NETWORK ANALYSIS OF A BENTHIC FOOD WEB MODEL OF A PARTLY RECLAIMED ISLAND IN THE SUNDARBAN MANGROVE ECOSYSTEM, INDIA

Network analysis is performed on a 14 species food web model of the ecosystem occupying a mudflat on a partly reclaimed island of the Sundarban mangrove ecosystem. The results demonstrate a dramatic difference between this heavily impacted mangrove ecosystem in its modes of primary and secondary production and its diminished role of detritus vis-a-vis its less disturbed counterparts. Unlike most benthic mangrove systems, the Sundarban bottom community receives a large contribution from the phytoplankton populations. In this system herbivory and detritivory are virtually equal, in contrast to the usual herbivory:detritivory ratio of 1:5. Anthropogenic impacts have changed the physiography of this system so as to increase the relative importance of zooplankton and meiobenthos as herbivores. Although a slight degree of omnivory is exhibited by the populations of larger organisms, all flows of each integer of trophic length into a food chain may be aggregated that represents the underlying trophic status of the starting food web. Only a small number of pathways of recycle can be identified (31), and the Finn cycling index for this system is quite low (8.4%). Litterfall comprises only 16% of the total system input, which is very little in comparison with most mangrove systems. Pathway redundancy is rather high in this ecosystem, indicating that the surviving system is probably highly resilient to further perturbations, as one might expect for a highly impacted system.

[1]  A. Ramanathan,et al.  Environmental geochemistry of the Pichavaram mangrove ecosystem (tropical), southeast coast of India , 1999 .

[2]  Aaron M. Ellison,et al.  Anthropogenic Disturbance of Caribbean Mangrove Ecosystems: Past Impacts, Present Trends, and Future Predictions , 1996 .

[3]  R. Ulanowicz,et al.  The Seasonal Dynamics of The Chesapeake Bay Ecosystem , 1989 .

[4]  T. Steinke,et al.  Litter production by mangroves. II. St Lucia and Richards Bay , 1988 .

[5]  Janusz Szyrmer,et al.  Total flows in ecosystems , 1987 .

[6]  T. Steinke,et al.  Litter production by mangroves. I: Mgeni Estuary , 1986 .

[7]  Robert E. Ulanowicz,et al.  Identifying the Structure of Cycling in Ecosystems , 1983 .

[8]  Paul E. Smith.  Ecological Methods with Particular Reference to the Study of Insect Populations , 1979 .

[9]  Robert E. Ulanowicz,et al.  Toward Canonical Trophic Aggregations , 1979, The American Naturalist.

[10]  J. Finn,et al.  Measures of ecosystem structure and function derived from analysis of flows. , 1976, Journal of theoretical biology.

[11]  F. A. Harris,et al.  Radioisotope Technique for Estimating Lady Beetle Consumption of Tobacco Budworm Eggs and Larvae , 1974 .

[12]  B. Hannon,et al.  The structure of ecosystems. , 1973, Journal of theoretical biology.

[13]  J. Lawton.  Feeding and Food Energy Assimilation in Larvae of the Damselfly Pyrrhosoma nymphula (Sulz.) (Odonata: Zygoptera) , 1970 .

[14]  Donald E. Wohlschag.  Differences in Metabolic Rates of Migratory and Resident Freshwater Forms of an Arctic Whitefish , 1957 .

[15]  A. B. Roy,et al.  Effect of time lag on non-living resource in a simple food chain. , 1996, Bio Systems.

[16]  A. B. Roy,et al.  The effect of diffusion on two predators exploiting a resource. , 1993, Bio Systems.

[17]  A. B. Roy,et al.  Permanent coexistence in a resource-based competition system , 1992 .

[18]  A. B. Roy,et al.  Permanence and oscillatory co-existence of a detritus-based prey−predator model , 1991 .

[19]  James J. Kay,et al.  A detailed guide to network analysis , 1989 .

[20]  J. G. Field,et al.  Network analysis of simulated succession after an upwelling event , 1989 .

[21]  Alain F. Vézina,et al.  Derivation and analysis of flow networks for open ocean plankton systems , 1989 .

[22]  P. J. Radford,et al.  Analysis of the flow network in an estuarine benthic community , 1989 .

[23]  R. Ulanowicz,et al.  A Comparative Anatomy of the Baltic Sea and Chesapeake Bay Ecosystems , 1989 .

[24]  M. Asmus,et al.  Network Analysis of the North Inlet Salt Marsh Ecosystem , 1989 .

[25]  S. Ray.  Ecology of littoral larval dipterans arthropoda insecta of the mangrove ecosystem of sundarbans India , 1987 .

[26]  Robert E. Ulanowicz,et al.  Growth and Development , 1987, Springer New York.

[27]  Robert W. Bosserman,et al.  17 – Propagation of Cause in Ecosystems , 1976 .

[28]  R. Wiegert,et al.  Trophic structure, available resources and population density in terrestrial vs. aquatic ecosystems. , 1971, Journal of theoretical biology.

[29]  T. Parsons,et al.  A practical handbook of seawater analysis , 1968 .

[30]  J. Strickland.  Measuring the production of marine phytoplankton , 1960 .

[31]  M. Uschold,et al.  Methods and applications , 1953 .