Search

The origin and evolutionary history of the European bison Bison bonasus (wisent) have become clearer after several morphological, genomic, and paleogenomic studies in the last few years, but these paleogenomic studies have raised new questions about the evolution of the species. Here, we present additional information about the population diversity of the species based on the analysis of new subfossil Holocene remains from the Balkan Peninsula. Seven ancient samples excavated from caves in Western Stara Planina in Bulgaria were investigated by mitochondrial D‐loop (HVR1) sequence analysis. The samples were dated to 3,800 years BP by radiocarbon analysis. Additionally, a phylogenetic analysis was performed to investigate the genetic relationship among the investigated samples and all mitochondrial DNA sequences from the genus Bison available in GenBank. The results clustered with the sequences from the extinct Holocene South‐Eastern (Balkan) wisent to the fossil Alpine population from France, Austria, and Switzerland, but not with those from the recent Central European (North Sea) one and the now extinct Caucasian population. In conclusion, these data indicate that the Balkan wisent that existed in historical time represented a relict and probably an isolated population of the Late Pleistocene‐Holocene South‐Western mountainous population of the wisent., Bison bonasus remains from Ponor part of Western Stara Planina Mountain (Bulgaria). The data indicate that the Balkan wisent that existed in historical time represented a relict and probably isolated population of a distinct South European mountainous population of the wisent.

Aim: The Expansion-Contraction model has been used to explain the responses of species to climatic changes. During periods of unfavourable climatic conditions, species retreat to refugia from where they may later expand. This paper focuses on the palaeoecology of red deer over the past 54 ka across Europe and the Urals, to reveal patterns of change in their range and explore the role of environmental conditions in determining their distribution. Location: Europe and western Asia to 63°E. Taxon: Red deer (Cervus elaphus). Methods: We collected 984 records of radiocarbon-dated red deer subfossils from the Late Pleistocene and the Holocene, including 93 original dates. For each deer sample we compiled climatic and biome type data for the corresponding time intervals. Results: During the last 54 ka changes in red deer range in Europe and the Urals were asynchronous and differed between western and eastern Europe and western Asia due to different environmental conditions in those regions. The range of suitable areas for deer during the Last Glacial Maximum (LGM) was larger than previously thought and covered vast regions not only in southern but also in western and eastern Europe. Throughout the period investigated the majority of specimens inhabited forests in the temperate climatic zone. The contribution of forests in deer localities significantly decreased during the last 4 ka, due to deforestation of Europe caused by humans. Mean January temperature was the main limiting factor for species distribution. Over 90% of the samples were found in areas where mean January temperature was above −10°C. Main conclusions: Red deer response to climatic oscillations are in agreement with the Expansion-Contraction model but in contradiction to the statement of only the southernmost LGM refugia of the species. During the last 54 ka red deer occurred mostly in forests of the temperate climatic zone. © 2020 John Wiley & Sons Ltd. European Social Fund, Grant/Award Number: UDA-POKL.04.01.01-00-072/09-00; University of Wroclaw, Grant/Award Number: 0410/2990/18; Institute of Environmental Biology, University of Wrocław, Grant/Award Number: 0410/2990/18; Mammal Research Institute Polish Academy of Sciences; Narodowe Centrum Nauki , Grant/Award Number: DEC-2013/11/B/NZ8/00888 and UMO-2016/23/B/HS3/00387; Romanian National Authority for Scientific Research, UEFISCDI, Grant/Award Number: PN-IIIP4-ID-PCE-2016-0676; National Centre for Atmospheric Science and the Centre for Environmental Data Analysis, UK; Faunal Database of the Stage Three Project; Leverhulme Trust, Grant/Award Number: F00568W.

Methods in Ecology and Evolution published by John Wiley & Sons Ltd on behalf of British Ecological Society Isotopic analyses of collagen, the main protein preserved in subfossil bone and tooth, has long provided a powerful tool for the reconstruction of ancient diets and environments. Although isotopic studies of contemporary ecosystems have typically focused on more accessible tissues (e.g. muscle, hair), there is growing interest in the potential for analyses of collagen because it is often available in hard tissue archives (e.g. scales, skin, bone, tooth), allowing for enhanced long-term retrospective studies. The quality of measurements of the stable carbon and nitrogen isotopic compositions of ancient samples is subject to robust and well-established criteria for detection of contaminants and diagenesis. Among these quality control (QC) criteria, the most widely utilized is the atomic C:N ratio (C:NAtomic), which for ancient samples has an acceptable range between 2.9 and 3.6. While this QC criterion was developed for ancient materials, it has increasingly being applied to collagen from modern tissues. Here, we use a large survey of published collagen amino acid compositions (n = 436) from 193 vertebrate species as well as recent experimental isotopic evidence from 413 modern collagen extracts to demonstrate that the C:NAtomic range used for ancient samples is not suitable for assessing collagen quality of modern and archived historical samples. For modern tissues, collagen C:NAtomic falling outside 3.00–3.30 for fish and 3.00–3.28 for mammals and birds can produce systematically skewed isotopic compositions and may lead to significant interpretative errors. These findings are followed by a review of protocols for improving C:NAtomic criteria for modern collagen extracts. Given the tremendous conservation and environmental policy-informing potential that retrospective isotopic analyses of collagen from contemporary and archived vertebrate tissues have for addressing pressing questions about long-term environmental conditions and species behaviours, it is critical that QC criteria tailored to modern tissues are established.

Permafrost thaw in peatlands is one of the most widespread and worrying consequences of climate warming in the sub-Arctic area. To predict future climate feedbacks, it is important to study the his ...

Knowledge of historic changes in vegetation, relief, and soil is key in understanding how the uplands in central Europe have changed during the last millennium, being an essential requirement for measures on forest conversion and nature conservation in that area. Evidence of forest‐clearing horizons from the medieval period could be systematically documented at four low‐ to mid‐altitudinal sites (360–640 meters above mean sea level) in the Harz (Harz Mountains), Erzgebirge (Ore Mountains), and Českomoravská vrchovina (Bohemian‐Moravian Highlands). Subfossil trees with traces of human cutmarks and burning were recovered from buried wet‐organic soils (paleosols) within a context of mining and settlement archaeology, applying a multiproxy‐approach by using data from archaeology, paleobotany, geochronology, dendrochronology, and pedology. Tree stumps and trunks, as well as small‐scale wood remains represent an in situ record of local conifer stands (spruce, fir, and pine). Some deciduous tree taxa also occur. Dating of the tree remains yielded ages from the 10th/11th to the 13th/14th centuries A.D. After deforestation, the tree remains were buried by technogenic and alluvial–colluvial deposits. The reconstructed conifer‐dominated woodlands on wet soils mirror the local vegetation structure immediately before the medieval deforestation. As such wet sites are common in the uplands, conifers were significantly present in the natural vegetation even at mid and lower altitudes.

