Wildlife can positively and negatively impact agriculture and food production. Positively, wild animals disperse seeds and pollinate plants. They also contribute fertilizer. Historically, agricultural practices created habitat for wildlife through odd areas, shelterbelts, and fields in rotation. Cultivated fields provided food for many species. However, wildlife populations have declined in recent decades due to agricultural changes. All wildlife require food, cover, water, and space to survive. The quality and arrangement of these factors determines what species an area can support.