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Fire regime shifts are driven by climate and natural vegetation changes, but can be strongly affected by human land management. Yet, it is poorly known how humans have influenced fire regimes prior to active wildfire suppression. Among the last 250 years, the human contribution to the global increase in fire occurrence during the mid-19th century is especially unclear, as data sources are limited. Here, we test the extent to which forest management has driven fire regime shifts in a temperate forest landscape. We combine multiple fire proxies (macroscopic charcoal and fire-related biomarkers) derived from highly resolved lake sediments (i.e., 3–5 years per sample), and apply a new statistical approach to classify source area- and temperature-specific fire regimes (biomass burnt, fire episodes). We compare these records with independent climate and vegetation reconstructions. We find two prominent fire regime shifts during the 19th and 20th centuries, driven by an adaptive socio-ecological cycle in human forest management. Although individual fire episodes were triggered mainly by arson (as described in historical documents) during dry summers, the biomass burnt increased unintentionally during the mid-19th century due to the plantation of flammable, fast-growing pine tree monocultures needed for industrialization. State forest management reacted with active fire management and suppression during the 20th century. However, pine cover has been increasing since the 1990s and climate projections predict increasingly dry conditions, suggesting a renewed need for adaptations to reduce the increasing fire risk.

The composition of perennially frozen deposits holds information on the palaeo-environment during and following deposition. In this study, we investigate late Pleistocene permafrost at the western coast of the Buor Khaya Peninsula in the south-central Laptev Sea (Siberia), namely the prominent eastern Siberian Yedoma Ice Complex (IC). Two Yedoma IC exposures and one drill core were studied for cryolithological (i.e. ice and sediment features), geochemical, and geochronological parameters. Borehole temperatures were measured for 3 years to capture the current thermal state of permafrost. The studied sequences were composed of ice-oversaturated silts and fine-grained sands with considerable amounts of organic matter (0.2 to 24 wt %). Syngenetic ice wedges intersect the frozen deposits. The deposition of the Yedoma IC, as revealed by radiocarbon dates of sedimentary organic matter, took place between 54.1 and 30.1 kyr BP. Continued Yedoma IC deposition until about 14.7 kyr BP is shown by dates from organic matter preserved in ice-wedge ice. For the lowermost and oldest Yedoma IC part, infrared-stimulated luminescence dates on feldspar show deposition ages between 51.1 ± 4.9 and 44.2 ± 3.6 kyr BP. End-member modelling was applied to grain-size-distribution data to determined sedimentation processes during Yedoma IC formation. Three to five robust end-members were detected within Yedoma IC deposits, which we interpret as different modes of primary and reworked unconfined alluvial slope and fan deposition as well as of localized eolian and fluvial sediment, which is overprinted by in situ frost weathering. The cryolithological inventory of the Yedoma IC preserved on the Buor Khaya Peninsula is closely related to the results of other IC studies, for example, to the west on the Bykovsky Peninsula, where formation time (mainly during the late Pleistocene marine isotope stages (MIS) 3 interstadial) and formation conditions were similar. Local freezing conditions on Buor Khaya

Grain-size distributions offer powerful proxies of past environmental conditions that are related to sediment sorting processes. However, they are often of multimodal character because sediments can get mixed during deposition. To facilitate the use of grain size as palaeoenvironmental proxy, this study aims to distinguish the main detrital processes that contribute to lacustrine sedimentation across the Tibetan Plateau using grain-size end-member modelling analysis. Between three and five robust grain-size end-member subpopulations were distinguished at different sites from similarly–likely end-member model runs. Their main modes were grouped and linked to common sediment transport and depositional processes that can be associated with contemporary Tibetan climate (precipitation patterns and lake ice phenology, gridded wind and shear stress data from the High Asia Reanalysis) and local catchment configurations. The coarse sands and clays with grain-size modes >250 μm and <2 μm were probably transported by fluvial processes. Aeolian sands (� 200 μm) and coarse local dust (60 μm), transported by saltation and in near-surface suspension clouds, are probably related to occasional westerly storms in winter and spring. Coarse regional dust with modes 25 μm may derive from near-by sources that keep in longer term suspension. The continuous background dust is differentiated into two robust end members (modes: 5–10 and 2–5 μm) that may represent different sources, wind directions and/or sediment trapping dynamics from long-range, upperlevel westerly and episodic northerly wind transport. According to this study grain-size end members of only fluvial origin contribute small amounts to mean Tibetan lake sedimentation (19±5 %), whereas local to regional aeolian transport and background dust deposition dominate the clastic sedimentation in Tibetan lakes (contributions: 42±14% and 51±11 %). However, fluvial and alluvial reworking of aeolian material from nearby slopes during sum

