Summary
Measurements of litter fall and litter removal by crabs, in conjunction with estimates of litter decay by microbes and tidal export of litter from three high-intertidal mangrove forests were made during a year-long study in tropical northeastern Australia. In forests dominated by Ceriops tagal and Bruguiera exaristata, litter standing stocks remained low on the forest floor (mean 6 g·m-2), although litter fall was high; 822 and 1022 g·m-2·y-1, respectively. Sesarmid crabs removed 580 (Ceriops) and 803 (Bruguiera) g·m-2·y-1, or 71 and 79%, of the total annual litter fall from the forest floor. Relative to the rate of litter removal by crabs, microbial turnover of whole, unshredded litter was insignificant, accounting for <1% of annual litter fall. Export of litter by tides was estimated to remove 194 (Ceriops) and 252 (Bruguiera) g·m-2·y-1 or 24 and 25% of annual litter fall. In a forest dominated by Avicenniamarina, in which an ocypodid crab was more abundant than sesarmids, litter standing stocks were higher (mean 84 g·m-2) and crabs removed less litter; 173 g·m-2·y-1 or 33% of the annual litter fall of 519 g·m-2·y-1. Microbial turnover of intact litter was more important in the Avicennia forest (168 g·m-2·y-1 or 32% of annual litter fall), and tides exported 107 g·m-2·y-1 or 21% of litter production. In areas where sesarmid crabs were absent or rare in Ceriops forests, there were significantly higher standing stocks of litter and slower rates of leaf removal. Taking into account the probable assimilation efficiencies of sesarmid crabs feeding on mangrove leaves, we estimate that in Ceriops and Bruguiera forests leaf processing by crabs turns litter over at >75 times the rate of microbial decay alone, thus facilitating the high sediment bacterial productivity in these forests. The importance of litter processing by crabs increases with height in the intertidal in tropical Australia, in contrast to New World mangrove forests, where the reverse is true.
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References
Alongi DM (1988) Bacterial productivity and microbial biomass in tropical mangrove sediments. Microb Ecol 15:59–79
Cundell AM, Brown MS, Stanford R, Mitchell R (1979) Microbial degradation of Rhizophora mangle leaves immersed in the sea. Est Coast Mar Sci 9:281–286
Davie PJF (1985) The biogeography of littoral crabs (Crustacea: Decapoda; Brachyura) associated with tidal wetlands in tropical and sub-tropical Australia. In: Bardsley KN, Davie JDS, Woodroffe CD (eds) Coastal and Tidal wetlands of the Australian monsoon region. Australian National University, North Australian Research Unit, Monograph No. 1, pp 79–94
Dowling EM, McDonald TJ (1982) Mangrove communities of Queensland. In: Clough B (ed) Mangrove ecosystems in Australia: structure, function and management. Canberra: Australian National University Press, pp 79–94
Fell JW, Masters IM (1980) The associated and potential role of fungi in mangrove detrital systems. Bot Mar 23:257–263
Flores-Verdugo FJ, Day Jr JW, Briseno-Duenas R (1987) Structure, litterfall, decomposition and detritus dynamics of mangroves in a Mexican coastal lagoon with an ephemeral inlet. Mar Ecol Prog Ser 35:83–90
Giddins RL, Lucas JS, Neilson MJ, Richards GN (1986) Feeding ecology of the mangrove crab Neosarmatium smithi (Crustacea: Decapoda: Sesarminae). Mar Ecol Prog Ser 33:147–155
Heald EJ (1971) The production of organic detritus in a south Florida estuary. Sea Grant Technical Bulletin No. 6. University of Miami Sea Grant Program (Living Resources), Miami, Florida, pp 110
Jones DA (1984) Crabs of the mangal ecosystem. In: Por FD, Dor I (eds) Hydrobiology of the mangal. Dr W Junk Publishers, The Hague, pp 89–110
Leh CMU, Sasekumar A (1985) The food of sesarmid crabs in Malaysian mangrove forests. Malay Nat J 39:135–145
Lugo AE, Snedaker SC (1974) The ecology of mangroves. Ann Rev Ecol Syst 5:39–64
Macnae W (1968) A general account of the fauna and flora of mangrove swamps and forests in the Indo-West-Pacific region. Adv Mar Biol 6:73–270
Malley DF (1978) Degradation of mangrove leaf litter by the tropical sesarmid crab Chiromanthes onychophorum. Mar Biol 49:377–386
Nakasone Y, Limsakul S, Tirsrisook K (1985) Degradation of leaf litter by grapsid crabs and a snail in the mangrove forests of Ao Khung Kraben and Mae Nam Wen, Thailand. In: Mangrove estuarine ecology in Thailand. Thai-Japanese cooperative research project on mangrove productivity and development 1983–84. Jap Ministry of Educ Sci and Culture, pp 21–38
Neilson MJ, Giddins RL, Richards GN (1986) Effects of tannins on the palatability of mangrove leaves to the tropical sesarmid crab Neosarmatium smithi. Mar Ecol Prog Ser 34:185–186
Odum WE (1971) Pathways of energy flow in a south Florida estuary. Sea Grant Technical Bulletin No. 7, University of Miami Sea Grant Program (Living Resources), Miami, Florida, pp 162
Odum WE, Heald EJ (1975) The detritus-based food web of an estuarine mangrove community. In: Cronin LE (ed) Estuarine Research. Academic Press Inc., New York, pp 265–286
Odum WE, McIvor CC, Smith III TJ (1982) The ecology of the mangroves of south Florida: a community profile. US Fish and Wildlife Service, Office of Biological Services, Washington, DC, FWS/OBS-81/24, p 144
Pool DJ, Lugo AE, Snedaker SC (1975) Litter production in mangrove forests of southern Florida and Puerto Rico. In: Walsh G, Snedaker S, Teas H (eds) Proceedings of the International Symposium on the biology and management of mangroves. University of Florida, Gainsville, pp 213–237
Robertson AI (1986) Leaf-burying crabs: their influence on energy flow and export from mixed mangrove forests (Rhizophora spp) in northeastern Australia. J Exp Mar Biol Ecol 102:237–248
Robertson AI (1988) Decomposition of mangrove leaf litter in tropical Australia. J Exp Mar Biol Ecol 116:235–247
Smith III TJ (1987) Seed predation in relation to tree dominance and distribution in mangrove forests. Ecology 68:266–273
Twilley RR (1985) The exchange of organic carbon in basin mangrove forests in a southwest Florida estuary. Est Coast Shelf Sci 20:543–557
Twilley RR, Lugo AE, Patterson-Zucca C (1986) Litter production and turnover in basin mangrove forests in southwest Florida. Ecology 67:670–683
Wells AG (1982) Mangrove vegetation of northern Australia. In: Clough BF (ed) Mangrove ecosystems in Australia: structure, function and management. Canberra, Australian National University Press, pp 57–78
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Contribution No. 445 from the Australian Institute of Marine Science
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Robertson, A.I., Daniel, P.A. The influence of crabs on litter processing in high intertidal mangrove forests in tropical Australia. Oecologia 78, 191–198 (1989). https://doi.org/10.1007/BF00377155
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DOI: https://doi.org/10.1007/BF00377155