, eco‐evolutionary models assume fitness functions for each trait and each ecological context, which often do not have empirical validation. We introduce a new type of model, Gillespie eco‐evolutionary models (GEMs), that resolves these concerns by tracking distributions of traits through time as eco‐evolutionary dynamics progress. This is done by allowing change to be driven by the direct fitness consequences of model parameters within the context of the underlying ecological model, without having to assume a particular fitness function. GEMs work by adding a trait distribution component to the standard Gillespie algorithm – an approach that models stochastic systems in nature that are typically approximated through ordinary differential equations. We illustrate GEMs with the Rosenzweig–MacArthur consumer–resource model. We show not only how heritable trait variation fuels trait evolution and influences eco‐evolutionary dynamics, but also how the erosion of variation through time may hinder eco‐evolutionary dynamics in the long run. GEMs can be developed for any parameter in any ordinary differential equation model and, furthermore, can enable modeling of multiple interacting traits at the same time. We expect GEMs will open the door to a new direction in eco‐evolutionary and evolutionary modeling by removing long‐standing modeling barriers, simplifying the link between traits, fitness, and dynamics, and expanding eco‐evolutionary treatment of a greater diversity of ecological interactions. These factors make GEMs much more than a modeling advance, but an important conceptual advance that bridges ecology and evolution through the central concept of heritable trait variation.     

Public information affects breeding dispersal in a colonial bird: kittiwakes cue on neighbours

Habitat selection and dispersal behaviour are key processes in evolutionary ecology. Recent studies have suggested that individuals may use the reproductive performance of conspecifics as a source of public information on breeding patch quality for dispersal decisions, but experimental evidence is still limited for species breeding in aggregates, i.e. colonial species. We addressed this issue by manipulating the local breeding success of marked individuals and that of their neighbours on a series of breeding patches of a colonial seabird, the black-legged kittiwake (Rissa tridactyla). Based on previous observations in this species, we predicted that individuals that lost their eggs on successful patches would attend their nest and come back to it the year after at a higher rate than individuals that lost their eggs on patches where their neighbours were also in failure. As predicted, the attendance of breeders and prospectors was strongly affected by the local level of breeding success, resulting in differential site fidelity and recruitment. This suggests that individuals used information conveyed by conspecific breeding performance to make decisions relative to breeding site selection. This process can amplify the response of these populations to environmental change and may have contributed to the evolution of colonial breeding.     

Predation-Related Costs and Benefits of Conspecific Attraction in Songbirds—An Agent-Based Approach

Songbirds that follow a conspecific attraction strategy in the habitat selection process prefer to settle in habitat patches already occupied by other individuals. This largely affects the patterns of their spatio-temporal distribution and leads to clustered breeding. Although making informed settlement decisions is expected to be beneficial for individuals, such territory clusters may potentially provide additional fitness benefits (e.g., through the dilution effect) or costs (e.g., possibly facilitating nest localization if predators respond functionally to prey distribution). Thus, we hypothesized that the fitness consequences of following a conspecific attraction strategy may largely depend on the composition of the predator community. We developed an agent-based model in which we simulated the settling behavior of birds that use a conspecific attraction strategy and breed in a multi-predator landscape with predators that exhibited different foraging strategies. Moreover, we investigated whether Bayesian updating of prior settlement decisions according to the perceived predation risk may improve the fitness of birds that rely on conspecific cues. Our results provide evidence that the fitness consequences of conspecific attraction are predation-related. We found that in landscapes dominated by predators able to respond functionally to prey distribution, clustered breeding led to fitness costs. However, this cost could be reduced if birds performed Bayesian updating of prior settlement decisions and perceived nesting with too many neighbors as a threat. Our results did not support the hypothesis that in landscapes dominated by incidental predators, clustered breeding as a byproduct of conspecific attraction provides fitness benefits through the dilution effect. We suggest that this may be due to the spatial scale of songbirds’ aggregative behavior. In general, we provide evidence that when considering the fitness consequences of conspecific attraction for songbirds, one should expect a trade-off between the benefits of making informed decisions and the costs of clustering.     

