Reliable quantitative vegetation reconstructions for Europe during the Holocene are crucial to improving our understanding of landscape dynamics, making it possible to assess the past effects of environmental variables and land-use change on ecosystems and biodiversity, and mitigating their effects in the future. We present here the most spatially extensive and temporally continuous pollen-based reconstructions of plant cover in Europe (at a spatial resolution of 1° × 1°) over the Holocene (last 11.7 ka BP) using the ‘Regional Estimates of VEgetation Abundance from Large Sites’ (REVEALS) model. This study has three main aims. First, to present the most accurate and reliable generation of REVEALS reconstructions across Europe so far. This has been achieved by including a larger number of pollen records compared to former analyses, in particular from the Mediterranean area. Second, to discuss methodological issues in the quantification of past land cover by using alternative datasets of relative pollen productivities (RPPs), one of the key input parameters of REVEALS, to test model sensitivity. Finally, to validate our reconstructions with the global forest change dataset. The results suggest that the RPPs.st1 (31 taxa) dataset is best suited to producing regional vegetation cover estimates for Europe. These reconstructions offer a long-term perspective providing unique possibilities to explore spatial-temporal changes in past land cover and biodiversity.

Forests in a time machine – possibilities and limits of paleoecology Paleoecology allows the reconstruction of ecological processes that take place on long timescales – for example the vegetation dynamics since the last Ice Age or changes in the species composition of forests due to anthropogenic land use. This can be achieved by analyzing plant remains like pollen, spores, leaves, seeds or charcoal that have been conserved over millennia under low oxygen conditions in the sediment of lakes and mires. In this article, we outline the principals, the limits and the potential of paleoecology. It becomes clear that nowadays, this discipline is more than just a descriptive science. Thanks to quantitative methods, it can be used to test ecological hypothesis and identify causal relationships. Paleoecology can therefore contribute to assess the resilience of vegetation communities to external disturbances, and provides important information on how our forests will react to past, current and future climate change.

Black and tan animals have tan-coloured ventral body surfaces separated by sharp boundaries from black-coloured dorsal body surfaces. In the at mouse mutant, a retroviral 6 kb insertion located in the hair cycle-specific promoter of the murine Asip gene encoding agouti signalling protein causes the black and tan phenotype. In rabbits, three ASIP alleles are thought to exist, including an at allele causing a black and tan coat colour that closely resembles the mouse black and tan phenotype. The goal of our study was to identify the functional genetic variant causing the rabbit at allele. We performed a WGS-based comparative analysis of the ASIP gene in one black and tan and three wt agouti-coloured rabbits. The analysis identified 75 at -associated variants including an 11 kb deletion. The deletion is located in the region of the hair cycle-specific ASIP promoter and thus in a region homologous to the site of the retroviral insertion causing the at allele in mice. We observed perfect association of the genotypes at this deletion with the coat colour phenotype in 49 rabbits. The comparative analysis and the previous knowledge about the regulation of ASIP expression suggest that the 11 kb deletion is the most likely causative variant for the black and tan phenotype in rabbits.

Invasions and collapses of tree species after the Ice Age Pollen and macrofossils are used to reconstruct mechanisms and processes of past invasions and collapses of tree species. They are also providing bottom lines for future invasions and collapses. The Swiss forest communities were always shifting to adjust to climate and land use changes. Some invasions occurred surprisingly synchronous in space. Ecosystem adjustment processes started rapidly after climate change or disturbance, but usually lasted several centuries, given that they involved several tree generations. The available climate and vegetation history evidence suggests that the today's rather homogenous sweet chestnut, oak, beech and spruce forests are particularly prone to be invaded, because the communities were created by millennial-long land use and also because the realized climatic niche of the dominant species is strongly anthropogenically widened. On the other hand, the realized climatic niche of silver fir is strongly narrowed by human impact. This implies that silver fir is far more resilient to climate change than its today's range would suggest. Thus new plant species may have considerable difficulties to enter quasi-natural mixed silver fir forest communities. A similar finding, although less pronounced, was obtained for linden, elm, ash and maple species. Evergreen broadleaved species from the Mediterranean region, which are native to Switzerland since millennia but were not able to expand due to climatic reasons (e.g. Quercus ilex), will presumably spread spontaneously within a few decades under changing climate. Such future invasions can be considered as a natural process from an ecological point of view, if the invading species involved originate from the neighboring subtropics.

