Major Climatic Events Research Articles

Strontium and carbon isotopic evidence for decoupling of pCO2 from continental weathering at the apex of the late Paleozoic glaciation

Earth's penultimate icehouse (ca. 340-285 Ma) was a time of low atmospheric pCO(2) and high pO(2), formation of the supercontinent Pangaea, dynamic glaciation in the Southern Hemisphere, and radiation of the oldest tropical rainforests. Although it has been long appreciated that these major tectonic, climatic, and biotic events left their signature on seawater Sr-87/Sr-86 through their influence on Sr fluxes to the ocean, the temporal resolution and precision of the late Paleozoic seawater Sr-87/Sr-86 record remain relatively low. Here we present a high-temporal-resolution and high-fidelity record of Carboniferous-early Permian seawater Sr-87/Sr-86 based on conodont bioapatite from an open-water carbonate slope succession in south China. The new data define a rate of long-term rise in Sr-87/Sr-86 (0.000035/m.y.) from ca. 334-318 Ma comparable to that of the middle to late Cenozoic. The onset of the rapid decline in Sr-87/Sr-86 (0.000043/m.y.), following a prolonged plateau (318-303 Ma), is constrained to ca. 303 Ma. A major decoupling of Sr-87/Sr-86 and pCO(2) during 303-297 Ma, coincident with the Paleozoic peak in pO(2), widespread low-latitude aridification, and demise of the pan-tropical wetland forests, suggests a major shift in the dominant influence on pCO(2) from continental weathering and organic carbon sequestration (as coals) on land to organic carbon burial in the ocean.

Too hot to trot? How horse owners in Australia have responded to major weather events

ABSTRACTThis article commences by outlining five perspectives on the sustainability of equestrian cultures covering the environment, the economy, human health, horse welfare, and social licence. Next, it presents findings from an online survey developed to understand how horse owners in Australia have been affected by major weather and climate events, how they responded in the short and long term, their considerations for the future, and the support they might require. Sixty-nine horse owners participated. Most (90%) reported being affected by major weather/climate event(s) in the last 10–20 years, four out of five (78%) took action at the time of the event and a similar proportion (80%) had taken actions for the longer term. Most (86%) had thought about preparations for future events, but had not yet taken any action, due to lack of time, money, materials, or storage. Almost all participants (93%) perceived a need for education, research, government policy. Since findings suggest horse owners may be less likely to engage with climate adaptation and sustainable horse keeping public education initiatives when they are related specifically to “climate change”, and more likely to engage when they are related to “land care, pasture management and improvement”, and “horse health and welfare”, an alternative rhetoric is recommended.

Changes of deep Pacific overturning circulation and carbonate chemistry during middle Miocene East Antarctic ice sheet expansion

East Antarctic ice sheet expansion (EAIE) at ∼13.9 Ma in the middle Miocene represents a major climatic event during the long-term Cenozoic cooling, but ocean circulation and carbon cycle changes during this event remain unclear. Here, we present new fish teeth isotope (εNd) and benthic foraminiferal B/Ca records from the South China Sea (SCS), newly integrated meridional Pacific benthic foraminiferal δ18O and δ13C records and simulated results from a biogeochemical box model to explore the responses of deep Pacific Ocean circulation and carbon cycle across EAIE. The εNd and meridional benthic δ13C records reveal a more isolated Pacific Deep Water (PDW) and a sluggish Pacific meridional overturning circulation during the post-EAIE with respect to the pre-EAIE owing to weakened southern-sourced deep water formation. The deep-water [CO2−3] and calcium carbonate mass accumulation rate in the SCS display markedly similar increases followed by recoveries to the pre-EAIE level during EAIE, which were probably caused by a shelf–basin shift of CaCO3 deposition and strengthened weathering due to a sea level fall within EAIE. The model results show that the ∼1‰ positive δ13C excursion during EAIE could be attributed to increased weathering of high-δ13C shelf carbonates and a terrestrial carbon reservoir expansion. The drawdown of atmospheric CO2 over the middle Miocene were probably caused by combined effects of increased shelf carbonate weathering, expanded land biosphere carbon storage and a sluggish deep Pacific meridional overturning circulation.