The ability of individuals to assess population density influences the evolution of emigration propensity and dispersal distance

We analyze the simultaneous evolution of emigration and settlement decisions for actively dispersing species differing in their ability to assess population density. Using an individual-based model we simulate dispersal as a multi-step (patch to patch) movement in a world consisting of habitat patches surrounded by a hostile matrix. Each such step is associated with the same mortality risk. Our simulations show that individuals following an informed strategy, where emigration (and settlement) probability depends on local population density, evolve a lower (natal) emigration propensity but disperse over significantly larger distances - i.e. postpone settlement longer - than individuals performing density-independent emigration. This holds especially when variation in environmental conditions is spatially correlated. Both effects can be traced to the informed individuals' ability to better exploit existing heterogeneity in reproductive chances. Yet, already moderate distance-dependent dispersal costs prevent the evolution of multi-step (long-distance) dispersal, irrespective of the dispersal strategy.     

The evolution of dispersal – the importance of information about population density and habitat characteristics

The evolution of mobility patterns and dispersal strategies depend on different population, habitat and life history characteristics. The ability to perceive and make use of information about the surrounding environment for dispersal decisions will also differ between organisms. To investigate the evolutionary consequences of such differences, we have used a simulation model with nearest-neighbour dispersal in a metapopulation to study how variation in the ability to obtain and make use of information about habitat quality and conspecific density affects the evolution of dispersal strategies. We found a rather strong influence of variation in information on the overall rate of dispersal in a metapopulation. The highest emigration rate evolved in organisms with no information about either density or habitat quality and the lowest rate was found in organisms with information about both the natal and the neighbouring patches. For organisms that can make use of information about conspecific density, positively density-dependent dispersal evolved in the majority of cases, with the strongest density dependence occurring when an individual only has information about density in the natal patch. However, we also identified situations, involving strong local population fluctuations and frequent local extinctions, where negatively density-dependent dispersal evolved.     

Information thresholds,habitat loss and population persistence in breeding birds

The combination of spatial structure and non‐linear population dynamics can promote the persistence of coupled populations, even when the average population growth rate of the patches seen in isolation would predict otherwise. This phenomenon has generally been conceptualized and investigated through the movement of individuals among patches that each holds many individuals, as in metapopulation models. However, population persistence can likewise increase as the result of individuals moving among sites (e.g. breeding territories) within in a single patch. Here I examine the latter: individuals making small‐scale informed decisions with respect to where to breed can promote population persistence in poor environments. Based on a simple algebraic model, I demonstrate information thresholds, and predict that greater information use is required for population persistence under lower spatial heterogeneity in habitat quality, all else equal. Second, I implement an individual‐based model to explore prior experience and prospecting on conspecific success within a more complex, and spatially heterogeneous environment. Uniquely, I jointly examine the effects of simulated habitat loss, spatial heterogeneity prior to habitat, and variation in information gathering on population persistence. I find that habitat loss accelerates population quasi‐extinction risk; however, information use reduces extinction probabilities in proportion to the level of information gathering. Per capita reproductive success declines with number of breeding sites, suggesting that information‐mediated Allee effects may contribute to extinction risk. In conclusion, my study suggests that populations in a changing world may be increasingly vulnerable to extinction where patch size and spatial heterogeneity constrain the effectiveness of information‐use strategies.     

Plasticity is a locally adapted trait with consequences for ecological dynamics in novel environments

Phenotypic plasticity is predicted to evolve in more variable environments, conferring an advantage on individual lifetime fitness. It is less clear what the potential consequences of that plasticity will have on ecological population dynamics. Here, we use an invertebrate model system to examine the effects of environmental variation (resource availability) on the evolution of phenotypic plasticity in two life history traits—age and size at maturation—in long‐running, experimental density‐dependent environments. Specifically, we then explore the feedback from evolution of life history plasticity to subsequent ecological dynamics in novel conditions. Plasticity in both traits initially declined in all microcosm environments, but then evolved increased plasticity for age‐at‐maturation, significantly so in more environmentally variable environments. We also demonstrate how plasticity affects ecological dynamics by creating founder populations of different plastic phenotypes into new microcosms that had either familiar or novel environments. Populations originating from periodically variable environments that had evolved greatest plasticity had lowest variability in population size when introduced to novel environments than those from constant or random environments. This suggests that while plasticity may be costly it can confer benefits by reducing the likelihood that offspring will experience low survival through competitive bottlenecks in variable environments. In this study, we demonstrate how plasticity evolves in response to environmental variation and can alter population dynamics—demonstrating an eco‐evolutionary feedback loop in a complex animal moderated by plasticity in growth.     

