Humans reduce the amount of land that is available for other animals and plants. Land is used up by building, quarrying, farming and dumping waste. Wild organisms lose their habitats as a result.
Peat bogs are one habitat that is being destroyed. Peat is dug up and sold to make garden compost. This reduces the area of the habitat, and so reduces the variety of different plant, animal and microorganism species that live there, which is the biodiversity of the bog.
The decay or burning of peat releases carbon dioxide into the atmosphere, which contributes to global warming.
There is a conflict here. Gardeners and farmers want cheap compost to help to increase food production, but peat bogs and other peatlands need to be conserved as habitats and to reduce carbon dioxide emissions.