Mean Temperature Of Coldest Month Research Articles

Climatic reconstruction at the early Miocene La Rinconada mine (Ribesalbes-Alcora Basin, eastern Spain) based on Coexistence Approach, CLAMP and LMA analysis

The early Miocene La Rinconada mine from eastern Iberian Peninsula contains a rich megafloral assemblage with abundant leaf fossils from a single stratigraphic level of the sedimentary succession. This has provided a good opportunity to undertake detailed comparative quantitative palaeoclimate reconstruction using different approaches, namely the Coexistence Approach (CA), Climate Leaf Analysis Multivariate Programme (CLAMP) and Leaf Margin Analysis (LMA). Considering the results of all techniques used, the palaeoclimate estimates are the following: mean annual temperature (MAT) CA = 10–16.5 °C/CLAMP = 11.48 °C, warmest month mean temperature (WMMT) CA = 25–26.4 °C/CLAMP = 23.31 °C, coldest month mean temperature (CMMT) CA = 4.3–4.8 °C/CLAMP = 0.84 °C, mean annual precipitation (MAP) CA = 1217–1297 mm, mean precipitation of the wettest month (MPWet) CA = 116–164 mm and mean precipitation of the warmest month (MPWarm) CA = 118–131 mm. Temperature and precipitation values obtained through CLAMP, LMA and CA indicate the occurrence of a wet and warm climate the whole year around with marked seasonality for rainfall and temperature but without a summer-dry regime. The climatic values obtained in the La Rinconada mine are in well accordance with other Burdigalian and late Burdigalian–early Langhian sites from the Iberian Peninsula (e.g. S 141 Borehole) and Central-Southern Europe (e.g. Holedeč, Čermníky, Přívlaky, Bílina Delta, Manisa-Soma, Spanokhorion and the Evia Island), suggesting the absence of a clear latitudinal gradient in temperature and precipitation for this period in Europe. This climate is consistent with the plant communities described in the area from taxonomic studies and IPR analysis.

Palaeovegetation and paleoclimate in the SW Turkey – a study based on the early-middle Miocene coal-bearing sediments from the Büyük Menderes Graben

This study provides the age of coal-bearing sediments of the Büyük Menderes Graben (BMG) and palaeoclimatic and palaeovegetational change from the early to late Miocene. Two palynofloras, the Başçayır and Kızılcayer, are distinguished in the late Burdigalian-early Langhian, and Serravallian-Tortonian boundary. According to the microfloral composition of the Başçayır palynoflora is characterized by subtropical elements, and palaeoclimate is warm subtropical, with the coldest month mean temperature (CMT) 8–13 oC. Based on the palynoflora, the coal-bearing sediments were deposited in the fluvial-lacustrine environments. The abundances of gymnosperm species and the mean annual range of temperature (MART) point out high and middle altitude areas during the deposition of coal-bearing sediments. Based on the Kızılcayer palynofloral composition, palaeoclimate is the warm temperate (CMT: 3.1–13.3 oC), also the abundant presence of herbaceous species indicate open land areas in the Aydın-Kızılcayer area despite the existences of swampy-lowland environments.According to described palynofloral composition, the palaeotopographic conditions of the southern part of the BMG (Aydın-Kuloğulları) are generally higher than the northern parts (Aydın-Başçayır), and deposition areas in this graben are significantly uplifted from the late Burdigalian to early Tortonian. The regional palaeoclimatic condition from the early to late Miocene changed from warm subtropical to temperate in western Anatolia. The palaeotopographic changes related to the tectonic events and/or uplift of the Menderes Massive in western Anatolia could have been effective on regional paleoclimate during the deposition in the BMG, and this uplifting existed in the late Burdigalian and continued until the late Miocene.

