Deforestation: A Lesson from the Permian Extinction

Satellite photo of Amazon fires. Credit: NASA

The recent fires at Amazonas, Gran Canaria (Spain), Australia, and Indonesia sparked international outcry. Climate change makes forests hotter and drier, thus more likely to sustain uncontrolled fires. But fires are also linked with deforestation. Almost 1 million km2 of Amazon forest has already been deforested, and a recent study indicates that the number of active fires in this August was actually three times higher than 2018. Deforestation is a threat to biodiversity and ecosystems stability. It also leads to the loss of cultural diversity, the alteration of the hydrological cycle and climate systems.

The geological records show that large and rapid global warming events occurred repeatedly during the course of Earth history. The End-Permian extinction event (EPE) serves as a powerful deep-time analogue for modern deforestation and diversity loss, with as much as 95% of the marine animal species and a similarly high proportion of terrestrial plants and animals going extinct . This great crisis ocurred about 252 million years ago (Ma) during an episode of global warming. A recent study focussed on the Sydney Basin, Australia, shows how the typical Permian temperate forest communities disappeared abruptly, followed by a short ‘dead zone’ characterized only by charcoal, wood fragments, and fungi, signatures of an interval of wildfire and saprotrophic breakdown of organic matter.

Global paleogeographic map for the Permian-Triassic transition showing the location of the Siberian Traps Large Igneous Province. From Vajda et al., 2019

Two palynological events marked the end-Permian Event: the ‘algal/fungal/acritarch event’ (a bloom of Reduviasporonites, and of acritarchs in marine environments); and the ‘spore-spike event’. The first event in post-extinction continental deposits has contributed to a continuing debate as to whether the EPE interval was marked by eustatic sea-level rise. The ‘spore-spike event’ indicates that many plant groups survived in regional refugia, possibly at higher altitudes, or in coastal settings where conditions were consistently cooler or wetter. Some of those survivors constituted the pioneer vegetation during the Early Triassic.

During the EPE the woody gymnosperm vegetation (cordaitaleans and glossopterids) were replaced by spore-producing plants (mainly lycophytes) before the typical Mesozoic woody vegetation evolved. Glossopterids were the prime contributors of biomass to the vast Permian coal deposits of Gondwana, therefore their disappearance had major implications for ecosystem structure. The very rapid appearance of drought-tolerant plant associations (dominated by conifers and the seed fern Lepidopteris) in the macroflora of the Sydney Basin, may represent immigration of drought-adapted biota from other regions of Pangea.

Spores and pollen identified in the post-extinction mudstone at the Frazer Beach section. From Vajda et al., 2019

The palynological record suggests that wooded terrestrial ecosystems took four to five million years to reform stable ecosystems, while spore-producing lycopsids had an important ecological role in the post-extinction interval. The disappearance of the Glossopteris that dominated the cool Permian wetland forest of Gondwana, had  enormous consequences for landscape coverage, ecosystem structure, food webs, and caused substantial perturbations to the hydrological and carbon cycles of the entire biosphere.

Since the industrial revolution, the wave of animal and plant extinctions that began with the late Quaternary has accelerated. Australia has lost almost 40 percent of its forests, and almost 20% of the Amazon has disappeared in last five decades.Calculations suggest that the current rates of extinction are 100–1000 times above normal, or background levels. If we want to stop the degradation of our planet, we need to act now.

 

References:

V. Vajda et al. (2020), End-Permian(252Mya) deforestation, wildfires and flooding—An ancient biotic crisis with lessons for the present, Earth and Planetary Science Letters 529 (2020) 115875 https://doi.org/10.1016/j.epsl.2019.115875

Jos Barlow et al, Clarifying Amazonia’s burning crisis, Global Change Biology (2019). DOI: 10.1111/gcb.14872

Meet Ferrodraco lentoni, the Iron Dragon

Ferrodraco lentoni gen. et sp. nov. holotype. Scale bar = 50 mm. From Pentland et al., Scientific Reports.

Pterosaurs were the first flying vertebrates. From the Late Triassic to the end of the Cretaceous, the evolution of pterosaurs resulted in a variety of eco-morphological adaptations, as evidenced by differences in skull shape, dentition, neck length, tail length and wing span. Their reign extended to every continent, but due to the fragile nature of their skeletons the fossil record of pterosaurs is rather patchy, with most occurrences limited to fragmentary remains. The newly described Ferrodraco lentoni, from the Winton Formation (Cenomanian–lower Turonian), is the most complete pterosaur specimen ever found in Australia. Previously, and only based on fossil skull fragments, two other species of pterosaurs were described from Australia: Mythunga camara and Aussiedraco molnari.

