The Collection of Aquatic and Wetland Plants (CAWP) was started in 1976 as a living collection of Czechoslovak aquatic higher plant species as part of the Section of Plant Ecology of the Institute of Botany at the Academy of Sciences of the Czech Republic (known as the Department of Hydrobotany before 1987). Research has been conducted continuously at the Institute in the fields of ecophysiology, production ecology, geobotany, phytosociology, and taxonomy of higher aquatic and wetland plants (and also algae). It became necessary to establish a limited plant collection to aid in this research.
The range of species in the Collection has widened markedly since its establishment. In 2001, about 350 species, hybrids, or cultivars were kept in the CAWP. The dominant majority of these species (>90 %) are indigenous in the Czech Republic; the others are mainly from Central Europe. Thus, the CAWP is focused on aquatic and wetland temperate plant species of Central Europe; the proportion of subtropical species or species from other continents is marginal. Taking into account the great number of items kept in the CAWP, it is evident that it is by far the greatest collection of native aquatic and wetland plants in Europe and one of the greatest in the world.
Many dozens of native aquatic and wetland plants can usually be found in several distinguished botanical gardens in Western Europe but the collection in such gardens is mainly focused on conspicuous ornamental species. The CAWP contains both higher plants and Charophytes (stoneworts). All ecological forms of aquatic and wetland plants are represented in the collection: rooted and rootless submersed, floating-leaved, free floating, and emergent plants, perennial species as well as annuals. The CAWP contains all Czech carnivorous plant species and many bog and fen plant species. Very common, as well as critically endangered, rare plant species are part of the Collection; some of the endangered plant species are almost extinct in the Czech flora. Importantly, the CAWP also contains species which were extinct in the Czech flora in the last decades (e.g., Aldrovanda vesiculosa, Pilularia globulifera, Typha minima). In spite of the continuous renewal of species in the CAWP, approximately 15-30 susceptible plant species may be lacking from the species list every year. The species most difficult to keep are aquatic annual species, lemnids, or those growing mostly in cold running waters (e.g., Ranunculus subgenus Batrachium spp.). A specific section of the CAWP is represented by ephemeral plants growing in wet denuded soils. These species (e.g., Centunculus minimus, Illecebrum verticillatum, Coleanthus subtilis, Cyperus flavescens, Juncus capitatus, J. tenageia ) belong to the most endangered taxa not only in the flora of the Czech Republic but also in Europe and to species most rapidly vanishing from natural sites. Some of them are grown and reproduced with difficulty.
Although for practical reasons the CAWP is not open to the general public as a botanical garden, our purpose has been to make the Collection accessible to as many specialists and students as possible. Every year, the staff guides dozens of school excursions through the CAWP, including primary school pupils, inland and foreign university students and staff, and participants of the UNESCO Training Course on Limnology. Moreover, the CAWP serves as a gene pool for rare and endangered species, provides plant material for experiments and studies, comparative material for determinations and botanical illustrations, and is used for the teaching of botany and plant ecology. Also, conservation-based (i.e., rescue) cultivations of ca. 30 endangered species originated with plant specimens from the CAWP. Plants of 17 species from these cultivations have been used for reintroductions mostly to the Trebonsko Biosphere Reserve in the last six years. In addition to the CAWP, a (sub)tropical carnivorous plant collection (ca. 55 species) is situated in a heated greenhouse.
The CAWP covers an area of ca. 0.04 ha. The temperate-zone plants are grown outdoors, while the several (sub)tropical species are in a heated greenhouse. Each plant species is usually grown in plastic pots, which are put in bigger containers. Robust helophyte species (e.g., reeds, cattails, sedges) grow individually in smaller plastic containers. All plastic containers are sunken and embedded in the ground to minimize thermal fluctuations, both in summer and winter. Smaller aquatic Utricularia species grow in 3-l miniaquaria floating in cooling water of a big container. Their winter buds (turions) overwinter in small flasks in a refrigerator. Rooted aquatic plants growing in deeper containers (65 cm) overwinter under water. During periods of frost, ice cover in these containers may be up to 40 cm thick but the dominant majority of aquatic plants survive these conditions without being damaged. Frost-sensitive (sub)Atlantic species (e.g., Pilularia globulifera, Littorella uniflora, Luronium natans) are overwintered for safety in a cool compartment of a greenhouse. During the summer, seasonal shading by wooden bands protects the plants from overheating and reduces the growth of filamentous algae. Nevertheless, the growth of filamentous algae (mainly of genera Oedogonium, Cladophora, Spirogyra ) is a crucial problem for growing submersed species. The only effective control is to repeatedly remove the mats gently and with patience by hand. On summer days, pH values in some containers may exceed 10 due to algal photosynthesis. We sometimes add ethanol (ca. 10-20 microliters per liter) or starch (ca. 20 mg. per liter) to the containers to decrease high pH by enhanced respiration. Soft tap water is used for watering the plants. In helophytes, sandy substrates are renewed every 2-3 years. One technical assistant and two curators (authors of this paper) look after the CAWP.
Using the Collection
We welcome interested colleagues to the Section of Plant Ecology at Trebon and are glad to guide them through our Collection and conservation-based cultivations. Our plant material may be offered for exchange to other plant collections or sent to colleagues abroad for study purposes. The complete species list of the CAWP is available on request by e-mail to the curators, or online at the CAWP web site at http://www.butbn.cas.cz Please send us your species list.
In our species list, all species are classed within three groups. A) species bearing seeds or spores more or less regularly; it is possible to mail them in the form of seeds or spores; B) species which may be mailed in vegetative form (turions, rhizomes, tubers, bulbs, parts of clones, shoots); C) problematic species which are difficult to grow and, thus, are not always at our disposal; they may be represented e.g. by annual terophytes, which do not set seeds in the CAWP, lemnids, and some other susceptible species.
Since 1998/1999, the seeds of CAWP (ca. 120-200 items) have been
listed in the Index Seminum which is regularly issued by the Institute
of Botany at Pruhonice (see
http://www.ibot.cas.cz)).
We would prefer your visit and personal selection and transport of the plants to their mailing by post.
Simply, we look forward to communication and cooperation with you!
Aquaphyte Contents | Aquaphyte page | Home