Hierarchical networks

Abstract

a b s t r a c tBiological networks are not operating in isolation, but are connected and interact with the other levels of the entire ecological hierarchy. It implies that both vertical and horizontal connections and interactions come into play and should be considered. The vertical effects and their integration with the horizontal networks are, however, a new challenge, as network theory up to now to a high extent has only considered the horizontal connections. It gives rise to the central questions, how two or more networks in two or more different levels of the hierarchy can work together and whether the interactions will change the network properties.The hierarchical levels in biology and ecology -molecules, cells, organs, organisms, populations, ecosystems, landscapes and the ecosphere -appears at first sight to be working two by two (molecules/cells, cells/organs, organs/organism, organisms/population, populations/ecosystems and landscapes/the ecosphere), with levels like molecules, organs, populations and landscapes forming competing horizontal network, which are driven by an energy input on the cell, organism, ecosystem and ecosphere level, respectively.A network model study of a landscape consisting of a network of ecosystems that are represented by networks -it means networks within a network -has been applied in these investigations to answer the raised questions. The study has shown that the ecosystem, which is able to use the resources with the highest efficiency in the landscape will win. Based on the obtained results from the model experiments it can be hypothesized that a "kind" of Darwinian selection may take place at all the levels of the hierarchy and that the winner is the one which is able under the prevailing conditions to obtain and exploit? most work energy. There are strong supports in the literature (see for instance Jørgensen, 2012) in the case for individuals and populations in ecosystems (formulated in the so called ELT, that have many observable supports; see Jørgensen, 2012). The model experiments presented here point toward an expansion of the ELT to ecosystems competing in the landscape, but a general expansion to all the hierarchical levels in ecology will require many more model experiments and more concrete observations (case studies).

Eco-exergy and emergy based self-organization of three forest plantations in lower subtropical China

“…biomass and genetic information, but not networks and the consequent emerging properties of ecosystems, which are the essential characteristics of systems, different from a simple combination of some isolated items 64 65 . How to account for eco-exergy in networks, in ecosystems and at multiple levels are some of the inevitable problems that need to be solved for further development of the eco-exergy methodology 66 67 .…”

Returning Home: Movement Strategies of Sub-Andean Birds in a Modified Landscape

“…The individual translocated 144 m (gap distance of 119 m) took three days to return to its source location, whereas the other Streak-capped Treehunter individual, translocated 250 m (gap distance of 172 m), did not return during the tracking period. These results suggest potential reluctance to cross wide inter-habitat gaps, as have been documented in other species in tropical lowland and boreal forests [14,26,27]. Presumably the absence of cover and perches in a pasture matrix may hinder, or at least delay, understory birds' decision to traverse openhabitat matrix [28,29].…”

Use of ecological indicators in models

“…His results show that networks depict wholeness and that they can be used as models for holism for human systems as well as for ecological systems. Jørgensen and Nielsen (2015) argue for stronger consideration of vertical connections in network analyses. They analysed four competing ecosystems as a 'network within a network' in a model landscape.…”