183

REVIEW ARTICLE

Benthic Animals in Mangrove Swamp: A Review
Keiji WADA
KYOUSEI Science Center for Life and Nature, Nara Women’s University,
Kitauoyahigashimachi, Nara 630-8506, Japane-mail: mbanzai@cc.nara-wu.ac.jp

Abstract
This paper reviews the current knowledge of macrobenthic animals in mangrove swamps, focusing on
their spatial organization and ecological functions. Spatial patterns are described separately for arboreal animals and animals living on the bottom, in dead wood, and in rivulets. Some sesarmid crabs and snails graze onhigher proportions of mangrove litter in various parts of the world. Positive influences of macrobenthic animals on mangrove plants have been identified: sesarmid crabs and fiddler crabs are beneficial to the growth ofmangrove trees, and some fouling and boring animals enhance the growth of mangrove prop roots.
Key words: macrobenthic animals, mangrove swamp, positive interaction, spatial organization

1. Introduction
Mangrove swamps contain diverse marine and terrestrial fauna. Mangrove-associated animals depend on
the environment created by mangrove plants and they, inturn, affect mangrove plants. The faunal composition ofmangrove swamps and their spatial organization havebeen described in various tropical areas (e.g., Berry,
1963; Macnae, 1966; Day, 1974; Sasekumar, 1974; Frithet al., 1976; Shokita et al., 1989). The intimate interrelationships between animals and mangrove plants haverecently been unraveled (e.g., Perry, 1988; Ellison et al.,
1996; Lee, 1998; Cannicci et al., 2008; Kristensen, 2008;
Smith et al., 2009; Chen & Ye, 2010). Knowledge about
the faunal composition of mangrove swamps and relationships among mangrove plants and associated fauna
are important for understanding the ecological structureof mangrove ecosystems.
This paper reviews two aspects of benthic animals
that occur in mangrove swamps: faunal composition andtheir spatial organization, and the ecological roles ofbenthic animals.

1992; Boneka, 1994). The bark of lower stems and aerialroots is inhabited by several gastropod species, such as
Nerita spp. and the pulmonates Cassidula mustelina andMelampus coffeus (Berry, 1963; Proffitt & Devin, 2005).
Typical arboreal crabs include the sesarmids Aratus
pisonii, Armases elegans, and Parasesarma leptosoma,
all of which spend their entire adult life on trees. Aratus
pisonii, a Caribbean species, moves up to six meters
above the ground to feed on mangrove leaves and buds
(Hagen, 1977: Beever III et al., 1979). Parasesarma
leptosoma occurs in East African mangrove forests andshows vertical migrations from the lower part of the mangrove aerial root to the canopy of the tree (ca 12-13 mheight) to forage on leaves (Vannini & Ruwa, 1994). This
species has recently been found to forage on mangrove
flowers on Iriomote Island, Japan (Takaso, unpublished).
Parasesarma leptosoma also shows conspicuous tree
fidelity: crabs that were moved to trees seven meters
away returned to the original tree within a few days
(Cannicci et al., 1996).

2. Benthic Animals and Spatial Organization
The spatial organization of benthic animals can be
described according to distinct habitat types. Arboreal
animals are found on leaves, stems and aerial roots ofmangrove trees. Littorinid snails live on leaves or stems
in the supratidal to uppermost intertidal zones. Their
vertical zonation in Japan and Indonesia has been described as Littoraria pallescens on leaves in the uppermost zone (Fig. 1), L. scabra on stems in the middle level,and L. intermedia on stems in the lower level (Ohgaki,
Global Environmental Research
17/2013: 183-188
printed in Japan