1. Population dynamics is a field rich in theory and poor in long-term observational data. Finding sources of long-term data is critical as ecosystems around the globe continue to change in ways that current theories and models have failed to predict. Here we show how long-term ecological data can improve our understanding about palaeo-population change in response to external environmental factors, antecedent conditions and community diversity. 2. We examined a radiometrically dated sediment core from the Didachara Mire in the mountains of south-western Georgia (Caucasus) and analysed multiple biological proxies (pollen, fern spores, non-pollen palynomorphs, charcoal, diatoms, chrysophyte cysts, midges, mites and testate amoebae). Numerical techniques, including multivariate ordination, rarefaction, independent splitting and trait analysis, were used to assess the major drivers of changes in community diversity and population stability. Integrated multi-proxy analyses are very rare in the Caucasus, making this a unique record of long-term ecological change in a global biodiversity hotspot. 3. Synthesis. Population changes in the terrestrial community coincided primarily with external environmental changes, while populations within the peatland community were affected by both internal and external drivers at different times. In general, our observations accord with theoretical predictions that population increases lead to greater stability and declines lead to instability. Random variation and interspecific competition explain population dynamics that diverged from predictions. Population change and diversity trends were positively correlated in all taxonomic groups, suggesting that population-level instability is greater in more diverse communities, even though diverse communities are themselves more stable. There is a continuing need to confront population theory with long-term data to test the predictive success of theoretical frameworks, thereby improving their ability to predict future change.

Gerhard Lang, one of the great German botanists and palaeoecologists of the 20th century, died on the 19th June 2016 in Biberach, southern Germany.He will be greatly missed by his friends and colleagues, not only for his vast expertise in botany, ecology, biogeography, and vegetation history, but also for his integrity, kindness, and humour.For many of his students and post-doctoral fellows he was not only an excellent teacher and mentor, but also an important role model (Fig. 1).Gerhard Lang was born on October 21st 1924 in Ravensburg.Already in his youth he was an

Herbert E Wright Jr was one of the foremost Quaternary scientists of the last century. He made wide ranging contributions to our understanding of the late-Quaternary of North and South America, Europe, Asia and Africa. This was based largely on reconstructing palaeoenvironments from lake sediments and included the important implications for glacial, vegetational, fire and climatic history, geoarchaeology and conservation. Many of his inter-disciplinary research projects involved fieldwork with his graduate students and co-workers from the University of Minnesota where he created and led the renowned Limnological Research Center. Perhaps his most outstanding contribution was as an instigator of the Co-operative Holocene Mapping Project (COHMAP). This triggered a paradigm shift in Holocene climatic research involving the comparison of climate-model simulations of past climates with palaeoclimatic data.

100 years ago, Lennart von Post first used pollen analysis to reconstruct past ecosystems

To estimate whether or not a plant taxon found in the fossil record was locally present may be difficult if only pollen is analyzed. Plant macrofossils, in contrast, provide a clear indication of a taxon’s local presence, although in some lake sediments or peats, macrofossils may be rare or degraded. For conifers, the stomata found on pollen slides are derived from needles and thus provide a valuable proxy for local presence and they can be identified to genus level. From previously published studies, a transect across the Alps based on 13 sites is presented. For basal samples in sandy silt above the till with high pollen values of Pinus, for example, we may distinguish pine pollen from distant sources (samples with no stomata), from reworked pollen (samples with stomata present). The first apparent local presence of most conifer genera based on stomata often but not always occurs together with the phase of rapid pollen increase (rational limit). An exception is Larix, with its annual deposition of needles and heavy poorly dispersed pollen, for it often shows the first stomata earlier, at the empirical pollen limit. The decline and potential local extinction of a conifer can sometimes be shown in the stomata record. The decline may have been caused by climatic change, competition, or human impact. In situations where conifers form the timberline, the stomata record may indicate timberline fluctuations. In the discussion of immigration or migration of taxa we advocate the use of the cautious term “apparent local presence” to include some uncertainties. Absence of a taxon is impossible to prove.

