Answer:
The variations in the ecosystem of the Great Plains is caused by the amount of precipitation.
Step-by-step explanation:
The Great Plains are a relatively flat area that dominates the central part of the United States (from the Gulf of Mexico to the border with Canada) and the south-central part of Canada. It occupies a huge area, much larger than the territory of most of the countries in the world, and considering it stretches in a roughly south-north direction, there are obvious changes in the landscape and ecosystem.
The main reasons for the variations in the ecosystem are climatic nature, with the precipitation levels having the primary role. The Great Plains have short-grass prairies, mixed-grass prairies, high-grass prairies, and riparian ecosystems. The riparian ecosystem is present at the transition from aquatic to terrestrial ecosystems. The high-grass prairies are present where there are the highest amounts of rainfall, the mixed-grass prairies where the precipitation is slightly lower, and the short-grass prairies where the precipitation is the lowest in the Great Plains.