Late Pleistocene - Holocene vegetation and climate from the palaeolake sediments, Rukti valley, Kinnaur, Himachal Himalaya

Vegetation and climate during later part of Pleistocene to major part of Holocene (∼16.6–3.5 ka) has been reconstructed based on the palynological and magnetic susceptibility proxies from an exposed section of lacustrine deposit at Rukti, Sangla valley, Kinnaur, western Himalaya. Study shows that along with the general tree line succession to higher altitudes since early Holocene, the area has also captured the major climatic events of late Pleistocene to early-mid Holocene time. The area exhibits a continuation of mixed conifer - broadleaved forest at least since ∼16.6 ka with intermittent phases of expansions of broadleaved tree taxa especially Oaks (Quercus) or invasion of conifers especially Pine (Pinus) with an increase (moist) or decrease (dry) of Indian Summer Monsoon (ISM) respectively. This is also supported by the variations in the magnetic susceptibility values. The climate was warm and moist during ∼16.6 ka and changed to cool ∼13.3 ka, followed by increasing ISM since ∼11.5 ka. Distinct spike in the magnetic susceptibility values between ∼8.7 and ∼7.8 ka could correspond to global 8.2 ka cool event thus indicating strengthening of westerly influence and low evaporation. Subsequent warm conditions could be generalized by the advancement of Birch (Betula) line to higher altitude following the resultant retreat of the glacial body. Study has put forth the potential of such Himalayan sites to uncover the major climatic events of global correlation captured by various proxies within a region.

History of Asian eolian input to the Sea of Japan since 15 Ma: Links to Tibetan uplift or global cooling?

We present high-resolution analyses of clay mineral assemblages combined with analysis of Sr–Nd–Pb isotopic compositions of the <2 μm silicate fraction of sediments from Integrated Ocean Drilling Program (IODP) Site U1430 in the southern Sea of Japan, in order to trace the sources of clay minerals and reconstruct proxy records of past changes in Asian eolian input to the basin since 15 Ma. The clay mineral assemblages at IODP Site U1430 mainly consist of smectite (∼51%) and illite (∼36%), with minor kaolinite (∼7%) and chlorite (∼6%). Provenance analysis suggests that the fine-grained sediment at the study site is a two end-member mixture of eolian dust from Central Asia and fluvial input from the Japanese islands. The Central Asian end member supplied illite-rich and high 87Sr/86Sr and low εNd(0) eolian dust to the study site by wind, while the Japanese end member, characterized by young volcanic rocks, contributed smectite-rich, low 87Sr/86Sr and high εNd(0) weathering products via rivers. The ratio of illite/smectite and εNd(0) values of clay-sized silicate sediments at Site U1430 were used as proxies for tracing the changing strength of central Asian eolian input to the Sea of Japan, and thus reconstruct the aridification history of its source region. Our study presents for the first time a continuous, high-resolution record that highlights the four-step drying of Central Asia that occurred at ∼11.8 Ma, 8 Ma, 3.5 Ma and 1.2 Ma. Considered the nature and timing of major climatic and tectonic events in Asia, we conclude that the strengthened aridification of Central Asia starting at ∼11.8 Ma was possibly driven by the combined effect of Tibetan surface uplift and global cooling, whereas the rapid drying at ∼8 Ma was caused primarily by the uplift of the northern Tibetan Plateau. In contrast, global cooling, overwhelming the influence of Tibetan Plateau uplift, has become the primary control on Central Asia aridification since ∼3.5 Ma.

