Forest fragmentation occurs when development severs a continuous area of forest, breaking it down into small patches  Some animals, such as white-footed mice, thrive in conditions of forest fragmentation, reaching their highest population densities in small forest patches
These mice are the main carrier of the bacteria that cause Lyme disease, a debilitating illness that is often transmitted from white-footed mice to humans by deer ticks
Deer ticks reach their highest population densities in small forest patches.