Science & Technology

First leaf fossil examine of Borneo’s rainforest reveals present ecosystem is historic — ScienceEvery day

The first examine of leaf fossils carried out within the nation of Brunei on the island of Borneo has revealed that the present dominant tree group, the dipterocarps, has dominated the rainforests for at the very least 4 million years, in line with a global analysis crew led by Penn State in partnership with Universiti Brunei Darussalam. The findings, printed within the journal PeerJ, recommend that the present panorama is much like what was current throughout the Pliocene Epoch, 5.3 to 2.6 million years in the past, and will present extra justification for conservation of those forests that assist many critically endangered species.

“This is the first demonstration that the characteristic dominant life form of Borneo and the entire Asian wet tropics, the dipterocarp trees, was not only present but actually dominant. We found many more fossils of dipterocarps than any other plant group,” mentioned Peter Wilf, professor of geosciences within the Penn State College Earth and Mineral Sciences and a co-funded school member within the Institutes of Energy and the Environment (IEE).

The dipterocarps are the world’s tallest tropical timber, and the most important of them can attain 100 meters (328 toes) in peak, roughly the peak of a 22-story constructing.

Wilf mentioned the dipterocarps embody a whole bunch of keystone species that assist tropical Asia’s critically endangered biodiversity by structuring rainforests and offering huge meals assets by way of pollination and their nutritious seeds. Borneo has virtually 270 dipterocarp species, greater than half the world’s complete.

“Fossil leaves in the wet tropics are very rare because of extensive forest cover and deeply weathered soils that obscure rock exposures,” Wilf mentioned.

Past research of the island’s vegetation typically concerned fossil pollen, which may be very immune to decay. However, as a result of dipterocarp pollen typically doesn’t protect effectively, that information doesn’t present full data on historic plant landscapes within the Asian tropics, in line with Wilf. This examine offered ample fossil proof from each leaves and pollen, at two websites that the crew found after intensive reconnaissance in Brunei, that helps the concept that the present panorama’s various, well-structured vegetation is much like what was current throughout the Pliocene Epoch, 5.3 to 2.6 million years in the past.

“From the same rocks that the dipterocarp leaf fossils are coming from in great numbers, there’s hardly any dipterocarp pollen,” he mentioned. “The pollen and spores represent many other plant groups, including huge numbers of ferns, but barely any dipterocarps. So that validates the idea that there’s a bias against the dipterocarp pollen.”

Ferry Slik, a professor on the Universiti Brunei Darussalam who research tropical forest ecology and is a co-author on the paper, mentioned that is a particularly essential examine of the nation’s fossil flora.

“There are very few fossil studies from the Asian tropics,” Slik mentioned. “I hope this study will stimulate more research efforts on fossils in the tropics as they will tell us a lot about the natural history of the region.”

Wilf and his crew unearthed all kinds of fossil leaves and fruits, together with many plant teams which might be native as we speak however had not been discovered earlier than as fossils within the Malay Archipelago. These included three totally different genera of dipterocarps, equivalent to Dryobalanops, whose species are practically all threatened; understory crops such because the jujube Ziziphus and melastomes; and a climbing aroid plant, Rhaphidophora, that’s associated to the favored home plant Monstera.

Slik mentioned the crew reconstructed an historic ecosystem virtually precisely like what’s present in Brunei as we speak.

“With the pollen included, we’re getting a fairly complete representation of mangrove and swamp environments, bordered by tropical lowland dipterocarp rainforests with very diverse fern understories and lots of climbing plants, including more ferns, jujubes and aroids. So we’re getting to actually seeing what the environment was like millions of years ago,” Wilf mentioned. “It was very much like what you can find there now, although those habitats have been cut down across much of tropical Asia.”

Wilf mentioned one of many motivations for doing this examine was to encourage conservation of those areas.

“The tropical rainforests are where biodiversity is. Brunei is about the size of Delaware, but it has more than seven times the plant diversity of all of Pennsylvania,” he mentioned. “This area has an ever-wet climate similar to the Amazon or the central African rainforests. It is home to spectacular animal life such as proboscis monkeys, crocodiles, rhinoceros hornbills, clouded leopards, sun bears, flying lizards, bearded pigs and slow lorises.”

Although Borneo is among the nice biodiversity hotspots on Earth and its rainforests are historic, its biodiversity is shrinking as a result of logging, agricultural conversion, and local weather change.

The dipterocarp timber are extremely wanted by the logging trade, and Borneo suffers from excessive deforestation charges, mentioned Slik, who’s working to enhance Asia’s tropical ecosystems.

“Borneo, and much of the Asian rainforests, are ground zero of the biodiversity crisis,” Wilf mentioned. “However, Brunei is a jewel in the system because it is one of very few countries in the region that still preserves more than half of its old growth rainforests.”

According to Wilf, every paleontological discovery highlights the significance of historical past and supplies foundational assist for establishing conservation areas and educating the general public.

“If a living group has a known paleo history, it has added preservation and educational value, and it’s less likely to be destroyed,” he mentioned. “Paleontology provides the primary evidence for how and why life on Earth is distributed the way it is and when different groups of plants and animals arrived.”

This challenge began as a 2015 IEE seed grant for Wilf’s challenge titled “Paleobotanical and Genomic Biogeography of Living-Fossil Gondwanan Trees in SE Asian Rainforests: Informing Biodiversity and Watershed Conservation in the Face of Climate Change and Deforestation.” Later funding got here from the National Science Foundation and Universiti Brunei Darussalam.

In addition to Wilf and Slik, authors embody Penn State graduates Xiaoyu Zou, who accomplished his senior thesis on the Brunei fossil leaves in tandem with this paper, and former doctoral pupil Michael Donovan, who now works on the Cleveland Museum of Natural History. Other authors embody László Kocsis, University of Lausanne; Antonino Briguglio, Università degli Studi di Genova; David Shaw, Biostratigraphic Associates (UK) Ltd; and Joseph Lambiase, Lambiase Geoscience.

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