Embedded Files
The previous Biancocene epoch was a transitional period leading towards the forest revolution of the Incertocene.
A new plant association formed with the start of the new epoch, driven by the dominant presence of doorpeas, a plant group known for its thermogenic abilities. While doorpeas typically grew no higher than 10 meters in the Biancocene, tree forms now reach up to 40 meters, dominating the Antarctic forests alongside brumbletrees, another highly successful tree species. The "warm-bloodness" of doorpeas creates a warmer microclimate in the undergrowth, favoring thermophilic species that would otherwise be restricted to lower latitudes. Due to its climatic properties, this plant association is called Heatforest.
Doorpeas went trough a rapid evolutionary radiation and count at least 20 genera adapted to different environments, with over 120 species. Some are large, while others are microscopic, like the grassy doorpeas, which have a vestigial underground trunk where leaf stems behave like a herbaceous species.
Like many endothermic animals, doorpea plants follow Bergmann's rule and Allen's rule: species found in the warmest areas of Antarctica tend to be smaller, even half the size of the doorpeas found in colder austral forestsBergmann's rule. In warm, humid areas, doorpeas tend to have more leaves, which are narrower, resembling needles or spaghetti, an adaptation to dissipate heatAllen's rule. In the humid valleys of the Antarctic Peninsula, some species possess leaves as long as a human arm but no wider than 2 cm, resembling a wig. These often not strictly related species are generally called wigtrees and form a plant association that is known as wigforest. Maintaining the ability of producing heat, even if energetically expensive, was extremely useful for doorpeas in order to create a correct temperature that increase seed germination and also to attract pollinators.
A willow doorpea shrub (Salicimimums arbutus) during the polar night. In southern coasts, we can find some areas that are almost snow free during most of the polar night. A very common scenario only during the early Cenozoic and Mesozoic.
Brumble trees, another extremely important plant group of the Biancocene, are less diverse compared to doorpeas (about 8 genera, although counting more than 50 species), but they are well widespread across the continent, typically growing as shrubs or small trees. The exception is the baobab cancerthorn, a species that reaches 20 meters in height and an astonishing circumference of 15 meters. This species has adapted to withstand long dry periods in the Great Depresseaon ecoregion, where rainfall can stop for up to three months locally. Brumbles and other rostrids are the main seed's dispersers of brumbletrees, and the diversity of the two is extremely correlated.
In addition to these, we must mention arboreal fern species found in the most humid and cool areas of Antarctica. These ferns are descendants of the dwarfy woody fern (genus Altridryopteris), a cycad-like fern species that was found in the Seamount during the late Biancocene. Since the start of the Incertocene, the trunk of these ferns has grown from just 20 cm to 4 meters in some species trough natural selection. However, they are still dwarfed compared to their ancestors from the Cambiocene, which could reach 15 meters. These species are found mainly in the humid mountain regions of the Antarctic Peninsula and the Transantarctic Range.
Conifer diversity, which greatly declined in the late Biancocene, has partially rebounded to the current five genera, including one derived from the western polar fir, called fire fir (Uniabies renitens). These conifers can reach a height of 10 meters after just ten years of growth. Thanks to their fast growth and endurance, these conifers are pioneer species, typically found in heatforests after large wildfires, where they eventually become uncommon as more resistant and taller tree species gradually develop. They are also found in other highly disturbed areas, such as rivers and landslides. Unlike most conifers, fire firs leaves are more palatable, which make them a very tasteful snack for many herbivores.
Another photo taken in the southern heatforest of the Transantarctic mountains, during polar night. Sun is almost absent in these months, but twilight can last for several hours per day.
During these crepuscular hours, some animals take advantage of the light to search food, like the crowned hoofpole and the dense wonderlont.
Page updated
Google Sites
Report abuse