Rationale The trophic enrichment factor (TEF) is a parameter reflecting the difference in isotopic ratio between a consumer's tissues and diet, used in isotopic ecology and paleoecology to track dietary habits. The TEF of sulfur is believed to be low, but was, until now, only documented in a limited number of taxa. In this study we use a subfossil accumulation of bones from a red fox (Vulpes vulpes) den to verify the TEF for sulfur in fox bone collagen. Methods Collagen was extracted from 30 samples of subfossil bones, including foxes and their prey. The δ34 S values of the bone collagen samples were measured with an elemental analyzer connected to an isotope ratio mass spectrometer. The TEF was calculated as [Δ34 S = (mean δ34 S in predator) - (mean δ34 S in prey)], using taphonomic indices to estimate the mean diet, and calculated separately for different age classes of the predator. Results We modeled 12 variants of TEF for different estimations of the diet composition and for three fox age classes (adult, subadult, and juvenile). The estimated TEF values range from -0.54 to +0.03‰ and are similar to TEFs known for other mammals. Absolute TEF values are nearly equal to or lower than the analytical error, which is ±0.4‰. Conclusions For the first time, we present direct δ34 S data for the bone collagen of a free-living predator and its naturally selected prey. Our results indicate very low or even slightly negative TEF values for sulfur. Furthermore, according to our results, the δ34 S value should not be considered a reliable indicator of trophic position in terrestrial food webs but rather, it should be used to disentangle different food webs based on different primary producers.

Rising summer temperatures are expected to increase tree mortality rates across the western United States. Here, we analyze subfossil wood samples from Colorado dating to the last interglacial to a...

The dynamics of the Late Glacial have been demonstrated by numerous records from the Northern Hemisphere and far fewer from the Southern Hemisphere (SH). SH paleoclimate records reveal a general warming trend, interrupted by a deglaciation pause Antarctic Cold Reversal (ACR; similar to 14,700-13,000 cal BP). Here, we present decadal tree-ring stable isotope chronologies (delta O-18, delta C-13) from New Zealand (NZ) subfossil kauri trees (n = 6) covering the post-ACR millennium from 13,020 to 11,850 cal BP. We find a distinct, simultaneous downturn (similar to 12,625-12,375 cal BP) in all tree-ring proxies paralleling regional tree growth declines, suggesting a widespread climate deterioration. This downturn was characterized by sustained high precipitation, low temperatures, and high relative humidity in NZ with incoming weather fronts from the South Ocean. Despite these promising results, questions remain about what drove the Kauri Downturn and how the hydroclimatic conditions were altered during this time period.

The jaw adductor muscles of extinct mammals are often reconstructed to elucidate paleoecological relationships and to make broad comparisons among taxa. Muscle lever arms, bite load arms, muscle dimensions, and gape are often also reconstructed to better understand feeding. Several different approaches to these and related goals are discussed here. A protocol for reconstructing muscle dimensions and bite force using biomechanically informative skull measurements and osteological proxies of muscle dimensions is described and applied to a case study of subfossil Malagasy lemurs. The results of this case study show that most subfossil lemurs emphasized the masseter and medial pterygoid muscles over the temporalis. This supports the inference that these extinct lemurs depended heavily on tough food like leaves. Exceptions include signals of hard-object feeding in Archaeolemur that vary between A. majori and A. edwardsi. Reconstructions of soft-tissue and function are important for understanding past ecological relationships. Even those based on well-supported osteological proxies from extant analogues have limitations for making precise inferences. Anat Rec, 301:343-362, 2018. © 2018 Wiley Periodicals, Inc.

The potential of using surface-sediment assemblages of Cladocera as bioindicators for reservoirs in Sri Lanka was assessed for their subfossil remains, along with contemporary physical and chemical measurements from each reservoir. The reservoirs span five climatic regions, from extremely arid environments to tropical montane forests, as well as three orders of magnitude changes in many physical and chemical variables. In total, although the remains of 39 Cladocera taxa from 21 genera were identified, only 31 taxa from 37 sites were present at sufficiently high abundances to assess their relation to measured environmental variables. Canonical correspondence analysis (CCA) identified surface area, maximum depth and chloride as the three most important measured environmental variables that could account for the variation in the cladoceran assemblages. Taxa such as Chydorus sphaericus, Alona aff. verrucosa and Leydigia acanthocercoides were more abundant in generally deeper, larger reservoirs, whereas Alonella excisa, Euryalona orientalis, Notoalona globulosa and Chydorus eurynotus were more abundant in shallow smaller reservoirs. Although there was a strong separation between climatic zones in terms of factors related to specific conductance, this factor only appears marginally important in separating cladoceran assemblages. Quantitative inference models developed to assess the strength of inferring environmental variables using partial least squares regression and calibration were all relatively weak, with jackknifed coefficient of determination values of 0.40, 0.28 and 0.27 for surface area, maximum depth and chloride, respectively. These results, in conjunction with large differences in eigenvalues between constrained and unconstrained ordinations, suggest that unmeasured environmental variables are also important in structuring cladoceran assemblages.

Despite wide-ranging interest in the vegetation and climate of Northland, New Zealand, during the last glacial cycle, the region and timeframe lack quantitative climate reconstructions while land-based pollen records have tended to be poorly dated and fragmentary. The region is also important for geochronology due to the co-occurrence of the Rotoehu tephra, a widely dispersed isochron near the current limits of radiocarbon dating, and extensive subfossil wood remains of Agathis australis, with strong dendrochronological and dendroclimatological potential. We present new pollen records and temperature reconstructions from three sites set in coastal dune belts from western mid-Northland (∼35°S), all containing Rotoehu tephra, that collectively span the last 70 ka. The phases and amplitude of temperature changes broadly align with those reported from elsewhere in New Zealand and with marine isotope climate–stratigraphic records, including maximum temperature depression of 6–8 °C during the last glacial maximum. We argue that these climatic patterns are intimately linked to shifts in the southern westerly wind belt, the northern margins of which extend to the region today. Correspondence between the Northland temperature shifts and atmospheric CO2 supports the model of ocean–atmosphere CO2 flux modulated by latitudinal migration of the southern westerlies. Copyright © 2017 John Wiley & Sons, Ltd.

Many German lakes experienced significant water level declines in recent decades that are not fully understood due to the short observation period. At a typical northeastern German groundwater-fed lake with a complex basin morphology, an acoustic sub-bottom profile was analysed together with a transect of five sediment cores, which were correlated using multiple proxies (sediment facies, μ-XRF, macrofossils, subfossil Cladocera). Shifts in the boundary between sand and mud deposition were controlled by lake level changes, and hence, allowed the quantification of an absolute lake level amplitude of ~8 m for the Holocene. This clearly exceeded observed modern fluctuations of 1.3 m (AD 1973–2010). Past lake level changes were traced continuously using the calcium-record. During high lake levels, massive organic muds were deposited in the deepest lake basin, whereas lower lake levels isolated the sub-basins and allowed carbonate deposition. During the beginning of the Holocene (>9700 cal. a BP), lake levels were high, probably due to final melting of permafrost and dead-ice remains. The establishment of water-use intensive Pinus forests caused generally low (3–4 m below modern) but fluctuating lake levels (9700–6400 cal. a BP). Afterwards, the lake showed an increasing trend and reached a short-term highstand at c. 5000 cal. a BP (4 m above modern). At the transition towards a cooler and wetter late Holocene, forests dominated by Quercus and Fagus and initial human impact probably contributed more positively to groundwater recharge. Lake levels remained high between 3800 and 800 cal. a BP, but the lake system was not sensitive enough to record short-term fluctuations during this period. Lake level changes were recorded again when humans profoundly affected the drainage system, land cover and lake trophy. Hence, local Holocene water level changes reflect feedbacks between catchment and vegetation characteristics and human impact superimposed by climate change at multiple temporal scales.

