Sometime in the late 70'ties or 80'ties I read this novel. It's about a man traveling to a planet where the human colony has a lot of trouble with the indigenous life. The man from the planet accompanying him is very big, muscular, with faster reflexes than ordinary men. This is an adaptation to the conditions on the planet they are traveling to. The conditions on the planet are getting worse all the time.
At the end of the book it is revealed that the local life is reacting telepathically to human aggression, so the situation is becoming worse as the human colonists are becoming more aggressive to save their lives. As the humans realise this they solve the problem by becoming less aggressive. Can anyone help me find out which novel this is?