Calibration of diversity indexes and search for ecologically tolerable levels of abiotic factors (case study: water objects of the Don river)

With the data obtained by hydrobiological monitoring of water objects of Don river for many years (1978–1988) calculation of rank distribution parameters and indexes of dominance for phytoplankton species abundance was conducted. The borders of investigated characteristics are calculated. They correspond to borders of ecological well-being — trouble conditions of phytoplankton communities. Ecologically tolerable levels for the core abiotic factors are found. Contribution of each of analyzed factors to a degree of ecological trouble is established.