How can a great biological diversity protect an ecosystem from environmental damage? Why are less biodiverse ecosystems at risk of suffering deep biological harm if submitted to even small changes?

In ecosystems with more biodiversity the food webs and ecological interactions among living beings are more complex and diverse. In these ecosystems environmental changes can be more simply compensated by the multiplicity of available resources, foods and survival options.

In ecosystems with less biodiversity the individuals are more dependent on some beings that serve them as food and they interact with a small number of dissimilar species. In these ecosystems generally abiotic factors are restrictive and the species are more specialized to as conditions and more sensitive to environmental alters. So even small environmental harm can cause big disturbances in the equilibrium of the ecosystem.