The fern spike

Wildfires, prolonged darkness and climate instability (because of volcanic activity) have greatly impacted secondary succession: most of the original antarctic forests were wiped away, in favor of Alcalodryopteris, a genus of drought-resistant ferns.
Diffuse fern-thickets no larger than 3 meters now cover the most disturbed areas of Antarctica, taking advantage of the absence of other competitive vascular plants. These ferns are known to contain coniine (an alkaloid), which is toxic to most of vertebrate species if eaten in large numbers, a further reason of the disruption of the trophic chain. Only few species of invertebrates, like fern-spiks (Carbohelix spp.) and fern-moths (Pteriagrius spp.), have increased exponentially during the END thanks to fern expansion. Despite the sharply increase of these invertebrates, the resulting biomass is far from being exploitable by predators; due to their toxic food, these organisms have also become indigestible.
The botanical replacement of seed plants by ferns during and after a catastrophic event is something well-documented in the fossil record and even present-day, being known as fern spike.
This very unique plant association will not be however maintained for long, nor will led to the total fall of seed plants: when climate will stabilize again, angiosperms and conifers will rise again, taking back their supremacy over ferns thanks to their physiological advantage.