V.S. Ivlev’s Monograph Revisited. The Role of Habitat Heterogeneity in Biological Interactions

Abstract

The fundamental regularities of trophology, such as the dependence of the fish diet on the food concentration, foraging selectivity, and competition for food, which are the key concepts in V.S. Ivlev’s book Experimental Ecology of the Fish Feeding are quite familiar to a broad community of ecologists. However, the range of problems addressed in this milestone study is not limited to the issues of fish trophology. The effect of habitat heterogeneity on biological interactions in ecosystems, which is one of the major objects of research in contemporary ecology, is discussed in the book in two aspects: the connection between the foraging intensity and selectivity to the heterogeneity of prey distribution (the degree of aggregation per Ivlev) and the role of physical obstacles in the regulation of intra- and interspecific competition for food. The dependence of the feeding rate on aggregation was even more substantial than the dependence on prey concentration. Ivlev demonstrated this in laboratory experiments and, which is even more important and difficult, studies of natural water bodies. In this paper, a brief analysis of the ideas and results included in the book and related to the ecological significance of habitat heterogeneity is followed by an overview of a number of modern studies that adhere to Ivlev’s working style and develop his approaches and ideas. It is apparent from these studies that habitat heterogeneity, which is determined by different factors and manifested on different scales, affects both the behavior and the population dynamics of the interacting organisms. As a result, both the mechanisms underlying biological interactions and the structure and functioning of organism communities are modified.