ZURICH BOTANICAL GARDEN AND THE MADAGASCAR'S GREENHOUSE
By CARLA DE AGOSTINI
Zurich's botanical areas are divided into two parts: on the one hand, the botanical garden and, on the other, the vast Madagascan greenhouse at the zoo. The former is situated on a hillock not far from the city centre and does not lose its charm even in winter. Established in the 1970s and initially private, the Zurich Botanical Garden is now part of the Department of Natural Sciences at the University of Zurich. The garden has three glasshouses that can be visited in half spheres with different climatic zones: the tropical mountain forest, the tropical dry wind area with a showcase dedicated to carnivorous plants and the tropical lowland rainforest, where the humidity is 90% and the temperature is around 26 °C in both summer and winter. The greenhouses, designed by Hans and Annemarie Hubacher, Peter Issler and Hansulrich Maurer, were completed in 1976 but have been renovated several times in Plexiglas because, over time, they had lost much of their transparency, creating harmful effects on plant growth.
The main entrance is from Zollikerstrasse, and as you climb the stairs you can already admire the attention and care characteristic of the Mixed Border: a style developed in England at the end of the 19th century, which allows plants to be enhanced during every season. Annual flowers, perennials and small shrubs are selected so that something is always in bloom. In spring the geophytes stand out, and in winter there are grasses with faded inflorescences, which get covered in frost and are a very special attraction. The aim is a didactic one and the interest is to highlight planting as a harmonious and natural process.
At Zurich Zoo, around 4,000 animals of 380 different species, with the oldest inhabitant being a giant Galapagos tortoise over 70 years old, are joined by more than 5.5 hectares of greenery with over a million species of plants from all over the world. The Madagascan greenhouse is 30 metres high and is made of EFTE "bladders" mounted on a metal structure, a material that simulates sunlight, insulates and allows the over 11,000 square metres of surface area to be covered in a light manner. Thanks to these cutting-edge, light-sensitive, highly insulating materials, since June 2003 it has been possible to immerse oneself in a dense tropical forest, populated by more than 20,000 plants and 45 species of tropical vertebrates, including animals left in the wild, such as lemurs. Here you can experience the Masoala forest, with temperatures ranging from 20° to 30° C and its very high humidity, with an average rainfall of 6 mm per day. This tropical rainfall is achieved through an interesting system of reusing rainwater, which allows an equivalent irrigation of 80,000 litres of water per day.
The coexistence of fauna and flora is designed to help preserve the biodiversity of Madagascar's ecosystems. Through the Masoala project, the Zurich Zoo has decided to support the Malagasy government in the conservation and protection of one of the world's most endangered areas. Despite the fact that Madagascar represents only 1% of the earth's surface, it is one of the richest areas in terms of biodiversity, home to around 3% of the planet's animal and plant species. Unfortunately, at least 70% of the primary plant cover has been lost. Flora and fauna can also be appreciated from above, where aquatic plants, ferns, lianas, bamboo and animals can be admired. This focus is in line with one of the main tasks assumed by the garden for the 21st century: to promote and strengthen the relationship between vegetation and mankind, seeking to convey and enhance the increasingly evident interconnection between plants, the environment and health.