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Ecological networks, which are representations of agent interactions via mass-energy flows in an ecosystem, are studied to understand the relation between the structural patterns of these networks (structure being an algebraic object) to the ecological processes that may mediate through these networks. The fundamental aim is to investigate the role of structure of the networks, as captured by some structural indices, in regulating the different ecological processes occurring on these networks.
A network representation of flow of ecological information and landscape connectivity of some anamochory forest species in the Western Himalaya region is established to showcase small-world architecture and a well formed community structure. Forest patches critically important for spread of ecological information across the network are identified using centrality indices and it is inferred that these anamochory floral species are likely to thrive in the Western Himalaya region as a result of the structural properties of the network. Likewise, movement and spread of Lantana camara is modelled in a part of Rajaji Tiger Reserve where important topographical features supportive of dispersion of lantana are identified using structural indices and a rapid spread of lantana in entire study area is inferred as a result of global properties of the associated network. Spectral projections of normalized graph Laplacian of ecological networks representing host-parasite, plant-pollinator and seed-dispersal ecosystems are analysed to identify universal structural patterns in these networks. It is observed that these networks are dissimilar in their structure and the observed difference is quantified using relative frequencies of some subgraphs present in these networks. A similar study conducted on predator-prey networks reveals difference in structure of networks originating from aqueous and terrestrial ecosystems. An interplay between structural patterns and processes in complex ecological systems is thus clearly established. |