Plant biodiversity is threatened world-wide due to habitat destruction, pollution, the spread of invasive species, overexploitation, and climate change. Plant diversity plays a crucial role in the functioning of ecosystems, and many species hold unknown treasures such as molecules with helpful medicinal properties. The safeguarding of plant diversity is therefore essential. Our research contributes to the development of tools for conservation of plants in natural habitats as well as in living collections or seed bank of the Botanic Garden.
The conservation research is organized in the following topics:
- Ex-situ conservation of plant species in our seed bank and living collection
- In-situ conservation of selected plant species by reintroduction and reinforcement of populations in threatened ecosystems.
- Vulnerability and threats (IUCN red-listing).
Meise Botanic Garden holds the only seed bank [link] in Belgium as defined by international standards. Its goal is maintaining viability, genetic integrity and quality of seed samples and making them available for conservation and research. Research on ex-situ seed conservation focuses on determining seed germination requirements and seed longevity of the taxa stored in the seed bank. The large amounts of data on seed characteristics collected is also used in studies on ecology and evolution of seed characteristics. Sampling efforts are optimized by studying genetic diversity of selected plant species, which can help us to decide on the sampling methodology and provides information on the diversity covered by the seed samples stored in our seed bank.
(Considerable seed sampling efforts have been conducted in the past and are ongoing at the Garden. The seeds are dried in air-conditioned chambers down to 5% moisture content, and then stored in freezers at -20 °C, which ensures long-term. Germination tests are regularly performed to determine the viability of the seeds. So far, the Gardens’ seed bank holds 44% of the Belgian red listed species. Crop wild relatives are also one of our core business with, for instance, 231 taxa of wild beans, a collection that is unique in its genetic diversity (23 genera originating from 94 countries) and about 10 taxa and over 50 accessions of wild bananas. The endangered flora of the Katangan Copper Belt is also safely stored in the seed vaults with 67 taxa of conservation concern (among which 26 endemics).
In the framework of the EU-LIFE project “Herbages” (LIFE11 NAT/BE/001060), Meise Botanic Garden, as a centre of excellence in ex-situ conservation and plant propagation, has implemented population transplantations in the wild for four critically endangered species (Dianthus deltoides, Helichrysum arenarium, Arnica montana and Campanula glomerata). The aim is to increase the effective size of remaining populations (reinforcement) and to restore extinct populations (reintroduction) in order to improve connectivity in the landscape. For each species, seeds have been collected on a minimum of 50 individuals in two to seven source populations in the closest possible similar habitats. In each source population, leaves were sampled on a minimum of 30 individuals in order to estimate population genetic diversity and structure. These population genetic data provide important information on the liveability of populations of these rare plant species in Belgium. Soil samples were collected in the target sites to study the soil seed bank. Propagation protocols have been successfully developed for all target species. Prior to in situ transplantation, morphometric measures (vegetative plant size) were recorded on each individual. For each species, a population of 500 to 700 young individuals was transplanted in three or six different sites. Once in situ these plants were labeled and precisely mapped to facilitate their long-term monitoring. A demographic survey (e.g. survival, floral production, reproductive success, and population extension by clonal propagation or seedling recruitment) is recorded yearly on the field. A germination experiment is carried out to estimate the fitness of the progeny in order to test for inbreeding or outbreeding depression.
The IUCN Red List of Endangered Species (www.iucnredlist.org) is a central database containing the vulnerability status of thousands of plant and animal species worldwide. The species are evaluated on the basis of a number of quantitative biological criteria such as geographical distribution and fragmentation, total population size and density, and the extent to which populations are declining. The information contained in the Red List is an important tool for assessing the status of global and regional biodiversity, and for setting conservation priorities.
The Botanic Gardens Conservation International (BGCI) and the IUCN/SSC Global Tree Specialist Group (GTSG) coordinate the work of two red list authorities for plant species in Central Africa: the Central African plants Red List Authority (CARLA, for the Democratic Republic of Congo) and the East African Plants Red List Authority (EAPRLA, for Rwanda and Burundi). Our researchers use advanced modelling methods to determine the geographical distribution of species, with the digitised herbarium data from Meise Botanic Garden providing an indispensable source of information