Dispersal is essential for the maintenance of populations in their natural habitats, particularly for endangered species living in fluctuating environments. Empirical evidence suggests that dispersal in territorial species is context-dependent, often depending on population density and sex. Here, we investigate the dispersal behavior of an endangered endemic damselfly Calopteryx exul in a lotic habitat of Northeast Algeria using capture-mark-recapture of adults. By sampling 10 gridded river stretches across the watercourse, we were able to estimate the distance of movement throughout individual lifespans and estimate dispersal probability for both males and females. We used multistate models to examine whether individual density and sex ratio influence survival and dispersal probability. We found that males and females had similar dispersal kernels with most individuals dispersing short distances (83% performing movements of <100 m and only 1% > 1000 m). Of the 547 marked individuals, 62.9% were residents, and 37.1% were dispersers. Survival probability showed higher estimates for females and density-dependence with high-male densities inducing survival costs for both males and females. Survival probability did not show a marked difference between residents and dispersers. Dispersal probability was neither dependent on density nor sex ratio. However, long-distance movements were positively correlated with individual density. These results are not in line with the common hypotheses of sex-biased dispersal and survival costs of dispersal. Our results suggest that future conservation plans for the species should maintain a network of nearby high-quality habitats to facilitate short-range dispersal and promote species persistence.
