Environmental stability is a multifaceted concept and includes properties such as asymptotic stability, robustness, persistence, variability, elasticity and resistance. Resistance reflects the ability of a community or population to remain in a substantially unaltered state under external influence. The reverse of resistance is sensitivity. This article suggests a way to assess the sensitivity of animal communities to factors of various character and explain sensitivity and resistance of the macrofauna community near the floodplain of the river Dnieper within the "Dnipro-Orelsky" Nature Reserve to the effects of edaphic and plant factors, as well as spatial variables. It is shown that the regulatory impact of environmental factors is refracted through the properties of ecological systems themselves, namely resistance and sensitivity. If an ecological system does not react to changing environmental factors, such a system is indifferent with respect to these factors. In the case of regulatory influence of factors, there may be resistance, sensitivity and the proportionality of the response of the ecological system. The ratio of the specific role of a factor in the variability of a community to the contribution of the main components of the total variability of the attributive space makes it possible to assess the resistance, sensitivity and proportionality of response the ecological system to the action of that factor. If the ratio is >1, then this indicates sensitivity: level of variability of a community is higher than the relative role of environmental factors in the changing of the attributive space. If <1, this indicates resistance: the level of variability of a community is lower than the relative role of environmental factors in the changing of the attributive space. If the ratio =1 (≈1), changes in the community are proportional to the level of the main components of variation in comparison with other components. Ecological factors (both external environmental and internal due to species interactions and which have a neutral nature) cause different levels of community response to their impact. These differences refracted through different aspects of stability of a community can be described using the categories resistance, sensitivity and proportionality. The proposed procedure for quantification of specified properties of sustainability has established that the floodplain soil macrofauna is endowed with resistance to factors that prevail on the level of its variation. However, macrofauna is highly sensitive to minor factors. The community of the soil inhabitants is sensitive to fine-scale variations, which have a neutral nature.
PROCESS-RESPONSE MODELS FOR DEPOSITIONAL SHORELINES: THE GERMAN AND THE GEORGIA BIGHTS
