Mainland Southeast Asia Research Articles

Molecular phylogeny of dragon millipedes (Diplopoda: Polydesmida: Paradoxosomatidae) from mainland South-East Asia, with description of a new genus and species

Abstract Recent taxonomic revision of the strikingly ornamented millipedes known as ‘dragon millipedes’ in the family Paradoxosomatidae, has revealed generic division into six genera. The majority of species are distributed in mainland South-East Asia and each genus is restricted to a well-delimited area. However, their evolutionary history has remained poorly understood, particularly the relationships among genera and their biogeographic distribution. We present a comprehensive and well-resolved molecular phylogeny based on mitochondrial and nuclear genes. A dataset of 256 sequences representing 40 dragon millipede species was newly generated and analysed in order to reveal the relationships and to explore the origin using ancestral range reconstruction. All dragon millipedes were retrieved together as monophyletic, each genus except Hylomus forming a distinct clade with strong statistical values, supporting the previous classification using morphology. A new monotypic genus and new species, Siamaxytes bifurca Srisonchai and Panha gen. nov. et sp. nov., was revealed based on distinct morphological and DNA data. The Tenasserim mountain range was inferred to be the centre of origin of dragon millipedes with a series of subsequent diversifications across mainland South-East Asia. Our analysis provides evidence that both dispersal and vicariance presumably played a role in shaping these millipedes’ distribution and diversification.

Competing influence of the Taiwan orogen and East Asian Summer Monsoon on South China Sea paleoenvironmental proxy records

Late Cenozoic changes in the intensity of the East Asian Summer Monsoon (EASM) are reconstructed using both terrestrial and marine proxy records; however, proxies from terrestrial (e.g., loess, pollen, and pedogenic isotopes) and marine environments (e.g., foraminifer assemblages and geochemistry) commonly display large discrepancies both in the direction and timing of changes in the EASM. In part, these discrepancies reflect long-term changes in paleogeography that are independent of climate variations. We assess the influence of a rapidly uplifting orogen on EASM records by comparing temporally constrained gamma-ray, δ13Corg, hematite/goethite, and magnetic susceptibility records from Late Miocene–Early Pleistocene strata of the Taiwan Western Foreland Basin to time-equivalent EASM proxy records in the South China Sea (SCS).Prior to the emergence of modern Taiwan (∼6.3–5.4 Ma), sediment in the SCS was largely derived from Eurasia and transported into the Pacific Ocean. Following its emergence and southwest migration of the collision zone ∼5.4 Ma, proto-Taiwan became a major sediment source to the SCS. The uplift and southwest migration of Taiwan and northwest migration of the Luzon volcanic arc resulted in the formation of southwest-flowing deep- (1500–2500 m water depth) and bottom-water (>2500 m water depth) currents and the SCS Branch of the Kuroshio Current. Together these currents transported sediment from Taiwan towards the SCS. Increased sediment input from Taiwan is recorded as a decline in hematite/goethite values in sediment records from the northern and central SCS. By ∼3.2 Ma, continued southwest migration and growth of the Taiwan orogen resulted in the formation of the Taiwan Warm Current, which remobilized some sediment from Taiwan towards the East China Sea. Despite strengthening of deep-water currents during the Late Pliocene–Early Pleistocene, relative sediment input from Taiwan to the wider SCS decreased. Consequently, relative contributions from Eurasia and Luzon increased. In the southern SCS, where the Mekong River has dominated sedimentation since the Late Miocene, proxy records show no influence from the Taiwan orogen and instead reflect environmental changes in Mainland Southeast Asia driven mainly by monsoon variability.Our results show that a rapidly uplifting orogen has the potential to significantly impact paleoclimate records >1000 km away from the collision zone. This highlights the influence of shifting sediment sources on paleoclimate proxy records, which must be considered in interpreting past climate change from the sedimentary record.

