Defining Suitability in Mixed Agropastoral Societies: A Case Study from Bactria in Northern Afghanistan

This paper explores the concept of suitability within applications of Ideal Distribution Models (IDMs). Specifically, we investigate the effectiveness of single measures of suitability in contexts where diverse local populations practised a range of subsistence strategies with different environmental requirements and sociocultural consequences. To do so, we draw on legacy survey data from northern Afghanistan, within the historic region of Bactria. This region of Central Asia has a rich history of nomadic pastoralism as well as dense urban settlement, with these two lifeways often occurring concurrently with complex social and economic interdependencies developing between pastoral and agricultural societies. Conceptually, we predict that such diversity should be difficult to model by conventional IDMs, as what may be defined as a low ranked habitat by one definition of suitability may be highly ranked in another. On the other hand, identifying strong deviations from IDMs may in fact indicate shifts in subsistence strategies and settlement patterns occurring across various periods of sociopolitical and cultural change. Based on our analysis, we conclude that single measures of suitability do not sufficiently model settlement patterns as predicted by IDMs but do in fact help highlight long-term processes of ecological engineering and inheritance.