The early lithic productions of Island Southeast Asia: Traditions or convergences?

Island Southeast Asia has been the subject of intense prehistoric investigations since the seminal work of Eugene Dubois in the late XIX^th century. This has resulted in several discoveries of a very diverse type of lithic productions of oftentimes debated age. Recent and old excavations have now secured the production of stone artefacts as early as 1 million years on Flores Island, 800,000 years on Java Island, 700,000 on Luzon Island and at least 118,000 years on Sulawesi Island. Along with these findings, several surface collections which most certainly date back to the Lower Palaeolithic are known, and adds to the diversity of the lithic productions. In this paper, we report what is at stake regarding our current knowledge over the early lithic productions of Island Southeast Asia, without giving more importance to one type of artefact over another. After describing the findings from each islands taken one by one, we compare the similarities and dissimilarities between these sometimes isolated and sometimes connected geographic entities. It appears that each of these islands might have had its own evolutionary trend with its own rhythm.     

Le site de Tögi Ndrawa, île de Nias, Sumatra nord : les premières traces d'une occupation hoabinhienne en grotte en Indonésie

The site of Tögi Ndrawa, Island of Nias, North Sumatra: The first record of a Hoabinhian cave occupation in Indonesia. Although in Indonesia, Hoabinhian sites usually refer to large shell midden dated back from the Holocene period, the Tögi Ndrawa cave in the Island of Nias (North Sumatra) has revealed a thick shell accumulation, sealed in a cavity, and beginning with the end of the Late Pleistocene. Excavations have produced classical Hoabinhian pebble artefacts, a forest and coastal fauna, and human bones. Beyond the new chronological landmarks provided by these findings, they question the extension of the Hoabinhian phenomenon originating from continental Asia, and provide hints about human settlement and use of the environment at this period of prehistory. Pour citer cet article : H. Forestier et al., C. R. Palevol 4 (2005).     

Feeding ecology of Late Pleistocene Muntiacus muntjak in the Padang Highlands (Sumatra)

The Dubois Collectie comprises around 1000 isolated fossil teeth of Muntiacus muntjak from the Padang Highlands in Sumatra. The majority were retrieved from one of the three fossil cave sites Lida Ajer, Sibrambang or Jambu. Lida Ajer is the only cave, for which exact location, geology as well as the age of the fossiliferous deposits are known. Using the mesowear method, we searched for differences in the dietary signal of Muntiacus muntjak and thus in the paleoenvironments of the three caves. Muntiacus muntjak from either one of the caves does not differ significantly in the composition of its diet, showing a mixed feeder signal. The samples of Lida Ajer and Sibrambang illustrate an increase of the mixed feeding component, which could be the result of higher seasonality.     

mtDNA Sequence Diversity of Orangutans from the Islands of Borneo and Sumatra

A comparison of mitochondrial DNA sequences was undertaken for two genes among orangutans from Borneo and Sumatra. The distribution of haplotypes among 42 individuals for NADH dehydrogenease subunit 3 and 39 individuals for cytochrome B was used to infer population structure. The haplotypes among all Bornean orangutans form a cluster of closely related individuals for both genes, with two distinct haplotypes occupying different regions of the island. Sumatran haplotypes fall into three distinct, and highly diverged, groups. Strikingly, one of the Sumatran haplotypes shares sequence identity with the most widespread Bornean haplotype. This haplotype distribution is considered in the context of the highly complex geological history for the area around the Malay Archipelago. Alternating periods of geographic isolation and reunion, resulting from glacially induced land bridge formation, presented substantial opportunity for population dispersal between periodically isolated demes. We present a paleodispersal model that is consistent with genetic, geological, paleoecological, and fossil data. The disparity of sequences present in orangutan populations argues against a simple Sumatra–Borneo dichotomy. Our evidence, and that of others, suggests that the Sumatran population alone contains the remnants of at least three separate lineages. Received: 3 February 1999 / Accepted: 2 August 2000     

Mapping and predicting deforestation patterns in the lowlands of Sumatra

Protected area managers have limited resources and so need fine-scale information to decide where to focus their budgets for law enforcement and community outreach. This study used satellite imagery to map and analyse forest loss in an area that overlaps with Kerinci Seblat National Park, Sumatra, to identify areas most susceptible to illegal logging. Between 1985 and 1992, forest located at lower elevation and close to roads was most vulnerable to clearance. These factors were also significant between 1992 and 1999, along with distance to newly created logging roads. The presence of these roads probably explained why the deforestation rate increased from 1.1% per year to 3.0% per year over the two study periods. The accuracy of the 1985–1992 model was measured in the field and successfully predicted subsequent deforestation patterns, suggesting that this methodology could be used to identify where future patrolling effort and community outreach programmes should be focussed. In addition, this approach could be used more widely in conservation planning to prioritise the protection of vulnerable sites.     

