The reasons for its decline are unknown, but possible threats include erosion and sedimentation, along with flow alterations.

Lessons include seasons, photosynthesis, erosion, the rock cycle and plate tectonics.

Possible explanations include headward erosion or a broken natural dam of a lake or river.

Other damage includes erosion, dust production, and the introduction of weeds.

Remaining threats include erosion, invasive grasses, and wildfire from military exercises.

Other developing problems include erosion, property damage, drinking water contamination and the unearthing of the dead.

Common examples of natural phenomena include sunrise, the weather, decomposition, free fall and erosion.

These include erosion, transport, fossil fuel combustion, and bacterial formation.

Threats to the survival of this endangered species include agriculture, development, and erosion.

Other threats include erosion and competitive introduced species of plants.