Koosluse

Koosluse is the Estonian term for an ecological community: the assemblage of populations of different species that occupy and interact within a defined area. A koosluse is characterized by its species composition, relative abundances, and the network of biological interactions among its members. It is a subsystem of an ecosystem, shaped by abiotic factors such as climate and soil, and by disturbances, but defined primarily by biotic relationships.

Key properties include species richness (the number of species present), evenness (how evenly individuals are distributed among species), and the organization of trophic levels and functional groups. Interactions such as competition, predation, herbivory, mutualism, and parasitism influence the structure and stability of the koosluse. The spatial arrangement and temporal dynamics of a koosluse can vary widely between habitats and over time, as new species colonize and others go extinct, or as disturbances reset successional stages.

Ecologists study kooslised by cataloging species, estimating abundances, and applying diversity and interaction metrics (for example indices of biodiversity, network analyses of food webs). Field methods include quadrats and transects for local communities and long-term monitoring to capture changes due to climate, land use, or natural disturbances.

Kooslused provide ecosystem services indirectly, such as sustaining pollination, nutrient cycling, habitat provision, and resilience against environmental change. Examples range from a forest understory community and a freshwater lake littoral zone to coral-reef assemblages.

Etymology: the term kooslus derives from Estonian, meaning assembly or grouping, with the genitive form koosluse used in referential expressions.