Unraveling the mitochondrial phylogenetic landscape of Thailand reveals complex admixture and demographic dynamics

The evolutionary dynamics of mitochondrial DNA within the Thai population were comprehensively explored with a specific focus on the influence of South Asian admixture. A total of 166 samples were collected through randomized sampling, ensuring a diverse representation. Our findings unveil substantial genetic and haplogroup diversity within the Thai population. We have identified 164 haplotypes categorized into 97 haplogroups, with a notable inclusion of 20 novel haplogroups. The distribution of haplogroups exhibited variations across different populations and countries. The central Thai population displayed a high diversity of haplogroups from both the M and N clades. Maternal lineage affinities were discerned between several Mainland Southeast Asia (MSEA) and South Asian populations, implying ancestral genetic connections and a substantial influence of South Asian women in establishing these relationships. f4-statistics indicates the presence of a Tibeto-Burman genetic component within the Mon population from Thailand. New findings demonstrate two phases of population expansion occurring 22,000–26,000 and 2500–3800 years ago, coinciding with the Last Glacial Maximum, and Neolithic demographic transition, respectively. This research significantly enhances our understanding of the maternal genetic history of Thailand and MSEA, emphasizing the influence of South Asian admixture. Moreover, it underscores the critical role of prior information, such as mutation rates, within the Bayesian framework for accurate estimation of coalescence times and inferring demographic history.

Impacts of vertical distribution of Southeast Asian biomass burning emissions on aerosol distributions and direct radiative effects over East Asia

The impacts of vertical distribution of biomass burning (BB) emissions on aerosol distributions and direct radiative effects over the BB source regions of Mainland Southeast Asia (MSEA) and downwind East Asian regions during spring (March to May) 2019 were investigated by applying an online coupled regional chemistry-aerosol-climate model (RIEMS-Chem). Model validation against a variety of observations demonstrated a generally good skill of the model in simulating aerosol chemical components, aerosol optical depth (AOD), and vertical distribution of aerosol extinction coefficient (EXT) when BB emissions were included. Four methods were adopted to represent injection height of BB emissions, including (1) a physical process-based parameterization (BB_param), (2) satellite-based prescribed profiles (BB_prof), (3) temporal-spatial varied injection profiles from the GFAS (Global Fire Assimilation System) dataset (BB_GFAS), and (4) BB emissions released at a fixed altitude (BB_high). The BB_param experiment generally produced better statistics compared to observations. Different BB injection height treatments considerably affected concentrations and distributions of BB aerosols, aerosol optical properties, direct radiative effects of BB aerosols (DREBB), atmospheric heating rate, and cloud fractions. The simulated sub-regional (100–120°E and 19–26°N, including major BB source and downwind areas) and seasonal mean DREBB at the top of the atmosphere (TOA) were +1.7 W m−2, +1.3 W m−2, +1.2 W m−2, and +1.7 W m−2 in the BB_param, BB_prof, BB_GFAS, and BB_high experiments, respectively, while the corresponding mean DREBB at the surface were −30.3 W m−2, -19.1 W m−2, -19.0 W m−2, and -22.1 W m−2. It is noticed that the DREBB at TOA and at the surface in BB_GFAS were just 68% and 63% of the values in BB_param, and the different injection height treatment had larger influences on DREBB at the surface than at TOA. The BB aerosol-induced atmospheric heating rate was up to 0.8–1.2 K/day in BB_param, which was larger than those in other experiments. Low cloud was enhanced while middle and high clouds were reduced by BB aerosols over northern MSEA. The BB aerosol-induced changes in cloud fractions in the BB_param experiment (up to 0.15 for low cloud and −0.05 for middle and high cloud) were approximately twice those in the other experiments. This study demonstrates the importance and necessity of properly representing the injection height of BB emissions in model estimation of radiative and climatic effects of BB aerosols.

