This study from the Luoxiao Mountains, southeastern China, combines historical information with paleoecological data from two wetlands, yielding a detailed reconstruction of landscape changes over recent centuries. The historical record suggests that people first settled in the region in the late Tang dynasty (618 to 907 CE), and wetland sediments show an increase in charcoal from about this time. During the Qing dynasty in the mid-seventeenth century, a temple complex and a Tea and Salt trade road were constructed near the study sites. Greater impacts are recorded in the wetland closer to the temple site. In the last few hundred years, pollen data show a regional decline of forest cover and the expansion of open vegetation as nearby lowland areas were settled and cleared for agriculture. Proxies for erosion show human impacts in the vicinity of the wetlands. Changes in charcoal inputs reflect regional fire activity, with elevated values around 1500 CE, low values during the Qing dynasty, and a subsequent peak during the twentieth century.

To assess the time scales and relative importance of temporal decoupling between hillslope erosion and the introduction of sediment to streams in a Yangtze River headwater basin, we used multiple techniques to date sediments in alluvial fans and terraces in a third-order stream valley draining a 30-km2 catchment in SW Sichuan, China. Poorly sorted angular sediments in tributary-junction alluvial fans ranged in age from 11261 BCE to 1844 CE, and predominantly fine-grained overbank sediments in alluvial terraces date to approximately 1700–1950. Ethnographic observations and field mapping of hillslope soil depths indicate that terrace sediments and upper strata of several fans correspond to a period of hillslope erosion associated with the intensification of hillslope swidden agriculture. Contemporary sediment production is dominated by lateral fluvial erosion of valley-bottom landforms rather than by hillslope erosion. The long-term temporal decoupling by valley storage of hillslope erosion from sediment delivery to streams has relevance to contemporary hillslope erosion and sedimentation control efforts in the Yangtze Basin. It also motivates investigating whether valley-filling anthropogenic “legacy sediments” may play a role in decoupling hillslope erosion from sediment production in other Yangtze Basin headwater basins.

Woodrats of the genus Neotoma are an important study system for ecological and paleoecological research. However, paleontological studies are often hindered by the difficulty of identifying woodrat remains to species. We address this limitation by using 2D landmark-based geometric morphometrics to classify 199 lower first molars (m1s) of five extant western North American Neotoma species (N. albigula, N. cinerea, N. fuscipes, N. lepida, and N. macrotis) collected throughout California. We then use discriminant analysis of principal components (DAPC) models to identify Late Pleistocene fossils of unknown species from the Rancho La Brea Tar Pits in Los Angeles, California. DAPC correctly identifies ∼85–90% of extant individuals to species, with most misclassifications occurring between sister taxa N. fuscipes and N. macrotis. Most fossil m1s are classified as N. macrotis by DAPC, which may be the first confirmation of N. macrotis in the fossil record. We show that landmark-based geometric morphometric analyses are generally effective at differentiating m1s of extant Neotoma species in California and they are an auspicious method for unknown fossil identification. Further applications of this method across a broader range of geographic locations and species will better contextualize its utility.

Identifying use-related residues from stone artefacts has become increasingly important in determining starchy plant exploitation over time and in different locales. Standard methods for processing residues samples are widely available but there is no clear consensus on suitable methods for attributing unknown starch grains to known plant taxa. We revisit the case study of a flaked stone artefact (K/76/S29B) recovered from Phase 1 (c. 10,000 ka) at Kuk Swamp in Papua New Guinea (PNG). Starch grains from taro (Colocasia esculenta) were identified in the residue extraction, but there were other grains that could not be attributed a plant origin at that time. The new analysis applied robust statistical methods, categorial attributes and expert input. In addition to C. esculenta, kudzu bean (Pueraria montana var. lobata) was identified, representing the earliest use of kudzu bean in the PNG highlands. Importantly, we also determined that starch grains from C. esculenta and Dioscorea esculenta are morphologically indistinguishable. We turned to other attributes of potential contributing plant taxa in determining distinguishing features: habit/growing requirements; the sedimentary context of the archaeological find; and environmental settings. Cultural use of both plants, artefacts and artefact technologies can be critical elements in confident identification outcomes, as exemplified here.