Palaeopropithecids, or "sloth lemurs," are a diverse clade of large-bodied Malagasy subfossil primates characterized by their inferred suspensory positional behavior. The most recently discovered genus of the palaeopropithecids is Babakotia, and it has been described as more arboreal than Mesopropithecus, but less than Palaeopropithecus. In this article, the within-bone and between-bones articular and cross-sectional diaphyseal proportions of the humerus and femur of Babakotia were compared to extant lemurs, Mesopropithecus and Palaeopropithecus in order to further understand its arboreal adaptations. Additionally, a sample of apes and sloths (Choloepus and Bradypus) are included as functional outgroups composed of suspensory adapted primates and non-primates. Results show that Babakotia and Mesopropithecus both have high humeral/femoral shaft strength proportions, similar to extant great apes and sloths and indicative of forelimb suspensory behavior, with Babakotia more extreme in this regard. All three subfossil taxa have relatively large femoral heads, also associated with suspension in modern taxa. However, Babakotia and Mesopropithecus (but not Palaeopropithecus) have relatively small femoral head surface area to shaft strength proportions suggesting that hind-limb positioning in these taxa during climbing and other behaviors was different than in extant great apes, involving less mobility. Knee and humeral articular dimensions relative to shaft strengths are small in Babakotia and Mesopropithecus, similar to those found in modern sloths and divergent from those in extant great apes and lemurs, suggesting more sloth-like use of these joints during locomotion. Mesopropithecus and Babakotia are more similar to Choloepus in humerofemoral head and length proportions while Palaeopropithecus is more similar to Bradypus. These results provide further evidence of the suspensory adaptations of Babakotia and further highlight similarities to both extant suspensory primates and non-primate slow arboreal climbers and hangers. J. Morphol. 277:1199-1218, 2016. © 2016 Wiley Periodicals, Inc.

A 1561-year tree-ring width (TRW) chronology covering the period 2668–1108 BC (4617–3057 BP) has been developed from 159 moisture-sensitive peatland pines (Pinus sylvestris L.) sampled at Abuamossen, southern Sweden. Tree population dynamics and annual growth responses of the trees were shown to reflect and give absolute age to regional hydro-climatological changes. The main wet-shifts recorded in the TRW data were precisely dated to 2150–2100, 1550 and 1230–1150 BC (4100–4050, 3500 and 3180–3000 BP) and are likely to be related to the stepwise Mid- to Late Holocene climate transition, during which the condition changed from relatively warm and dry towards cold and moist in the northern hemisphere. The tree-colonization phase was ended by several long-lasting periods showing depressed annual tree growth and an abrupt dying-off phase, possibly caused by increasing water level in the peatland as well as the adjacent river Helge A. This study demonstrates that TRW data obtained from subfossil peatland trees can provide detailed information and exact age control on moisture variability in peatlands associated with regional hydroclimatic changes. Moreover, the combined information from the stratigraphical and the TRW analyses enabled a detailed temporal and spatial site development reconstruction.

The Southern Ocean plays a significant role in driving global climate–ocean–carbon dynamics. Unfortunately, a relative dearth of datasets across the region limits our ability to understand past and future mechanisms of change. Here we report a new dataset from the south-west Pacific: radiocarbon-dated subfossil tree stumps (Dracophyllum) eroding out from peat exposures on Campbell and Auckland Islands (52–50°S). Dracophyllum are the southernmost growing trees in the south-west Pacific and their growth on exposed sites and at altitude is strongly controlled by the prevailing westerly airflow, providing a unique measure of past changes in zonal wind strength. Here we demonstrate a significant collapse in the altitudinal limit of growth between approximately 2000 and 1000 years ago (hereafter 2–1 ka), consistent with other records across the Southern Hemisphere that indicate westerly airflow was significantly enhanced. Importantly, this period in the late Holocene was one of marked change across the broader region, suggesting westerly airflow played a key role in driving Southern Ocean variability at this time.

Climate change is one of the key drivers of changes in the biodiversity of the planet. There is, however, a general lack of long-term data sets showing trends in taxonomic diversity of aquatic insects in high mountain environments particularly vulnerable to climate change. Using palaeolimnological techniques, we explored the changes in subfossil chironomid assemblages from three remote water bodies in the Eastern Alps, with the main focus on taxonomic turnover over different intervals of the late Holocene. Major changes in the assemblages coincided with shifts between different climate regimes and were mainly associated with the taxonomic shifts indicating the crossing ecological thresholds related to the ice-cover duration in alpine lakes. Patterns of assemblage turnover through the past 2000 years differ between the study sites. Nevertheless, despite site-specific differences in the physical setting and taxonomic composition, the study sites reveal substantial chironomid assemblage turnover (>1.0 SD) since AD 1850. The highest chironomid turnover (0.87 SD) over the last 30 years (AD 1980–2010), more than three times greater (0.26 SD) than in the previous 30 years, is observed in the lake situated at the highest elevation among the study lakes. Applying non-linear structural equation modelling, we found that cold-season (October–May) temperatures and therefore lake ice phenology are among the most important environment variables affecting the chironomid assemblages. The results of this study suggest that further climate warming will increase the risk of ecological alterations in remote Alpine freshwaters, including major shifts in chironomid fauna.

As a result of long-term metal mining and metallurgical activities, the sediment of Ross Lake (Flin Flon, MB, Canada) is highly contaminated with metals and other elements. Although the effluents likely were discharged into Ross Lake as early as the late 1920s, lake biophysical data were not collected until 1973, more than 4 decades after the onset of mining and municipal activities. The early influence of these activities on the ecology of Ross Lake is unknown, as are the effects of improvements to metallurgical effluent quality and discontinuation of municipal wastewater discharge into the lake's north basin. To address this knowledge gap, analyses typical of paleolimnological investigations were applied to cores of sediment collected in 2009 from the south basin of Ross Lake. Stratigraphic analyses of physicochemical sediment characteristics (e.g., the concentrations of metals and other elements, organic C, total N, and δ(13)C and δ(15)N values) and subfossil remains (diatoms, Chironomidae, Chaoborus, and Cladocera) were used to infer historical biological and chemical changes in Ross Lake. With the onset of mining activities, concentrations of various elements (e.g., As, Cr, Cu, Zn, and Se) increased dramatically in the sediment profile, eventually declining with improved tailings management. Nevertheless, concentrations of metals in recent sediments remain elevated compared with pre-industrial sediments. Constrained cluster analyses demonstrated distinct pre-industrial and postindustrial communities for both the diatoms and chironomids. The biodiversity of the postindustrial diatom assemblages were much reduced compared with the pre-industrial assemblages. The postindustrial chironomid assemblage was dominated by Chironomus and to a lesser extent by Procladius, suggesting that Ross Lake became a degraded environment. Abundances of Cladocera and Chaoborus were severely reduced in the postindustrial era, likely because of metals toxicity. Overall, improvements to the management of both metallurgical and municipal effluent are reflected in the physicochemical sediment record; nevertheless, the ecology of Ross Lake remains impaired and shows minimal signs of returning to a pre-industrial state. Recommendations are made regarding possible future investigations at this site and the need for a framework to help assess causation using paleolimnological and other site data.

