By Hassan Rankou, Mediterranean Conservation Programme Director, Global Diversity Foundation
26 April 2019
A herbarium is a collection of dried plants carefully prepared, mounted and classified. These plant specimens, deposited for future reference as herbarium vouchers, play a key role in the knowledge, research, valorization and conservation of floristic diversity, which contribute effectively to scientific and educational activities that raise awareness of the need to conserve biodiversity. Herbarium vouchers are scientific references necessary for publications relating to the systematic studies of ecology, phytochemistry and conservation biology.
Adopting a participatory approach, the Global Diversity Foundation (GDF) and the Moroccan Biodiversity & Livelihoods Association (MBLA) set out to create community herbaria with researchers and communities from the High Atlas that are accessible for them to learn about their local flora, how to conserve plants and preserve their plant heritage. After obtaining the necessary approvals and permits through the MARK Regional Herbarium of the Faculty of Sciences, Cadi Ayyad University, Marrakech, a series of fieldwork and plant collection expeditions were carried out on data collection, taxonomic status verification and herbarium specimen preparation. This led to the creation of community herbaria in Imegdal and Ait M’hamed.
Why do we prepare specimens?
Well-prepared and labelled herbarium specimens provide valuable records and proof that a plant grew in a particular place at a given time for conservation and research needs, including the cataloguing of biodiversity. They serve as resources to identify further specimens and as a source of plant material for taxonomic and botanical research. Samples from herbarium specimens are used for leaf anatomy identification, phytochemical screening, pollen studies, DNA extraction, production of field guides and monographs on flora, and more.
How do we prepare specimens?
Here, we describe the steps and considerations we have taken to prepare the community herbaria in Imegdal and Ait M’hamed.
Before plant collection commences, we must consider the species’ conservation status. Is the plant rare? Is it protected by law? Are permits required to enter the area to collect the species? During collection, it is important to obtain specimens that present as many features of the plant as possible such as stems, leaves, flowers, fruits and seeds. Quality is always more important than quantity.
The most important element of plant collection is to take notes and record data such as location, habitat type, associated plants and any features of the plant that will not be obvious once it is removed from its collection site, such as height, color and scent. We use a collection book to document all these details.
Drying and pressing plants
Drying the collected plants properly and quickly preserves many, or all, of the features of the specimen long into the future. We use wooden boards with two ‘rucksack-style’ straps to slowly tighten the press. The presses are opened, and the drying papers are changed daily. In wet conditions, these are placed in a specialist drying cabinet.
The plants are mounted on a standard herbarium-size sheet supported by corrugated cardboard, using PVA to make effective “glue staple” at appropriate points of the stems. Special care is taken to make the mounting inconspicuous. We glued the labels (see below) at the bottom right corner of the sheets.
The plants collected in both sites were identified in the MARK Regional Herbarium with the community researchers, GDF and MBLA staff, the herbarium curator and Moroccan flora experts.
The label provides information that cannot be found by looking at the specimen, which we presented in a particular sequence for ease of subsequent data retrieval. Information includes the name of herbarium, territory of collection, scientific name of the plant, locality, latitude and longitude, altitude, habitat, plant community, additional notes such as flower color and scent, collector’s name and date collected. Our herbarium specimens were labelled using the Botanical Research and Herbarium Management System (BRAHMS).
Specimens of the same species or taxon are stored in a paper folder following a specific sequence. In the community herbaria, we stored specimens in specially-made metal herbarium cabinets to ensure the specimens are kept dry to prevent fungal attack, deterioration and are free from pests.
The final step in the process was to develop an initial species database for the community herbaria using the BRAHMS database software. This database contains information on the plant collector, scientific and vernacular names of the plants, locality, habitat description, plant description, abundance of the species, threats to the species locally, uses of the species and ethnobotanical data.