Latest Neogene monsoon of the Chotanagpur Plateau, eastern India, as revealed by fossil leaf architectural signatures

A fossil leaf assemblage from latest Neogene (Pliocene) sediments exposed in Jharkhand of Chotonagpur Plateau, eastern India, is subjected to a CLAMP (Climate Leaf Analysis Multivariate Program) analysis using a new high spatial resolution (~1 km2) WorldClim2 gridded climate data and PhysgAsia2 calibration. The CLAMP analysis of 80 different morphotypes of fossil leaves indicates a mean annual temperature (MAT) of 21.9 °C ± 2.3 °C; a cold month mean temperature (CMMT) of 16.7 °C ± 3.5 °C and a warm month mean temperature (WMMT) of 26.9 °C ± 2.9 °C. Precipitation estimates have high uncertainties but suggest a weak monsoon with a growing season (11.7 ± 1 months) precipitation (GSP) of 201.2 ± 64.3 cm. The new calibration also provides for the first time in India more detailed insights into the hydrological regime through the return of annual and seasonal vapour pressure deficit (VPD) and potential evapotranspiration (PET) estimates, as well as new thermal overviews through measures of thermicity and growing degree days. The new results confirm the overall warmth of the region. Although rainfall estimates have large uncertainties due to year-round wet soils, measures of VPD and PET show persistent high humidity, but with higher evaporative stress in the summer during late Neogene times than now.

Stable isotope compositions of herbivore teeth indicate climatic stability leading into the mid-Miocene Climatic Optimum, in Idaho, U.S.A

The effects of global climate change are manifested at the regional level; consequently, evaluation of links between palaeoenvironmental change and turnover of past biotas must use regional-scale climate data. Here we test whether climate change influenced faunal and floral patterns leading up to, and during, the mid-Miocene Climatic Optimum (MMCO) based on datasets collected in the Railroad Canyon section (RCS), central-eastern Idaho, U.S.A. Specifically, we use isotope compositions of herbivore tooth enamel to investigate how Mean Annual Precipitation (MAP), Mean Annual Temperature (MAT), Cold Month Mean Temperature (CMMT), and temperature seasonality varied through the RCS and how this local record compares to global climate reconstructions. Isotope compositions of teeth from the fossil equid Merychippus and rhinocerotid Diceratherium were compared across five time bins from c. 23 to c. 15 Ma. Bulk δ18O values of both taxa indicate that meteoric water compositions were unchanged through the study interval (consistently c. −15.6‰) but were c. 1.9‰ higher than current regional meteoric water. This difference points to warmer climates in central-eastern Idaho during the Miocene, post-middle Miocene topographic uplift in western North America, and/or shifts to air mass trajectories. Serial sampling of enamel shows seasonal fluctuations in water compositions and temperature. Bulk δ13C values indicate an average MAP of 190 (range: 10–510 mm·yr−1), with no significant change through the study interval, comparable to today's MAP (236 mm·yr−1). The reconstructed semi-arid, seasonal, warm climate for the RCS agrees with phytolith assemblage data from the same strata indicating dominantly open, grassy habitats. However, it is inconsistent with previously held ideas of warm-wet mid-Miocene climates in the northern Rocky Mountains (NRM) based on paleosol analyses. Our inferred, stable climate conditions for the MMCO of the NRM contrast with coeval records from Europe and Asia indicating sustained or enhanced warm and wet climates. These differences point to a decoupling of regional climate from global trends and highlight the necessity of studying regional variation to understand the biotic impacts of global climate change.

Palaeoclimatic estimates for a latest Miocene-Pliocene flora from the Siwalik Group of Bhutan: Evidence for the development of the South Asian Monsoon in the eastern Himalaya