The paper presents an evaluation of subfossil bird bones from archaeological and geological sites in Europe that shows that birds of the genus Pelecanus occurred far out of their present range between 7.4 and 5.0 ka BP in the Danish archipelago. Additionally, from other northwestern European regions mid-Holocene records of pelicans are known. However, due to morphological similarities there are difficulties in species identification. In this paper ancient DNA barcoding techniques were used to clarify the species assignment of one of these records for the first time. Our results show that the bone derives from Dalmatian pelican Pelecanus crispus, a species that today breeds in 15 colonies in the eastern Mediterranean. This species identification is especially remarkable since the Dalmatian pelican is known to be less migratory. We demonstrate that the appearance and disappearance of pelicans in northwestern Europe coincide with climate parameters, since all records fall within warm periods. This applies for the larger group of Danish records during the Holocene thermal maximum in northern Europe as well as for two more groups of records from central Europe and Britain dating to 1.9 and 0.8 ka ago. Recent ecological research on the Dalmatian pelican shows that the species seems to profit from the modern climate changes and is starting to expand its range. Our paper documents that under special circumstances short-distance migrant birds are also able to expand their ranges to areas far outside of the former distribution areas. Finally, the Dalmatian pelican is presented as an indicator species reflecting special climate conditions. The present study demonstrates not only the possibility to recover avian DNA from at least 7 ka old bones, but the relevance of such genetic analysis in combination with archaeological data, particularly if bones could not be assigned to species level by morphological features. In such cases, aDNA is shown as a valuable tool for the reconstruction of the avifauna of the past.

A high-resolution diatom analysis of a varved sediment sequence from Lac Brule, southwestern Quebec, was used to study temporal patterns of environmental change in the late Holocene. Key periods of interest in the record included the Medieval Warm Period (~800–1300 CE), the Little Ice Age (~1450–1850 CE), and post-European settlement (~1850–present). Subfossil diatom assemblages were compared to previously published pollen, cladocera, and sediment records from Lac Brule, revealing complex dynamics between terrestrial vegetation succession, nutrient fluxes, and trophic interactions. Generalized additive models showed a response to long-term climate variability in the diatom record, although it was not the most influential driver of community changes at Lac Brule. Catchment-mediated processes instead played the largest role in governing the structure of diatom assemblages in the lake. For example, nutrient loading following a local fire in the watershed at 1345 CE led to an abrupt and significant increase in Fragilaria spp. Human activity associated with deforestation and the Wallingford-Back Mine (1924–1972 CE) also had strong impacts on the landscape, which triggered further responses in the aquatic communities of Lac Brule.

1. Although wildfire is the main natural disturbance factor driving changes in the North American boreal forest, understanding how the fire history of the last millennium shaped the present-day landscape diversity is a difficult task due to the lack of palaeoecological reconstructions with high spatial (few hundreds of square metres) and temporal (annual) resolutions. 2. We combined a detailed inventory of the present-day lakeshore forest of two lakes of the Eastern Canadian taiga with the dendrochronological dating of the subfossil logs that accumulated in the lit-toral zones facing these shores. Our objective was to compare the millennial impact of wildfires among stands of various structures and compositions. Past stem densities and fire years were reconstructed from log recruitment rates and dating of charred logs. 3. Multivariate analysis of the present-day lakeshore forest revealed three and two homogeneous shore segments per site (i.e. clusters). Cluster 1 at both sites exhibited denser forest, higher dead wood values and a higher percentage of balsam fir, a fire-sensitive species. 4. In total, 426 and 611 subfossil logs (mostly black spruce) were crossdated over the last ~1400 years. Their dendrochronological analysis confirmed that each lakeshore cluster, identified from the traits of the present-day forest, experienced a specific fire history over the last millennium (i.e. 0–5 fires of variable severity) that locally influenced forest composition, tree density and growth. Each fire triggered a specific forest structure trajectory characterized by a different stem density and rate of recovery. 5. Synthesis. This study provides a long-term perspective that helps explain how the present-day landscape diversity in the Eastern Canadian taiga reflects the site-specific fire history over the last millennium. Fires have caused persistent and cumulative impacts resulting in a progressive opening of the forest cover along with balsam fir exclusion. Present-day landscapes are mosaics of forest stands characterized by different times since fire and different post-fire forest structure trajectories.

Species intolerant of changing climate might avoid extinction within refugia buffered from extreme conditions. Refugia have been observed in the fossil record but are not well documented or understood on ecological time scales. Using a 37-year record from the eastern Pacific across the two most severe El Nino events on record (1982-1983 and 1997 1998) we show how an exceptionally thermally sensitive reef-building hydrocoral, Millepora intricata, twice survived catastrophic bleaching in a deeper-water refuge (> 11 m depth). During both events, M. intricata was extirpated across its range in shallow water, but showed recovery within several years, while two other hydrocorals without deep-water populations were driven to regional extinction. Evidence from the subfossil record in the same area showed shallow-water persistence of abundant M. intricata populations from 5000 years ago, through severe El Nino-Southern Oscillation cycles, suggesting a potential depth refugium on a millennial timescale. Our data confirm the deep refuge hypothesis for corals under thermal stress.

Summary European-settlement-related impacts over the past 200 years pose many challenges for the conservation and restoration of Australia's ecosystems. Landscape modification, associated habitat loss and the introduction of exotic species have caused the extinction and mainland extirpation of numerous vertebrates. This process happened so quickly that many species became locally or functionally extinct before their presence was documented. A growing body of research on Holocene fossil accumulations is providing insights into the composition and biogeography of Australian ecosystems prior to European settlement. This review explores the similarities between palaeo- and neo-ecology and how Holocene (last 10,000 years) assemblages can be used by neo-ecologists, conservation managers and policy makers to identify and fill gaps in knowledge and contribute to the management and restoration of Australia's degraded ecosystems.

Aim To understand the role and significance of the reindeer, Rangifer tarandus (Linnaeus, 1758), as a specific indicator in terms of late Quaternary biogeography and to determine the effects of global climate change on its range and local extinction dynamics at the end of the Ice Age. Location Late Pleistocene/early Holocene range of reindeer over all of central and western Europe, including southern Scandinavia and northern Iberia, but excluding Russia, Belarus and the Ukraine. Methods Radiocarbon-dated subfossil records of R. tarandus from both archaeological and natural deposits younger than 25,000 years were assembled in a database. The distribution area was divided into six representative regions. The C-14 dates were calibrated and plotted chronologically in maps in order to compare presence and absence and regional extinction patterns from one region to another. Results After the Last Glacial Maximum, R. tarandus disappeared from southeastern Central Europe but survived in the south-west until the Younger Dryas period. The 'Allerod warming' did not result in complete extirpation of reindeer in Central Europe. Reindeer probably disappeared c. 11,250 years ago in the North European Plain and c. 11,000 years ago in the British Isles. In southern Scandinavia the species survived until c. 10,300 years ago. Main conclusions The late Quaternary record for reindeer in Europe during the last 25 kyr shows a climate-driven dispersal and retreat in response to climate change, with regional variations. The collapse of the mammoth steppe biome did not lead to the local extinction in Europe, as in the case of other megafaunal species. Rangifer tarandus co-existed for about 3000 years during the Late Glacial and early Holocene with typical temperate species such as red deer and roe deer in non-analogue faunal communities. The regional extinction at the end of the Pleistocene coincides with the transition from light open birch/pine forests to pine/deciduous forests. (Less)