Late Paleocene-middle Eocene hydrocarbon source rock potential in the Arctic Beaufort-Mackenzie Basin

The Natsek E-56 oil and gas exploration well from the Arctic Beaufort-Mackenzie Basin (BMB) was selected for a multi-disciplinary study because its strata contain a record of two major Eocene climate events that affected source rock deposition: the Paleocene/Eocene Thermal Maximum (PETM) at ∼55.5 Ma and the early mid-Eocene Azolla event at ∼49 Ma. Rock-Eval data from Natsek E-56 indicates a previously overlooked potentially economically significant interval that occurs just below PETM strata. The pre-PETM unit is an organic rich (∼30% TOC) coaly-shale deposit with good hydrocarbon source rock potential and marginal thermal maturity. This carbonaceous deposit is characterized by a relatively elevated hydrogen index (HI∼149 mg HC/TOC; S2 ∼ 38 mg HC/g Rock) which suggests increased input of liptinitic-rich material similar to the sapropelic boghead coal formed in lacustrine environments in the vicinity of the modern Beaufort-Mackenzie delta plain.In recent years, source rock predictions for the Eocene Arctic were postulated from cores on the Lomonosov Ridge, focusing on organic matter (OM) produced during the Azolla event. OM associated with Azolla also occurs in the Natsek E-56 (TOC ranges from 1 to 14%) but reworked terrestrial matter is a dominant component. The pre-PETM organic rich interval of Natsek E-56 was not recorded at the Lomonosov Ridge, while in Natsek E-56 the interval consists of TOC values double that recorded at any point in the Lomonosov Ridge wells. The occurrence of multiple potential source rocks from the unique depositional environments in the BMB indicates oil and gas potential in late Paleocene-middle Eocene strata of the Beaufort-Mackenzie region.

Effects of long term nutrient and climate variability on subfossil Cladocera in a deep, subalpine lake (Lake Garda, northern Italy)

Albeit subfossil Cladocera remains are considered as a reliable proxy for tracking historical lake development, they have been scarcely studied in large subalpine lakes south of the Alps. In this study, subfossil Cladocera remains from Lake Garda in northern Italy were analyzed to track the lake’s environmental changes since the Middle Ages. One core was retrieved from the largest sub-basin of Lake Garda (Brenzone, 350 m deep) and two cores were retrieved from the profundal and littoral zone of the smaller lake sub-basin (Bardolino, 80 and 40 m deep, respectively). The species distribution of Cladocera remains in recent sediment layers was similar to that observed in contemporary water samples. The deepest sections of the three cores were characterized by species sensitive to water temperature, which suggest a key role of major climatic events in driving the lake response during the late Holocene. The most evident change in Cladocera assemblages in the studied cores was observed during the 1960s, when planktonic taxa such as Daphnia spp. and Bosmina spp. became dominant at the expense of littoral taxa. Despite the highly coherent general pattern of subfossil Cladocera, the cores showed a set of minor differences, which were attributed to different morphological and hydrological features of the two basins forming Lake Garda. Multivariate analysis revealed a clear relation of Cladocera to climate variability during periods of low lake nutrient levels (i.e. before the 1960s). This provides additional information on past ecological responses of Lake Garda, as contrast previous data from subfossil diatom and pigment analyses did not fully capture effects of climate change during the same period. Since the 1960s shifts in assemblage composition of Cladocera and diatoms were highly coherent, in response to nutrient increase and the following, less pronounced, decrease in nutrient concentrations. During the last five decades, the response of the Cladocera to climate variability appeared to be masked by nutrient change. This work points up the potential of the multi-proxy approach for disentangling the multifaceted biological responses to multiple environmental stressors in large and deep lakes.