Fossil leaf floras, from the latest Miocene-Pliocene Siwalik Group exposed in Bhutan, sub-Himalaya, are subjected to a CLAMP (Climate Leaf Analysis Multivariate Program) analysis using a high-resolution gridded climate calibration. The CLAMP analysis of 27 different morphotypes of fossil leaves indicates a mean annual temperature (MAT) of 24.1 °C ± 2.8 °C; a cold month mean temperature (CMMT) of 18.9 °C ± 4 °C and a warm month mean temperature (WMMT) of 27.8 °C ± 3.3 °C. The analysis also suggests a weak monsoonal climate (the monsoon index, MSI 46.7; present MSI 52) with growing season precipitation (GSP) of 1819 ± 916 mm (present GSP 2490 mm). Here we also compare palaeoclimate estimates of the latest Miocene-Pliocene Siwalik Group flora from Bhutan (c. 6 to 3.8 Ma) with those of previously investigated Siwalik Group floras from the Miocene-Pleistocene of Arunachal, India and Miocene Siwalik floras of Darjeeling, India which characterise the monsoon signature at the time of deposition. Since all the Siwalik floras of the eastern Himalaya (Darjeeling and Arunachal Pradesh) spanning the mid-Miocene to Pleistocene yield almost the same values we suggest that overall the eastern Himalayan Siwalik climate appears to have been remarkably uniform over the past 15 million years. The MAT result of the Bhutan Siwalik flora differs by just 0.6 °C from Arunachal and 1.2 °C from Darjeeling Siwalik floras. For all Siwalik fossil assemblages, WMMTs, CMMTs and LGSs (length of the growing season) are similar and consistent (WMMTs around 28 °C, CMMTs around 18 °C and LGSs around 12 months). Similarly, the mean annual relative humidity (RH) and specific humidity (SH) appear to have been uniformly around 80% and 14 g/kg respectively throughout the Neogene of the eastern Himalayan Siwaliks. Changes in the monsoon index suggest that in both Bhutan and Arunachal sub-Himalaya, there has been little change in the intensity of the monsoon since mid-Miocene time, while further west in the Darjeeling area precipitation seasonality has increased since the mid-Miocene.

The relation between global palm distribution and climate

Fossil palms provide qualitative evidence of (sub-) tropical conditions and frost-free winters in the geological past, including modern cold climate regions (e.g., boreal, or polar climates). The freeze intolerance of palms varies across different organs and life stages, with seedlings in particular less tolerant of sub-zero temperatures than adult plants, limiting successful establishment of populations while permitting adult palms to survive in cultivation outside their natural ranges. Quantitatively, palms indicate minimum cold month mean temperature (CMMT) at 2–8 °C in palaeoclimate reconstructions. These data have accentuated model-proxy mismatches for high latitudes during Paleogene hyperthermals when palms expanded poleward in both hemispheres. We constructed a manually filtered dataset of >20,000 georeferenced Arecaceae records, by eliminating cultivars. Statistically derived mean annual temperature, mean annual temperature range, and CMMT thresholds for the Arecaceae and lower rank subfamilies and tribes reveal large differences in temperature sensitivity depending on lower taxonomic classification. Cold tolerant tribes such as the Trachycarpeae produce thresholds as low as CMMT ≥ 2.2 °C. However, within the palm family, CMMT < 5 °C is anomalous. Moreover, palm expansion into temperate biomes is likely a post-Palaeogene event. We recognize a CMMT ≥ 5.2 °C threshold for the palm family, unless a lower taxonomic rank can be assigned.

Miocene vegetation shift and climate change: Evidence from the Siwalik of Nepal

Abstract We reconstruct climate and vegetation applying the Coexistence Approach (CA) methodology on two palaeofloras recovered from the Lower (middle Miocene; ~ 13–11 Ma) and Middle Siwalik (late Miocene; 9.5–6.8 Ma) sediments of Surai Khola section, Nepal. The reconstructed mean annual temperature (MAT) and cold month mean temperature (CMT) show an increasing trend, while warm month mean temperature (WMT) remains nearly the same during the period. The reconstructed precipitation data indicates that the summer monsoon precipitation was nearly the same during the middle and late Miocene, while the winter season precipitation significantly decreased in the late Miocene. The overall precipitation infers increased rainfall seasonality during the late Miocene. The vegetation during the middle Miocene was dominated by wet evergreen taxa, whereas deciduous ones increased significantly during the late Miocene. The reconstructed climate data indicates that high temperature and significantly low precipitation during the winter season (dry season) in the late Miocene might have enhanced forest fire which favoured the expansion of C4 plants over C3 plants during the period. This idea gets further support not only from a recent forest fire in northern India that was caused by the weakening of winter precipitation, but also from the burnt wood recovered from the late Miocene Siwalik sediments of northern India.