Researchers who work with animals commonly face the dilemma of euthanizing some animals. Euthanasia of animals, especially where it concerns pest wildlife or feral species, is often a sensitive and emotive topic and can raise vigorous public debate. However, little is known about the experiences of those who euthanize animals. This study interviewed a number of people about their experiences of animal euthanasia in order to attain a better understanding of any impacts on the person involved in the euthanasia. Participants were mainly researchers, including some no longer working directly with animals and some who provide support services. The participants had a range of experience in wildlife research, and veterinary practices as well as laboratory, farm, and animal shelters. Thematic analysis was used to analyse qualitative interview data. Key emerging themes included the language used to describe euthanasia, the coping strategies that individuals applied, and the organizational factors which could ensure an appropriate context for researchers carrying out euthanasia. Participants reported that social support for emotional stress arising from euthanasia was generally not available. Organizational factors which impacted on participants included decision making processes, availability of training and support, work practices and justifications for euthanasia. The paper concludes that it is important not to pathologize the experiences of researchers but to recognize that the way the decision to euthanize is reached and the training it is based on can make a significant difference to a person's attitudes and levels of comfort when euthanizing animals.

Unmixing of grain-size distributionswithmultivariate statistical analysis gives indications of themain sediment transport processes and related environmental conditions in an area. We performed end-member mixing analysis (EMMA) of sedimentological data from 912 terrestrial sediment samples collected in the Donggi Cona catchment, north-eastern Tibetan Plateau. Up to the present, this is the largest sedimentological dataset on the Tibetan Plateau. EMMA resulted in the characterisation of three end-members that explain 88% of the variance within the dataset. The end-members all represent aeolian deposits. The first end-member EM 1 represents very fine dune sediments that were deflated from a former lake system. EM 2 represents medium sand deposits that were blown out from playa and alluvial fan sediments. EM 3 represents fine loess(−like) sediments mainly found at higher elevations. Different transformations, adding of a fourth end-member and adding of up to 200 loess samples do not change the composition of the end-members, demonstrating the robustness of themodel. EMMA allows the synchronous interpretation of very large datasets, resulting in a general characterisation of sediment transport in a particular area. Performing EMMA on the dataset demonstrates the importance of aeolian transport in this part of the world.

Lake Donggi Cona is located in the north-eastern part of the Tibetan Plateau at the boundary between monsoon and westerly climate influence on an elevation of 4090 m. Donggi Cona is an oligotrophic freshwater lake with a recent open-basin system. The 30 km long, 8 km wide, and up to 98 m deep lake basin is a tectonic pull-apart structure as part of Kunlun fault. Sub-bottom profiling of the lake basin revealed the presence of graben structures, conjugate faults, subaquatic terraces, and ancient fan systems, draped by 4 to 5 m thick postglacial lacustrine sediments. The aim of our investigations is the reconstruction of palaeo-environmental changes of the lake catchment.After analysis of the seismic pre-survey, five sediment cores have been retrieved at 35-40 m and at 2 m water depth. The cores are partly laminated and composed of calcareous muds with changing amounts of carbonate micrite, organic matter and detrital silt and clay. Furthermore, the cores contains remarkable amounts of ostracods and plant remains. Dating results from the top of three sediment cores obtain a hardwater effect of about 2000 years. Nineteen AMS dates from the entire cores suggest a sedimentary history throughout the Holocene. Despite possible reservoir errors the sandy bottom sediments were deposited during or after the last glacial maximum (LGM). With a multi-proxy approach using grain size, XRF, XRD, CNS, TOC and multivariate statistical endmember-modelling (EMMA) we hereby represent an interpretation concerning changes in hydrological conditions and sedimentation processes during the last about 20 kyears: Prior to 18 kyears, terrestrial loess and sand suggest a very low lake level. From 18 to 13 kyrs. BP the lake level rise during a period of climate-driven glacier melt. For the same time period the detrital supply is at its maximum and seems to control the high sedimentation rate.Grain-size coarsening and hiatuses in four sediment cores, document a repeated lake-level fall after 13 kyr

