A group of individuals of different species, inhabiting a given area is called:
community
Population is defined as a group of individual of the same species, plant or animal, inhabiting a given area. Many such populations that are interacting with each other together form the community. The biotic community together with the abiotic environment together forms the ecosystem. And a biome is formed due to the similar climatic conditions in a region, these regions are generally large covering many continents. It can be considered a collection of many ecosystems.