Lakes in Yunnan Province, SW China, have been subjected to increased environmental stress over the last century. In order to assess the impacts of these stresses on the biota, a sediment core was collected from Lugu Lake covering the past 120 years, and detailed chemical, biological (subfossil chironomids), and physical analyses of the lake sediments were undertaken. The analyses indicated consistent trends of increased soil erosion since the early 1970s associated with significant changes in chironomid assemblages, which occurred simultaneously with the sedimentological proxies. A redundancy analysis (RDA) using a range of sedimentary proxies indicated that the shifts in the chironomid communities were mainly attributable to soil erosion. Constant soil erosion caused dramatic reductions in the available organic materials and large increases in fine sediments, leading to changes in the chironomid fauna and reduced chironomid abundance. The chironomid succession revealed that Procladius, the likely top predator in the chironomid community food chain, decreased in abundance under the impact of soil erosion, whereas the proportion of small forms of filter feeders, represented by Tanytarsus mendax-type, increased rapidly. Due to the loss of suitable habitats, the population of some bottom collector-gatherers (e.g., Polypedilum nubeculosum-type) decreased sharply. The results of this study suggest that increased catchment soil erosion may seriously impact benthic communities and potentially alter ecosystem functioning.

Siliceous hot spring deposits form at Earth's surface above terrestrial hydrothermal systems, which create low-sulphidation epithermal mineral deposits deeper in the crust. Eruption of hot spring waters and precipitation of opal-A create sinter apron complexes and areas of geothermally influenced wetland. These provide habitat for higher plants that may be preserved in situ, by encrustation of their surfaces and permineralization of tissues, creating T0 plant assemblages. In this study, we review the fossil record of hot spring floras from subfossil examples forming in active hot spring areas, via fossil examples from the Cenozoic, Mesozoic and Palaeozoic to the oldest known hot spring flora, the Lower Devonian Rhynie chert. We demonstrate that the well-known megabias towards wetland plant preservation extends to hot spring floras. We highlight that the record of hot spring floras is dominated by plants preserved in situ by permineralization on geothermally influenced wetlands. Angiosperms (members of the Cyperaceae and Restionaceae) dominate Cenozoic floras. Equisetum and gleicheniaceous ferns colonized Mesozoic (Jurassic) geothermal wetlands and sphenophytes and herbaceous lycophytes late Palaeozoic examples. Evidence of the partitioning of wetland hydrophytic and dryland mesophytic communities, a feature of active geothermal areas, is provided by well-preserved and well-exposed fossil sinter apron complexes, which record flooding of dryland environments by thermal waters and decline of local forest ecosystems. Such observations from the fossil record back-up hypotheses based on active hot springs and vegetation that suggest removal of taphonomic filtering in hot spring environments is accompanied by an increase in ecological and ecophysiological filtering. To this end we also demonstrate that in the hot spring environment, the wetland bias extends beyond broad ecology. We show that ecosystems preserved from the Cenozoic to the Mesozoic provide clear evidence that the dominant plants preserved in situ by hot spring activity are also halophytic, tolerant of high pH and high concentrations of heavy metals. By extension, we hypothesize that this is also the case in Palaeozoic hot spring settings and extended to the early land plant flora of the Rhynie chert.

The Loky-Manambato region, located in northern Madagascar, is a biotically rich contact zone between different forest biomes. Local current forest cover is composed of both humid and dry formations, which show elevational stratification. A recent phylogeographical study of a regional dry forest rodent, Eliurus carletoni (subfamily Nesomyinae), found genetic evidence of forest contractions between 18 750 and 7500 years BP, which based on extrapolation of the pollen subfossil record, was thought to be associated with an expansion of local humid forests. Herein, we conduct a genetic test of this hypothesis and focused on populations on two neighbouring massifs of forest-dependent rodent species, one associated with low-elevation dry forests (E. carletoni) and the other with higher elevation humid forests (Eliurus tanala). Using mitochondrial markers and a combination of traditional and coalescent-based phylogeographical, historical demographic and population genetic methods, we found evidence of historical connections between populations of E. tanala. Adjacent populations of E. carletoni and E. tanala exhibit opposite historical demographic patterns, and for both, evidence suggests that historical demographic events occurred within the last 25 000 years BP. These findings strongly support the proposed late Quaternary shifts in the floristic composition of the Loky-Manambato region.

The recent discovery of a subfossil polar bear (Ursus maritimus) jawbone in the Poolepynten coastal cliff sequence, western Svalbard, and its implications for the natural history of the polar bear motivated an effort to better constrain the environmental history and age envelope of the Poolepynten sediment sequence. The focus of the present study is on the lithostratigraphy of the coastal cliffs and on re-dating the sequence using the Optically Stimulated Luminescence (OSL) dating technique. We report a revised lithostratigraphy and nine new OSL ages. It is concluded that the Poolepynten sequence contains evidence of four regional glaciation events, recorded in the strata as erosional unconformities or glacial deposits followed by shallow-marine deposition signifying transgressions and subsequent glacio-isostatic rebound and regression. Our OSL ages refine previous age determinations (14C and IRSL) and support the interpretation that the subfossil polar bear jawbone is probably of last interglacial (Eemian) age.

Understanding the paleoecology of extinct subfossil lemurs requires reconstruction of dietary prefer- ences. Tooth morphology is strongly correlated with diet in living primates and is appropriate for inferring dietary ecology. Recently, dental topographic analysis has shown great promise in reconstructing diet from molar tooth form. Compared with traditionally used shearing metrics, dental topography is better suited for the extraordinary diversity of tooth form among subfossil lemurs and has been shown to be less sensitive to phylogenetic sources of shape variation. Specifically, we computed orientation patch counts rotated (OPCR) and Dirichlet normal energy (DNE) of molar teeth belonging to 14 species of subfossil lemurs and compared these values to those of an extant lemur sample. The two metrics succeeded in separating species in a manner that provides insights into both food processing and diet. We used them to examine the changes in lemur community ecology in Southern and Southwestern Madagascar that accompa- nied the extinction of giant lemurs. We show that the poverty of Madagascar's frugivore community is a long- standing phenomenon and that extinction of large-bodied lemurs in the South and Southwest resulted not merely in a loss of guild elements but also, most likely, in changes in the ecology of extant lemurs. Am J Phys Anthropol 148:215-227, 2012. V C 2012 Wiley Periodicals, Inc.

Dendrochronological analysis was applied to subfossil remains of Scots pine (Pinus sylvestris L.) buried in a South Swedish peat deposit. In combination with peat stratigraphy, this approach was explored for its potential to provide information on the local hydrological and depositional history at the site, forming the basis for a regional palaeohydrological analysis. A 726-year ring-width chronology was developed and assigned an absolute age of 7233-6508cal a BP (5284-4559 BC) through cross-dating with German bog-pine chronologies, whereas two short additional records of older ages were radiocarbon dated. Registration of growth positions of individual trees allowed assessment of the spatial dynamics of the pine population in response to hydrological changes and peatland ontogeny. Annually resolved growth variability patterns in the pine population reveal several establishment and degeneration phases, probably reflecting fluctuations in bog-surface wetness. A major establishment phase at 7200-6900?cal a BP reflects the onset of a period of lowered groundwater level, also indicated by increased peat humification, and a development consistent with regional temperature and lake level reconstructions revealed from other proxies. This study demonstrates that subfossil bog-pine populations may provide annually to decadally resolved reconstructions of local groundwater variability, which are highly relevant in a long-term palaeoclimatic context. Copyright (c) 2012 John Wiley & Sons, Ltd.

