Why are niches important to the ecosystem?

"The notion of ecological niche is central to ecological biogeography, which focuses on spatial patterns of ecological communities."Species distributions and their dynamics over time result from properties of the species, environmental variation..., and interactions between the two — in particular the abilities of some species, especially our own, to modify their environments and alter the range dynamics of many other species." Alteration of an ecological niche by its inhabitants is the topic of niche construction. The majority of species exist in a standard ecological niche, sharing behaviors and adaptations similar to the other closely related species within the same broad taxonomic class, but there are exceptions. A premier example of a non-standard niche filling species is the flightless, ground-dwelling kiwi bird of New Zealand, which feeds on worms and other ground creatures, and lives its life in a mammal-like niche. Island biogeography can help explain island species and associated unfilled niches."

The hawk receives 0.1% energy from the caterpillar although the caterpillar gets eaten by another bird smaller than the hawk first