Early Jurassic carbon and oxygen isotope records and seawater temperature variations: Insights from marine carbonate and belemnite rostra (Pieniny Klippen Belt, Carpathians)

New carbon and oxygen isotope records and discussion of the main variations in seawater temperature through the Sinemurian–Aalenian of the Pieniny Klippen Basin (northern Tethys Ocean) are presented herein. Comparison of the recorded changes in stable-isotope compositions of bulk carbonate and belemnite rostra from an open-marine environment with previously documented, predominantly restricted epicontinental data enables determination of major climatic events that were most likely of worldwide extent. A slight positive δ13C shift is recorded in the lowermost Upper Pliensbachian. A significant positive excursion in carbonate carbon isotope values is documented in the Lower Toarcian Serpentinum Zone. Furthermore, the δ13C values display a falling trend in the Lower–Upper Toarcian and relatively constant values in the Aalenian. Temperatures inferred from the δ18O values of well-preserved belemnite rostra suggest rather cool seawater conditions (10–13 °C) in the Pieniny Klippen Basin during the Late Sinemurian, warming by 4 °C in the Early Pliensbachian and then cooling by 8 °C in the Late Pliensbachian. The seawater temperature rose once more in the Early Toarcian and began to fall again during the Middle Toarcian. In the Middle–?Late Aalenian, seawater temperatures oscillated between 10 and 13 °C.

Australian uranium industry climate change vulnerability assessment

Australia holds 31% of the global uranium resources and currently supplies 12% of the worldwide market. Based on the expected increase in global energy consumption, the demand for uranium is projected to increase, and Australia is well positioned to ensure it remains a significant supplier in the market. However, due to future climate change, the local uranium industry may be impacted as more intense and more frequent extreme weather events are expected, leading to potential disruption to operations and damage to mining infrastructure. Therefore, Australia’s reputation as a reliable industry supplier may be at risk in the future. This paper conducts a review of the vulnerability of the Australian uranium industry to climate related impacts, based on surveys conducted around currently operating uranium mines. Operational disruptions, loss of revenue and increased costs have all been reported as existing impacts by major climatic events. Survey respondents identified tailings/waste storage facilities, ore extraction, processing, transport within the mine site and maintenance activities as the most affected. Through this research, critical aspects to improve the adaptive capacity of the industry have been revealed.

Lineage Diversity and Size Disparity in Musteloidea: Testing Patterns of Adaptive Radiation Using Molecular and Fossil-Based Methods.

Adaptive radiation is hypothesized to be a primary mechanism that drives the remarkable species diversity and morphological disparity across the Tree of Life. Tests for adaptive radiation in extant taxa are traditionally estimated from calibrated molecular phylogenies with little input from extinct taxa. With 85 putative species in 33 genera and over 400 described extinct species, the carnivoran superfamily Musteloidea is a prime candidate to investigate patterns of adaptive radiation using both extant- and fossil-based macroevolutionary methods. The species diversity and equally impressive ecological and phenotypic diversity found across Musteloidea is often attributed to two adaptive radiations coinciding with two major climate events, the Eocene-Oligocene transition and the Mid-Miocene Climate Transition. Here, we compiled a novel time-scaled phylogeny for 88% of extant musteloids and used it as a framework for testing the predictions of adaptive radiation hypotheses with respect to rates of lineage diversification and phenotypic evolution. Contrary to expectations, we found no evidence for rapid bursts of lineage diversification at the origin of Musteloidea, and further analyses of lineage diversification rates using molecular and fossil-based methods did not find associations between rates of lineage diversification and the Eocene-Oligocene transition or Mid-Miocene Climate Transition as previously hypothesized. Rather, we found support for decoupled diversification dynamics driven by increased clade carrying capacity in the branches leading to a subclade of elongate mustelids. Supporting decoupled diversification dynamics between the subclade of elongate mustelids and the ancestral musteloid regime is our finding of increased rates of body length evolution, but not body mass evolution, within the decoupled mustelid subclade. The lack of correspondence in rates of body mass and length evolution suggest that phenotypic evolutionary rates under a single morphological metric, even one as influential as mass, may not capture the evolution of diversity in clades that exhibit elongate body shapes. The discordance in evolutionary rates between body length and body mass along with evidence of decoupled diversification dynamics suggests that body elongation might be an innovation for the exploitation of novel Mid-Miocene resources, resulting in the radiation of some musteloids.