Investigation on the Distribution Status of Transboundary Ethnic Groups in the Mountainous Regions of Mainland Southeast Asia in Southwest China

Through the compilation and analysis of relevant research in the papers and works of international scholars, this study aims to understand the attention and research of international and domestic scholars on transboundary ethnic groups in the mountainous regions of Mainland Southeast Asia, and explore the significance of studying these groups in Southwest China. By investigating their distribution, the study focuses on the survival situation of transboundary ethnic groups from the mountainous regions of Mainland Southeast Asia in Southwest China, examining aspects such as population size, areas of residence, ethnic background information, socioeconomic conditions, and cultural characteristics. The goal is to contribute to the international development of research on transboundary ethnic groups in Southwest China and eliminate barriers by adopting an international perspective. Furthermore, it should be noted that the mountainous transboundary ethnic groups in Mainland Southeast Asia have long faced challenges related to politics, drugs, and socio-economic underdevelopment. However, since the last century, the Chinese government has been committed to the development of ethnic groups residing in the mountainous regions of Southwest China, achieving remarkable results. This development is set to positively impact the healthy growth of transboundary ethnic groups in the mountainous regions of Mainland Southeast Asia.

A new species of Rhagophthalmus Motschulsky, 1854 (Coleoptera, Rhagophthalmidae) from Laos represents the smallest known member of the genus.

Rhagophthalmus Motschulsky, 1854 is the most speciose genus in Rhagophthalmidae, distributed in the region encompassing South, East, and Southeast Asia. Here, we describe R.nanussp. nov. from the Houaphanh Province of eastern Laos, which represents the smallest known species in Rhagophthalmus and one of the smallest in Rhagophthalmidae. We compare it with the morphologically similar and geographically close congeners and provide a preliminary identification key to adult males of Rhagophthalmus species from mainland Southeast Asia. Additionally, we discuss the morphology and variability of male genitalia within Rhagophthalmus.

Integrated Remote Sensing Observations of Radiative Properties and Sources of the Aerosols in Southeast Asia: The Case of Thailand

Aerosols in Southeast Asia (SEA) are entangled with complex land–sea–atmosphere–human interactions, and it is difficult for scientists to understand their dynamic behaviors. This study aims to provide an insightful understanding of aerosols across SEA with respect to their radiative properties using several lines of evidence obtained from remote sensing instruments, including those from onboard Earth observation satellites (MODIS/Terra and MODIS/Aqua, CALIOP/CALIPSO) and from ground-based observation (AERONET). The findings, obtained from cluster analysis of aerosol optical properties, showed seven aerosol types which were dominant across the country, exhibiting diverse radiative forcing potentials. The light-absorbing (prone to warm the atmosphere) aerosols were likely found in mainland SEA, both for background and high-aerosol events. The light-scattering aerosols were associated with aging processes and hygroscopic growth. The neutral potential, which comprised a mixture of oceanic and local anthropogenic aerosols, was predominant in background aerosols in insular SEA. Further studies should focus on carbonaceous aerosols (organic carbons, black carbon, and brown carbon), the aging processes, and the hygroscopic growth of these aerosols, since they play significant roles in the regional aerosol optical properties.

Phylogenetic evidence reveals early Kra-Dai divergence and dispersal in the late Holocene

Studying language evolution brings a crucial perspective to bear on questions of human prehistory. As the most linguistically diverse region on earth, East and Southeast Asia have witnessed extensive sociocultural and ethnic contacts among different language communities. Especially, the Kra-Dai language family exhibits tremendous socio-cultural importance in these regions. Due to limited historical accounts, however, there are several controversies on their linguistic relatedness, ambiguities regarding the divergence time, and uncertainties on the dispersal patterns. To address these issues, here we apply Bayesian phylogenetic methods to analyze the largest lexical dataset containing 646 cognate sets compiled for 100 Kra-Dai languages. Our dated phylogenetic tree showed their initial divergence occurring approximately 4000 years BP. Phylogeographic results supported the early Kra-Dai language dispersal from the Guangxi-Guangdong area of South China towards Mainland Southeast Asia. Coupled with genetic, archaeological, paleoecologic, and paleoclimatic data, we demonstrated that the Kra-Dai language diversification could have coincided with their demic diffusion and agricultural spread shaped by the global climate change in the late Holocene. The interdisciplinary alignments shed light on reconstructing the prehistory of Kra-Dai languages and provide an indispensable piece of the puzzle for further studying prehistoric human activities in East and Southeast Asia.

