Integrating Indigenous and local knowledge (ILK) into project practice can enhance the relevance, legitimacy, and longevity of interventions, yet approaches and outcomes remain inconsistently reported. This systematic review synthesizes empirical studies that explicitly operationalized ILK within project design, implementation, monitoring, governance, or evaluation, aiming to identify integration mechanisms, enabling conditions, observed outcomes, methodological limitations, and ethical risks. We combined structured database searches with targeted hand searches. Using standardized extraction fields, we recorded geographic context, project stages, types of ILK, stakeholder roles, monitoring metrics, ethical safeguards, and outcome measures. Quality appraisal used QuADS alongside design-specific checklists to assess trustworthiness, reflexivity, and ethical reporting. Quantitative outcomes were tabulated where comparable, and qualitative materials were synthesized thematically to derive integration mechanisms and enabling conditions. Findings indicate that projects explicitly integrating ILK achieved measurable environmental, social, or governance improvements when integration featured genuine co-production, shared governance arrangements, and community control over data. Environmental outcomes included positive trends in species status and habitat condition; social outcomes encompassed reinforcement of cultural practices and improved livelihood resilience; governance outcomes included co-management arrangements and formal recognition of tenure or customary authorities. Successful projects commonly implemented concise hybrid indicator sets pairing scientific metrics with culturally meaningful signals and sustained partnerships through locally governed budgets or data custodianship. Nevertheless, the evidence base has recurring limitations: many studies were short term, indicator sets lacked standardization, Indigenous research methods were underreported, and power asymmetries constrained meaningful co-governance. Ethical risks included data extractivism, intellectual property misappropriation, and donor timelines that short-circuit relational work. These limitations weaken causal attribution and reduce generalizability. We recommend that practitioners and funders ensure Indigenous leadership in co-design and governance; adopt compact hybrid monitoring packages; fund multi-year partnerships with flexible milestones; and embed Indigenous data governance and free, prior and informed consent (FPIC) into agreements. Implementing these measures should strengthen evidence quality, protect community rights, and improve long-term project effectiveness while promoting equitable benefit distribution.
Mosiali et al. (2026) studied this question.