Great Elephant Census

"The Great Elephant Census (the largest wildlife survey in history) was an African-wide census designed to provide accurate data about the number and distribution of African elephants by using standardized aerial surveys of hundreds of thousands of square miles or terrain in Africa.

Explanation:

"The final results from Great Elephant Census show 352,271 African savanna elephants in 18 countries, down 30% in seven years"

because the light is a great source of energy for the plants to survive. (i hope this )