Analysis of heatwaves based on the universal thermal climate index and apparent temperature over mainland Southeast Asia.

Heatwaves have caused significant damage to human health, infrastructure, and economies in recent decades, and the occurrences of heatwaves are becoming more frequent and severe across the globe under climate change. The previous studies on heatwaves have primarily focused on air temperature, neglecting other variables like wind speed, relative humidity, and radiation, which could lead to a serious underestimation of the adverse effects of heatwaves. To address this issue, this study proposed to the use of more sophisticated thermal indices, such as universal thermal climate index (UTCI) and apparent temperature (AT), to define heatwaves and carry out a comprehensive heatwave assessment over mainland southeast Asia (MSEA) from 1961 to 2020. The traditional temperature-based method was also compared. The results of the study demonstrate that the annual maximum temperature in heatwave days (HWA) and the annual average temperature in heatwave days (HWM) are significantly underestimated if only air temperature is considered. However, UTCI and AT tend to predict a lower frequency of yearly heatwave occurrences and shorter durations. Trend analysis indicates a general increase in heatwave occurrences across MSEA under all thermal indices in the past six decades, particularly in the last 30years. This study's approach and findings provide a holistic view of heatwave characteristics based on thermal indices and highlight the risk of intensified heat stress during heatwaves in MSEA.

Bi-decadal trend of atmospheric emissions from thermal power plants in Mainland Southeast Asia: Implications on acid deposition and climate change Mitigation

Steady increase in electricity generation and heavy reliance on coal in Mainland Southeast Asia (M-SEA) create huge pressure on the environment. This study used information collected from individual thermal power plants (TPPs) in M-SEA to calculate emissions of air pollutants and greenhouse gases (GHG) for 2010, 2015 and 2019. The emissions were projected to 2030 following the latest national Power Development Plans. The emission results were analyzed in relation to the power development by country and fuel type, and environmental impacts. The region collective annual TPP emissions in 2019, in Gg/yr, were 27 PM2.5, 77 PM10, 0.7 BC, 4.9 OC, 255 SO2, 451 NOx, 91 CO, 12 NMVOC, 0.4 NH3, 260 CO2, 13 CH4, and 26 N2O. Coal-fired TPPs dominated the emissions of most species while NG-fired contributed the largest amounts of NH3 and CH4. Bi-decadal increase in energy production from TPPs of nearly 3 times is accompanied by 2.7 times increase in emissions. The 2010–2019 period saw average emissions increase by 1.9 times (TPPs' energy production increased 1.6 times), slightly higher than the rate of 1.4 times projected for 2019–2030 (double TPPs’ energy production). The current intrusion rate of renewable energy accompanied by phasing-out of old TPPs are still by far insufficient to reverse the emission trend. Aggressive power development in Vietnam with its heavy coal reliance made it the largest emitter in 2019 and the projected for 2030, followed by Thailand. Spatially, higher emissions are seen over locations of large coal-fired TPPs in Vietnam and Thailand. Available rainwater composition monitoring data showed higher deposition amounts of sulfate and nitrate in areas located near or downwind of large TPPs. Significant GHG emissions projected for TPPs in 2030 indicated that TPPs should be the priority for emission reduction to achieve Nationally Determined Contribution targets. Emission database produced by this study can be used in dispersion modeling studies to assess impacts of TPPs on air quality, health, and acid deposition.