The incorporation of trace metals into land snail shells may record the ambient environmental conditions, yet this potential remains largely unexplored. In this study, we analyzed modern snail shells (Cathaica sp.) collected from 16 sites across the Chinese Loess Plateau to investigate their trace metal compositions. Our results show that both the Sr/Ca and Ba/Ca ratios exhibit minimal intra-shell variability and small inter-shell variability at individual sites. A significant positive correlation is observed between the shell Sr/Ca and Ba/Ca ratios across the plateau, with higher values being recorded in the northwestern sites where less monsoonal rainfall is received. We propose that shell Sr/Ca and Ba/Ca ratios, which record the composition of soil solution, may be controlled by the Rayleigh distillation in response to prior calcite precipitation. Higher rainfall amounts may lead to a lower degree of Rayleigh distillation and thus lower shell Sr/Ca and Ba/Ca ratios. This is supported by the distinct negative correlation between summer precipitation and shell Sr/Ca and Ba/Ca ratios, enabling us to reconstruct summer precipitation amounts using the Sr/Ca and Ba/Ca ratios of Cathaica sp. shells. The potential application of these novel proxies may also be promising for other terrestrial mollusks living in the loess deposits globally.

The Balkan Peninsula is considered to have acted as a glacial refugium as well as a biogeographic crossroads during the Pleistocene, playing an important role in the survival of biota and population dynamics through time. Furthermore, rather than being a homogeneous habitat, it is thought to have hosted a number of diverse, isolated “refugia within refugia,” providing suitable conditions for the persistence of different plant and animal species, as well as, potentially, Pleistocene hominins. We present the first palynological and charcoal record, although discontinuous, from the middle Pleistocene archaeological site Marathousa 1 (MAR-1; Megalopolis Basin) to reconstruct the local environment along with the first multispecies record of coprophilous fungal spores from Greece to track herbivore activity during the Marine Isotope Stage (MIS) 12. Our data show that during the early and late MIS 12, when the forest cover substantially decreased, mesophilous trees and aquatic vegetation persisted, reflecting wetter and milder conditions at MAR-1. Herbivore presence is documented by ∼473 ka, while its intensification coincides with increased vegetation biomass and local fire activity during the late MIS 12. Our findings suggest that MAR-1 likely served as a glacial refugium for middle Pleistocene hominins, providing essential resources for their survival during MIS 12.

The glacial history of northeast Siberia is poorly understood compared with other high-latitude regions. Using 10Be and 26Al exposure dating together with remote sensing, we have investigated the glacial history of a remote, formerly glaciated valley in the Tas-Kystabyt Range of the Chersky Mountains in central northeast Siberia. Based on measurements from moraine boulders and bedrock samples, we find evidence for deglaciation of the valley 45.6 ± 3.4 ka ago, that is during the peak of Marine Isotope Stage 3. Satellite imagery of the range reveals at least two generations of moraines in other nearby valleys, indicating that multiple stages of glaciation took place across the Tas-Kystabyt Range. Based on calculated equilibrium-line altitudes, we speculate that the outer set of moraines is linked to the 45.6 ± 3.4 ka deglaciation event identified by our dating, while the inner generation of moraines is associated with a younger glaciation event, possibly the last glacial maximum (LGM). Thus, our results reaffirm current impressions that the maximum ice extent during the last glacial cycle was reached before the global LGM in northeast Siberia.

Landscape evolution in karst terrains affects both subterranean and surface settings. For better understanding of controlling processes and connections between the two, multiple geochronometers were used to date sediments and speleothems in upper-level passages of Fitton Cave adjacent to the Buffalo River, northern Arkansas, within the southern Ozark Plateau. Burial cosmogenic-nuclide dating of coarse sediments indicates that gravel pulses washed into upper passages at 2.2 Ma and 1.25 Ma. These represent the oldest epigenetic cave deposits documented in this region. Associated sands and clay-rich sediments mostly have reversed magnetic polarity and thermally transferred optically stimulated luminescence dates of 1.2 to 1.0 Ma. Abandonment of these upper passages began before 0.72 Ma, when coarse sediment was deposited in a passage incised below older sediment. Maximum U-series dates of 0.7–0.4 Ma for flowstones capping clastic deposits mark the stabilization of older sediments and a change to vadose conditions that allowed post–0.4 Ma stalagmite growth. Resulting valley incision rates since 0.85 Ma are estimated at 27 m/Ma. Coarse cave-sediment pulses correlate to Laurentide glacial tills about 300 km to the north, suggesting climate influence on periglacial sediment production. Dated cave sediments also may correlate with undated older strath terraces preserved at similar heights above the Buffalo River.