An Eocene brontothere and tillodonts (Mammalia) from British Columbia, and their paleoenvironments

We describe Eocene fossils of the tillodont Trogosus from the Allenby Formation in Princeton, British Columbia (B.C.), as well as teeth of Brontotheriina from the lower Australian Creek Formation near Quesnel, B.C. These fossils represent the only occurrence of Tillodontia and Brontotheriidae in B.C. Further, the presence of the largest species of Trogosus — T. latidens — as well as a smaller species identified only as Trogosus sp. supports a late early – early middle Eocene (Bridgerian) age for the Vermilion Bluffs Shale of the Allenby Formation. Based on their morphology and large size, the teeth referred here to Brontotheriina represent one of the larger, more derived brontothere genera, and suggest a Uintan–Chadronian (middle–late Eocene) age range for the lower Australian Creek Formation that is consistent with radiometric ages of underlying volcanic rocks. Paleobotanical data from sediments correlative to those that produced these Eocene mammal fossils suggest they inhabited forested landscapes interspersed with swamps and open water environments, under mild and wet temperate climates (mean annual temperature (MAT) ∼10–16 °C; cold month mean temperature (CMMT) −4–4 °C; mean annual precipitation (MAP) &gt;100 cm/year). These mixed conifer–broadleaf forests included tree genera typical of modern eastern North American forests (e.g., Tsuga, Acer, Fagus, and Sassafras), together with genera today restricted to east Asia (e.g., Metasequoia, Cercidiphyllum, Dipteronia, and Pterocarya). The paleobotanical evidence is consistent with the hypothesized habitats of both tillodonts and brontotheres.

Paleoenvironment of the Quilchena flora, British Columbia, during the Early Eocene Climatic Optimum

The Quilchena fossil locality is dated (51.5 ± 0.4 Ma) to the Early Eocene Climatic Optimum, and this locality is reconstructed as the warmest and wettest of the Early Eocene upland sites from the Okanagan Highlands of British Columbia and northern Washington State. Mean annual temperature (MAT) is estimated from leaf margin analysis, using 55 dicot morphotypes, as 16.2 ± 2.1 °C/14.6 ± 4.8 °C. Using bioclimatic analysis of 45 nearest living relatives, a moist mesothermal climate is indicated (MAT 12.7–16.6 °C; cold month mean temperature (CMMT) 3.5–7.9 °C; mean annual precipitation (MAP) 103–157 cm/year. Leaf size analysis estimates MAP at 121 ± 39 cm/year. Estimates from the climate leaf analysis multivariate program corroborate these results, although with a slightly cooler MAT (13.3 ± 2.1 °C). Plants that support an interpretation of warm winters with minimal or no frost include Azolla, Glyptostrobus, Taxodium, Keteleeria, Pseudolarix, Eucommia, Dipteronia, Hovenia, Ternstroemia, and others. These thermophilous elements occur together with temperate genera such as Alnus, Betula, Ulmus, Calocedrus, and Fraxinus. Palynological assemblages at Quilchena are dominated by bisaccate conifers and Cupressaceae. Common angiosperms include Ulmus type, triporates, Pterocarya, and Alnus. Insect fossils at Quilchena that today inhabit tropical and subtropical regions also support warm and equable climate without significant frost, and include obligate palm-feeding beetles (Pachymerina), which indicate CMMT perhaps as high as 8 °C. These are found together with temperate aphids, wasps, giant lacewings, brown lacewings, and a panorpoid scorpionfly, supporting an interpretation of equable climatic conditions during the Early Eocene Climatic Optimum.

Using Ecological Niche Modeling for Biodiversity Conservation Guidance in the Western Podillya (Ukraine): Reptiles

Abstract Using Ecological Niche Modeling for Biodiversity Conservation Guidance in the Western Podillya (Ukraine): Reptiles. Tytar, V., Sobolenko, L., Nekrasova, O. Mezhzherin, S. - Maximum entropy niche modeling was employed as a tool to assess potential habitat suitability for 10 reptile species and to map their potential distribution in the Western Podillya (Ukraine). We used climate, topography and human impact (assessed by the Human Footprint) as predictor variables. “Isothermality”, “temperature seasonality” and the “mean temperature of coldest month” were three most important factors in predicting habitat suitability and distribution. A profound contribution to the modeling has been displayed by the Human Footprint, meaning that human infrastructure may benefit reptile species. Areas have been distinguished that in the first place should be of interest to biodiversity conservationists targeting reptiles and maps summarizing predicted habitat suitability and species richness were produced for guiding conservation efforts.