Intertwined maritime Silk Road and Austronesian routes: A Taiwanese archaeological perspective

AbstractThis article analyses recent archaeological work on the flow of materials and their influences on the communities in the South China Sea maritime regions, primarily from a local, Taiwanese perspective. The intertwined Austronesian Routes and maritime Silk Road acted as the primary conduit for the movement of both people and materials. Archaeological findings demonstrate intermittent interaction and cultural exchange between Taiwan and the regions around the South China Sea during the period 1,500-500 BCE. However, starting from 500 BCE, the gradual increase of glass beads, agate beads, and metal products which were made in mainland Southeast Asia and adjacent regions indicate an intensified interaction between Taiwan and Southeast Asia via the Maritime Silk Road and the Austronesian Routes. The author hypothesizes that trade diasporic craftspeople were the carriers of these exotic materials and knowledge, and that external cultural elements had a profound impact on the development of contemporary prehistoric Formosan society. This can be seen most notably in the shifting of decoration systems, the changing methods of subsistence, and technological leaps. Some of the impacts have faded into the archaeological records, but others are still traceable in the modern Indigenous society of Taiwan.

Are there suitable global datasets for monitoring of land use and land cover in the tropics? Evidences from mainland Southeast Asia

Are there suitable global datasets for monitoring of land use and land cover in the tropics? Evidences from mainland Southeast Asia

Genetic diversity and ancestry of the Khmuic-speaking ethnic groups in Thailand: a genome-wide perspective

The Khmuic-speaking populations are believed to be the descendants of one of the earliest groups to settle in Mainland Southeast Asia. In Thailand, there are two agricultural Khmuic-speaking ethnic groups, the Khamu and Lua (Htin). These peoples primarily reside in scattered locations along the mountainous Thailand–Laos border in Nan province. In this study, we conducted genome-wide SNP analysis on 81 individuals from three Khamu and two Lua villages in northern Thailand. Our findings revealed that both the Khamu and Lua groups possess genetic structures that are distinct from other ethnicities in Southeast Asia, indicating a unique history of migration and settlement. Within the Khmuic group, the Khamu populations living in different locations exhibited similar genetic structures and displayed genetic affinities only with some hill-tribes and Tai-Kadai (Kra-Dai)-speaking groups in Thailand, suggesting potential intermixing or cultural exchange. Furthermore, the Lua people displayed a distinctive population structure, which could be attributed to the founder effect and endogamous marriage practices. Additionally, we discovered a relationship between the Khmuic-speaking populations in Thailand and a Neolithic ancient sample obtained from the Tham Pha Ling archaeological site in Laos. This study provides new insight into genetic substructure within the Khmuic-speaking people and their potential relationship to the indigenous inhabitants of Mainland Southeast Asia.

The Role and Position of Hong Kong in the Belt and Road Initiative

Situated between mainland China and Southeast Asia, Hong Kong serves as a crucial node and gateway city for the Belt and Road Initiative. With a mature financial system encompassing a robust banking sector, well-developed capital markets, diversified financial services, and a professional workforce, Hong Kong is strategically positioned. This research aims to uncover the pivotal role of Hong Kong's financial industry in the Belt and Road Initiative and evaluate its internal and external factors and competitive advantages. Leveraging its unique strengths and contributions, Hong Kong will continue to be a vital partner in the Belt and Road Initiative, promoting mutually beneficial and sustainable development across various domains such as the economy, education, and culture.

South Asian maternal and paternal lineages in southern Thailand and the role of sex-biased admixture.

