Is it possible that productivity and diversity of a natural community remain constant over a time period of, say one hundred years ?

Is it possible that productivity and diversity of natural community remain constant over a time period of, say one hundred years?

What are the materials that remain unchanged over long periods of time?

Assertion: The bob of a simple pendulum is a full of water if a fine hole is made at the bottom of the of the ball , then the time period will no more remain constant Reason : The time period of simple pendulum does not depend open mass