Conservation psychology: Bat killing in southern Costa Rica
Effective conservation action requires an understanding of the reciprocal relationships between humans and their environments. Conservation psychology provides a framework and methods to address this knowledge gap. In this project I used a theory of human behavior to evaluate the determinants of bat killing behavior in a rural population in southern Costa Rica. Indiscriminate killing is an important threat to Latin American bats, particularly those that roost in large aggregations. A partial explanation for this behavior is that people kill bats in order to reduce damage to livestock inflicted by the common vampire bat (Desmodus rotundus). However, the bats that are killed are frequently fruit-, insect-, and nectar-eating species that benefit rural people, e.g., by dispersing tree seeds and suppressing agricultural pests. Targeted methods exist to control vampire bat damage without harming co-occurring species, but these methods may go unused if individuals do not know about them, cannot access them, or do not want to use them. To differentiate among these potential causes of bat killing and identify appropriate conservation actions, I combined focus group interviews (N=4), door-to-door surveys (N=500), and a structural equation model based on the theory of reasoned action.
Men and women in focus groups expressed predominantly negative perceptions of bats and limited knowledge of their natural history. Whereas women commonly encountered bats around their homes, men more often discovered bats in roosts. In a survey of 500 men, 14% reported killing roosting bats within the last five years, and 27% said they would kill bats if they discovered a roost. The best predictor of bat killing intention was expected outcome; men who intended to kill bats expected that doing so would reduce disease transmission to livestock by vampire bats. In contrast, men who did not intend to kill bats expected that doing so would harm nature or reduce ecosystem services. These expectations varied demographically; men who scored higher on a natural history quiz believed that bat killing would reduce ecosystem services. But men whose cattle suffered from vampire bats believed bat killing would reduce livestock damage. My observations support the conclusion that bat killing in southern Costa Rica is caused predominantly by men motivated to reduce livestock damage by vampire bats and who have little knowledge of bat-specific natural history. Environmental education and vampire bat assistance for farmers are likely effective conservation actions to reduce bat killing.