Previous genome-wide studies have reported South Asian (SA) ancestry in several Mainland Southeast Asian (MSEA) populations; however, additional details concerning population history, in particular the role of sex-specific aspects of the SA admixture in MSEA populations can be addressed with uniparental markers. Here, we generated ∼2.3 mB sequences of the male-specific portions of the Y chromosome (MSY) of a Tai-Kadai (TK)-speaking Southern Thai group (SouthernThai_TK), and complete mitochondrial (mtDNA) genomes of the SouthernThai_TK and an Austronesian (AN)-speaking Southern Thai (SouthernThai_AN) group. We identified new mtDNA haplogroups, e.g. Q3, E1a1a1, B4a1a and M7c1c3 that have not previously reported in Thai populations, but are frequent in Island Southeast Asia and Oceania, suggesting interactions between MSEA and these regions. SA prevalent mtDNA haplogroups were observed at frequencies of ~35-45% in the Southern Thai groups; both of them showed more genetic relatedness to Austroasiatic (AA) speaking Mon than to any other group. For MSY, SouthernThai_TK had ~35% SA prevalent haplogroups and exhibited closer genetic affinity to Central Thais. We also analyzed published data from other MSEA populations and observed SA ancestry in some additional MSEA populations that also reflects sex-biased admixture; in general, most AA- and AN-speaking groups in MSEA were closer to SA than to TK groups based on mtDNA, but the opposite pattern was observed for the MSY. Overall, our results of new genetic lineages and sex-biased admixture from SA to MSEA groups attest to the additional value that uniparental markers can add to studies of genome-wide variation.

Phylogenomics of Fresh and Formalin Specimens Resolves the Systematics of Old World Mud Snakes (Serpentes: Homalopsidae) and Expands Biogeographic Inference

Our knowledge of the biodiversity of Asia and Australasia continues to expand with more focused studies on systematics of various groups and their biogeography. Historically, fluctuating sea levels and cyclic connection and separation of now-disjunct landmasses have been invoked to explain the accumulation of biodiversity via species pump mechanisms. However, recent research has shown that geological shifts of the mainland and species dispersal events may be better explanations of the biodiversity in these regions. We investigate these processes using the poorly studied and geographically widespread Mud Snakes (Serpentes: Homalopsidae) using a target capture approach of ~4,800 nuclear loci from fresh tissues and supplemental mitochondrial data from formalin tissues from museum specimens. We use these datasets to reconstruct the first resolved phylogeny of the group, identify their biogeographic origins, and test hypotheses regarding the roles of sea-level change and habitat selection on their diversification. Divergence dating and ancestral range estimation yielded support for an Oligocene origin and diversification from mainland Southeast Asia and Sundaland in the rear-fanged group ~20 million years ago, followed by eastward and westward dispersal. GeoHiSSE models indicate that niche expansion of ancestral, rear-fanged lineages into aquatic environments did not impact their diversification rates. Our results highlight that Pleistocene sea-level changes and habitat specificity did not primarily lead to the extant species richness of Homalopsidae and that, alternatively, geological shifts in mainland Southeast Asia may have been a major driver of diversity in this group. We also emphasize the importance of using fresh and degraded tissues, and both nuclear and mitochondrial DNA, for filling knowledge gaps in poorly known but highly diverse and conceptually important groups. Here, Homalopsidae represents a non-traditional but effective model study system for understanding transitions between terrestrial, marine, and freshwater environments.

Early paintings of central-western Thailand

In the field of rock art, Mainland Southeast Asia remains the least understood region in the world. Thailand has a rich corpus of rock art, particularly in the central-west of its mountainous uplands. This paper takes an empirical approach to the study of central-western Thai rock art presenting for the first time a comprehensive inventory of the region's motifs and contextualising them against the archaeological and anthropological records of central-western Thailand and neighbouring regions (southwest China and northern Vietnam) to re-examine existing interpretations of the art.

