Final answer:
The tropical rain forest ecosystem is the best choice for an ecological preserve design aiming for high biodiversity and diverse niches. Its complex structure offers abundant habitats for species, and its conservation requires strategic size and shape considerations.
Step-by-step explanation:
When planning an ecological preserve with highly diversified niches and habitats for a rich diversity of species, the tropical rain forest ecosystem would be the best foundation for the design. Tropical rain forests are known for their high biodiversity, with numerous species adapted to a variety of habitats within different forest layers. These ecosystems provide a multitude of niches that can support an abundance of wildlife and plant species, ensuring a rich gene pool and ecological diversity.
Lasting preservation in such ecosystems often requires careful consideration of factors like size and shape of the preserve. A square or circular preserve is more effective as it maximizes core habitat and reduces edge effects. Additionally, when land is set aside, creating sufficiently large, contiguous areas or utilizing wildlife corridors to connect smaller areas can promote genetic diversity and species survival, following the theory of island biogeography. Therefore, when considering preserve design, the tropical rain forest surpasses other options like desert, islands, and the temperate rain forest in fulfilling the criteria of high biodiversity and diversified ecological niches within a limited area.