Paleoclimate proxies based on the measurement of xylem cell anatomy have rarely been developed across the temperature range of a species or applied to wood predating the most recent millennium. Here we describe wood anatomy-based proxies for spring temperatures in central North America from modern bur oaks (Quercus macrocarpa Michx.). The strong coherence of temperature signals across the species range supports the use of these proxies across thousands of years of climatic change. We also used 79 subfossil oak log cross sections from northern Missouri, 14C-dated to 9.9–13.63 ka (ka is 1000 cal yr BP), to assess the frequency of oak deposition into alluvial sediments and a subset of these oaks for a wood anatomy-based reconstruction of spring paleotemperatures. Temperatures during the Younger Dryas cold period (YD) were up to 3.5°C lower than modern temperatures for that region, equivalent to or lower than those experienced at the northern edge of the modern species range. Compared to extant oaks growing a...

The peatlands of northern Scotland (one of the largest and most intact areas of blanket bog in the world) contain a rare widespread horizon of subfossil pine in stratigraphic context. Eighteen bog pine from three new sites are incorporated into a mean Neolithic pine chronology now composed of subfossil pine from 12 sites, which is tree-ring-dated against Irish bog pine chronologies to span 3198–2757 BC. Germination and peaks of radial growth infer drier conditions between 3199 and 3130 BC. Dying-off phases and depression of growth reflect a change to wetter conditions between 3023 and 3002 BC and a terminal decline of pine between 2809 and 2782 BC. The close synchronization of germination/die-off phases and major ring-width variations between sites across this region indicates that the environmental changes are probably triggered by climate change. Twenty-four bog pine samples remain unmatched. Future multi-discipline research into this important example of climatic change at the Neolithic/Bronze Age transition is recommended. Copyright © 2012 John Wiley & Sons, Ltd.

An accurate body size estimate is essential for reconstructing and interpreting many aspects of the paleobiology of an extinct taxon. With this in mind, the purpose of this study is two-fold: first, to create statistically robust predictive regression equations for body mass, total body length, and head and body length from postcranial elements using a platyrrhine reference sample, data that do not exist elsewhere in the literature; and, second, to apply those regression equations to the "giant" subfossil platyrrhine Protopithecus brasiliensis, a little-studied taxon represented by a nearly complete skeleton. Building on results of previous work with other primate groups, different skeletal elements, subgroups of the reference sample, and regression models lead to different body size estimates with different standard errors and prediction errors. However, relatively tight clusters of estimates around 20 kg, total length of 1,675 mm, and head and body length of 710 mm are obtained, placing the fossil in the size range of a large male baboon. While not quite as large as the original 25 kg body mass estimate for the fossil, this new estimate is still approximately 150% larger than the largest living New World monkey. Confirmation of its place in a large-bodied size class of platyrrhines has a profound effect on reconstructing the locomotor repertoire of Protopithecus and the evolutionary trajectory of the alouattin lineage.

An understanding of modern relationships between the stable oxygen isotope composition (δ18O) of lake water and aquatic invertebrates is essential for the interpretation of paleoclimate records based on δ18O of organic remains of these organisms. We analyzed δ18O of lake water and invertebrate remains, including head capsules of chironomid larvae and resting eggs (ephippia) of planktonic Cladocera, in surface sediments from 31 large, deep, and stratified lakes along a latitudinal transect through Europe. The δ18O values measured for both lake water and aquatic invertebrate remains were compared to estimated δ18O in precipitation. A strong linear relationship between mean annual air temperature and δ18O of precipitation was observed along the north–south transect (r = 0.97), whereas the relationship between precipitation δ18O and lake-water δ18O was weaker (r = 0.80). A strong positive correlation was observed between δ18O in lake water and aquatic invertebrates (r = 0.95 and 0.94 for chironomids and cladocerans, respectively). Although slopes of linear regressions between lake-water δ18O and δ18O of both aquatic invertebrate groups are similar, a systematic offset between the absolute δ18O values of chironomids and cladocerans was observed; chironomids were on average 2.4‰ heavier than Cladocera. We attribute this offset to differences in ecology, metabolism, and/or behavior between benthic chironomid larvae and planktonic Cladocera. δ18O records based on subfossil chironomid and cladoceran remains have the potential to quantitatively characterize past lake-water δ18O and, indirectly, past climatic changes.

The transition from forest to tundra in Arctic and alpine regions, frequently referred to as treeline, has preoccupied biogeographers and ecologists for more than a century. It is widely hypothesized that treelines will advance in response to current and anticipated future temperature increases worldwide. Monitoring of these ecotones is important in light of the potential for change. Equally important is an understanding of past changes so that future changes and their impacts can be forecast. This paper provides an overview of methods that have been used to detect and measure change at forest–tundra ecotones worldwide, with examples drawn from studies of treelines in alpine areas of the subarctic. These methods include resurveys of field plots and transects, repeat photography, dendrochronology, use of historical records, remote sensing, and paleoecological techniques such as palynology and subfossil analysis. The benefits and limitations of each approach are identified and evaluated. It is shown that there is no single best method, largely because each is only capable of resolving change within a specific range of temporal and spatial extents. Multiscale approaches that integrate several methods and techniques provide a more comprehensive picture of change and can be used to identify the variables that influence treeline dynamics and better understand functional mechanisms of response.

The wild horse Equus ferus was one of the most frequent species of the Late Pleistocene large ungulate fauna in Eurasia and played an important role in the subsistence of human groups, especially at the end the Late Glacial. It is frequently assumed that E. ferus became extinct in Europe at the beginning of the Holocene because of the development of woodlands and loss of open habitats. Because of its preference for open habitats and in spite of its adaptability, the appearance or disappearance of the wild horse could therefore be a suitable palaeoecological indicator for the opening of the Holocene primeval woodlands. We revised the dating and reliability of the subfossil record and dated several bones by atomic mass spectrometry 14C dating. From the beginning of the Holocene (9600 cal a BC) to the end of the Atlantic Period (3750 cal a BC) there are 207 archaeological sites with wild horse records available in Europe. E. ferus survived the Pleistocene Holocene transition in Europe, but the spatiotemporal dynamics of populations fluctuated remarkably in the early and middle Holocene. Small and sparse populations increasingly became extinct during the early Holocene, until between 7100 and 5500 cal a BC the wild horse was almost absent in central parts of the European Lowlands. Particular conditions in natural open patches in the canopy forests, chalklands and floodplains may have maintained the local survival of the horse in some regions of the Lowlands, however. In the Late Atlantic, between 5500 and 3750 cal a BC the range of the wild horse was again extended. It re-immigrated into central and western Europe, probably as a consequence of increasing landscape opening by Neolithic peoples. The data presented here may be a valuable part of the debate on the degree of openness of the early and middle Holocene landscape. Copyright © 2011 John Wiley & Sons, Ltd.