Environmental constraints on terrestrial vertebrate behaviour and reproduction in the high Arctic of the Late Cretaceous

Reconstructions of temperature and moisture regimes based on fossil leaves, combined with tree ring studies, detail the light regime, length of the growing season, and summer and winter temperatures of the Late Cretaceous Arctic. Such constraints have important implications for dinosaur feeding and reproductive behaviour, and the capacity to reside year-round in near-polar environments.At the highest palaeolatitudes where dinosaurs have been found (82–85 °N) winter darkness lasted for ~120days and the spring and autumn twilight periods for ~15days. A mostly cloud and mist-shrouded environment witnessed a mean annual temperature (MAT) of 6–7°C, a warm month mean temperature (WMMT) of 14.5±3.1°C and a cold month mean temperature (CMMT) of −2±3.9°C. Growth rings in wood suggest summer temperatures frequently fell below +10°C. Winter temperatures as low as −10°C were likely for short periods. Spring bud break in late February to early March and leaf fall in early October limited the time when fresh food was available in any quantity to not more than 6months.The diversity of Arctic dinosaur body sizes implies a range of overwintering strategies but year-round residency requires reproduction. Burrowing and enclosed nest building no doubt facilitated overwintering for small animals, but for larger dinosaurs shelter was problematical. No dinosaur egg remains have yet been found as far north as 82° palaeolatitude, but they occur 6° further south in the Early Maastrichtian Kakanaut Formation, Northeastern Russia. Here the winter darkness was shorter (45days), and the temperature regime warmer (MAT 10°C, WMMT 19°C, CMMT +3°C). The growing season (temperatures>10°C) was ~6.3months and fresh food was available in quantity for slightly longer. These summer temperatures constrain the thermal regime of nest environments and suggest sophisticated nest management and possibly brooding strategies for the necessary rapid incubation and hatching before the onset of winter.

Estimation of late Eocene (Bartonian–Priabonian) terrestrial palaeoclimate: Contributions from megafloral assemblages from central Germany

Abstract The Eocene, the world’s last global greenhouse period, shows distinct climatic developments through time, from subtropical towards warm-temperate conditions in Europe. The present paper investigates the response of five floras of the central German Weiselster Basin from different stratigraphic ages to terrestrial palaeoclimatic variations. The floras were selected from the Zeitz Floral Assemblage (“Florenkomplex”) and cover a time interval of ca. 3.5 Myr within the late Eocene, which is supposed to be a period of gradual decline of global mean annual temperatures. The Zeitz Floral Assemblage was characterized by mainly evergreen, notophyllous intrazonal vegetation, consisting of subtropical and warm-temperate elements. The five floras as well as the entire Zeitz Floral Assemblage have been analysed using the following quantitative techniques: leaf margin analysis (LMA), Climate Leaf Analysis Multivariate Program (CLAMP) and Coexistence Approach (CA). Furthermore, the results have been compared with previously published estimates for additional localities from the same area and age. The temperature estimates derived for the Zeitz Floral Assemblage are in a good agreement with those of previous studies i.e. mean annual temperature (MAT) 16.1–20.0 °C, warmest month mean temperature (WMMT) 24.9–26.4 °C, coldest month mean temperature (CMMT) 9.2–13.3 °C. Deviations have been determined for the calculated mean annual precipitation (MAP 1308–1335 mm) compared to previously published data, indicating values of about 2000 mm. Both CLAMP and CA reveal clear hints for seasonality in precipitation which is in agreement with previous phytosociological assumptions and palynological data. The estimates for the individual sites differ between the different techniques as well as among the individual sites, but generally indicate no temporal trends in temperature and precipitation development. Additionally, the applicability of these techniques for fluvial-estuarine plant assemblages, as well as the applicability of intrazonal vegetation for reconstructing transregional climate conditions are discussed. Taphonomic and methodical biases are also subject of debate.