Fidelity and breeding probability related to population density and individual quality in black brent geese Branta bernicla nigricans

1. Patterns of temporary emigration (associated with non-breeding) are important components of variation in individual quality. Permanent emigration from the natal area has important implications for both individual fitness and local population dynamics. 2. We estimated both permanent and temporary emigration of black brent geese (Branta bernicla nigricans Lawrence) from the Tutakoke River colony, using observations of marked brent geese on breeding and wintering areas, and recoveries of ringed individuals by hunters. We used the likelihood developed by Lindberg, Kendall, Hines & Anderson 2001 (Combining band recovery data and Pollock's robust design to model temporary and permanent emigration. Biometrics, 57, 273-281) to assess hypotheses and estimate parameters. 3. Temporary emigration (the converse of breeding) varied among age classes up to age 5, and differed between individuals that bred in the previous years vs. those that did not. Consistent with the hypothesis of variation in individual quality, individuals with a higher probability of breeding in one year also had a higher probability of breeding the next year. 4. Natal fidelity of females ranged from 0.70 +/- 0.07-0.96 +/- 0.18 and averaged 0.83. In contrast to Lindberg et al. (1998), we did not detect a relationship between fidelity and local population density. Natal fidelity was negatively correlated with first-year survival, suggesting that competition among individuals of the same age for breeding territories influenced dispersal. Once females nested at the Tutakoke River, colony breeding fidelity was 1.0. 5. Our analyses show substantial variation in individual quality associated with fitness, which other analyses suggest is strongly influenced by early environment. Our analyses also suggest substantial interchange among breeding colonies of brent geese, as first shown by Lindberg et al. (1998).     

The evolution of dispersal distance in spatially-structured populations

Most evolutionary models of dispersal have concentrated on dispersal rate, with emigration being either global or restricted to nearest neighbours. Yet most organisms fall into an intermediate region where most dispersal is local but there is a wide range of dispersal distances. We use an individual-based model with 2500 patches each with identical local dynamics and show that the dispersal distance is under selection pressure. The dispersal distance that evolves is critically dependent on the ecological dynamics. When the cost of dispersal increases linearly with distance, selection is for short-distance dispersal under stable and damped local dynamics but longer distance dispersal is favoured as local dynamics become more complex. For the cases of stable, damped and periodic patch dynamics global patch synchrony occurs even with very short-distance dispersal. Increasing the scale of dispersal for chaotic local dynamics increases the scale of synchrony but global synchrony does not neccesarily occur. We discuss these results in the light of other possible causes of dispersal and argue for the importance of incorporating non-equilibrium population dynamics into evolutionary models of dispersal distance.     

Density-dependence across dispersal stages in a hermaphrodite land snail: insights from discrete choice models

Dispersal movements, i.e. movements leading to gene flow, are key behaviours with important, but only partially understood, consequences for the dynamics and evolution of populations. In particular, density-dependent dispersal has been widely described, yet how it is determined by the interaction with individual traits, and whether density effects differ between the three steps of dispersal (departure, transience, and settlement), remains largely unknown. Using a semi-natural landscape, we studied dispersal choices of Cornu aspersum land snails, a species in which negative effects of crowding are well documented, and analysed them using dispersal discrete choice models, a new method allowing the analysis of dispersal decisions by explicitly considering the characteristics of all available alternatives and their interaction with individual traits. Subadults were more dispersive than adults, confirming existing results. In addition, departure and settlement were both density dependent: snails avoided crowded patches at both ends of the dispersal process, and subadults were more reluctant to settle into crowded patches than adults. Moreover, we found support for carry-over effects of release density on subsequent settlement decisions: snails from crowded contexts were more sensitive to density in their subsequent immigration choices. The fact that settlement decisions were informed indicates that costs of prospecting are not as important as previously thought in snails, and/or that snails use alternative ways to collect information, such as indirect social information (e.g. trail following). The observed density-dependent dispersal dynamics may play an important role in the ability of C. aspersum to successfully colonise frequently human-disturbed habitats around the world.     