Spatiotemporal characteristics and the national variations of borderland use change in Laos within the geopolinomical context

Laos, the only landlocked country in Mainland Southeast Asia (MSEA), has established over 40 geopolinomical mechanisms with its neighboring countries (including China, Vietnam, Cambodia, Thailand, and Myanmar), leading to significant land-use change (LUC) in the border areas. However, the spatial characteristics and national differences of LUC in the border areas of Laos remain unknown. Through the use of land-use products from 1985 to 2020 and by employing GIS spatial analysis, the results indicate that (1) LUC along the Laos border has led to severe and extensive deforestation, primarily attributed to the rapid expansion of construction land and the consistent growth of cropland. (2) With strengthened border cooperation, differences between LUC in Laos and its neighboring countries have decreased since 1985. (3) Cropland and construction land on the Laos–China and Laos–Thailand borders show obvious bordering characteristics, with increasing land-use homogeneity in near-border areas. In contrast, the Laos–Vietnam, Laos–Cambodia, and Laos–Myanmar borders display the opposite trend. (4) Port areas (e.g., Boten–Mohan port) driven by geopolinomical relations have drastic LUC, but they have huge differences. This study provides a database for quantitative research on the interaction between geopolinomical relations and border LUC to promote border geography, including impact and response.

Agricultural expansion and forest retreat in Mainland Southeast Asia since the late 1980s

AbstractAgrarian expansion and intensification in the tropical agricultural‐forest frontiers (TAFF) are continuously encroaching on forests, yet the magnitudes and processes of agricultural‐forest advances and retreats remain lacking investigation systematically and quantitatively. With over three‐decade (1987–2018) of land‐cover products, here, we revealed the spatiotemporal dynamic processes of agricultural advance and forest retreat and then quantified forest loss (FL) due to cropland and plantation expansion (PE) in Mainland Southeast Asia (MSEA). First, the agricultural expansion and FL peaked in the late 1990s to early 2000s and decelerated afterward in MSEA. Meanwhile, the continuous decline in deforestation rates was accompanied by a decline in the patches of forest fragments, while cropland and plantations first decreased and then increased. Second, 85% of cropland expansion (CE) occurred in forest frontiers of Myanmar (37%) and Thailand (32%) in particular, compared with 72% of PE in plantation‐forest frontiers, for example, 24% in Thailand and 22% in Cambodia. Third, 51% and 37% of the forests that declined were converted into cropland and plantations, respectively, with obvious national variations. In the least developed countries, such as Myanmar and Cambodia, CE dominated (65%), while the proportion of PE in Thailand and Vietnam was up to 56%. Finally, over 10% of the advances and retreats (re‐)occurred in various protected areas, with the expansion ratio of cropland and plantations nearly 1:2, particularly the Cambodia‐Thailand border. We thus appeal for more effective efforts from governments, the scientific community, and international initiatives (e.g., the UN‐REDD and Sustainable Development Goals) to further study and solve the issues of forest retreat and agricultural advance across the entire TAFF. Our new findings and insights about agricultural‐forest advances and retreats in their frontiers can enrich existing pan‐regional research of forest conversion or FL and agricultural expansion and provide an encouraging basis for action to reduce environmental degradation in tropical forests, including protected areas.

Final Pleistocene-Early Holocene (∼40–8 ka) Lithic Industries in Southern China and Their Implications for Understanding the Prehistory of Mainland Southeast Asia

ABSTRACT The cultural relationship between southern China and mainland Southeast Asia during the final Pleistocene-early Holocene is a major concern in prehistoric studies among scholars in both regions. During this period, the lithic assemblages are known to be predominantly cobble-based industries, grouped under the term “chopper-chopping tools tradition”. The analytical simplification of different assemblages may make typological sense, and this could explain why local technical expressions are not well documented; while the Hoabinhian technocomplex is a good example of cobble diversity and technological variability. To provide information on the various techno-cultural expressions on cobbles in southern China, this paper presents the results of four representative cobble assemblages from southern China studied from the chaîne opératoire perspective, and the inter-site comparison allowed us to identify their similarities and differences qualitatively and quantitatively. Finally, we discussed the strategic importance of southern China in the interpretation of techno-cultural phenomena in mainland Southeast Asia.