Deforestation rates in insular Southeast Asia between 2000 and 2010

Insular Southeast Asia experienced the highest level of deforestation among all humid tropical regions of the world during the 1990s. Owing to the exceptionally high biodiversity in Southeast Asian forest ecosystems and the immense amount of carbon stored in forested peatlands, deforestation in this region has the potential to cause serious global consequences. In this study, we analysed deforestation rates in insular Southeast Asia between 2000 and 2010 utilizing a pair of 250 m spatial resolution land cover maps produced with regional methodology and classification scheme. The results revealed an overall 1.0% yearly decline in forest cover in insular Southeast Asia (including the Indonesian part of New Guinea) with main change trajectories to plantations and secondary vegetation. Throughout the region, peat swamp forests experienced clearly the highest deforestation rates at an average annual rate of 2.2%, while lowland evergreen forests declined by 1.2%/yr. In addition, the analysis showed remarkable spatial variation in deforestation levels within the region and exposed two extreme concentration areas with over 5.0% annual forest loss: the eastern lowlands of Sumatra and the peatlands of Sarawak, Borneo. Both of these areas lost around half of their year 2000 peat swamp forest cover by 2010. As a whole this study has shown that deforestation has continued to take place on high level in insular Southeast Asia since the turn of the millennium. These on‐going changes not only endanger the existence of numerous forest species endemic to this region, but they further increase the elevated carbon emissions from deforested peatlands of insular Southeast Asia thereby directly contributing to the rising carbon dioxide concentration in the atmosphere.     

A natural hybrid ofMonophyllaea (Gesneriaceae) in the tropical rain forests of West Sumatra

A natural hybrid (2n = 21) between the parapatric rain forest speciesMonophyllaea hirtella (2n = 20) andM. horsfieldii (2n = 22) (Gesneriaceae) has been observed at Sg. Lubuk Paraku, Padang, W. Sumatra. The hybrids showed intermediary characters between the parental species in the inflorescence structure, flower size and colour, indumentum, chromosome numbers, and habitat. The 29% pollen fertility of a single hybrid specimen suggests that the genetical isolation between the parental species may break down and reproduction over subsequent generations may occur.     

Growth Analysis of Sumatran Monophyllaea, Possessing Only One Leaf Throughout Perennial Life

Abstract Growth and allometry were analyzed for populations of Monophyllaea hirtella Miq and M. horsfieldii R. Br. (Gesneriaceae), forest floor herbs that have only one cotyledonous leaf throughout life, in an equatorial rain forest in West Sumatra. Monophyllaea populations consisted of individuals of various sizes up to 30 g dry weight and 50x70 cm in leaf width and length. The relative growth rate (RGR) declined with size to an asymptotic value of 0.015–0.018 gg^-1 week^-1 for large individuals at sexual maturity (>2 g dry weight). The size-RGR relation did not differ among observations at three differen times of year and between two species in different habitals, indicating that it takes 4.6 years for seedlings to attain sexual maturity and 6.4 years to reach 10 g dry weight. Irrespective of embryonic organization of Monophyllaea , clear allometry existed among organs. Net assimilation rate was constant for juveniles and increased with size for adults. Decline of both the specific leaf area and the ratio of assimilate allocation to leaf caused the decrease of RGR with size. Reproductive allocation was 31% to reproductive organs and at most 5% to seeds in net production in a large individual of 20 g dry weight.     

Identifying spatial patterns in the tropical rain forest structure using hemispherical photographs

This work emphasises the usefulness of hemispherical photography for identifying spatial patterns in the tropical rain forest structure. Structural variability was investigated at a local (intra-site) scale, in relation to the forest mosaic, and at a regional (inter-sites) scale, for its implication in forest typology. Four primary forest sites, from 0.6 to 1 ha, were investigated in Central Sumatra, Indonesia.In a first instance, a qualitative analysis of the forest 3-D structure was found to be very helpful in the interpretation of quantitative results related to forest dynamics. The quantitative analysis was undertaken through the assessment of three structural characteristics: (1) the canopy openness (CO), or visible sky as seen from all directions of the hemisphere, (2) the spherical variance (SV), which quantifies the spatial dispersion of gaps and, (3) the plant area index (L_p), defined as half the surface area of canopy elements per unit ground area. At the local scale, maps of the CO values gave an indication about disturbance location and extent, providing an interesting document for studies on forest dynamics. At the regional scale, between-sites comparisons of CO, SV and L_p values added new information on forest structural differences when compared to dendrometric measurements. These results emphasised the fact that rain forest may exhibit high structural variability, even within a same bioclimatic region and a narrow altitude range. Hemispherical photographs could be a quick means of further investigating this spatial variability and it's relation to physical environment, thus providing information that is crucial for the refining of forest typology in the area.