Community identification promotes cooperation around shared natural resources: Field experimental evidence on communal land protection among agro-pastoralist communities in Northern Tanzania

Sustainable management of shared natural resources is one of the biggest challenges of our day, and addressing it requires sustained cooperation. Yet how to support such cooperation in specific field contexts is not well understood, as existing evidence is largely correlational and drawn from laboratory or Western settings. To address this gap, the present research conducted a field experiment with agro-pastoralist communities in Northern Tanzania facing the environmental threat of communal land degradation (N = 207). Drawing on the social identity framework, we tested whether an intervention strengthening community identification and perception of land degradation as a shared threat could foster communal land protection. When community (vs. individual household) identification was strengthened, participants allocated more of a valuable resource (fodder-grass seeds) to communal rather than household land. Community condition also affected participants’ intentions to cooperate around nature-based solutions (e.g., rotational grazing) to protect communal land, with this effect operating through a set of identity-based processes (i.e., community identification, collective efficacy, shared threat, perceived support, communal norms). Taken together, these findings provide experimental, behavioral evidence from a Global South field context for the role of community identification in cooperative responses to a shared environmental threat. The study also offers a viable example of a low-cost intervention that could complement policy-level approaches by engaging the social psychological dimension of communal cooperation.