The article considers the meaning and content of the concept of ecological landscape. The author shows that the ecological landscapes of plant and animal organisms, fungi and microorganisms are built and modified through the processes of semiosis, signification of environmental elements and mutual recognition of signs. Landscapes are complex networks of interactions between organisms and with different types of environmental factors. The author argues that, for understanding the network interactions and communications of living organisms, the approaches from the network science and systems science are useful. Consideration of ecological landscapes from the perspective of complex systems opens up additional aspects of a possible analysis: spatial and temporal configurations of landscapes, elements of symmetry and asymmetry, order and chaos in them, their possible scale invariance, and the fractality of their structural organization. The concept of ecological landscape is correlated with the concept of ecological niche, a place occupied by a species in specific environmental conditions. When describing the coexistence of various organisms in a biocenosis in terms of niches, the author uses the concept of a fitness landscape or an adaptive landscape. She also analyzes the subtle nuances of meanings of the concepts “ecological landscape”, “ecological niche”, “habitat, “umwelt” and “eco-field, and “ecosemiosphere”, and the question of what determines the structure and diversity of the umwelts of living beings. Umwelt is the subjective world of perception and action of living beings belonging to the same species. Particular features of each individual are superimposed on the species-specific features of umwelts. Umwelt is built thanks to the active connection of a living organism and its environment, which it masters and turns into its own environment. Since environmental conditions are constantly changing, the umwelt of a living organism is partly rebuilt under the changing environmental conditions. A diachronically living organism lives in a plurality, a historical chain of states of its umwelt. There are several meanings in understanding the spatio-temporal properties of ecological landscapes and the interconnection of umwelts, the construction of landscape designs of nature. Curious features of the configuration of landscapes are short-range and long-range orders, the imposition of large and small scales, the division of ecological niches, cooperation and mutual assistance, and the synergy of living organisms. In the light of evolutionary holism, all types of umwelts (umwelts of plants, animals, human beings as social and cultural creatures) can be united and combined into a hierarchical ladder. An integral view entails an understanding of the need to promote global environmental ethics as a concern for the preservation of biological, social and cultural diversity, life and health of all parts and the whole of ecological landscape. By taking care of the whole, we take care of ourselves. By paying attention to and preserving the small in biological diversity, we support the sustainable development of large and global ecological entities and structures.