Certain events can only take place on your world when you are playing with the Biospheres feature enabled, instead of the Biomass feature. In order for these events to take place, you also need to have, or have had, species alive on your world.
Harsh Winter
A particularly harsh winter has temporarily reduced the health of [species] by [-%]
Temporary health reduction for that species, visible in 'modifier' part of a species' health calculations. This event only occurs when your world's date in in the winter times.
Poaching
Poachers have begun aggressively targeting [species] specimens, resulting in a permanent reduction of the species health by [-%].
Permanent health reduction for that species, visible in 'modifier' part of a species' health calculations.
Rough Weather
A terrible storm has temporarily reduced the health of the [species] by [-%]
The same effect as Harsh Winter.
Favorable Summer
A particularly favorable summer has temporarily boosted the health of the [species] by [-%].
This can be good, but if you are playing on Expert mode, you may need to stop this from happening by culling the species a little bit, as you don't want this species to eat species that support it to extinction. The change in health is represented within the 'modifier' part of species' health calculations. Can only occur when the world's date is in the summer times.
Popular Pet
After a popular celebrity started raving about their new [species], people all across (the) [world] have started getting their own, resulting in a [-%] boost to its health.
The popular pet event does indeed provide a permanent boost to the species health.
Resurrection
A wild [species] has been discovered surviving on the surface of (the) [world]! Previously thought to be extinct, our scientists are thrilled to announce that the [species] has not completely died out after all!
An extinct species comes back alive.
Prerequisite: Have a species that's gone extinct.
Mutation
Scientists have discovered a very unusual [species] during a routine conservation sweep. Further investigation revealed that the species has mutated, spawning a sister species that is being called [-species]!
Adds a new species with a fixed name and random genes.
New Niche
Specimens of the [species] have found a new niche in their local ecosystem. Our scientists are predicting that it will results in a [-%] boost to the species overall health!
This can be good, but if you are playing on Expert mode, you may need to stop this from happening by culling the species a little bit, as you don't want this species to eat species that support it to extinction. The change in health is represented within the 'modifier' part of species' health calculations.
New Disease
A new disease has struck the [species], reducing its health by [-%].
This is a modifer event so the negative health effect is permenant.
Anthropocentric Adaptation
Several [species] specimens have begun exhibiting anthropocentric behaviors, benefiting from nearby human populations to boost their own wellbeing by as much as [+%].
This can be good, but if you are playing on Expert mode, you may need to stop this from happening by culling the species a little bit, as you don't want this species to eat species that support it to extinction. The change in health is represented within the 'modifier' part of species' health calculations.