Ciencia habilitada por datos de especímenes

Reichgelt, T., D. R. Greenwood, S. Steinig, J. G. Conran, D. K. Hutchinson, D. J. Lunt, L. J. Scriven, and J. Zhu. 2022. Plant Proxy Evidence for High Rainfall and Productivity in the Eocene of Australia. Paleoceanography and Paleoclimatology 37. https://doi.org/10.1029/2022pa004418

During the early to middle Eocene, a mid‐to‐high latitudinal position and enhanced hydrological cycle in Australia would have contributed to a wetter and “greener” Australian continent where today arid to semi‐arid climates dominate. Here, we revisit 12 southern Australian plant megafossil sites from the early to middle Eocene to generate temperature, precipitation and seasonality paleoclimate estimates, net primary productivity (NPP) and vegetation type, based on paleobotanical proxies and compare to early Eocene global climate models. Temperature reconstructions are uniformly subtropical (mean annual, summer, and winter mean temperatures 19–21 °C, 25–27 °C and 14–16 °C, respectively), indicating that southern Australia was ∼5 °C warmer than today, despite a >20° poleward shift from its modern geographic location. Precipitation was less homogeneous than temperature, with mean annual precipitation of ∼60 cm over inland sites and >100 cm over coastal sites. Precipitation may have been seasonal with the driest month receiving 2–7× less than mean monthly precipitation. Proxy‐model comparison is favorable with an 1680 ppm CO2 concentration. However, individual proxy reconstructions can disagree with models as well as with each other. In particular, seasonality reconstructions have systemic offsets. NPP estimates were higher than modern, implying a more homogenously “green” southern Australia in the early to middle Eocene, when this part of Australia was at 48–64 °S, and larger carbon fluxes to and from the Australian biosphere. The most similar modern vegetation type is modern‐day eastern Australian subtropical forest, although distance from coast and latitude may have led to vegetation heterogeneity.

Sluiter, I. R. K., G. R. Holdgate, T. Reichgelt, D. R. Greenwood, A. P. Kershaw, and N. L. Schultz. 2022. A new perspective on Late Eocene and Oligocene vegetation and paleoclimates of South-eastern Australia. Palaeogeography, Palaeoclimatology, Palaeoecology 596: 110985. https://doi.org/10.1016/j.palaeo.2022.110985

We present a composite terrestrial pollen record of latest Eocene through Oligocene (35.5–23 Ma) vegetation and climate change from the Gippsland Basin of south-eastern Australia. Climates were overwhelmingly mesothermic through this time period, with mean annual temperature (MAT) varying between 13 and 18 °C, with an average of 16 °C. We provide evidence to support a cooling trend through the Eocene–Oligocene Transition (EOT), but also identify three subsequent warming cycles through the Oligocene, leading to more seasonal climates at the termination of the Epoch. One of the warming episodes in the Early Oligocene appears to have also occurred at two other southern hemisphere sites at the Drake Passage as well as off eastern Tasmania, based on recent research. Similarities with sea surface temperature records from modern high southern latitudes which also record similar cycles of warming and cooling, are presented and discussed. Annual precipitation varied between 1200 and 1700 mm/yr, with an average of 1470 mm/yr through the sequence. Notwithstanding the extinction of Nothofagus sg. Brassospora from Australia and some now microthermic humid restricted Podocarpaceae conifer taxa, the rainforest vegetation of lowland south-eastern Australia is reconstructed to have been similar to present day Australian Evergreen Notophyll Vine Forests existing under the sub-tropical Köppen-Geiger climate class Cfa (humid subtropical) for most of the sequence. Short periods of cooler climates, such as occurred through the EOT when MAT was ~ 13 °C, may have supported vegetation similar to modern day Evergreen Microphyll Fern Forest. Of potentially greater significance, however, was a warm period in the Early to early Late Oligocene (32–26 Ma) when MAT was 17–18 °C, accompanied by small but important increases in Araucariaceae pollen. At this time, Araucarian Notophyll/Microphyll Vine Forest likely occurred regionally.

Xue, T., S. R. Gadagkar, T. P. Albright, X. Yang, J. Li, C. Xia, J. Wu, and S. Yu. 2021. Prioritizing conservation of biodiversity in an alpine region: Distribution pattern and conservation status of seed plants in the Qinghai-Tibetan Plateau. Global Ecology and Conservation 32: e01885. https://doi.org/10.1016/j.gecco.2021.e01885

The Qinghai-Tibetan Plateau (QTP) harbors abundant and diverse plant life owing to its high habitat heterogeneity. However, the distribution pattern of biodiversity hotspots and their conservation status remain unclear. Based on 148,283 high-resolution occurrence coordinates of 13,450 seed plants, w…

Magri, D., I. Parra, F. Di Rita, J. Ni, K. Shichi, and J. R. P. Worth. 2020. Linking worldwide past and present conifer vulnerability. Quaternary Science Reviews 250: 106640. https://doi.org/10.1016/j.quascirev.2020.106640

Inventories of species recently extinct or threatened with extinction may be found in global databases. However, despite the large number of published fossil based-studies, specific databases on the vulnerability of species in the past are not available. We compiled a worldwide database of published…

de Jesús Hernández-Hernández, M., J. A. Cruz, and C. Castañeda-Posadas. 2020. Paleoclimatic and vegetation reconstruction of the miocene southern Mexico using fossil flowers. Journal of South American Earth Sciences 104: 102827. https://doi.org/10.1016/j.jsames.2020.102827

Concern about the course of the current environmental problems has raised interest in investigating the different scenarios that have taken place in our planet throughout time. To that end, different methodologies have been employed in order to determine the different variables that compose the envi…

Karger, D. N., M. Kessler, O. Conrad, P. Weigelt, H. Kreft, C. König, and N. E. Zimmermann. 2019. Why tree lines are lower on islands—Climatic and biogeographic effects hold the answer J. Grytnes [ed.],. Global Ecology and Biogeography 28: 839–850. https://doi.org/10.1111/geb.12897

Aim: To determine the global position of tree line isotherms, compare it with observed local tree limits on islands and mainlands, and disentangle the potential drivers of a difference between tree line and local tree limit. Location: Global. Time period: 1979–2013. Major taxa studied: Trees. Method…

Xie, S.-P., S.-H. Zhang, T.-Y. Chen, X.-C. Zhang, X. Zeng, and Y. Yu. 2018. Late Miocene occurrence of monogeneric family Oleandraceae from southwest China and its implications on evolution of eupolypods I. Review of Palaeobotany and Palynology 256: 13–19. https://doi.org/10.1016/j.revpalbo.2018.05.002

Yunnan in SW China is a world renowned hotspot for diverse species of vascular plants such as ferns. However, fossil records of the Cenozoic ferns there are insufficient to clarify their phylogeny and historical biogeography from a geological perspective. Among these derived ferns, the monogeneric f…