Individual heterogeneity in fitness in a long‐lived herbivore

Heterogeneity in the intrinsic quality and nutritional condition of individuals affects reproductive success and consequently fitness. Black brant (Branta bernicla nigricans) are long‐lived, migratory, specialist herbivores. Long migratory pathways and short summer breeding seasons constrain the time and energy available for reproduction, thus magnifying life‐history trade‐offs. These constraints, combined with long lifespans and trade‐offs between current and future reproductive value, provide a model system to examine the role of individual heterogeneity in driving life‐history strategies and individual heterogeneity in fitness. We used hierarchical Bayesian models to examine reproductive trade‐offs, modeling the relationships between within‐year measures of reproductive energy allocation and among‐year demographic rates of individual females breeding on the Yukon‐Kuskokwim Delta, Alaska, using capture–recapture and reproductive data from 1988 to 2014. We generally found that annual survival tended to be buffered against variation in reproductive investment, while breeding probability varied considerably over the range of clutch size‐laying date combinations. We provide evidence for relationships between breeding probability and clutch size, breeding probability and nest initiation date, and an interaction between clutch size and initiation date. Average lifetime clutch size also had a weak positive relationship with apparent survival probability. Our results support the use of demographic buffering strategies for black brant. These results also indirectly suggest associations among environmental conditions during growth, fitness, and energy allocation, highlighting the effects of early growth conditions on individual heterogeneity, and subsequently, lifetime reproductive investment.     

Informed dispersal in plants: Heterosperma pinnatum (Asteraceae) adjusts its dispersal mode to escape from competition and water stress

Informed‐dispersal theory (IDT) states that organisms may use information on the quality of the local environment when deciding whether to disperse or not. Dispersal is expected to occur from adverse patches where the costs of philopatry (lack of dispersal) are greater than those of dispersal. Evidence of informed dispersal in plants is scarce, and experiments under natural conditions are lacking. We tested IDT in a semiarid grassland using the annual forb Heterosperma pinnatum, which produces awned, zoochorous achenes and unawned, philopatric ones. We expected the proportion of awned seeds to increase under adverse conditions that reduce fitness, (i.e. under high competition and water stress). Heterosperma pinnatum was sown along natural moisture gradients with and without a shade that increased water availability. We found that competition (number of conspecific neighbors) and water stress reduced fitness. As expected, the proportion of highly dispersible seeds increased under such conditions, probably as a strategy to escape from unsuitable patches. Many plants species do not behave as expected by IDT. Our results suggest that experiments under natural conditions in systems where the assumptions of IDT are met may prove to be a wealthy source of evidence for informed dispersal in plants.     

Habitat choice stabilizes metapopulation dynamics by enabling ecological specialization

Dispersal is a key trait responsible for the spread of individuals and genes among local populations, thereby generating eco‐evolutionary interactions. Especially in heterogeneous metapopulations, a tight coupling between dispersal, population dynamics and the evolution of local adaptation is expected. In this respect, dispersal should counteract ecological specialization by redistributing locally selected phenotypes (i.e. migration load). Habitat choice following an informed dispersal decision, however, can facilitate the evolution of ecological specialization. How such informed decisions influence metapopulation size and variability is yet to be determined. By means of individual‐based modelling, we demonstrate that informed decisions about both departure and settlement decouple the evolution of dispersal and that of generalism, selecting for highly dispersive specialists. Choice at settlement is based on information from the entire dispersal range, and therefore decouples dispersal from ecological specialization more effectively than choice at departure, which is only based on local information. Additionally, habitat choice at departure and settlement reduces local and metapopulation variability because of the maintenance of ecological specialization at all levels of dispersal propensity. Our study illustrates the important role of habitat choice for dynamics of spatially structured populations and thus emphasizes the importance of considering that dispersal is often informed.     

