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The transition from dispersed to aggregated forms of settlement reflects a critical shift in the relative value of social and primary (food) modes of production. However, investigating trade-offs between these different forms of settlement requires estimates of the extent of community territories, including their nearby arable land. Here we demonstrate a simple algorithm to do that. Our algorithm is analogous to that used to define core-based statistical areas for the US census, though instead of central business districts, we rely on community centers (or areas of known and persistent interaction between unrelated individuals). We provide examples of our algorithm by applying it to archaeological sites in the central Mesa Verde, northern Rio Grande, and Cibola regions in the US Southwest. A sensitivity analysis is also conducted to demonstrate how each tuning parameter contributes to the algorithm. 

Past population change is connected to significant shifts in human behavior and experience including landscape manipulation, subsistence change, sedentism, technological change, material inequality and more. However, population change appears to result from a complex interplay of human-environment interactions that feedback on each other, influencing and simultaneously impacted by processes such as subsistence intensification and climate change. Here we explore complex system dynamics of population change using theoretical and Approximate Bayesian Computational modeling combined with the archaeological record of the past 4,000 years in the Colorado Plateau and Great Basin regions of western North America as case studies to identify causal relationships and the different manners in which climate change may have interplayed with subsistence economic intensification and population dynamics. Using standard distance metric evaluation on the performance of 1,000,000 simulations compared with reconstructed past population sizes in each region reveals how climate change impacting landscape productivity can influence carrying capacity and structure population growth such that, when populations reach carrying capacity (Malthusian ceilings), intensification in their subsistence economy can send feedbacks into the socioecological system spurring rapid, differential, population growth. Comparisons of the two regions highlights how varied socioecological circumstances can produce alternative pathways to, and limitations on, population expansions. 

Humans have both intentional and unintentional impacts on their environment, yet identifying the enduring ecological legacies of past small-scale societies remains difficult, and as such, evidence is sparse. The present study found evidence of an ecological legacy that persists today within an semiarid ecosystem of western North America. Specifically, the richness of ethnographically important plant species is strongly associated with archaeological complexity and ecological diversity at Puebloan sites in a region known as Bears Ears on the Colorado Plateau. A multivariate model including both environmental and archaeological predictors explains 88% of the variation in ethnographic species richness (ESR), with growing degree days and archaeological site complexity having the strongest effects. At least 31 plant species important to five tribal groups (Navajo, Hopi, Zuni, Ute Mountain Ute, and Apache), including the Four Corners potato ( Solanum jamesii ), goosefoot ( Chenopodium sp.), wolfberry ( Lycium pallidum ), and sumac ( Rhus trilobata ), occurred at archaeological sites, despite being uncommon across the wider landscape. Our results reveal a clear ecological legacy of past human behavior: even when holding environmental variables constant, ESR increases significantly as a function of past investment in habitation and subsistence. Consequently, we suggest that propagules of some species were transported and cultivated, intentionally or not, establishing populations that persist to this day. Ensuring persistence will require tribal input for conserving and restoring archaeo-ecosystems containing “high-priority” plant species, especially those held sacred as lifeway medicines. This transdisciplinary approach has important implications for resource management planning, especially in areas such as Bears Ears that will experience greater visitation and associated impacts in the near future.