By itself, the term "habitat fragmentation" certainly sounds bad, but what does it actually mean? Habitat fragmentation is actually exactly what it sounds like: the separation of a habitat into smaller sections. This may not sound as bad as habitat destruction, since all the resources are still available, but the animals can no longer access all of these resources. For example, pandas have to eat a large amount of bamboo to survive since they derive less nutrients than other species. If their foraging area is suddenly cut in half because of a new road, finding food could become a serious problem. Some innovative solutions, like the inclusion of tunnels underneath roads to allow animals to cross safely, are helpful but insufficient in many cases. Likewise, clearing forests to create farmland devastates the local wildlife, which is why it's so frowned upon.
For more information, check out another article about habitat loss in the Arctic here