A tension zone is a transitional zone between two distinctive zones, the zones may be influenced by climatic factors,^[1][2] and geological variation.^[3] creating a floristic tension zone.^[4] A marine tension zone may be affected by variables such as depth, climate or salinity.^[5] In a tension zone there is the increased probability of hybridization between species of the separate zones and thus the tension zone may also be a hybrid zone.^[6]

Historically tension zones were entirely natural in origin, however human activity has altered the tension zones in a variety of areas all over the world.^[7]