Final answer:
Climate change is not a commonly cited reason for the decline of buffalo populations in the 1800s; rather, hunting for sport, disease, and habitat loss are the main reasons. Human activities were the primary drivers of the decline in buffalo numbers during this period.
Step-by-step explanation:
The commonly cited reasons for the decline of buffalo populations during the 1800s include hunting for sport, disease, and habitat loss.
One option that is not a commonly cited reason for their decline is climate change.
While climate change has been a significant factor in the extinction of other species such as the woolly mammoth, it was not a primary driver for the buffalo's decline during this period.
During the 1800s, the population decrease was more directly connected to human activities such as overhunting and expanding settlements which led to habitat destruction.