Effects of ionizing radiation on populations and ecosystems

Abstract

Observations of effects of radiation exposure on populations and ecosystems are briefly discussed. The typical reactions of phytocenosis to irradiation at high doses are known to be reduction in species diversity, changes in species dominance, reduction in productivity and changes in a community structure. Irradiation of plants and animals with lethal and sublethal doses results in disruption of ecological relationships between the components of ecosystems. Such effects may act as a trigger of perturbation and lead to consequences that may differ radically from expected ones based on effects observed at the organismal level. In addition, considerable differences in a way of life and ecological niches occupied by different species lead to substantial distinction in doses absorbed by biota species, even when they all are presented in the same environment at the same time. It is especially evident in the case of a-emitting radionuclides. Radioactive contamination may result in the enhanced resistance in affected populations. However, there are radioecological situations where the elevated radioresistance has not evolved or persisted. The complexity and non-linearity of the ecosystem structure and functioning can lead to unexpected consequences of stressors’ effects which otherwise would appear harmless when they were assessed within a narrower context of the traditional organism-based approach. Therefore, the use of the ecological knowledge is essential for understanding the responses of populations and ecosystems to radiation exposure. Integrating of the basic ecological principles into the design and implementation of radioecological research is essential for prediction of radiation effects within the context of rapidly changing environmental conditions.