The Convention on Biological Diversity, ratified in Rio de Janeiro in 1992, is the first legally binding treaty to provide a legal framework for the protection of biodiversity. It has three main objectives: the conservation of biological diversity, the sustainable use of the components of biological diversity, and the fair and equitable sharing of the benefits arising out of the utilization of genetic resources. The plant collections held at botanical gardens took on a new level of significance when the treaty came into force.
The HHU botanical garden houses extensive collections that are used as work and study materials in teaching and research. Most collections are accessible to the public, too. It focuses particularly on cold-house cultivation, e.g., of the plants in the domed greenhouse and the South Africa House.