via Science Daily, 26 April 2018:
Working closely with Wanniyalaeto (Vedda) elders in Sri Lanka during the repatriation of skeletal remains, a team of researchers have demonstrated that while some indigenous hunter-gatherers in Sri Lanka made use of agricultural resources and trade connections with farmers and colonial power structures, others continued to subsist primarily on tropical forest resources as late as the 19th century.
Source: Evidence for persistent forest reliance by indigenous peoples in historical Sri Lanka
New paper in PNAS; a study of Batek Negrito lifestyle patterns in Peninsular Malaysia and what it can tell us about hunter-gatherer mobility.
Hunter-gatherers are notable for their high levels of mobility, but the ecological and social cues that determine the timing of camp movements (residential mobility) are poorly understood. Using models from foraging theory, we found that, for one population of hunter-gatherers, camp movements coincided with the point at which resource acquisition declined to a critical threshold level, but before local resources were completely depleted. These results suggest that hunter-gatherer residential mobility is constrained in a predictable fashion by rates of local resource depletion.
Source: Hunter-gatherer residential mobility and the marginal value of rainforest patches