Palynology provides the opportunity to make inferences on changes in diversity of terrestrial vegetation over long time scales. The often coarse taxonomic level achievable in pollen analysis, differences in pollen production and dispersal, and the lack of pollen source boundaries hamper the application of diversity indices to palynology. Palynological richness, the number of pollen types at a constant pollen count, is the most robust and widely used diversity indicator for pollen data. However, this index is also influenced by the abundance distribution of pollen types in sediments. In particular, where the index is calculated by rarefaction analysis, information on taxonomic richness at low abundance may be lost. Here we explore information that can be extracted from the accumulation of taxa over consecutive samples. The log-transformed taxa accumulation curve can be broken up into linear sections with different slope and intersect parameters, describing the accumulation of new taxa within the section. The breaking points may indicate changes in the species pool or in the abundance of high versus low pollen producers. Testing this concept on three pollen diagrams from different landscapes, we find that the break points in the taxa accumulation curves provide convenient zones for identifying changes in richness and evenness. The linear regressions over consecutive samples can be used to inter- and extrapolate to low or extremely high pollen counts, indicating evenness and richness in taxonomic composition within these zones. An evenness indicator, based on the rank-order-abundance is used to assist in the evaluation of the results and the interpretation of the fossil records. Two central European pollen diagrams show major changes in the taxa accumulation curves for the Lateglacial period and the time of human induced land-use changes, while they do not indicate strong changes in the species pool with the onset of the Holocene. In contrast, a central Swedish pollen diagram shows comparatively little change, but high richness during the early Holocene forest establishment. Evenness and palynological richness are related for most periods in the three diagrams, however, sections before forest establishment and after forest clearance show high evenness, which is not necessarily accompanied by high palynological richness, encouraging efforts to separate the two.

Corrigendum to “Responses to rapid warming at Termination 1a at Gerzensee (Central Europe): Primary succession, albedo, soils, lake development, and ecological interactions” [Palaeogeogr. Palaeoclimatol. Palaeoecol. 391PB (2014) 111–131] Brigitta Ammann ⁎, Ulrike J. van Raden , Jakob Schwander , Ueli Eicher , Adrian Gilli , Stefano M. Bernasconi , Jacqueline F.N. van Leeuwen , Heike Lischke , Stephen J. Brooks , Oliver Heiri , Katařina Novakova , Maarten van Hardenbroek , Ulrich von Grafenstein , Soumaya Belmecheri , W.O. van der Knaap , Michel Magny , Werner Eugster , Daniele Colombaroli , Ebbe Nielsen , Willy Tinner , Herbert E. Wright m

