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

Explanation

No, it is not possible that productivity of a natural community remain constant over a certain time period.
This is because
(i) The natural habitat is never maintained in real.
(ii) Abundant resources are never available, they are always in short supply or just enough.
(iii) Environment conditions for survival and reproduction are continuously changing.