Characterization of the Medieval Climate Anomaly, Little Ice Age and recent warming in northern Lapland

ABSTRACTThe major climate events of the Common Era (CE) have global imprints but significant variations in their timing and magnitude have been suggested. For reliable assessments of the past climate patterns and their applications for evaluations of the ongoing changes, spatially comprehensive network of high‐fidelity paleorecords are necessary. In this study, we reconstruct summer air temperatures of the past 2000 years from northern Lapland (Utsjoki, Finland). We use fossil Chironomidae (Diptera) assemblages from sediments of a remote subarctic lake (Loažžejávri) and the transfer function approach for quantitative temperature reconstruction. The results indicate that the Chironomidae fauna were responding to air temperature and the core assemblages had good modern analogues in the calibration set allowing reliable paleoclimate reconstruction. In our reconstruction, a warm period between ∼900 and 1300 CE is synchronous with the globally defined extent of the Medieval Climate Anomaly (MCA), though beginning considerably later than previously reconstructed for eastern Scandinavia. The MCA was also relatively mild, as the temperatures were only 0.5 °C higher than the record average. Similar to eastern Scandinavia, a cold period corresponding to the Little Ice Age (LIA) was longer that typically observed in hemispheric reconstructions beginning already at ∼1400 CE and lasting very close to modern times. We also found confirming evidence that the LIA was interrupted by a short‐lived warmer period dividing it into two separate cold events in the region. Based on our results, the present is warmer than during any time of the MCA displaying how rapid and severe the ongoing climate change is.

Systematics and evolution of the Meriones shawii/grandis complex (Rodentia, Gerbillinae) during the Late Quaternary in northwestern Africa: Exploring the role of environmental and anthropogenic changes

Rodents of the Meriones shawii/grandis complex have been attested to in North Africa since the Middle Pleistocene and are abundant in archaeological sites. Today, they are widely spread and represent a major pest to local human populations. This complex, therefore, represents an accurate model for investigating the roles of climate change and human impact in shaping Quaternary faunal diversity and distribution. Many gray areas still exist regarding the systematics, ecology and geographical distribution of this complex, for both present and past populations. The purpose of this study is to compare modern genotyped and fossil Meriones specimens in order to 1) clarify the current systematics and distribution of the Meriones populations of the shawii/grandis complex, 2) document the taxonomic diversity in fossil Meriones from northwestern Africa, and 3) track their phenotypic and biogeographic evolution through time. To answer these questions we used geometric morphometrics on skulls (landmarks) and first upper molars (landmarks and sliding landmarks). We evidenced the existence of two morpho-groups within the M. shawii/grandis complex, with a clear geographic pattern (M. grandis in Morocco vs. M. shawii in Algeria and Tunisia). Currently only one morpho-group, attributed to M. grandis, seems to exist in Morocco, with a small overlap with M. shawii in the most eastern part of the country. However, according to fossil data, M. shawii was also present in Atlantic Morocco during the Late Pleistocene. We have also highlighted the impact of Holocene climate change and habitat anthropization on this arid adapted group. During the Middle Holocene, a major climatic event (last interglacial optimum) seems to have induced a demographic collapse in Moroccan populations and the disappearance of the shawii clade from Morocco (except in the most eastern areas). Both species then re-expanded, benefitting from the increasing aridity and the new ecological niche driven by agriculture dispersal from the Neolithic onwards.

Molecular substitution rate increases with latitude in butterflies: evidence for a trans‐glacial latitudinal layering of populations?

A well‐documented consequence of repeated global ice ages is the negative relationship between latitude and intraspecific genetic diversity. However, little is known about additional effects of such major climatic events on population genetic structure. Here we studied the phylogeographic structure of five lycaenid butterfly species with varied ecological adaptations, sampled across a latitudinal gradient in the Holarctic region. We found a positive correlation between latitude and substitution rate of mitochondrial DNA sequences in all species investigated. We propose that this result is the signal of increased genetic drift and founder effects during post‐glacial recolonization of northern populations. Given that phylogenetic branch length is the result of a cumulative process over evolutionary time, we hypothesize that a latitudinal layering of populations has generally been maintained during repeated cycles of glaciation, possibly due to a neutral spatial effect and/or local adaptive advantage. This trans‐glacial latitudinal layering could be viewed as a particular case of the more general phenomenon of intraspecific structuring that is created and maintained in a fluctuating environmental gradient.

