The ÖBG as an “Ark” for Endangered Tropical Plants

Climate change, land-use change and invasive species—plants and animals that are not native—pose severe threats to tropical biodiversity. Shrinking mountain forests, declining pollinators and the resulting lack of plant regeneration are just some of the serious consequences. Endangered plants, or those already extinct in the wild, find a safe home in gardens such as the ÖBG. Thus, the ÖBG acts not merely as an exhibition space but as a kind of “Noah’s Ark” for threatened plant species.

The importance of this work became clear during the stop in the ÖBG’s Cloud Forest House. Using the laurel forests (Laurisilva) of the Canary Islands as an example, the guides illustrated just how vulnerable global biodiversity has become: of the once vast tropical montane forests of the Canary Islands, the Azores and Madeira, hardly anything remains. Protected areas on Gran Canaria are now only tiny remnants of a former splendour. In Bayreuth, that splendour is kept alive.

Species conservation, however, often requires painstaking manual labour. In the wild, the introduced Red-whiskered Bulbul threatens the pollination of the Mauritius bellflower (Nesocodon mauritianus), as the bird steals nectar without pollinating the bloom. The result: reduced regeneration in the wild. In Bayreuth, gardeners ensure the survival of the Mauritius bellflower: the five Bayreuth plants are part of a global network and are pollinated by hand.

However, conservation is only one central aspect of the ÖBG’s mission. Education is another: the plants serve as ambassadors, helping visitors grasp the complex interconnections and ecological fragility of natural systems.

A similar case occurred in London’s Kew Gardens in 2014: a tiny Rwandan dwarf waterlily (Nymphaea thermarum) just a few centimetres tall was stolen. At the ÖBG, it grows safely out of public view.

The banana: a clone at risk

The banana prompted a particular “aha” moment during the tour. Through spontaneous hybridisation, bananas without bothersome seeds emerged—unlike wild bananas, whose fruits still contain numerous hard seeds. But the price of our cherished supermarket banana is high: because cultivated bananas no longer produce seeds, they are biologically at a dead end and must be propagated vegetatively by humans. As a result, almost all banana plants worldwide are clones, belonging to a single group of cultivars known as Cavendish. This makes them extremely vulnerable to disease, and currently, Cavendish plantations worldwide are threatened by a fungal pathogen. Intensive work is under way to select resistant varieties. The genetic diversity of wild bananas—preserved in greenhouses like those of the ÖBG—may prove to be the life insurance for our future fruit salads.

A highly successful tour

The strong turnout showed that interest in nature and species conservation remains high and continues to grow. On this Sunday, the ÖBG once again proved itself a vibrant place of learning, making global ecological relationships tangible right on our doorstep and demonstrating how vital the preservation of biological diversity is for us all.