Abstract: Landscape connectivity is a parameter which measures the ecological process by which the subpopulations of a landscape arc interconnected into a demographic functional unit. It is a landscape phenomenon which describes the relationships between landscape subunits. The landscape connectivity is different from the landscape connectedness which describes the characteristics of landscape pattern, the landscape connectivity mainly describes the function of landscape elements and their relationship, which can be measured by measuring the degree to which the landscape pattern facilitates or impedes movement among resource patches. The landscape connectivity is relative and abstract, which is changeable for different ecological process and studying objective. The emergence and application of connectivity in landscape study are very useful for biodivcrsity protection, biological resource management, landscape design and planning.

Key words: ecosystem service, water source supply, InVEST model, Three Rivers Source Area.