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.

Colli-Silva, M., J. R. Pirani, and A. Zizka. 2022. Ecological niche models and point distribution data reveal a differential coverage of the cacao relatives (Malvaceae) in South American protected areas. Ecological Informatics 69: 101668. https://doi.org/10.1016/j.ecoinf.2022.101668

For many regions, such as in South America, it is unclear how well the existent protected areas network (PAs) covers different taxonomic groups and if there is a coverage bias of PAs towards certain biomes or species. Publicly available occurrence data along with ecological niche models might help to overcome this gap and to quantify the coverage of taxa by PAs ensuring an unbiased distribution of conservation effort. Here, we use an occurrence database of 271 species from the cacao family (Malvaceae) to address how South American PAs cover species with different distribution, abundance, and threat status. Furthermore, we compared the performance of online databases, expert knowledge, and modelled species distributions in estimating species coverage in PAs. We found 79 species from our survey (29% of the total) lack any record inside South American PAs and that 20 out of 23 species potentially threatened with extinction are not covered by PAs. The area covered by South American PAs was low across biomes, except for Amazonia, which had a relative high PA coverage, but little information on species distribution within PA available. Also, raw geo-referenced occurrence data were underestimating the number of species in PAs, and projections from ecological niche models were more prone to overestimating the number of species represented within PAs. We discuss that the protection of South American flora in heterogeneous environments demand for specific strategies tailored to particular biomes, including making new collections inside PAs in less collected areas, and the delimitation of more areas for protection in more known areas. Also, by presenting biasing scenarios of collection effort in a representative plant group, our results can benefit policy makers in conserving different spots of tropical environments highly biodiverse.

Tazikeh, S., S. Zendehboudi, S. Ghafoori, A. Lohi, and N. Mahinpey. 2022. Algal bioenergy production and utilization: Technologies, challenges, and prospects. Journal of Environmental Chemical Engineering 10: 107863. https://doi.org/10.1016/j.jece.2022.107863

Increasing demand for energy and also escalating environmental pollution show that industries cannot rely on fossil fuels, and it is necessary to adopt an alternative. In recent decades, algal bioenergy has emerged as a renewable energy source in different industries. However, algal bioenergy production is costly and faces different challenges and unknown aspects that need to be addressed. Experimental and theoretical research works have revealed that the efficiency of algal bioenergy production is influenced by several factors, including algae species, temperature, light, CO2, cultivation method, and available nutrients. Algal bioenergy production on commercial scales in cost-effective ways is the main aim of industries to compete with fossil fuels. Hence, it is vital to have a comprehensive knowledge of the previous findings and attain a suitable pathway for future studies/activities. In the present review paper, the potential of microalgae bioenergy production, influential parameters, previous experimental and theoretical studies, and different methods for microalgae biofuel production from cultivation stage to utilization are reviewed. Moreover, this work discusses the engineering activities and economic analysis of microalgae cultivation to utilization, and also useful suggestions are made for future research works. The outcomes of the present work confirm that innovative engineering methods can overcome scale-up challenging, increase the rate of production, and decrease the cost of algae bioenergy production. Hence, there is no long way to produce cost-effective algae bioenergy on commercial scales.

Chevalier, M. 2022. <i>crestr</i>: an R package to perform probabilistic climate reconstructions from palaeoecological datasets. Climate of the Past 18: 821–844. https://doi.org/10.5194/cp-18-821-2022

Abstract. Statistical climate reconstruction techniques are fundamental tools to study past climate variability from fossil proxy data. In particular, the methods based on probability density functions (or PDFs) can be used in various environments and with different climate proxies because they rely on elementary calibration data (i.e. modern geolocalised presence data). However, the difficulty of accessing and curating these calibration data and the complexity of interpreting probabilistic results have often limited their use in palaeoclimatological studies. Here, I introduce a new R package (crestr) to apply the PDF-based method CREST (Climate REconstruction SofTware) on diverse palaeoecological datasets and address these problems. crestr includes a globally curated calibration dataset for six common climate proxies (i.e. plants, beetles, chironomids, rodents, foraminifera, and dinoflagellate cysts) associated with an extensive range of climate variables (20 terrestrial and 19 marine variables) that enables its use in most terrestrial and marine environments. Private data collections can also be used instead of, or in combination with, the provided calibration dataset. The package includes a suite of graphical diagnostic tools to represent the data at each step of the reconstruction process and provide insights into the effect of the different modelling assumptions and external factors that underlie a reconstruction. With this R package, the CREST method can now be used in a scriptable environment and thus be more easily integrated with existing workflows. It is hoped that crestr will be used to produce the much-needed quantified climate reconstructions from the many regions where they are currently lacking, despite the availability of suitable fossil records. To support this development, the use of the package is illustrated with a step-by-step replication of a 790 000-year-long mean annual temperature reconstruction based on a pollen record from southeastern Africa.

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.

Laeseke, P., B. Martínez, A. Mansilla, and K. Bischof. 2021. Invaders in waiting? Non-equilibrium in Southern Hemisphere seaweed distributions may lead to underestimation of Antarctic invasion potential. Frontiers of Biogeography 13. https://doi.org/10.21425/f5fbg50879

Bioinvasions pose a major threat to global biodiversity. Correlative Ecological Niche Models (ENMs) can be a valuable tool to identify invaders and invasion sites. However, in cases when species are in non-equilibrium with their native environment (i.e. do not fill their niche), correlative approach…

Meller, P., M. Stellmes, A. Fidelis, and M. Finckh. 2022. Correlates of geoxyle diversity in Afrotropical grasslands. Journal of Biogeography 49: 339–352. https://doi.org/10.1111/jbi.14305

Aim: Tropical old-growth grasslands are increasingly acknowledged as biodiverse ecosystems, but they are understudied in many aspects. Geoxyle species are a key component in many of these ecosystems, their belowground storage organs and bud banks are functionally diverse and contribute to the grassl…

Lim, J. Y., H. Huang, A. Farnsworth, D. J. Lunt, W. J. Baker, R. J. Morley, W. D. Kissling, et al. 2021. The Cenozoic history of palms: Global diversification, biogeography and the decline of megathermal forests. Global Ecology and Biogeography 31: 425–439. https://doi.org/10.1111/geb.13436

Aim: Megathermal rain forests and mangroves are much smaller in extent today than in the early Cenozoic, primarily owing to global cooling and drying trends since the Eocene–Oligocene transition (c. 34 Ma). The general reduction of these biomes is hypothesized to shape the diversity and biogeographi…

Beaulieu, W. T., D. G. Panaccione, Q. N. Quach, K. L. Smoot, and K. Clay. 2021. Diversification of ergot alkaloids and heritable fungal symbionts in morning glories. Communications Biology 4. https://doi.org/10.1038/s42003-021-02870-z

Heritable microorganisms play critical roles in life cycles of many macro-organisms but their prevalence and functional roles are unknown for most plants. Bioactive ergot alkaloids produced by heritable Periglandula fungi occur in some morning glories (Convolvulaceae), similar to ergot alkaloids in …

Vasconcelos, T., J. D. Boyko, and J. M. Beaulieu. 2021. Linking mode of seed dispersal and climatic niche evolution in flowering plants. Journal of Biogeography. https://doi.org/10.1111/jbi.14292

Aim: Due to the sessile nature of flowering plants, movements to new geographical areas occur mainly during seed dispersal. Frugivores tend to be efficient dispersers because animals move within the boundaries of their preferable niches, so seeds are more likely to be transported to environments tha…