The late-glacial climatic warming indicated in the Greenland ice-core record about 14,685 years before 1950 AD belongs to a type of very rapid high-amplitude warming similar the onsets of Dansgaard-Oeschger events during marine isotope stage 3 (MIS 3). In order to estimate the nature and rates of change of biotic responses to such a major climatic shift we need a reliable time scale as well as climatic indicators independent of the biota. Both are provided by a high-resolution oxygen-isotope record from precipitated carbonates of lake marl in Gerzensee, Switzerland (van Raden et al., 2013-this issue). On the basis of the assumption of synchronous climatic changes between Greenland and Gerzensee, the close correlation of the oxygen-isotope changes at the two sites allows the use of the NGRIP GICC05-timescale at Gerzensee (with the zero point at 1950 AD to maintain comparability with the numerous radiocarbon dates in Europe). The delta O-18-record measured in precipitated carbonates is checked and refined by the delta O-18 measured in mono-specific ostracod samples (Von Grafenstein et al., 2013-in this issue). The shift of 3.6 parts per thousand delta O-18 PDB in only about 112 years at the end of the GS-2 represents a very rapid temperature increase of at least 6.2 degrees C. This increase is confirmed by reconstructions based on transfer functions for pollen and chironomids by Lotter et al. (2012) (possibly 4-7 degrees C in the annual mean and 2-5 degrees C in summer temperatures). After this major shift the Greenland late-glacial interstadial GI-1 (corresponding to the regional biozones Bolling and Allerod) delta O-18-records of both Greenland and Gerzensee exhibit four minor fluctuations (about 1.0-1.2 parts per thousand delta O-18), of which the second and the fourth are especially clearly correlated with several of terrestrial records in the northern hemisphere.The oxygen-isotope record is used as a template for all these sediment- and bio-stratigraphies.The biotic responses may include at least five types of process: (1) changes in productivity of individuals (within a year or two), (2) changes in populations (usually somewhat slower, depending on life cycles and environmental constraints), (3) changes due to migration (often rather slow, depending again on life cycles and environmental constraints), (4) changes in the terrestrial and aquatic communities and (5) changes on the level of ecosystems (including pedogenesis, nutrient cycling, and species interactions). These biotic responses to the early rapid warming about 14.685 ka BP are elaborated in subsequent papers for plants, chironomids, ostracods, and Cladocera (Ammann et al., 2013-in this issue-a; Brooks and Heiri, 2013-this issue; Von Grafenstein et al., 2013-in this issue; Novakova et al., 2013-this issue). In addition, lake levels are reconstructed by Magny (2013-this issue) and vegetation dynamics and N2O-emissions are modelled (Lischke et al., 2013-this issue; Pfeiffer et al., 2013-this issue). The changes in the mammal fauna of the Swiss Plateau are summarized by Nielsen (2013-this issue). (C) 2013 Elsevier B.V. All rights reserved.

The aim of this study was to explore potential causes and mechanisms for the sequence and temporal pattern of tree taxa, specifically for the shift from shrub-tundra to birch-juniper woodland during and after the transition from the Oldest Dryas to the Bolling-Allerod in the region surrounding the lake Gerzensee in southern Central Europe. We tested the influence of climate, forest dynamics, community dynamics compared to other causes for delays.For this aim temperature reconstructed from a delta O-18-record was used as input driving the multi-species forest-landscape model TreeMig. In a stepwise scenario analysis, population dynamics along with pollen production and transport were simulated and compared with pollen-influx data, according to scenarios of different delta O-18/temperature sensitivities, different precipitation levels, with/without inter-specific competition, and with/without prescribed arrival of species. In the best-fitting scenarios, the effects on competitive relationships, pollen production, spatial forest structure, albedo, and surface roughness were examined in more detail. The appearance of most taxa in the data could only be explained by the coldest temperature scenario with a sensitivity of 0.3 parts per thousand/degrees C, corresponding to an anomaly of - 15 degrees C. Once the taxa were present, their temporal pattern was shaped by competition. The later arrival of Pinus could not be explained even by the coldest temperatures, and its timing had to be prescribed by first observations in the pollen record. After the arrival into the simulation area, the expansion of Pinus was further influenced by competitors and minor climate oscillations. The rapid change in the simulated species composition went along with a drastic change in forest structure, leaf area, albedo, and surface roughness. Pollen increased only shortly after biomass.Based on our simulations, two alternative potential scenarios for the pollen pattern can be given: either very cold climate suppressed most species in the Oldest Dryas, or they were delayed by soil formation or migration. One taxon, Pious, was delayed by migration and then additionally hindered by competition. Community dynamics affected the pattern in two ways: potentially by facilitation, i.e. by nitrogen-fixing pioneer species at the onset, whereas the later pattern was clearly shaped by competition. The simulated structural changes illustrate how vegetation on a larger scale could feed back to the climate system.For a better understanding, a more integrated simulation approach covering also the immigration from refugia would be necessary, for this combines climate-driven population dynamics, migration, individual pollen production and transport, soil dynamics, and physiology of individual pollen production. (C) 2012 Elsevier B.V. All rights reserved.

