On Saturday 2nd March 2024, the Orchid Society of Great Britain will be holding a Zoom talk. The meeting opens with OSGB members' chatting about orchids from 10.30am; the talk starts at 11am.  

This meeting is for OSGB members only. New members are always very welcome - join online on our website. 

Many orchids grow as epiphytes in rainforests around the world. Orchids form part of a complex interdependent ecosystem with other epiphytes in the same habitats, each depending on the other for the high humidity they all need in these environments. The orchids and other epiphytes all pay vital roles in each other’s’ survival. 

This talk aims to explain the importance of the rainforest water cycle, the roles that each plant group plays and how the water cycle is maintained through the joint roles of the xylem tubes and stomata. And of course - the part that orchids play and a little about their special adaptations which fit them to life as epiphytes. 

Other epiphyte  groups considered are mosses, lichen and ferns. All of which depend on the high humidity of the rainforest to reproduce and to enable their minute spores to ‘germinate’. The importance of bromeliads in rainforests is often overlooked.  The water held in their leaf rosettes forms small reservoirs for hundreds of aquatic organisms found nowhere else. The enormous total volume of water held by these plants is responsible for maintaining high humidity levels in the rainforest.

It is important to remember that plants are dependent not only on each other but also on the fauna of the rainforest for pollinators so that they can set seed and thus ensure the survival of their next generation. Orchids are renowned for their highly evolved and complex relationships with their pollinators. Many are ‘species specific’ and can only be pollinated by one species of wasp, bee or fly. This means, that they are highly vulnerable to any changes affecting their pollinating insect species.  These ecosystems of interdependent organisms are in reality very fragile, since if one link is broken or damaged, then everything else is also in danger.

Life as a epiphyte?  It is really hanging on a knife edge. If any one of the numerous other things that they depend on are damaged, by what ever means, then they are also in danger.  Orchids are potentially most at risk due to their highly specific pollinator relationships. Small, delicate orchids such as some Pleurothallids are also highly threatened as they have no water or food reserves within the plant unlike other orchids which have large pseudobulbs.