He largest density an ecosystem can support for a particular population is called

Carrying Capacity

Explanation:

The carrying capacity depicts the largest  population of an organism which can be easily sustained and supported by an ecosystem. If the population increases beyond carrying capacity, the ecosystem destabilizes as it do not have sufficient resources to feed/nourish such large population.

Population density is the number of individual living in an ecosystem in a given unit area. Thus, it is nothing but the population living in a confined boundary. Thus, the maximum population density or the maximum number of organism in a given unit area of an ecosystem that can be easily supported by  the ecosystem is called the carrying capacity of the ecosystem.

where is the scientific experiment?