Differences in group affiliation may affect the level of cooperation in global commons situations such as programs for the conservation of resources which generate benefits that transcend state boundaries. We design a real-time, cross-cultural common pool resource (CPR) experiment purposely using participants from cultures that derive different benefits from biodiversity (extraction versus conservation) to analyze the effect of group affiliation on cooperative behavior. In addition, we elicit real donations to local and international conservation funds to augment our CPR results. In the CPR environment, we find evidence that group affiliation affects hehavior such that heterogeneity contributes to over-extraction in the commons. In the donation stage, we show that nationality affects the distribution of donated earnings between the local and global funds. We also examine the possibility that altruistic preferences to donate to a conservation fund are endogenous, in that they reflect the level of cooperation in the CPR game.