Lineage‐specific climatic niche drives the tempo of vicariance in the Rand Flora

AbstractAimThe disjunct distribution patterns of sister taxa can arise when previously continuous distribution ranges are fragmented by environmental changes such as major climatic events. Populations become isolated on either side of the newly established environmental barrier, and absence of gene flow promotes allopatric speciation, in a process that is known as ecological vicariance. If climate change altered the ancestral range gradually, such as along temporal temperature or moisture gradients, the age of divergence of disjunct species should be related to the lineage tolerance to climatic conditions. Here, we investigate this hypothesis using as a study model the African Rand Flora, a continental‐scale floristic pattern that relates sister taxa distributed on either side of the Saharan Desert.LocationAfrica, Macaronesia, Mediterranean Basin and the Middle East.MethodsWe estimated the extant climatic tolerances of 14 Rand Flora lineages based on present occurrence data, and correlated the phylogenetic age of divergence between vicariant clades. We tested whether the tempo of the vicariance in the Rand Flora lineages was associated with the average values of their climatic niches in agreement with niche‐driven divergence. We hindcasted species ranges using species distribution models combined with palaeoclimate simulations to infer the potential distribution of each lineage's ancestors.ResultsWe found a positive relationship between the lineage temperature niche and the age of the Rand Flora disjunction: lineages with subtropical affinities diverged first, whereas those with a higher tolerance to drier conditions (temperate or sub‐xeric adaptations) exhibited younger disjunctions. The range reconstructions showed the existence of climatic corridors south of the Sahara in the wetter Late Miocene, which became interrupted during the mid‐Pliocene warming event.Main conclusionsOur results suggest that climate change leading to the formation of the Sahara Desert drove Rand Flora lineages divergences along a temporal sequence that matched the climatic niche of species.

Early to Late Maastrichtian environmental changes in the Indian Ocean compared with Tethys and South Atlantic

Planktic foraminiferal analysis, including species populations, diversity trends, high-stress indices and stable isotopes of the latest Campanian through Maastrichtian in the South Atlantic, Tethys and Indian oceans reveal four major climate and faunal events that ended with the Cretaceous-Paleogene (K/Pg), formerly Cretaceous-Tertiary (K/T), mass extinction. The prelude to these events is the late Campanian cooling that reached minimum temperatures in the earliest Maastrichtian (base C31r) correlative with low primary productivity and species diversity. Event-1 begins during the persistent cool climate of the early Maastrichtian (lower C31r) when primary productivity rapidly increased accompanied by rapid species originations, attributed to increased nutrient influx from increased upwelling, erosion during the sea-level fall ~70.6Ma, and Ninety East Ridge volcanism. During Event-2 (upper C31r to lower C30n), climate rapidly warmed by 2–3°C in deep waters and peaked at 22°C on land, primary productivity remained high and diversification reached maximum for the entire Cretaceous. We attribute this climate warming to intense Ninety East Ridge volcanic activity beginning ~69.5Ma, accompanied by rapid reorganization of intermediate oceanic circulation. Enhanced greenhouse conditions due to the eruption of Deccan Phase-1 in India resulted in detrimental conditions for planktic foraminifera marking the end of diversification. Global cooling resumed in Event-3 (C30n), species diversity declined gradually accompanied by dwarfing, decreased large specialized species, increased small ecologically tolerant taxa, and ocean acidification. Event-3 is mainly the result of enhanced weathering and volcanogenic CO2 adsorption by the oceans during the preceding warm Event-2 that led to cooling and lower pH in the surface ocean. Event-4 marks the last 250kyr of the Maastrichtian (C29r), which began with the largest Deccan eruptions (Phase-2) that caused rapid climate warming of 4°C in deep waters and 8°C on land, acid rain and ocean acidification leading to a major carbonate crisis preceding the K/T mass extinction.