Fig. 1 An arboreal snail, Littoraria pallenscens.
©2013 AIRIES184

K. WADA

Mangrove roots, trunks, branches, and leaves bearrich sessile animals, including sponges, hydroids,
anemones, polychaetes, bivalves, barnacles and ascidians.
The most conspicuous are barnacles (Balanus spp.),which foul trunks, aerial roots, and leaves (Fig. 2).
Zonation in sessile animals on red mangrove prop
roots was described by Rützler (1995); the mangrove
oyster Isognomon alatus occupied the uppermost part,followed by the sponges Haliclona implexiformis andLissodendoryx isodictyalis, and the lower area was occupied by the sponge Scopalina ruetzleri.
Macrofauna that live underground in mangrove forests show vertical zonation. The dominant animals are
crustaceans, mollusks and polychaetes. Shaded areas
under the mangrove canopy are inhabited by various
decapod crustaceans. The most conspicuous is the mud
shrimp Thalassina anomala (Fig. 3), which constructs
large mounds and burrows that are 2.5 m deep (Sankolli,1963). The mounds created by this species harbor manyother benthic animals, such as sesarmid crabs. Sesarmid
crabs are generally decomposers of mangrove litter andare most common in forested areas. Benthic animals inforested areas are difficult to sample quantitatively because of the underground root systems. However, Wadaet al. (1987) investigated the depth distributions of burrowing animals to a depth of one meter in a natural man-

Fig. 2 Barnacles encrusting a mangrove trunk.

Fig. 3 The mud shrimp Thalassina anomala in a mangrove
forest.

grove forest (tree height: ca. 30 m) in southern Thailand.
Most species, including polychaetes (Leonnantes
sp., Glycera sp. and Dasybranchus sp.) and sesarmid
crabs (Chiromanthes haswelli, Sarmatium germaini,
Neosarmatium smithi (Fig. 4) and Clistocoeloma
merguiense), occurred above 60 cm depth and only two
crustaceans, Alpheus euphrosyne (Fig. 5) and Callianasa
ranongensis, were found from the shallow layer to thebottom layer (1 m depth).
Nakasone (1977) described the vertical zonation ofbrachyuran crabs in a mangrove swamp in Okinawa,
Japan. The uppermost supratidal area was occupied byland crabs such as Cardisoma carnifex and was termed
the cardisomine zone. This was followed by the upperintertidal area under mangrove stands, which was occupied by sesarmid crabs (the sesarmine zone). The middle
intertidal area of open flats was occupied by fiddler crabs
such as Uca perplexa (Fig. 6; the ocypodine zone).
This was followed by the lower intertidal area, which
was occupied by macrophthalmid crabs such as
Macrophthalmus convexus (Fig. 7; the macrophthalminezone); a mixed zone; and the lowermost subtidal area,
where the portunid crab of Scylla spp. occurred (theScylla zone).
The zonation of mollusks in mangrove forests has a
Littorina zone, represented by Littorina scabra and L.
melanostoma, on the upper parts of trees; a Nerita zone,
represented by Nerita birmanica and N. planospira, on
the lower parts of trees and on the mud surface; and a

Fig. 4 The sesarmid crab Neosarmatium smithi in amangrove forest.

Fig. 5 The pistol shrimp Alpheus euphrosyne in a mangrove
forest.

Benthic Animals in Mangrove Swamp: A Review

Fig. 6 The fiddler crab Uca perplexa near a mangrove forest.

Fig. 8185

Dead wood in a mangrove swamp.

Fig. 7 Macrophthalmus convexus on an open flat around amangrove forest.

bivalve zone, represented by Enigmonia rosea andTrapezium sublaevigatum, on the mud surface of theseaward fringe of forested areas (Berry, 1963).
Dead wood (Fig. 8) has characteristic fauna that liveon the wood surface, such as gastropods and barnacles,
and inside the wood, including boring animals such as thebivalve Teredo and sphaeromatid isopods. Interstices inrotten wood are inhabited by the gastropod Ellobium(Fig. 9), grapsoid crabs, sea anemones, and sipunculids.
However, dead wood fauna in mangrove swamps have
not yet been studied quantitatively.
Rivulets bear fauna that differ from other habitats inmangrove swamps. They include both a variety of fishlarvae and mudskippers. In mangrove swamps in the
Ryukyu Islands, rivulet bottoms are inhabited bybrachyuran crabs of Scylla and Deiratonotus cristatus(Fig. 10), and shrimps of Palaemon and Penaeus.
Benthic animals in mangrove channel areas have not yet
been surveyed quantitatively.

