It has been another 100,000 years since we last checked in on Apterra. The extinction rate has slowed, as various species have adjusted to the current state of affairs. With another degree and a half of cooling, glaciers have expanded significantly. At the same time, the forests and pseudoforests that remain have rebounded quite a bit. Boreal woodlands in particular have expanded greatly; not only have their native species largely recovered, but there has also been an influx of migrants from other habitats. The Great Northern Taiga spans from the west coast of Ailuropia to northeastern Loxodia, occupying the same space as the Middle Muricene northern temperate zone. It has similar advantages, being the largest and most well-connected ecosystem in an increasingly fragmented world. Over a quarter of all land-dwelling species now live here, though relatively few are endemic.
The Plants
Floral communities of the boreal pseudoforest have changed a lot over the past hundred millennia. Basket-bushes have been driven out of mature taigas, now growing only in the immediate aftermath of disturbances like wildfires and avalanches. Wax-palms, a genus that adapted to this environment in the Middle Muricene, took over as the predominant pseudotrees here after the Great Decarbonisation. During warmer times, they evolved a suite of traits that now helps them keep alive as the ice advances. With waxy cuticles covering their leaves, they can withstand subzero temperatures for months on end. Partnering with a group of arboreal woodlice that hibernates in the winter also allows them to avoid expending vital carbon during the harshest months. Instead, they fill their cells with sugar, using the high solute concentration as a natural antifreeze. Their roots reach deep, cracking apart layers of frozen soil to access nutrients below. The descendants of these early-Ice Age wax-palms remain successful, but not without radical changes.
Hybrid Trees (Polygenodendron) are the result of several recent interbreeding events between multiple palm-grasses. While belonging to distinct genera, all of them were still genetically similar enough to produce fertile offspring. In normal conditions, factors like the timing of pollination, geographic distribution, and niche partitioning generally prevented hybrids from flourishing, keeping all their gene pools separate. All this has changed during the Ice Age, with many far-flung palm-grasses contributing to the hybrid trees' genome. New combinations of old genes permit new lifestyles and innovations, creating hardier and more adaptable offspring that continue to mix and reshuffle their DNA to suit nearly every environment Apterra has to offer. Nowhere are they more widespread than here; in fact, many of the original hybridization events took place in this area.
In all, five palm-grasses have contributed meaningfully to the genetic makeup of these plants. Wax-palms, of course, were one of the biggest factors; in places like the Great Northern Taiga, over 90% of hybrid tree DNA comes from them. Admixture from canopy-palms and palm-brush introduced genes that allowed for branching structures and underground rhizomes, creating opportunities for their hybrids to create massive, sprawling colonies, though such extreme forms are more common in the remaining temperate regions. In the taiga, more orderly shapes are the norm, with whorls of branches splitting off from axillary buds after each year's vertical growth is complete. Sand-palms were another component; though little of their DNA is found in taiga hybrid trees, they make up nearly half the genetic material of some desert-growing varieties. Finally, tree mycads have introgressed slightly into hybrid tree populations. Few of their traits are advantageous in today's world; their soft, pinnate leaves and affinity for moderate temperatures have been weeded out from most of their descendants. However, the gene that originally caused them to accept Poamyces dendrifex as a symbiont has spread throughout all hybrid trees, granting palm-grasses worldwide the fungus's ability to promote true secondary growth.
In the taiga, this has resulted in long-lived trees that support a stable climax community of understory plants like ratbriars, loop-grasses, featherstalks, and many more. This diversity of plant life creates new niches for animals, including refugees from other biomes, allowing many to survive the collapse of their old homes. Rat-grasslands, for instance, have seen a massive decline after rattalox herds evolved to spend more of their time in more productive habitats. This created a feedback loop; as more rattaloxen fled to the taiga, rat-grasses dwindled, forcing more of the herbivores to vacate the area, accelerating the rat-grassland's demise. Woodlouse-grasslands have held out, protected from the harshest conditions by walls of stone and ice on all sides. Only the temperate forests, which now grow where the Remnant Jungle once stood, rival the taiga in terms of species-richness.
The Animals
Despite the increasing numbers of prairie species migrating into the area, older pseudoforest-dwellers that survived the Great Decarbonisation have not been pushed out. Raspbirds are the most common browsers, using their long necks to reach high into trees that other species find inaccessible. They take advantage of the sugar-rich wax-hybrid foliage, which offers far more calories than that of the original wax-palms. Ratjackals and other large ratweasels are extinct, but their genus is survived by the Boreal Scurmint (Tondendens longispinus), a tiny but fierce hunter that preys on insects, isopods, downlings, and other small rats and birds. Smaller pseudoforest species of terror kiwi are the top predators, with some like the Downy-Faced Terror Kiwi (Aepyapteryx plumosops) growing to sizes rivaling their now-extinct woodlouse-grassland specialist cousins.
One of the first species to immigrate to the Great Northern Taiga was the rattalox, which finds ample food as a low-browsing/grazing generalist. While the density of low-growing plants is, of course, lower here than on the old rat-grasslands, the local basket-grasses and skystalks provide a far more nutritious meal than the rattaloxen's former diet. Though peaceful amongst themselves, they react aggressively to any carnivores, for despite their status as megafauna they are not large enough to be entirely protected from predation. Their young are especially vulnerable, and adults will protect them ferociously against terror kiwis and other predators.
Beakbucks, a group that still persists in the remaining woodlouse-grasslands, have populations here as well. Unlike its ancestors, the taiga subspecies (Cursoriapteryx latirostris rhizophila) can reach the buried tubers and rhizomes of various plants, occasionally even digging beneath hybrid trees to reach their massive root systems. Such extreme measures are only taken when absolutely necessary, for pill bug colonies are known to fight back fiercely. Taiga basketbucks have also shrunk relative to their woodlouse-grassland cousins, which themselves are about 10% smaller than they were 200,000 years ago.
Scythesnouts made a similar journey, arriving about fifty millennia ago. Upon establishing themselves here, they found their preferred niche already taken by rattaloxen, forcing them to adapt in novel directions. One group, the Leafclipping Scythesnout (Cursoriapteryx falcirostris brevirostris) is a highly selective feeder; while rattaloxen eat everything in sight, leafclippers seek only out the most nutritious skystalks, moving quickly to stay ahead of the rats and getting the first pick of the tastiest plants. Their close relative, the Hookjawed Scythesnout (C. f. spiculorostris) has become increasingly generalistic, using a sharp, downward-pointing protrusion of its lower bill to strip mosses from trees. This tool also allows it to incorporate small amounts of meat into its diet by using its downturned beak to cut the Achilles tendons of fleeing prey. While still primarily plant-eaters, this limited degree of omnivory is a vital feature during the lean winter months.