We reconstructed the long-term spruce budworm (SBW) (Choristoneura fumiferana Clem.) outbreak dynamics in the boreal forest of Quebec (Canada) using a dendrochronological approach with subfossil trees. Although the majority of the excavated wood belonging to the genus Picea could potentially reveal the past activity of spruce budworms in the tree rings, very few were cross- dated due to a lack of marker rings. All cross-dated trees were found within a particular zone of the peat bogs and the floating chronology was radiocarbon dated to ca. 5.1 cal ka BP. The results presented in this study suggest that the dynamics of SBW outbreaks in the studied area fluctuated during the last millennia and that severe outbreaks as observed during the 20th century seldom occurred in that part of the boreal forest since the end of the last glaciation. These results are in agreement with observations from other parts of eastern North America. Copyright # 2011 John Wiley & Sons, Ltd.

Question: Can investigations of subfossil bog-pine woodlands contribute to the understanding of mire development, especially the influence of climate fluctuations on the fen‐bog transition? Location: Lowlands of northwest Germany. Methods: We investigated pine (Pinus sylvestris L.) tree remains (stumps and trunks) buried in peat deposits. Dendrochronology was used to date each sampled tree to calendar years and to reconstruct population dynamics of the pine woodlands. Ecological changes, especially changes in site hydrology during the pine woodland phases were inferred from peat stratigraphic analyses and investigations of stem and root morphology of the tree remains. Results: The subfossil pine woodlands occurred mostly during the transition from fen to raised bog conditions within the mire development. The population dynamics are strikingly wave-like whereas woodland phases of 100 to 250 years duration are separated by much shorter (10‐50 years) phases of high germination and dying-off rates (GDO phases). Such GDO phases are often synchronous at different sites and are also linked to growth depressions of the independent regional oak master chronology (LSBOC), indicating a climate trigger. Conclusions: The development of raised bogs started about 7000 BC and had a main phase between 5100 and 3600 BC in northwest Germany. The subfossil bog-pine woodlands document the transitional phase towards the onset of raised bog formation, as characterized by initial dry conditions that were followed by increasing wetness of the sites, whereas this development is at least partly the result of climate variations.

Aim For decades, subfossil shells of the bivalve Mytilus edulis Linnaeus, 1758 in Svalbard have been taken as evidence of higher surface temperatures during the early Holocene because the modern northern occurrence of this mollusc was, until recently, in the southern Barents Sea. Here, we elucidate and discuss the spatial and temporal Late Pleistocene and Holocene distribution of the species within the entire Barents Sea region. Location The Barents Sea region. Methods Radiocarbon dates of Mytilus shells from the Barents Sea region and information about the present distribution of the species were compiled, including two new radiocarbon dates from north-eastern Spitsbergen. The dataset was divided into time slices, each covering 1000 years, and compared with Holocene temperature variations, ocean current systems and present-day temperature patterns. Results Maps show the Late Pleistocene and Holocene spatial and temporal distribution of Mytilus edulis in the Barents Sea region. M. edulis was already present in northern Norway about 14,000 cal. yr bp. It appeared at western Spitsbergen about 11,000 cal. yr bp, and slowly spread to the rest of the archipelago. The maximum distribution in the region was reached 10,000–7000 cal. yr bp, coinciding with the Holocene climatic optimum. The species gradually disappeared in the late Holocene and became absent from the northern and eastern parts of the region 3000–1000 cal. yr bp. Today, M. edulis lives in the southern part and has begun to recolonize the northern parts. Main conclusions The time slices illustrate strong connections between the ocean current regimes, the climate and the distribution of M. edulis. The species settled in the southern part of the Barents Sea region several thousand years before it spread to the northern part during the Holocene climatic optimum. It may even have been completely absent from the region for a short time during the late Holocene cold period. The Holocene distribution of Mytilus implies that the underlying pattern of coastal sea surface temperatures in the region was very stable.

We investigated the evolutionary radiation of a freshwater zooplankter that possesses a mixed breeding system and a detailed, dated, subfossil record. We estimated the phylogenetic relationships among the proposed species with complete nicotinamide adenine dinucleotide dehydrogenase subunit 2 mitochondrial gene sequence variation. We sequenced 374 Eubosmina specimens representing 10 out of 11 distinct morphospecies from 86 water bodies in three separate Holarctic regions. As expected for a Holocene radiation, there was a lack of monophyly for the proposed species and rare sharing of derived haplotypes among some species. Nevertheless, the proposed species exhibited little or no sharing of mitochondrial deoxyribonucleic acid haplotypes. Moreover, the phylogenetic and haplotype network results revealed a radiation pattern that is concordant with the subfossil record—with an older Bosmina (E.) longispina radiating into several new forms. Our results bolster the subfossil, morphometric, experimental, and within-population genetic evidence that B. (E.) longispina has radiated into several incipient species during the Holocene.

Summary 1. The distributions of subfossil remains of chironomid larvae in 28 large, deep and stratified lakes in Europe were examined in surface sediments along a latitudinal transect ranging from northern Sweden to southern Italy. 2. Canonical correspondence analysis (CCA) showed that summer surface water and July air temperature, as well as total phosphorus (TP) concentrations, hypolimnetic oxygen availability and conductivity were statistically significant (P

Summary 1. Monitoring of the ecosystem of Lake Mývatn, Iceland, since 1975 has revealed extreme fluctuations in important food web components, such as chironomids and cladocerans, with amplitudes of several orders of magnitude and a period of 5–8 years. This study uses sediment cores from the lake to examine if the food web fluctuations appear in the microfossil record of the sediment. 2. Dating was achieved by means of a combination of 137Cs and volcanic tephra and was fine-tuned by wiggle-matching of chironomid microfossil and monitoring data. 3. Cladocera exuviae and chironomid egg capsules in the uppermost 34 cm of sediment were compared with the monitoring record that consisted of 30 years of window trap catches of flying chironomids and a 16-year record of chydorid Cladocera caught in activity traps. 4. The observed chironomid and cladoceran population fluctuations were reflected in the sediment record of chironomid eggs and of the exuviae of three of seven cladocerans: Alonella nana, Alona rectangula and Eurycercus lamellatus, which also had the most extreme fluctuations in the monitoring data (3–4 orders of magnitude). Chydorus sphaericus, and to some extent Alona quadrangularis and Acroperus harpae, showed regular fluctuations in the core that the monitoring did not reveal. Density of subfossil chironomid eggs correlated positively with that of larval head capsules but not with other microfossils. 5. This study shows a reasonably good correspondence between the fossil records of chironomids and cladocerans on the one hand and biomonitoring data on the other. The results pave the way for an extension of the food web history to much earlier time intervals of the ecosystem, allowing the study of long-term variation in the food web dynamics, including the impact of climatic variation and other external forcing. The results also indicate the usefulness of chironomid egg capsules in palaeolimnological studies.

