Nomads, pastoralists and certain subsistence farmers have property rights defined by tradition. This does not necessarily give them a clearly defined right to the land that they use. This lack of any clear legal tenure may be abused by those with appropriate influence and expertise. As a result such groups may be driven off their lands onto more marginal lands.
In slum areas around major cities in the developing countries ill-defined property rights increase the risk of buying and selling a site and discourages squatters from improving their buildings.
In agricultural settings, several studies have demonstrated that as long as farmers' security of tenure is of a short duration, they can hardly be expected to take the long view and invest in the sustainability of their farm systems.
In many developing countries, agricultural land is occupied and farmed without legal land title. In Thailand, for instance, over 40% of agricultural land is farmed this way. Moreover, especially in rice production, it is common that a large portion of the land is farmed by those who rent fields on short-term contracts. One effect is that the land is used for short-term gains rather than maintenance of long-term productivity.
In southeastern Nigeria, the differing situations in two Igbo villages, Ndubia and Umuokele, illustrates that indigenous land tenure is not only plastic and complex, but that it is not an independent variable dictating land use. In Ndubia, communal tenure dominates, while in Umuokele, individual land holding arrangements are most common; nonetheless, farming systems between the two villages are relatively homogenous.
Over the last few decades attempts have been made, for equity as well as efficiency reasons, to alter the existing tenure structure through redistributive land reforms. The results achieved have failed to bring a decisive change. Beside the fact that the reform efforts in individual countries differed in the initial political resolve and extent of the programmes (compare, for example, the extensive reforms in Mexico in the 1930s or Bolivia in the 1950s with the much weaker efforts in Brazil), the post-reform situation suffered from such factors as the poor quality of the land redistributed, insecure titles, a lack of farming expertise on the part of the beneficiaries, plus a number of policy distortions.
If environmental degradation shrinks the resource pie, and population growth divides the pie into smaller pieces, then skewed resource access means that farmers will continue to clear forest as long as they lack clear title to a permanent plot. When land tenure is uncertain or disputed as it is throughout much of the developing world, those who work the land do not invest in it and do not conserve it, and soil is nowhere near as healthy or as productive as it could be.