3. Mangrove Litter Decomposers
Stable isotope analysis suggests that fiddler crabs andbivalves consume algae, and grapsoid crabs and gastropods eat a variety of food items, from algae to mangrove
plants (Rodelli et al., 1984). Grapsoid crabs and somegastropod species function as decomposers of mangrove
litter. The most well-known are sesarmid crabs, which
graze on litter or bury litter in their burrows for later

Fig. 9 A pulmonate gastropod, Ellobium sp., in dead wood in amangrove swamp.

Fig. 10 Deiratonotus cristatus in a rivulet of a mangrove swamp.

feeding. These species include Sesarma plicata in China(Chen & Ye, 2008); Perisesarma eumolpe and P.
onychophorum in Peninsular Malaysia (Malley, 1978;
Ashton, 2002); Sesarma messa, Sesarma erythrodactyla,
and Neosarmatium smithi in Australia (Giddins et al.,
1986; Robertson, 1986; Camilleri, 1989; Micheli, 1993);
and Sesarma guttatum, Sesarma ortmanni, andNeosarmatium meineriti in East Africa (Emmerson &McGwynne, 1992; Dahdouh-Guebas et al., 1999). In
Brazil, litter consumption is led by the ocypodoid crab
Ucides cordatus (Nordhaus et al., 2006; Nordhaus &Wolff, 2007). It is estimated that this species eats

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K. WADA

Fig. 11 The potamidid snail Terebralia palustris grazing on
mangrove leaves.

approximately 81% of total litter fall from mangroves(Nordhaus et al., 2006). In Australia, the sesarmid crab
Sesarma messa can remove 28% of the annual litter fallof Rhizophora stylosa (Robertson, 1986). In southern
Africa, Sesarma meinerti is estimated to consume 44%of leaf litter from Avicennia marina (Emmerson &McGwynne, 1992).
Some gastropod species are also responsible for the
degradation of mangrove litter. The potamidid snail
Terebralia palustris (Fig. 11) is a grazer of mangrove leaf
litter in Japan (Nishihira, 1983) and Kenya (Slim et al.,
1997; Fratini et al., 2004). Mangrove leaves on the substrate surface are grazed on by aggregations of large
snails of this species (Nishihira, 1983), but juvenile snails
do not graze on leaves (Slim et al., 1997). In Africanmangroves, it is estimated that 11.2% and 18.6% oflitter is processed by macrobenthic animals, including
Terebralia palustris, in Ceriops tagal and Rhizophoramucronata vegetation, respectively (Slim et al., 1997). In
Florida, USA, the pulmonate gastropod Melampus
coffeus consumes 40.5% of the litter from Rhizophora
mangle and Avicennia germinans (Proffitt & Devlin,
2005). Recently, cellulase activity has been found in the
potamidid snail Terebralia palustris (Niiyama &Toyohara, 2011) as well as some sesarmid crabs (Adachi
et al., 2012), which indicates that the ability to digest
cellulose using enzymes is responsible for the breakdownof mangrove litter by these animals.

4. Positive Influences of Macrofauna on
MangrovesFiddler crabs in salt marshes have beneficial effects
on marsh plants (Bertness, 1985); similarly, sesarmid
crabs have a positive influence on mangroves. Smith III
et al. (1991) was the first to demonstrate such positiveeffects of burrowing crabs (mainly Sesarma messa and S.
temperi) through field manipulation experiments inRhizophora-dominated forests in Australia. They foundthat when crabs were removed by pitfall traps over a
twelve-month period, there was a significant reduction in
cumulative forest growth (measured as the stipule fallrate) and increased soil sulfide and ammonium concentrations. Similar experiments were conducted in a Florida

Fig. 12 A propagule inserted into a crab burrow.

