What maintains the distinct vegetation of ancient Aleut village sites long after habitation?

We have shown that the vegetation of ancient village sites of the Aleut, the endemic people of the Aleutians, is distinct in species composition from that of nearby areas that were not previously settled. Village sites usually have more diverse, abundant, and productive vegetation that contains more plants of cultural significance to the Aleut. Where cattle have been introduced, vegetation of villages is no longer more diverse and does not have more culturally-valued plants, but still is distinct in species composition from its surroundings. Archaeological and anthropological literature asserts that the vegetation of village sites results from more fertile soils, because soil nitrogen is higher or soil pH is more neutral, both of these thought to be results of decomposition of kitchen middens and other household waste associated with villages. We sampled the soils of paired village and reference sites from the Lower Alaska Peninsula and Sanak Island and found that neither total soil nitrogen nor pH differed substantially or consistently between village and reference sites. Additionally, soil texture varied inconsistently between village and reference sites. Village sites did show a substantially higher amount of soil nitrogen of marine origin, presumably reflecting the use of marine resources by the Aleut long ago, and plants on village sites had higher nitrogen content and total standing crop of nitrogen. Positive feedbacks from use by animals and increased nutrient transformation and supply by different microbes are possible contributors to the long-term maintenance of distinct, productive, and usually biodiverse, ancient village sites.