Read the text and answer the question. In the past, elephants roamed freely across vast savannas. Their large numbers helped maintain the ecosystem by spreading seeds. However, in recent decades, their population has drastically declined due to poaching for ivory and habitat destruction. This decline has a negative impact on the environment because fewer elephants mean less seed dispersal, affecting plant growth and biodiversity. What is the main reason for the decline in elephant population and its impact on the environment?
A) Elephants are migrating to new areas, which is good for biodiversity.