Aware that humans and nature are inseparably linked many organisations in Madagascar support the community-based natural resource management approach to promote the international policy of biodiversity conservation and protection. In this context, community associations have been introduced to transfer management and use rights for natural resources to the local population. However, the fast, donor-driven top-down procedure of establishing new rules contradicts the local rhythm and handling of rules. Against this background, this paper focuses on the ethnic group Tanalana and explores key actors and locally initiated rules and agreements, analyses their level of effectiveness and discusses their possible application for community-based natural resource management in the buffer zone of Tsimanampesotse National Park in southwestern Madagascar. The paper looks at an example of rule negotiation outside the community-based management context concerning the use of a key resource in raising livestock. The example demonstrates that, on the one hand, the overlapping memberships in different social and kinship groups, and on the other hand, different individual economic interests can hinder successful collective action for natural resource management. Moreover, this example shows that already existing or newly introduced rules can be further called into question and are variously interpreted depending on the context. The degree of sanctions depends on several factors: (i) frequency of transgression, (ii) amount of affected persons, (iii) social relationships between the concerned parties and (iiii) social and communicative behaviour of the transgressor (in the past and present). This study finds that rules serve as rough guidelines, as a basis for discussion in cases of transgression, but do not function as fixed prescriptions. The data for this study was collected through semi-structured interviews and participative observation in six fokontany (village and related hamlets) to the east and west of Tsimanampesotse National Park.