Summary 1. Assemblages of Chaoborus were examined in 80 thermally stratified southern central Canadian Shield lakes to explore whether subfossil mandibles could be useful in assemblage-level studies of Chaoborus. 2. Chaoborus (Sayomyia) (probably Chaoborus punctipennis in this study region) and Chaoborus flavicans were the most common taxa recorded, while Chaoborus trivittatus was rarer. Chaoborus americanus was not recorded in subfossil assemblages, because no fishless lakes were included in this study. Chaoborus flavicans had higher relative abundances (%) in lakes with higher dissolved organic carbon (DOC), probably because of reduced fish predation in less transparent water. 3. Results from logistic regression indicate that patterns of presence/absence for Chaoborus mandibles in the study lakes were influenced primarily by hypolimnetic oxygen concentration, probably because of the presence or extent of a hypolimnetic refugium from fish predation. 4. Chaoborus species richness in lakes, derived from subfossil assemblages, did not differ significantly from species richness estimates derived from plankton sampling with a net. Patterns of dominance and coexistence [e.g. the widespread co-occurrence of C. flavicans and C. (Sayomyia)] determined from subfossil assemblages agreed with previous studies of the contemporary living assemblage. 5. These results suggest that subfossil assemblages may be used as an alternative to nocturnal plankton sampling to carry out research on the community ecology of Chaoborus. 6. We propose a hierarchical conceptual model of assemblage-level patterns of Chaoborus in temperate lakes. Chaoborus americanus dominates in fishless lakes, whereas in lakes with fish Chaoborus is typically absent where there is no anoxic hyplimnion. In lakes with anoxic strata, C. trivittatus tends to dominate in lakes with few fish; in the remaining lakes, C. flavicans and C. (Sayomyia) dominate, although C. flavicans is more relatively abundant in lakes with lower water clarity (higher DOC).

In the present study, structural xeromorphic features in modern and subfossil Quercus laurifolia leaves from southern Florida were quantified to reconstruct past precipitation changes in sensitive terrestrial settings. Absolute cell numbers/mm2, quantified as epidermal cell density (ED) have been analyzed on leaves from herbarium collections as well as the leaves accumulated during the past 125 years in peat deposits. The results reveal a common principal correlation between the measured ED and winter precipitation (November through March, NDJFM: Herbarium r = - 0.74; peat profiles FAK98 r = - 0.72, FAK02 r = - 0.53) providing a measure of seasonal drought stress. In Florida, the amount of winter precipitation depends on El Nin o-Southern Oscillation (ENSO) activity, where El Nin o years produce wet and cold winters, while La Nin a winters are dry and warm. The negative correlation between cell numbers and winter precipitation has the potential to record precipitation variability from subfossil leaves on near-annual to decadal time scales. In subtropical, terrestrial environments, where traditional paleo-proxies are limited, systematic analysis of leaf morphological characteristics can provide important information on precipitation changes through time. © 2010 Botanical Society of America.

Using ancient DNA sequences of subfossil European pond turtles (Emys orbicularis) from Britain, Central and North Europe and accelerator mass spectrometry radiocarbon dating for turtle remains from most Swedish sites, we provide evidence for a Holocene range expansion of the pond turtle from the southeastern Balkans into Britain, Central Europe and Scandinavia, according to the 'grasshopper pattern' of Hewitt. Northeastern Europe and adjacent Asia were colonized from another refuge located further east. With increasing annual mean temperatures, pond turtles reached southern Sweden approximately 9800 years ago. Until approximately 5500 years ago, rising temperatures facilitated a further range expansion up to Ostergötland, Sweden (approximately 58 degrees 30'N). However, around 5500 years ago pond turtle records suddenly terminate in Sweden, some 1500 years before the Holocene thermal maximum ended in Scandinavia and distinctly earlier than previously thought. This extinction coincides with a temporary cooling oscillation during the Holocene thermal maximum and is likely related to lower summer temperatures deteriorating reproductive success. Although climatic conditions improved later again, recolonization of Sweden from southern source populations was prevented by the Holocene submergence of the previous land connection via the Danish Straits that occurred approximately 8500 years ago.

Numerical techniques were used to study chironomid distribution and abundance in lakes from a 1000 km transect in Finland, with special interest on the effect of local summer air temperatures on chironomid assemblages. The final aim of the study was to develop a chironomid-based palaeotemperature inference model. The dataset consisted of 82 lakes (of which 77 were used in the model after deletion of outliers), with catchments spanning from boreal coniferous forests to mountain birch woodland and tundra vegetation. Numerical analysis showed that the mean July air temperature was the most significant variable explaining the distribution and abundance of chironomids in Finnish lakes. Weighted-averaging partial least squares techniques were used to develop a palaeotemperature inference model for mean July air temperature reconstructions. The model performance statistics were favourable, with cross-validated coefficient of determination (r2) of 0.78, root mean squared error of prediction of 0.721°C and maximum bias of 0.794°C. Based on these values, the transfer function is a valid means of performing quantitative palaeotemperature estimates in downcore studies. Copyright © 2008 John Wiley & Sons, Ltd.

At the end of the Pleistocene, environmental conditions in the Baltic Basin were affected by the melting glaciers and the resultant freshwater bodies. In contrast to various seal species, there is no subfossil evidence of the harbour porpoise (Phocoena phocoena) from the early Holocene stages of the Baltic Basin. This article is an attempt to clarify the colonization of the harbour porpoise into the Baltic Sea and to reveal the ecological background of this process. All published Holocene subfossil records from the porpoise in the Baltic region were sought and supplemented with those from museums and zoological collections; 148 records document the porpoise's occurrence. The earliest records of the harbour porpoise date from the time between 9600 and 7000 cal. yr BP and originate from the early and middle Mesolithic coastal settlements of the Maglemose and Kongemose culture during the early Littorina stage. Around 7500–5700 cal. yr BP, the porpoise is recorded frequently at many localities from late Mesolithic (Ertebolle culture) and Neolithic in the coastal areas of the western Baltic Sea, as well as for the first time in the Gulfs of Bothnia and Finland. Since 4000 cal. yr BP, P. phocoena has only been recorded in the western Baltic. We suggest that immigration and dispersion of P. phocoena into the Baltic Sea was connected with the Littorina transgression beginning around 9000 cal. yr BP. The continuous influx of seawater and the associated ecological changes led to a new, very species-rich, fish community and adequate living conditions for the harbour porpoise.

Wood samples from above the present-day pine limit were collected from within a limited area in central Sweden. New dates from an intensively investigated part of that area all fall within the period 8550 ± 110 to 4270 ± 90 14C years B. P. No evidence at present exists to suggest that any drastic change, or fluctuations, in the pine tree-limit, took place within that period. Some dates support the view that the present-day altitude of the pine tree-limit was established during the historic period and perhaps is still declining.

The Kakapo Strigops habroptilus is unique amongst parrots in many respects, not least its use of a lek breeding system. Since Merton et al. first described the phenomenon, little new information has come to light, chiefly as a result of the extreme rarity of Kakapo. Observation of an extreme sex ratio skew in favour of males has received little attention and has been considered spurious. I used subfossil material to examine the nature of the sex ratio prior to the arrival in New Zealand of humans and demonstrated that a sex bias in favour of males in the order of 2:1 existed at that time. Although apparently untenable on traditional theoretical grounds, this extreme skew has been persistent and has resulted from the interaction of sexual and natural selection on dimorphic male and female Kakapo. Relatively small, sole caring females may suffer the consequences of parental investment as a result of demands made by offspring over an extended rearing period. In particular, larger male chicks may exert a greater cost on the parent bird than do female siblings. Additionally, brood reduction in certain circumstances may favour the survival of dominant male siblings.