Zoneamento agroclimático da cultura do abacaxizeiro no Estado do Paraná

O estado do Paraná localiza-se em uma região de transição climática, abrangendo regimes térmicos diferentes e variações no risco de geadas. O abacaxizeiro ( Ananas comosus L.) é uma cultura sensível às condições climáticas e o conhecimento dos riscos a que a cultura estará exposta é importante para o seu sucesso. O objetivo deste trabalho foi efetuar o zoneamento agroclimático para o cultivo do abacaxizeiro no estado do Paraná. Foram verificados os limites adequados das variáveis climáticas e avaliadas a temperatura média anual, a temperatura do mês mais frio, o risco anual de geadas, o risco de deficiência hídrica, o número de horas de insolação anual e o fotoperíodo no Estado. O Paraná possui áreas com baixo risco climático para a cultura do abacaxizeiro. A temperatura média anual acima de 19°C, a temperatura média do mês mais frio superior a 15,5°C e a altitude inferior a 600 m permitiram delimitar áreas aptas ao cultivo do abacaxizeiro no Paraná. A deficiência hídrica anual não é limitante ao cultivo do abacaxi no Estado. A temperatura média anual e o fotoperíodo podem induzir naturalmente o florescimento do abacaxi no Estado. Destacam-se as regiões Oeste, Noroeste e Norte, com temperatura média anual superior a 22°C, que são as mais recomendadas ao cultivo. Nas regiões com temperatura média anual entre 19 e 22°C, a escolha do local de cultivo deve ser criteriosa, levando-se em conta o risco de geada local. As regiões Centro, Sul e Leste não são recomendadas, por apresentarem faixas de temperatura abaixo do mínimo exigido.

The Eocene Thomas Ranch flora, Allenby Formation, Princeton, British Columbia, Canada

A flora from Thomas Ranch near Princeton, British Columbia, Canada, is assessed for biodiversity and paleoclimate. This latest Early to early Middle Eocene flora occurs in the Allenby Formation. Seventy-six megafossil morphotypes have been recognized, representing at least 62 species, with 29 identified to genus or species. Common taxa include Ginkgo L., Metasequoia Miki, Sequoia Endl., Abies Mill., Pinus L., Pseudolarix Gordon, Acer L., Alnus Mill., Betula L., Fagus L., Sassafras J Presl, Macginitiea Wolfe &amp; Wehr, Prunus L., and Ulmus L. More than 70 pollen and spore types are recognized, 32 of which are assignable to family or genus. The microflora is dominated by conifers (85%–97% abundance), with Betulaceae accounting for most of the angiosperms. The Climate Leaf Analysis Multivariate Program (CLAMP) calculates a mean annual temperature (MAT) of 9.0 ± 1.7 °C and bioclimatic analysis (BA) calculates a MAT of 12.8 ± 2.5 °C. Coldest month mean temperature (CMMT) was &gt;0 °C. Mean annual precipitation (MAP) was &gt;70 cm/year but is estimated with high uncertainty. Both the CLAMP and BA estimates are at the low end of the MAT range previously published for other Okanagan Highland localities, indicating a temperate climate consistent with a mixed conifer–deciduous forest.

Endemism due to climate change: Evidence from Poeciloneuron Bedd. (Clusiaceae) leaf fossil from Assam, India

A fossil leaf resembling Poeciloneuron indicum Bedd. (Clusiaceae) is described from the Late Oligocene (Chattian 28.4–23 Myr) sediments of Assam. The modern analogue is endemic to the Western Ghats which is situated in the same palaeolatitude. Its presence, along with other known fossil records, indicates that the seasonality in temperature was less pronounced and CMMT (cold month mean temperature) was not less than 18°C with plenty of rainfall, in the region during the period of deposition. The study also indicates that the plant phenology is sensitive towards climate change. The present study is in congruence with the global data.

