Iquitos NGOs
Wildlife rescue centers
One of the best ways to save the rainforest is to support NGOs like these two wildlife rescue centers. They rehabilitate animals that police confiscate from the illegal pet trade for release to the wild.
Amazon Rescue Center
I highly recommend visiting the Amazon Rescue Center. This is an effective non-profit that is making a real difference in rescuing, rehabilitating and releasing wildlife. If you have time, sign up to volunteer at the center!
Isla de los Monos
Another great non-profit is Isla de los Monos, which is about 30 k from Iquitos. Visiting and donating will go a long way in helping their efforts to preserve wildlife in the Amazon.
There are also numerous NGOs that focus on education and services for Indigenous communities. None are as well set up for visitors as the NGOs for wildlife. However, if you stay at an eco-lodge in the rainforest, ask if they partner with an NGO that you could visit or donate to.