What factors affect biodiversity? why do wetlands have a high level of biodiversity

Biodiversity is affected by such things as the types of wildlife ie bears, deer, skunks, grouse, ravens, robins etc ie the flora and also the fauna or the vegetation such as types of trees, shrubs, mosses, lichens etc. Wetlands are good for biodiversity since they provide an environment for many types of both vegetation and also wildlife ie such as ducks.