This article provides ethnographic insight into the more-than-human relationships enacted through young people's participation in school grounds conservation activities. As a response to the escalating biodiversity crisis, conservation appears well-placed to facilitate young people's development of an environmental ethic of care, and a capacity to work towards addressing environmental issues. Proponents of posthuman pedagogies, however, argue that the 'stewardship' perspective underlying these activities fails to achieve the radical shift in human-environment relations required in response to the Anthropocene, given its apparent reinforcement of a perceived human/nature binary, and narrow 'solutions'-based approach. Considering these critiques, this article demonstrates that where there is openness to unplanned more-than-human encounters and the enactment of young people's own 'lived curricula' , conservation activities can nonetheless enable forms of 'collective thinking with the more-than-human world' that transcend any underlying 'stewardship' perspective. We therefore point to the potential role of conservation activities within posthuman responses to the Anthropocene, provided such openness is maintained. Introduction: conservation, stewardship and posthumanismIn October 2019, the International Union for Conservation of Nature (IUCN) issued an urgent call for action to address the "unprecedented, unsustainable and growing impacts on wild species from human activities" (IUCN 2019, 1), highlighting an accelerating biodiversity crisis often referred to as the Earth's "sixth mass extinction" (Cole and Malone 2019). People across the world, the IUCN (2019, 1) states, "must accept responsibility for this emergency and act now to ensure we pass on a rich natural heritage to future generations". This article provides ethnographic insight into young people's lived experience of the Polli:Nation project -a UK-wide, school-linked conservation initiative that engaged them in a direct response to this call for action.Young people's participation in conservation activities, particularly in formal education contexts, has seen relatively little coverage in academic literature. "Conservation" here refers to the transformation of a particular site in order to have positive impacts on biodiversity. Students need not travel to celebrated or protected landscapes to participate in conservation activities.