Limnogeological studies at Lake Donggi Cona on the NE Tibetan PlateauS. Opitz (1), E. Dietze (4), J. IJmker (2), K. Hartmann (4), F. Lehmkuhl (2), G. Stauch (2), B. Wünnemann (3, 4), B. Diekmann (1),(1) Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam Germany (Stephan.Opitz@awi.de), (2) Department of Geography, RWTH Aachen University, Germany (3) School of Geography and Oceanography, Nanjing University, China, (4) Institute of Geographical Sciences, Interdisciplinary Center of Ecosystem Dynamics of Central Asia (EDCA), Freie Universität Berlin, Germany,Lake Donggi Cona is located in the north-eastern part of the Tibetan Plateau at the boundary between monsoon and westerly climate influence. The main objective is to infer late glacial to Holocene lake development in response to monsoon dynamics. Donggi Cona is an oligotrophic freshwater lake with a recent open-basin system. The 30 km long, 8 km wide, and up to 90 m deep open lake basin is a tectonic pull-apart structure, situated along the Kunlun suture. Sub-bottom profiling of the lake basin revealed the presence of graben structures, conjugate faults, subaquatic terraces, and ancient fan systems, draped by 4 to 5 m thick postglacial lacustrine muds.After analysis of the seismic pre-survey, five sediment cores have been retrieved at 35-40 m and at 2 m water depth. The cores are partly laminated and composed of calcareous muds with variable amounts of carbonate micrite, organic matter, detrital silt and clay, and are rich in ostracods and plant remains. Dating results from the top of cores obtain a hardwater effect of about 2000 years. 19 14C AMS dates from the entire cores suggest a sedimentary history throughout the Holocene. Despite possible reservoir errors the sandy bottom sediments were deposited during or after the last global glacial maximum (LGM). With a multi-proxy approach using grain size, XRF, XRD, CNS, TOC and statistical modelling (EMMA) we reconstruct the lake development

The catchment of Lake Donggi Cona, situated at north-eastern Tibetan Plateau, is a region influenced by monsoonal air masses of different origin and character, highly variable in space and time. Reconstruction of Quaternary monsoon dynamics focuses mainly on high-resolution archives (e.g. glacier ice and speleothem records) with detailed proxy information on temperature and precipitation regimes in the past. However, also sedimentological and geomorphological processes respond to and register monsoon dynamics, mainly amount and spatio-temporal variation of precipitation. In lake catchments, climatic signals affect the whole process system within the geomorphological inventory on different scales. Sediment traps store these signals and the landscapes response to them, though buffering and topological dependencies of archives have to be considered. Within temporal or final sediment storage basins, sediment properties represent a mixture of terrestrial and lacustrine processes during and after deposition (e.g. aeolian, fluvial transport, and water current directions). Each process as well as different sediment sources (e.g. sub-catchments with a certain geochemical and mineralogical fingerprint) can be regarded as an end-member.We present an approach of unmixing lake sediment properties, i.e. grain size distributions, geochemical and mineralogical compositions, to reveal end-members of geomorphological processes and sediment source. In a first step, modern surface samples from the bottom of Lake Donggi Cona are used to test a flexible iterative end-member modelling algorithm (EMMA) with different types of data transformation, eigenspace analysis and goodness-of-fit tests. Empirical end-members are derived and compared to natural end-members, i.e. terrestrial surface samples from locations dominated by a single geomorphological process regime or sediment source. Using Bayesian approaches, conditional probabilities can be given for the variation within and between sedime