Mechanistic modelling of animal dispersal offers new insights into range expansion dynamics across fragmented landscapes

Understanding and predicting the dynamics of range expansion is a major topic in ecology both for invasive species extending their ranges into non‐native regions and for species shifting their natural distributions as a consequence of climate change. In an increasingly modified landscape, a key question is ‘how do populations spread across patchy landscapes?‘ Dispersal is a central process in range expansion and while there is a considerable theory on how the shape of a dispersal kernel influences the rate of spread, we know much less about the relationships between emigration, movement and settlement rules, and invasion rates. Here, we use a simple, single species individual‐based model that explicitly simulates animal dispersal to establish how density‐dependent emigration and settlement rules interact with landscape characteristics to determine spread rates. We show that depending on the dispersal behaviour and on the risk of mortality in the matrix, increasing the number of patches does not necessarily maximise the spread rate. This is due to two effects: first, individuals dispersing at the expanding front are likely to exhibit lower net‐displacement as they typically do not travel far before finding a patch; secondly, with increasing availability of high quality habitat, density‐dependence in emigration and settlement can decrease the number of emigrants and their net‐displacement. The rate of spread is ultimately determined by the balance between net travelled distance, the dispersal mortality and the number of dispersing individuals, which in turn depend on the interaction between the landscape and the species’ dispersal behaviour. These results highlight that predicting spread rates in heterogeneous landscapes is a complex task and requires better understanding of the rules that individuals use in emigration, transfer and settlement decisions.     

Natal dispersal of Whooping Cranes in the reintroduced Eastern Migratory Population

Natal dispersal is a key demographic process for evaluating the population rate of change, especially for long‐lived, highly mobile species. This process is largely unknown for reintroduced populations of endangered avian species. We evaluated natal dispersal distances (NDD) for male and female Whooping Cranes (Grus americana) introduced into two locations in central Wisconsin (Necedah National Wildlife Refuge, or NNWR, and the Eastern Rectangle, or ER) using a series of demographic, spatial, and life history‐related covariates. Data were analyzed using gamma regression models with a log‐link function and compared using Akaike information criterion corrected for small sample sizes (AIC_c). Whooping Cranes released in the ER dispersed 261% further than those released into NNWR, dispersal distance increased 4% for each additional nesting pair, decreased about 24% for males as compared to females, increased by 21% for inexperienced pairs, and decreased by 3% for each additional year of age. Natal philopatry, habitat availability or suitability, and competition for breeding territories may be influencing observed patterns of NDD. Whooping Cranes released in the ER may exhibit longer NDD due to fragmented habitat or conspecific attraction to established breeding pairs at NNWR. Additionally, sex‐biased dispersal may be increasing in this population as there are more individuals from different natal sites forming breeding pairs. As the population grows and continues to disperse, the drivers of NDD patterns may change based on individual or population behavior.     

Age is not just a number—Mathematical model suggests senescence affects how fish populations respond to different fishing regimes

Senescence is often described as an age‐dependent increase in natural mortality (known as actuarial senescence) and an age‐dependent decrease in fecundity (known as reproductive senescence), and its role in nature is still poorly understood. Based on empirical estimates of reproductive and actuarial senescence, we used mathematical simulations to explore how senescence affects the population dynamics of Coregonus albula, a small, schooling salmonid fish. Using an empirically based eco‐evolutionary model, we investigated how the presence or absence of senescence affects the eco‐evolutionary dynamics of a fish population during pristine, intensive harvest, and recovery phases. Our simulation results showed that the presence or absence of senescence affected how the population responded to the selection regime. At an individual level, gillnetting caused a larger decline in asymptotic length when senescence was present, compared to the nonsenescent population, and the opposite occurred when fishing was done by trawling. This change was accompanied by evolution toward younger age at maturity. At the population level, the change in biomass and number of fish in response to different fishery size‐selection patterns depended on the presence or absence of senescence. Since most life‐history and fisheries models ignore senescence, they may be over‐estimating reproductive capacity and under‐estimating natural mortality. Our results highlight the need to understand the combined effects of life‐history characters such as senescence and fisheries selection regime to ensure the successful management of our natural resources.     

