When seasons change, the biological and chemical functions of an entire ecosystem are altered. This is because energy consumption and resources are cut or added drastically depending on the season.
Most ecosystems work in a cause-effect relationship. When one resource is lost or added, it affects the entire ecosystem. A good example is the food chain, an integral part to an ecosystem. If the lowest life form in the food chain disappears, then larger animals may begin to die off.
Seasonal shifts do not last long and there does not have to be a drastic effect on the ecosystem. When winter occurs and a plant dies, there is no mass extinction or environmental damage. The ecosystem is prepared for the winter, allowing all aspects of the ecosystem to survive even with limited resources.
Climate change is expected to negatively impact ecosystems. A longer than normal winter, for example, would impact the environment severely since other aspects of the ecosystem have not adapted to such a shift. Hence, ecosystems adapt to the cycles of the seasons, but climate change radically shifts the cycles, harming all parts of the ecosystems.