If you don’t hunt, or at least cull animals... They tend to increase unabated.
In the Maritimes of Canada and the state of Maine for instance, they kill close to 10,000 moose every year... If they didn’t, they’d be swimming in moose sh*t!
Humans have increased the amount of biomass the earth can maintain in several ways.
1. They regulate the water cycle with dams and irrigation, so there are fewer droughts and floods.
2. They increase the amount of nitrogen in the soil by making fertilizer from natural gas which was trapped in rock.
3. They release CO2 which was trapped in coal and petroleum. Plants grow better with more CO2.