Low latitude floral assemblage from the Late Oligocene sediments of Assam and its palaeoclimatic and palaeogeographic significance

There are many outcrops of the Tertiary sediments in northeast India and a large number of plant megafossils have been described from there. Among all, the Late Oligocene sedimentary basin of Makum Coalfield is very important because there is no other exposure having such a rich palaeofloral assemblage not only from northeast India but also from the whole country. The assemblage is also important to confirm whether the suturing between the Indian and Eurasian plates was complete to facilitate plant migration or not. All the reported plant fossils clearly indicate the prevalence of tropical climate in the region during the deposition of the sediments. As the majority of taxa occur in tropical evergreen to moist deciduous and littoral and swampy forest, a warm and humid climate may be envisaged in Upper Assam during the Late Oligocene. The abundance of palms and pantropical megathermal plant families in the Makum Coalfield indicate that the cold month mean temperature (CMMT) was not less than 18°C. The quantitative palaeoclimate reconstruction indicates a monsoonal climate during the period with the same intensity as that of the modern day. The absence of Southeast Eurasian elements in the fossil assemblage provides clear evidence that suturing between the Indian and Asian plates was not complete till the Late Oligocene. Several modern analogues of the fossil taxa are now endemic to the Western Ghats which lies in the same palaeolatitude.

Palm leaves from the Late Oligocene sediments of Makum Coalfield, Assam, India

Two new palm leaf impressions, cf. Iguanura wallichiana and Palmacites makumensis sp. nov. are described from the Makum Coalfield, Tinsukia District, Assam. They belong to the Tikak Parbat Formation being considered as Late Oligocene (Chattian 28–23 Myr) in age. Their presence, along with the other known fossil records indicates that CMMT (cold month mean temperature) was not less than 18°C with plenty of rainfall, in the region during the period of deposition.

Palaeoclimatic Estimates for the Late Pliocene Based on Leaf Physiognomy from Western Yunnan, China

Based on leaf physiognomy of the Late Pliocene Tuantian megaflora from the Mangbang Formation of Tengchong County in western Yunnan, a quantitative reconstruction of palaeoclimate was performed with Leaf Margin Analysis (LMA) methodology and the Climate-Leaf Analysis Multivariate Program (CLAMP). The latter produced the following parameters: mean annual temperature (MAT) from 17.2 to 17.7°C; warmest month mean temperature (WMMT) from 25 to 25.5°C; coldest month mean temperature (CMMT) from 9.5 to 10.8°C; length of growing season (GRS) from 9.5 to 9.7 months; growing season precipitation (GSP) from 1834.3 to 1901.2 mm; mean monthly growing season precipitation (MMGSP) from 222.4 to 230.5 mm; precipitation during the three consecutive wettest months (3-WET) from 892.1 to 917.8 mm; precipitation during the three consecutive driest months (3-DRY) from 474.5 to 512.8 mm; relative humidity (RH) from 76.7 to 77.8%; specific humidity (SH) from 10.7 to 10.8 g/kg; and enthalpy (ENTHAL) from 31.8 to 32 kj/kg. However, the MAT obtained from the Chinese LMA regression at 18.7°C, is slightly higher than that from CLAMP. The integrated analysis of these data and three adjacent pollen floras in western Yunnan suggests that the Gaoligong Mountains (a southern portion of the Hengduan Mountains) were only raised to modest altitudes in the Late Pliocene.

Depositional setting, fossil flora, and paleoenvironment of the Early Eocene Falkland site, Okanagan Highlands, British Columbia

The fossil flora and depositional setting of the Early Eocene Falkland site in the southern interior of British Columbia, Canada, is reported in detail for the first time, using a census sampling approach. The Falkland site is part of the series of Okanagan Highlands fossil localities in British Columbia and Washington State that represent relatively cool upland environments within the context of the greenhouse world of the Early Eocene, providing microthermal (mean annual temperature (MAT) &lt; 13 °C) climatic conditions for the establishment of cool-adapted plants geographically adjacent to subtropical elements from lowland floras. Plant community composition of the Falkland flora is most similar to the Republic (Washington) and McAbee (British Columbia) floras based on high Sørenson similarity coefficients, together forming a southern cluster of Okanagan Highlands sites. The site is a lacustrine deposit that formed in a volcanically active landscape. Paleoclimate reconstructions based on leaf physiognomy characterize the site as microthermal (MAT 8.9 ± 2.0 °C by leaf margin analysis or 11.9 ± 2.0 °C by climate leaf analysis multivariate program (CLAMP)), mesic (mean annual precipitation (MAP) 114 [Formula: see text]cm/year), and equable (cold month mean temperature (CMMT) 3.0 ± 2.0 °C). Paleoelevation of the site is estimated to be similar to or slightly higher than modern levels (&gt;1.3 km) during the Early Eocene. The Falkland locality adds new data to the temporal, latitudinal, and altitudinal gradients of the Okanagan Highlands series, reflecting the regional landscape of northwestern North America during the warmest period of the Cenozoic.

