Final answer:
The dispersal of seeds to new locations is considered a positive biotic effect following a natural disaster as it aids in ecological recovery and increases genetic diversity which is critical to the resiliency of ecosystems.
Step-by-step explanation:
The question asks which of the listed options is a positive biotic effect after a natural disaster. The correct answer is 'd) Seeds being dispersed to new locations'. This is a beneficial biotic effect because post-disaster seed dispersal can lead to repopulation of plants in the affected area, contributing to ecosystem recovery and resilience. Moreover, spreading to new areas can increase plant genetic diversity and provide new habitats for various species.
Option 'a)' pertains to physical changes in the environment and does not necessarily involve biotic components directly. Options 'b)' and 'c)' can have biotic components, but falling trees and the death of wildlife are generally not positive effects.
Therefore, the dispersal of seeds to new locations stands out as a clear positive biotic effect as it can facilitate the restoration of an ecosystem after a disturbance, contributing to biodiversity and future stability of the environment.