Information thresholds, habitat loss and population persistence in breeding birds

Abstract

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.

Social information drives ecological outcomes among competing species

“…), and this work has been used to inform demographic models of socially enhanced resource acquisition (Schmidt et al. , Schmidt ), social information is shared through more nuanced behaviors, such as movements, in many systems. Fortunately, recent advances in the collection of large, high‐resolution data sets on individual behaviors in the wild, combined with probabilistic models, are able to reveal strong information‐mediated behavioral effects that emerge from subtle individual movements (Strandburg‐Peshkin et al.…”

Social Information Links Individual Behavior to Population and Community Dynamics

“…phenomenon can drive positive density dependence in the growth rate of a population [23,31,32]. Positive density dependence can also result from mechanisms that do not involve social information (e.g., mate limitation or habitat amelioration) [27,33,34] and these can occur alongside information-mediated mechanisms.…”

“…As noted above, an individual that follows the behavior of others to locate resources or avoid predators can increase its own fitness, and, in doing so, increase its population size (i.e., the number of information-producing individuals that it and other conspecifics can follow in the future) [23,45,46]. For example, models reveal that higher densities of individuals can improve breeding success of eavesdropping conspecifics and, thus, increase the population growth rate at small population sizes [23,32]. Furthermore, individuals with different phenotypes can vary in traits that underlie the provision and use of social information.…”

“…Computational models have shown that social information can improve the ability of groups of foragers to track resources that shift at small spatial scales and over relatively short, behavioral timescales [5,9,79] or between breeding seasons [32], but that large-scale or longterm environmental changes can eliminate these benefits or cause social information to become highly detrimental to populations [32,80,81]. For example, habitat fragmentation can reduce or cease migration in populations that rely on information from a small number of leaders, the leadership by which can fail to evolve in a fragmented landscape [ 2 9 6 _ T D $ D I F F ] [80].…”

“…Here, we build on several key reviews -4,18] to formalize and generalize ideas presented in recent theoretical (e.g., [23,32,39]) and empirical (e.g., [22,24,40]) papers. Our synthesis unifies…”