For me, this question boils down to governance and the effectiveness of institutions in meeting their objectives. The exclusionary approach will only be effective if there is sufficient surveillance and control to prevent unsustainable forest use, otherwise it will continue to occur in any case, and the further loss of biodiversity will ensue. Likewise, any participatory approach will require careful design, appropriate incentives and effective monitoring to ensure that permitted extractive uses are sustainable.

A secondary consideration concerns the management objectives of the system - your question considers only the sustainability of biodiversity, but this may need to be traded-off against objectives such as povertyy alleviation, depending on the objectives of the managers.

I would suggest that there is no clear answer as to whether exclusionary or participatory approaches are more effective - each situation will be highly context specific and will require you to carry out research (both social and biological) to develop a sufficient evidence base on which you can base your decisions. However, globally, Porter-Bolland et al. (2011) (Forest Ecology and Management 268, 6-17) found that community-managed forest had lower and less variable deforestation rates than strict protected areas.

The preservation founded on exclusion also probably lead to a cultural disconnect between the local population and the object of conservation (territory or biodiversity or both). This would favor the lack of interest in the local nature ("I do not protect what we do not know"). The process is called "extinction of experience", and consists in progressive removing of contact (physical and mental) between man and surrounding natural reality.

It's a well known phenomenon in industrialized societies, and I don't know if it can be well applied to other contests; for me, however, should never be underestimated, because it results in favouring over-exploitation actions by stakeholders in a society that no longer know what it loses.