Discovered in 2017, the holotype specimen AODF 876 (Australian Age of Dinosaurs Fossil) includes a partial skull, five partial neck vertebrae, and bones from both the left and right wings. The wingspan of Ferrodraco was approximately 4 m, with a skull probably reaching 60 cm in length. The generic name comes from the Latin language: ferrum (iron), in reference to the ironstone preservation of the holotype specimen, and draco (dragon). The species name, lentoni, honours former Winton Shire mayor Graham Thomas ‘Butch’ Lenton.

Ferrodraco lentoni gen. et sp. nov. holotype rostral sections AODF 876. Cross-section. Scale bar = 20 mm. From Pentland et al., Scientific Reports.

Based on several cranial synapomorphies, including the presence of a mandibular groove, smooth and blade-like premaxillary and mandibular crests, and spike-shaped teeth, Ferrodraco falls within the clade Anhangueria. This group has also been recorded in the Early Cretaceous of Brazil, China and England. It has been suggested that anhanguerians went extinct at the end of the Cenomanian. This interval was characterised by an increase in atmospheric and oceanic surface temperatures, a global oceanic anoxic event, and marine transgression. Given that Ferrodraco was recovered from a locality northeast of Winton, which is considered as early Turonian in age, the new specimen potentially represents a late-surviving member of the anhanguerians.

 

References:

Adele H. Pentland et al., Ferrodraco lentoni gen. et sp. nov., a new ornithocheirid pterosaur from the Winton formation (cenomanian-lower turonian) of Queensland, Australia, DOI: 10.1038/s41598-019-49789-4

Forgotten women of paleontology: Irene Crespin

Irene Crespin (1896-1980)

Irene Crespin was born on November 12, 1896, in Kew, Victoria, Australia. In her memories, she wrote that her interest in Palaeontology began early in her life, when she was one of the first students to attend the Mansfield High School in northeastern Victoria. The head master of for a short period was the eminent Australian geologist Charles Fenner.

In 1919, she graduated with a B.A. from the University of Melbourne. In 1927 she joined the Commonwealth Government as Assistant Palaeontologist to Frederick Chapman at the National Museum of Victoria. Chapman was an authority on Foraminifera and was president of the Royal Society of Victoria. About her time at the Museum she wrote: “In the early days, we passed through the depression era. Our salaries were reduced overnight. I was reduced to six pounds a week. They were difficult times for us all. One would walk a long distance to save a threepenny tram fare.”

Dr Irene Crespin with W. Baragwanath, Secretary of Mines for Victoria, probably visiting a Cooksonia plant site, c. 1927 (From Turner 2007)

In 1936, Crespin succeeded Chapman as Commonwealth Palaeontologist. On February 10th, she was transferred from the National Museum, Melbourne to join the Commonwealth Geological Adviser, Dr. W.G. Woolnough, in Canberra. About her new position she wrote: “Of course, being a woman, and despite the tremendous responsibility placed upon me with the transfer to Canberra, I was given a salary of about half of that which Chapman received. Later the Chairman of the Public Service Board told me that I was being put on trial.”

She becoming greatly interested in the Tertiary microfaunas, and for some time she was the only professional micropaleontologist on the Australian mainland. Her research took her all over Australia. In 1939, she received permission from the Minister of the Interior to visit Java and Sumatra to discuss the problems of Tertiary correlation in the Netherlands East Indies with Papua and New Guinea.

Crespin’s photo of her aeroplane and crew on an overseas trip to Java, Indonesia, 1939 (From Turner 2007)

Crespin was well respected internationally and was a regular participant in national and international scientific conferences. In 1953, many of her books and specimens were destroyed as a result of a fire in the Canberra offices. The same year, she received Queen Elizabeth II’s coronation medal. In 1957 she was president of the Royal Society of Canberra, and was awarded with the Clarke medal of the Royal Society of New South Wales.

During her career she published 86 papers as sole author and more 22 in collaboration with other scientists. She was made an honorary fellow of the Royal Microscopical Society, London, in 1960. She became an honorary member of the Australian and New Zealand Association for the Advancement of Science in 1973. She died in Canberra, on January 2, 1980.

References:

Turner, S. (2007). Invincible but mostly invisible: Australian women’s contribution to geology and palaeontology. Geological Society, London, Special Publications, 281(1), 165–202. doi: 10.1144/sp281.11

Crespin, Irene (1975). “Ramblings of a micropalaeontologist”. BUREAU OF MINERAL RESOURCES, GEOLOGY AND GEOPHYSICS.