The human factor

Already around 3200 BP pollen studies show a change in vegetation from forest to grass and savannah areas (Athens and  Ward 1999, 2002). This appears to be due to deliberate deforestation in order to create open areas for settlement and cultivation. Another factor for the changes in vegetation were the plant species that the Austronesian settlers deliberately introduced. These were not only edible plants such as taro (Colocasia esculenta), breadfruit (Artocarpus altilis) and bananas (Musa sp.) but also a number of trees species, whose wood was needed for building material, firewood, or for building boats. In addition, there are various medicinal plants that were indispensable for a successful settlement of a new island. Ornamental plants were also brought along for body decoration and to embellish the gardens in the villages.

Not only plants but also animals were introduced, namely pigs and rats. For the latter, it is still debated whether they were imported deliberately as a source of protein or whether the rats reached the remote islands as “stowaways” on board the boats. The introduction of dogs was usually also part of the Austronesian expansion, but to date no dog bones from the pre-contact era have been detected in Palau.

The introduced animal species had a major impact on the islands' ecosystem. The growing number of rats had a direct impact on the population of land and sea birds. On many islands, a direct connection can be seen between the introduction of rats and the extinction or sharp decline of many bird species. Domestic or feral pigs also have many disadvantages for the ecosystem. As omnivores, they directly compete directly with humans for food resources. Therefore, on some Pacific islands, pigs were deliberately extirpated before the arrival of the first Europeans, as they not only caused destruction in the planted gardens, but also severely damaged the natural vegetation by digging for food. Palau is one of the archipelagos where pigs were exterminated (cf. Clark et al. 2013).

 

Introduction
Challenges of an Island Ecosystem
The human factor
The monumental earthworks of Babeldaob
The first contact with the outside world
Brief history and state of research
Open questions
Geoarchaeological and archaeological research
Involvement of the local population
Project data