Uniting ecological and genetic data for the conservation of wild ibex

There are few taxa more endangered than the Ethiopian Walia ibex. This wild mountain goat inhabits the Simen Mountains of Ethiopia and is known for its enormous backwards curving horns that exceed a meter in length on some males. Historically, hunting and habitat degradation endangered this ibex’s persistence. Now this national symbol of Ethiopia is threatened by the small population dynamics of living in a very restricted patch of remaining habitat. In order to develop the best conservation plans and justify current conservation measures it is important to understand if the Walia ibex is a valid species or if it is better considered a subspecies or ecotype of Capra ibex or Capra nubiana. Often molecular genetic tools alone are used for this type of assessment, but in this issue of Animal Conservation Gebremedhin et al. (2009) combine bioclimatic niche modeling and phylogenetic analysis to assess the species and conservation status of the Walia ibex. Frequently the first step in providing protection for a species is determining that the taxonomic unit that we are interested in conserving is significantly unique from more common taxa. Under the US Endangered Species Act this falls under the task of evaluating if a species represents a ‘Distinct Population Segment.’ One key to being considered a Distinct Population Segment is in the evaluation of the ‘discreteness’ of the population segment in relation to the remainder of the species to which it belongs. This according to Federal policy can occur if the taxon is markedly separated from other populations as a ‘consequence of physical, physiological, ecological or behavioral factors.’ The US policy further goes on to state: ‘Quantitative measures of genetic or morphological discontinuity may provide evidence of this separation.’ Partially due to this type of legal language, and partially due to the boom in new technologies, there has been an avalanche of cases where the distinctness of a taxon has been debated based solely on molecular genetics. Many have criticized the over-dependence of assessing taxa discreteness based on molecular data alone (e.g. Crandall et al., 2000; Pearman, 2001). In this study, Gebremedhin and colleagues heed this admonishment and evaluate conservation status not only with a suite of molecular markers, but with the added approach of bioclimatic niche modeling. Using mitochondrial cytochrome b sequence data Gebremedhin et al. (2009) found that there is support for a Walia ibex Capra walie and Nubian ibex C. nubiana clade separate from other ibex clades. This joint clade deviated from the Capra sibirica group, which now inhabits the central Asian deserts, c. 6 million years ago. The authors also present data that the divergence between the Walia and Nubian ibex occurred around 0.8 million years ago, but given that this date is based on an unsupported node, more sequence data should be collected before value is placed on this claim. With the genetic data alone we might be left debating whether the Walia ibex should be lumped with the Nubian ibex (see Fig. 1). Fortunately, Gebremedhin et al. (2009) also examine the geographic range of Walia and Nubian ibex in light of six bioclimatic variables and two topographic variables. Using a boosted regression tree approach they show that altitude, mean temperature of the coldest month, and precipitation of the warmest quarter were best correlated with the species distributions demonstrating the strong niche separation between the two species. Walia ibex select high altitudes in relatively wet environments with extreme temperatures; while Nubian ibex select low altitudes. Thus, the combination of phylogenetic data and bioclimatic data show the different niches that these ibex select for and support their discreteness. What we can hope for now is for someone to fundGebremedhin and colleagues to further their studies to find the genes under selection that drive these habitat preferences and further evaluate the founding of additional populations to help ensure Walia ibex persistence. While showing their discreteness will be helpful for the conservation of the Walia ibex, other data presented in this study does not foretell good news for this flagship species. The authors use microsatellite data on Walia ibex to make demographic inferences. They showed a strong past decline