We present evidence for a significant shift in human landscape use in post 1000 AD East Timor towards fortified and defensively-oriented settlement sites. We propose a model of agents selecting to invest in fortification building that is based on the spatial and temporal variation in the availability of rainfall-dependent resources. These resources may have been significantly impacted by climatic events associated with ENSO variation, and we discuss spatial and temporal correlation with ENSO warm phase frequency and dates of initial fortification building.
Keywords: Climate change, ENSO, fortifications, warfare, East Timor
Hundreds of stone walled structures are visible on hilltops and cliff edges in the contemporary landscape of north coastal East Timor (Figure 1). These structures are remembered by local inhabitants as places occupied in the past during a time of internecine warfare, mostly before living memory. Recent archaeological work supports the interpretation that these structures served as fortified settlements, and that people shifted suddenly to this settlement pattern only after 1000 AD, despite over 35,000 years of human occupation of Timor (e.g. Lape 2006). In this paper, we propose a model based on rainfall dependent resource distribution across time and space that could explain this sudden shift in settlement pattern, and then apply paleoenvironmental and recently collected archaeological data to test this model. Of particular interest is the history of the El Nino Southern Oscillation (ENSO), which may have had considerable impact on East Timor during the past 1000 years. In recent decades, El Nino caused drought in much of Island Southeast Asia and the Western Pacific. Although there are not yet any paleoenvironmental data from East Timor itself, a variety of proxy data from regions with demonstrated teleconnections to East Timor's climate indicate that El Nino events were much more frequent in the past than in the 20th century. Below we will review the culture history of East Timor, introduce our model, test it with archaeological and paleoenvironmental data and discuss the results.
Culture history of East Timor in a regional context
Prior to its separation and subsequent independence from Indonesia in 1999, East Timor had seen relatively little attention from archaeologists. Most work published to date has been conducted on an uplifted limestone plateau in the easternmost Lautem district, where dates of human occupation as early as 35,000 BP have been identified in several solution cave sites (O'Connor 2003; O'Connor and Veth 2005; O'Connor, et al. 2002; Spriggs, et al. 2003). The rich rock art of this region has also been subject to recent investigation (Lape, et al. 2007; O'Connor 2003; O'Connor and Oliveira 2007).
This research, building on earlier work in the 1950s and 1960s (Almeida 1961a, 1961b; Almeida and Almeida 1959; Almeida and Zbyszewski 1967; Glover 1970, 1986), indicates that East Timor's culture history follows patterns found elsewhere in Island Southeast Asia. The earliest sites dating to 30-40,000 BP are in limestone caves, probably because caves provide better conditions for preservation and site visibility. Between 4000 and 3500 years ago, there was a shift from a hunting/fishing/gathering economy to a farming economy, characterized archaeologically by the presence of domesticated animals including pigs, chickens, dogs, agriculture and earthenware pottery (Bellwood 1997, 2004). Goats were likely to have been introduced after 1000 AD. Although Glover claims a date of 5000 BP for goats in East Timor, this is not supported anywhere else in Island Southeast Asia (Glover 1986). Rice agriculture appears to have been practiced in the Philippines, but early agriculture in southern Island Southeast Asia, including Timor, is poorly understood (O'Connor 2006; Spriggs 2003). It is likely to have included the cultivation of fruit and nut beating trees, sago and root crops such as taro and yams (Latinis 2000; Stark and Latinis 1992). …