Payments for ecosystem services (PES) programs exist globally and at times shifting behaviors. Unlike protected areas, PES compensate land users raising local acceptance of conservation. Yet some worry that if payments are temporary, as is often the case, conservation behaviors can be reduced by PES, ‘crowded-out’ to be lower after payments than if no PES had existed. We conducted lab-in-the-field experiments in Colombia, where PES policies are expanding, with individual or collective conditional payments to 676 farmers,potential PES participants. Payments end, in each experimental session, randomly for all or only for some participants. We consistently find that conservation is not lower after PES than before. Also, without PES conservation contributions tend to fall, over time, in keeping with public-goods literatures. Taken together, these results imply that even after our payments end, conservation is above the baseline defined by our controls, suggesting some form of at least short-run crowding in