The stable isotope signature of ostracods, molluscs, and charophyte remains from the late glacial section of a shallow core from lake Gerzensee, Switzerland, is analyzed along with the bulk carbonate isotope composition in a multi-proxy study aiming to document the biotic responses to the first strong warming ca. 14.6ka ago after full glacial conditions. The main goal of our contribution is to understand the climatic significance of the oxygen-isotope variations in and between the different carbonate species and ideally provide a quantitative estimate of the oxygen isotopic composition of meteoric precipitation, which then could be translated to mean temperature estimates. Corrected for the respective vital offsets, the different carbonates show almost identical oxygen-isotope ratios for the time preceding and after the rapid transition from Greenland climate stages GS2 to GI1, indicating low and seasonally constant water temperatures at the sediment–water interface for this period. In the following the difference between cold season and warm-season carbonates increases gradually, pointing to a summer–winter temperature difference of roughly 10K at the end of GI1. We conclude that this gradual water-temperature increase is independent of climate and is mainly due to sedimentation, shallowing the sediment–water interface, eventually accentuated by a gradual decrease of Gerzensee's water level during GI1. Corrected for the isotope fractionation induced by the long term trend of such water temperature change, the higher resolved δ18O record from the bulk carbonates allows calculation of the presumed oxygen–isotope ratio of former lake water (δ18OL), which shows striking similarity to the record from Ammersee. Introducing a tentative hydrological correction close to the present day offset between δ18OL and the oxygen–isotopes in meteoric precipitation (δ18OP), we propose a quantitative δ18OP and mean air temperature record for the Gerzensee region.

A number of hydrological, botanical, macro- and micro-climatological processes are involved in the formation of patterned peatlands. La Grande Tsa at 2336 m a.s.l. is probably the highest bog in the central Swiss Alps and is unique in its pattern. In two of five pools there is in the contact zone between the basal peat and the overlying gyttja an unconformity in the depth-age models based on radiocarbon dates. Palynostratigraphies of cores from a ridge and a pool confirm the occurrence of an unconformity in the contact zone. We conclude that deepening of the pools results from decomposition of peat. The fact that the dated unconformities in the two pools and the unconformity in the ridge-core all fall within the Bronze Age suggest they were caused by events external to the bog. We hypothesize that early transhumance resulted in anthropogenic lowering of the timberline, which resulted in a reduction in the leaf-area index and evapotranspiration, and in higher water levels and thus pool formation.

High-resolution pollen analyses made on the same samples on which the ratios of oxygen isotopes were measured that provided the time scale and a temperature proxy after correlation to NorthGRIP.(1) A primary succession: The vegetation responded to the rapid rise of temperatures around 14,685 yr BP, with a primary succession on a decadal to centennial time scale. The succession between ca 15,600 and 13,000 yr BP included:(1.1.) The replacement of shrub-tundra by woodland of Juniperus and tree birch (around 14,665 yr BP)(1.2.) The response of Juniperus pollen to the shift in oxygen isotopes in less than 20 yr,(1.3.) A sequence of population increases of Hippophae rhamnoides (ca 14,600 yr BP), Salix spp. (ca 14,600 yr BP), Betula trees (ca.14,480 yr BP), Populus cf. tremula (ca. 14,300 yr BP), and Pinus cf. sylvestris (ca. 13,830 yr BP).(2) Biological processes: Plants responded to the rapid increase of summer temperatures on all organisational levels:(2.1) Individuals may have produced more pollen (e.g. Juniperus);(2.2) Populations increased or decreased (e.g. Juniperus, Betula, later Pinus), and(2.3) Populations changed their biogeographical range and may show migrational lags.(2.4) Plant communities changed in their composition because the species pools changed through immigration and (local) extinction. Some plant communities may have been without modern analogue. These mechanisms require increasing amounts of time.(2.5) Processes on the level of ecosystems, with species interactions, may involve various time scales. Besides competition and facilitation, nitrogen fixation is discussed.(3) The minor fluctuations of temperature during the Late-Glacial Interstadial, which are recorded in delta O-18, resulted in only very minor changes in pollen during the Aegelsee Oscillation (Older Dryas biozone, GI-1d) and the Gerzensee Oscillation (GI-1b).(4) Biodiversity: The afforestation at the onset of Bolling coincided with a gradual increase of taxonomic diversity up to the time of the major Pinus expansion. (C) 2012 Elsevier B.V. All rights reserved.