An international research team collected about 25,000 samples of amber containing fossils and about 5,000 fossil plants in southeastern China from 2010 to 2019. It turned out that winter warming was the main driving force behind the spread of megothermal biota northward in southern China during the climatic optimum of the Middle Miocene. Scientists now know what changes can occur with global warming and whether ecosystems can adapt.
The Zhangpu biota, including the amber biota and accompanying mega fossils, is the richest biota in the tropical seasonal rainforest. An extraordinary variety of species has existed in this 14.7 million year old rainforest. The varied winged fruits of Dipterocarpaceae and legumes, as well as the leaves of 78 different broadleaf trees, showed that the tropical seasonal rainforest extended further north than today.
Zhangpu’s amber biota contains a diverse, well-preserved fossil arthropod fauna, as well as numerous botanical and other inclusions such as mushrooms, snails and even feathers. Botanical inclusions include bryophytes (liverworts and mosses) and flowering plants. The Zhangpu amber insect fauna includes a variety of ants, bees, lacewings, stick insects, termites and grasshoppers, which today only inhabit the tropics of Southeast Asia and New Guinea.
The arthropod inclusions in the discovered amber span an impressive array of more than 250 families, including a variety of spiders, ticks, millipedes, and no less than 200 insect families in 20 orders. The extremely large diversity of arthropods makes the Zhangpu amber biota one of the four richest in the world, along with the well-known Cretaceous Burmese amber biota (> 568 families), the Baltic amber biota of the Eocene (> 550 families) and the Miocene Dominican amber biota (205 families).
“The most surprising finding was that a wide variety of ants and collembolans belong to living (now existing) genera. In addition, the vast majority of previously identified insects in Zhangpu amber, such as root lice, grasshoppers, beetles and bees, are also living species. ”
Professor Wang Bo of Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences (NIGPAS)
These results suggest that Asian rainforest insect communities have remained stable since the Middle Miocene (15 million years ago). In general, rainforests act as biodiversity museums on a general level. The relative ecological stability of such mega-thermal environments contributes to the continuous accumulation of species diversity and makes them even more valuable.
The Zhangpu amber biota is unique because the species count is minimally distorted by human selective bias. Moreover, its exact age is strictly limited by radioisotope dating, and the associated compression / imprint fossils of plants allow quantitative reconstruction of the ancient climate.
Compared to the current climate of Zhangpu, the most notable difference is the warmer winters in the Middle Miocene climate, which resulted in relatively stable temperatures throughout the year.
In global warming scenarios, winter warming is usually more pronounced than summer warming, and has more severe and widespread impacts on terrestrial and marine ecosystems.