The evolution of an 'intelligent' dispersal strategy: biased, correlated random walks in patchy landscapes

Theoretical work exploring dispersal evolution focuses on the emigration rate of individuals and typically assumes that movement occurs either at random to any other patch or to one of the nearest‐neighbour patches. There is a lack of work exploring the process by which individuals move between patches, and how this process evolves. This is of concern because any organism that can exert control over dispersal direction can potentially evolve efficiencies in locating patches, and the process by which individuals find new patches will potentially have major effects on metapopulation dynamics and gene flow. Here, we take an initial step towards filling this knowledge gap. To do this we constructed a continuous space population model, in which individuals each carry heritable trait values that specify the characteristics of the biased correlated random walk they use to disperse from their natal patch. We explore how the evolution of the random walk depends upon the cost of dispersal, the density of patches in the landscape, and the emigration rate. The clearest result is that highly correlated walks always evolved (individuals tended to disperse in relatively straight lines from their natal patch), reflecting the efficiency of straight‐line movement. In our models, more costly dispersal resulted in walks with higher correlation between successive steps. However, the exact walk that evolved also depended upon the density of suitable habitat patches, with low density habitat evolving more biased walks (individuals which orient towards suitable habitat at quite large distances from that habitat). Thus, low density habitat will tend to develop individuals which disperse efficiently between adjacent habitat patches but which only rarely disperse to more distant patches; a result that has clear implications for metapopulation theory. Hence, an understanding of the movement behaviour of dispersing individuals is critical for robust long‐term predictions of population dynamics in fragmented landscapes.     

Variation in dispersal mortality and dispersal propensity among individuals: the effects of age, sex and resource availability

1.  Dispersal of individuals between habitat patches depends on both the propensity to emigrate from a patch and the ability to survive inter-patch movement. Environmental factors and individual characteristics have been shown to influence dispersal rates but separating the effects of emigration and dispersal mortality on dispersal can often be difficult. In this study, we use a soil mite laboratory system to investigate factors affecting emigration and dispersal mortality.
2.  We tested the movement of different age groups in two-patch systems with different inter-patch distances. Differences in immigration among age groups were primarily driven by differences in emigration but dispersal mortality was greater for some groups. Immigration declined with increasing inter-patch distance, which was due to increasing dispersal mortality and decreasing emigration.
3.  In a second experiment, we compared the dispersal of recently matured males and females and tested the impact of food availability during the developmental period on their dispersal. Dispersal was found to be male biased but there was no significant sex bias in dispersal mortality. There was some evidence that food availability could affect emigration and dispersal mortality.
4.  These results demonstrate that both emigration and dispersal mortality can be affected by factors such as individual age and resource availability. Understanding these effects is likely to be important for predicting the fitness costs and population consequences of dispersal.     

Unraveling the dispersal patterns and the social drivers of natal emigration of a cooperative breeding mammal,the golden lion tamarin

The study of the social drivers of animal dispersal is key to understanding the evolution of social systems. Among the social drivers of natal emigration, the conspecific attraction, aggressive eviction, and reduced social integration hypotheses predict that sexually mature individuals who receive more aggressive behavior and are engaged in less affiliative interactions are more likely to disperse. Few reports have explored these proximate factors affecting emigration in cooperatively breeding species, particularly of Neotropical primates. In this study, we investigated the dispersal patterns and tested the social drivers of natal emigration in the golden lion tamarin (Leontopithecus rosalia) — an endangered species inhabiting Atlantic rainforests fragments in Brazil. We used behavioral and demographic data collected during 7 years from 68 groups of tamarins inhabiting 20 forest fragments. Our analyses from the 160 dispersing individuals showed that dispersal success is higher for males and for those engaged in parallel dispersal, but that males and females use different strategies to enhance their dispersal success, males immigrate into established groups while females form new groups. We did not find high levels of agonistic behavior among group members before natal emigration. Instead we found that conspecific attraction drives natal emigration in both sexes, while additionally the low level of affiliative interactions within the natal group triggers male emigration. We discuss natal emigration in the broader perspective of the cooperative breeding system and the implications of these findings for the conservation of the species.