For Pinatubo the particles were small enough for a slight world-wide cooling. I'm afraid I don't know how the ecological balance of the Philippines has been affected. Whole rivers disappeared under a couple hundred meters of pyroclastic flow material in places, and these are only now starting to be re-exposed by erosion. Perhaps another way in which the ecology was affected is due to the displacement of all the people who lived on or near the volcano. They might have moved somewhere else that previously didn't have a heavy human impact.
People are a pretty strong method of ruining the ecology.
I hope these answers will help a little. I'm sorry if they are not exactly what you were hoping to learn.