Ecological divergence of Chaetopteryx rugulosa species complex (Insecta, Trichoptera) linked to climatic niche diversification

Climate is often considered to be an important, but indirect driver of speciation. Indeed, environmental factors may contribute to the formation of biodiversity, but to date this crucial relationship remains largely unexplored. Here we investigate the possible role of climate, geological factors, and biogeographical processes in the formation of a freshwater insect species group, the Chaetopteryx rugulosa species complex (Trichoptera) in the Western Balkans. We used multi-locus DNA sequence data to establish a dated phylogenetic hypothesis for the group. The comparison of the dated phylogeny with the geological history of the Western Balkans shows that lineage formation coincided with major past Earth surface and climatic events in the region. By reconstructing present-day habitat conditions (climate, bedrock geology), we show that the lineages of C. rugulosa species complex have distinct climatic but not bedrock geological niches. Without exception, all splits associated with Pliocene/Pleistocene transition led to independent, parallel split into ‘warm’ and ‘cold’ sister lineages. This indicates a non-random diversification on the C. rugulosa species complex associated with late Pliocene climate in the region. We interpreted the results as the diversification of the species complex were mainly driven by ecological diversification linked to past climate change, along with geographical isolation.

The role of forest expansion and contraction in species diversification among galagos (Primates: Galagidae)

AbstractAimHere, I investigate galagid diversification and current distribution in the context of major climatic and geological events in sub‐Saharan Africa. Given their widespread distribution and presence in a large range of diverse habitats, galagids represent an excellent group to investigate the role of forest contraction and expansion on biological diversification in sub‐Saharan Africa.LocationSub‐Saharan Africa (Afrotropical Region).MethodsI assembled a supermatrix including 53 nuclear loci and three mitochondrial markers for 94% of the galagid species currently recognized. Bayesian and maximum likelihood methods were used to infer phylogenetic relationships and times of divergence within the family. Ancestral ranges were estimated using several methods, including ‘BioGeoBEARS’ and rasp.ResultsPhylogenetic analyses corroborated previous results regarding the evolutionary history of this family: (1) early origin of the family soon after the Eocene‐Oligocene boundary; (2) dwarf galagos (Galagoides spp.) represent a polyphyletic group with two well‐defined clades, one in central‐west Africa and one in the east; and (3) divergences within galagids are relatively old with most genera already present by the Late Miocene. The biogeographical analysis indicates central African origins and subsequent expansion to the east in the Early‐Middle Miocene. An expansion to the northern and southern savannas occurred between the Late Pliocene and the Middle Pleistocene.Main conclusionsThe results of this study clarify several questions related to the evolutionary history of the Galagidae in the context of sub‐Saharan African biogeography. This study suggests that galagid evolution and diversification was affected by three major climatic episodes: (1) the global cooling and forest contraction in the Early Oligocene, (2) the forest expansion and the uplift of the African rifts in the Miocene and (3) the aridification and extension of open woodlands and savannas in the Late Miocene and Plio‐Pleistocene.

Modelling the evolution of the financial impacts of flood and storm surge between 2015 and 2050 in France

