One of the main challenges the four common types of coastal wetlands face today is habitat loss. Most coastal watersheds lose vast chunks of land to erosion, drainage, development, sea-level rise, and subsistence. The next major one is human activities. Humans alter coastal habitats for selfish reasons, and this trend has led to the degradation, disappearance, and disconnection of many wetlands worldwide. The effects of climate change also pose a significant threat to these resources.