BOTANY WITH BASICS OF HYDROBOTANY (AQUATIC PLANTS OF UKRAINE) - B.Ye. Yakubenko - 2011

XIV. INSTRUMENTS AND METHODS FOR RESEARCH ON AQUATIC VEGETATION

Determination of Species Composition and Structure of Plant Communities

Vegetation descriptions are carried out within sampling plots or along ecological transects. The number, size, and shape of the plots depend on the canopy Structure, density, homogeneity, etc. They must encompass the full diversity of habitats. The optimal plot size is considered to be the area sufficient to reveal all species of a phytocoenosis. For species-poor aquatic coenoses, this is 1-10 m [128].

Depending on the research objectives, the following parameters are described for each plant community:

Species (floristic) composition — a list of species (a community may be represented by a single species or many species) indicating Abundance according to a specific scale [68], vitality, morphological anomalies, and phenological state. Vitality is usually assessed using a five-point scale:

1 — suppressed plants; 2 — vegetative development below normal, capacity for flowering and fruiting not lost; 3 — plants with a complete developmental cycle, growing, flowering, and fruiting normally; 4 and 5 — plants exhibiting above-normal and hypertrophied development.

Vegetation phases are designated by individual letters: ю (ju) — juvenile plant, б (bu) — budding phase; к (fl) — flowering; п (fr) — presence of ripe fruits and seeds; вп (pfv) — post-fruiting vegetation; в (dy) — dying-off; зб (wb) — winter buds.

Based on The Study of the floristic composition of plant communities or specially conducted floristic surveys, lists of aquatic and wetland flora or partial floras are compiled. If a plant is unknown to the researcher, it is assigned a number and preserved in a herbarium for subsequent identification. Rare plants should be collected only when it causes no harm to the population.

For accurate identification, it is advisable to collect all plant Organs from the ROOT to the flower or fruit. Drying of aquatic plants is carried out according to established rules [11]: the leaves and flowers are arranged on a herbarium sheet so that several of them lie with their lower side facing upward. For large plants, only a portion of the root and stem with a lower leaf, a stem section with a cauline leaf, and a part of the inflorescence are taken for the herbarium. Thick and fleshy stems or rhizomes are cut lengthwise; for small plants, several specimens are taken so that the entire sheet is filled. Delicate, fragile plants whose leaves stick together out of Water are laid out on a sheet of parchment in a basin of water or a photographic tray. To ensure that fleshy flowers dry well and retain their color, their petals should be interleaved with small pieces of paper previously moistened in a saturated solution of salt, sugar, or alum and dried.

A herbarium specimen must be accompanied by a label indicating the region of research, the nearest settlement, the collection site (preferably specifying depth and sediment type), the date, and the researcher's name. Plants are dried in herbarium presses in the open air, and the absorbent layers (newspapers, filter paper, cotton pads, cloth) must be changed once a day.

The field notebook must indicate the identification keys used in the work;

The vertical STRUCTURE OF THE community, which determines the presence and composition of submersed, floating-leaved, and emergent layers within it;

The horizontal structure, which accounts for the distribution pattern of coenopopulations in the community (random, uniform, clumped, and combined), projective cover (the area of horizontal projections of plants onto the bottom surface, expressed as a percentage of the community area) for a species and layer, as well as total projective cover (which may exceed 100% due to layer overlapping).