Robust quantitative estimates of land use and land cover change are necessary to develop policy solutions and interventions aimed towards sustainable land management. Here, we evaluated the combination of Landsat and L-band Synthetic Aperture Radar (SAR) data to estimate land use/cover change in the dynamic tropical landscape of Tanintharyi, southern Myanmar. We classified Landsat and L-band SAR data, specifically Japan Earth Resources Satellite (JERS-1) and Advanced Land Observing Satellite-2 Phased Array L-band Synthetic Aperture Radar-2 (ALOS-2/PALSAR-2), using Random Forests classifier to map and quantify land use/cover change transitions between 1995 and 2015 in the Tanintharyi Region. We compared the classification accuracies of single versus combined sensor data, and assessed contributions of optical and radar layers to classification accuracy. Combined Landsat and L-band SAR data produced the best overall classification accuracies (92.96% to 93.83%), outperforming individual sensor data (91.20% to 91.93% for Landsat-only; 56.01% to 71.43% for SAR-only). Radar layers, particularly SAR-derived textures, were influential predictors for land cover classification, together with optical layers. Landscape change was extensive (16,490 km 2 ; 39% of total area), as well as total forest conversion into agricultural plantations (3214 km 2). Gross forest loss (5133 km 2) in 1995 was largely from conversion to shrubs/orchards and tree (oil palm, rubber) plantations, and gross gains in oil palm (5471 km 2) and rubber (4025 km 2) plantations by 2015 were mainly from conversion of shrubs/orchards and forests. Analysis of combined Landsat and L-band SAR data provides an improved understanding of the associated drivers of agricultural plantation expansion and the dynamics of land use/cover change in tropical forest landscapes.

Large prehistoric rockslides tend to occur within spatio-temporal clusters suggesting a common trigger such as earthquake shaking or enhanced wet periods. Yet, trigger assessment remains equivocal due to the lack of conclusive observational evidence. Here, we use high-resolution lacustrine paleoseismology to evaluate the relation between past seismicity and a spatio-temporal cluster of large prehistoric rockslides in the Eastern Alps. Temporal and spatial coincidence of paleoseismic evidence with multiple rockslides at ~4.1 and ~3.0 ka BP reveals that severe earthquakes (local magnitude ML 5.5–6.5; epicentral intensity I0 VIII¼–X¾) have triggered these rockslides. A series of preceding severe earthquakes is likely to have progressively weakened these rock slopes towards critical state. These findings elucidate the role of seismicity in preparing and triggering large prehistoric rockslides in the European Alps, where rockslides and earthquakes typically occur in clusters. Such integration of multiple datasets in other formerly glaciated regions with low to moderate seismicity will improve our understanding of catastrophic rockslide drivers.

Abstract:We investigated the use of multi-spectral Landsat OLI imagery for delineating mangrove, lowland evergreen, upland evergreen and mixed deciduous forest types in Myanmar's Tanintharyi Region and estimated the extent of degraded forest for each unique forest type. We mapped a total of 16 natural and human land use classes using both a Random Forest algorithm and a multivariate Gaussian model while considering scenarios with all natural forest classes grouped into a single intact or degraded category. Overall, classification accuracy increased for the multivariate Gaussian model with the partitioning of intact and degraded forest into separate forest cover classes but slightly decreased based on the Random Forest classifier. Natural forest cover was estimated to be 80.7% of total area in Tanintharyi. The most prevalent forest types are upland evergreen forest (42.3% of area) and lowland evergreen forest (21.6%). However, while just 27.1% of upland evergreen forest was classified as degraded (on the basis of canopy cover <80%), 66.0% of mangrove forest and 47.5% of the region's biologically-rich lowland evergreen forest were classified as degraded. This information on the current status of Tanintharyi's unique forest ecosystems and patterns of human land use is critical to effective conservation strategies and land-use planning.

Myanmar’s recent transition from military rule towards a more democratic government has largely ended decades of political and economic isolation. Although Myanmar remains heavily forested, increased development in recent years has been accompanied by exceptionally high rates of forest loss. In this study, we document the rapid progression of deforestation in and around the proposed Lenya National Park, which includes some of the largest remaining areas of lowland evergreen rainforest in mainland Southeast Asia. The globally unique forests in this area are rich in biodiversity and remain a critical stronghold for many threatened and endangered species, including large charismatic fauna such as tiger and Asian elephant. We also conducted a rapid assessment survey of the herpetofauna of the proposed national park, which resulted in the discovery of two new species of bent-toed geckos, genus Cyrtodactylus. We describe these new species, C. lenya sp. nov. and C. payarhtanensis sp. nov., which were found in association with karst (i.e., limestone) rock formations within mature lowland wet evergreen forest. The two species were discovered less than 35 km apart and are each known from only a single locality. Because of the isolated nature of the karst formations in the proposed Lenya National Park, these geckos likely have geographical ranges restricted to the proposed protected area and are threatened by approaching deforestation. Although lowland evergreen rainforest has vanished from most of continental Southeast Asia, Myanmar can still take decisive action to preserve one of the most biodiverse places on Earth.

The Eastern European Alps are characterized by slow active deformation with low- to moderate seismicity. Recurrence rates of severe earthquakes exceed the time span of historical documentation. Therefore, historical and instrumental earthquake records might be insufficient for seismic hazard assessment and high-quality paleoseismic data is required. However, primary geological observations of postglacial fault activity are scarcely found, because major faults are buried below thick sedimentary sequences in glacially overdeepened valleys. Moreover, high erosion rates, gravitational slope processes and penetrative anthropogenic landscape modification often obscure geomorphic features related to surface ruptures. Here we present one of the rare paleoseismic data sets showing both on-fault evidence as subaqueous surface ruptures and off-fault evidence as multiple coeval mass-transport deposits (MTDs) and megaturbidites within a single high-resolution seismic-stratigraphic framework of the inner-alpine lake Achensee. Co-occurrence of on-fault and off-fault paleoseismic evidence on three stratigraphic levels indicates seismic activity with inferred moment magnitudes MW ∼6–6.5 of the local, lake-crossing Sulzgraben-Eben thrust at ∼8.3 ka BP and twice in Late Glacial times. Additional eight stratigraphic levels with only off-fault paleoseismic evidence document severe seismic shaking related to the historical MW ∼5.7 earthquake in Hall (CE 1670) and seven Holocene earthquakes, which have exceeded a local seismic intensity of ∼VI (EMS-98) at Achensee. Furthermore, we discuss natural and methodological influencing factors and potential pitfalls for the elaboration of a subaqueous paleoseismic record based on surface ruptures and multiple, coeval MTDs.