CCR (Caisse Centrale de Reassurance) is a French reinsurance company playing a major role in the natural catastrophe coverage in France. Since 2003, CCR has been developing tools for the estimation of its exposure to climatic risks. These tools cover three main perils: flood, storm surge and drought. Models are used to estimate the insurance losses and are systematically used for all major climatic events. Both modelling calibration and validation are based on an important policy and claim database. It was created in 2003 and supplied every year with insurer’s data. In order to evaluate the financial exposure for insurance of extreme events, a stochastic approach has been developed since 2011, for flood, storm surge and drought. The simulation of the stochastic event set allows us to estimate the mean annual losses and losses associated with different return periods. The objective of this approach is to connect the impact models for all perils with a large set of climate simulations. ARPEGE-Climate (Meteo-France) is a model that is used to generate two sets of 200 years of hourly atmospheric time series: at current conditions and at year 2050 conditions according to RCP (Representative Concentration Pathways) 4.5. The main climate data used are: hourly rainfall, wind speed and atmospheric pressure and the Soil Wetness Index that is issued from a complementary surface model. The hazard and vulnerability models developed are based on the climatic data to compute continuous loss estimations. The method proposed will take into consideration development scenarios to evaluate the consequences of demographic growth and insured values evolution. The simulations show a global loss increase in 2050 which can be attributed to climatic factors such as extreme rainfall increase or sea level rise as well as, for a major part, the population and insured value growth in areas at risk.

Continuity and change in the anthropomorphic figures of Australia’s northwest Kimberley

One of the largest concentrations of rock paintings in Australia is found in the rugged Kimberley region in the northwest of the continent. A temporal sequence of visually distinctive figurative styles is presumed to span periods of cultural change and major climatic events. As the nature and course of these changes are poorly understood, this paper investigates the relationships between continuity and change in the stylistic attributes of the selected anthropomorphic figures in the rock art assemblage. Some previous Kimberley rock art researchers have argued for an abrupt discontinuity in the art assemblage between the Wararrajai Gwion (the most recent of the Gwion styles) and Painted Hand Periods (formally Clothes Peg Figure and Clawed Hand Periods respectively), while others have argued for more gradual change. Based on the study of 204 rock art sites from 15 site complexes, which included a total of 7,579 motifs and 3,685 identifiable anthropomorphic figures, we identify the core characteristics of anthropomorphic figures in each of the established stylistic periods and show that there is no evidence to support notions of an abrupt discontinuity of art through time. Rather, attribute preferences changed gradually, existing as clades of variation rather than discrete units, with identifiable threads of continuity and periods when certain attributes (core characteristics) are preferentially adopted. A quantitative analysis supports our interpretation.

Old Lineage on an Old Island: Pixibinthus, a New Cricket Genus Endemic to New Caledonia Shed Light on Gryllid Diversification in a Hotspot of Biodiversity.

Few studies have focused on the early colonization of New Caledonia by insects, after the re-emergence of the main island, 37 Myr ago. Here we investigate the mode and tempo of evolution of a new endemic cricket genus, Pixibinthus, recently discovered in southern New Caledonia. First we formally describe this new monotypic genus found exclusively in the open shrubby vegetation on metalliferous soils, named ‘maquis minier’, unique to New Caledonia. We then reconstruct a dated molecular phylogeny based on five mitochondrial and four nuclear loci in order to establish relationships of Pixibinthus within Eneopterinae crickets. Pixibinthus is recovered as thesister clade of the endemic genus Agnotecous, mostly rainforest-dwellers. Dating results show that the island colonization by their common ancestor occurred around 34.7 Myr, shortly after New Caledonia re-emergence. Pixibinthus and Agnotecous are then one of the oldest insect lineages documented so far for New Caledonia. This discovery highlights for the first time two clear-cut ecological specializations between sister clades, as Agnotecous is mainly found in rainforests with 19 species, whereas Pixibinthus is found in open habitats with a single documented species. The preference of Pixibinthus for open habitats and of Agnotecous for forest habitats nicely fits an acoustic specialization, either explained by differences in body size or in acoustic properties of their respective habitats. We hypothesize that landscape dynamics, linked to major past climatic events and recent change in fire regimes are possible causes for both present-day low diversity and rarity in genus Pixibinthus. The unique evolutionary history of this old New Caledonian lineage stresses the importance to increase our knowledge on the faunal biodiversity of ‘maquis minier’, in order to better understand the origin and past dynamics of New Caledonian biota.