Modelling the occurrence and abundance of a colonial species, the arctic tern Sterna paradisaea in the archipelago of SW Finland

摘要: Knowledge of the habitat requirements and suitable breeding areas sea birds is crucial for their management conservation. However, there are still few studies that have modelled distribution abundance colonial birds. In this study, we created predictive models a species, arctic tern Sterna paradisaea, using 14 environmental variables calculated 525 islands in Archipelago Sea SW Finland. We occurrence (presence-absence) generalised additive (GAMs) (pair numbers/colony size) hurdle fitted with GAM. tested spatial autocorrelation model residuals evaluated on independent data. Critical factors influencing were proportions boulder or gravel forest island area, as well maximum elevation such species seemed to prefer large low sparse vegetation. Abundance was influenced by bare rock exposure area. To some extent, different abundance. The evaluation results good, an AUC value 0.91 most accurate presence-absence Pearson's correlation coefficient 0.60 model. ability increased when removed single pairs from data set. Although did not produce pair number estimates, they indicated which larger colonies. factor species. This modelling technique can therefore be great conservation similar