1.   Factory-farming makes pollution, excessive meat-eating upsets the ecological balance, trapping and hunting can injure habitat, and so on.

2.   Human activity is ruining the ecological balance of our planet.

3.   In general landowners were expected to work the land and to increase productivity, but not to upset the ecological balance.

4.   The effluents we pour heedlessly into its waters are a threat to its delicate ecological balance.

5.   There are warnings that the building of the dam will upset the ecological balance of the river basin.

6.   They harvest its riches without destroying the ecological balance.

7.   ...the ecological balance of nature.

8.   ...the ecological balance of the forest.

9.   They warn that the dam will upset the ecological balance in the Yangtze basin, with unforeseeable consequences.