Fig. 13 The grapsoid crab Pseudohelice subquadrata, which iscommon in mangrove swamps in southern Japan.

mangrove swamp by Wada and Hines (unpublished), in
which the removal of fiddler crabs (Uca pugilator and U.
rapax) via pit traps caused a significant decrease inmangrove (Avicennia germinans) survivorship after two
years. Smith et al. (2009) also examined the effect offiddler crab presence on the mangrove Laguncularia
racemosa in a Florida mangrove swamp. They found thatthe removal of fiddler crabs over a one-year periodcaused significant decreases in mangrove growth and leaf
production, together with increases in interstitial watersalinity and the oxidation-reduction potential of loworganic sediments. Predation on mangrove propagules
can cause damage that hinders mangrove regeneration. In
Australia, seed predation by grapsoid crabs affects ca.
75% of the seeds on the bottom surface (Smith III, 1987).
However, some propagules are found inserted into crab
burrows, with some parts grazed (Fig. 12). On AmamiOshima Island, a similar phenomenon has been observedin burrows of the grapsoid crab Pseudohelice subquadrata (Fig. 13). It is likely that by carrying
propagules into burrows, these crabs enhance the regeneration of mangrove plants.
The boring isopod Sphaeroma peruvianum and theencrusting barnacle Balanus spp., which are closely
associated with prop roots of the mangrove Rhizophora
mangle, cause 50% and 30% reductions in the root
growth rate, respectively (Perry, 1988). However, theseeffects are indirectly mediated by predation by the snails
Thais kiosquiformis and Morula lugubris and the hermit

Benthic Animals in Mangrove Swamp: A Review

Fig. 14 The fiddler crab Uca vocans foraging on a mangrove
prop root.

crab Clibanarius panamensis (Perry, 1988). On the other
hand, the boring isopod can be beneficial to mangroves.
Damage to prop roots by this boring animal causes
branching, so that the number of roots that actually reachthe soil surface increases, helping to stabilize the mangrove tree (Simberloff et al., 1978).
Mangrove roots host a range of epibionts, such as
macroalgae, barnacles, mollusks, sponges, tunicates,
serpulid annelid worms, hydroids, and bryozoans. Encrustations of these organisms can reduce root growth.
For example, encrustation by the barnacle Balanus candecrease root production by 52% by blocking lenticels
and reducing gas exchange and respiration (Perry, 1988).
In contrast, epibionts can benefit mangrove roots in somecases. Ellison and Farnsworth (1990, 1992) found that
epifaunal sponges and ascidians reduced damage to theroots of Rhizophora mangle by wood-boring isopods.
Foraging by some ocypodoid crabs on prop roots(Fig. 14) can be beneficial for mangroves because theactivity removes algae and mud covering the root
surfaces (Wada & Wowor, 1989).
Symbiotic nutrient exchange occurs between mangrove roots (Rhizophora mangle) and fouling sponges(Tedania ignis and Haliclona implexiformis) (Ellison
et al., 1996). A transplant experiment that moved sponges
to bare roots found significant increases in root growth.
Furthermore, the transplanted sponges grew 1.4 to 10
times faster than control sponges that were attached to
PVC pipes in the same habitat. That study also provided
evidence that mangrove roots obtain inorganic nitrogenfrom sponges and that sponges obtain carbon frommangrove roots.

5. Concluding Remarks
Due to the diversified environmental conditions created by mangrove plants, the diversity and spatialorganization of macrobenthos are yet to be fully described. For example, few quantitative studies have described the zonation of macrobenthos because it is difficult to dig into substrates containing mangrove root systems. The spatial organization of organisms living in
unique habitats, such as dead wood and rivulets, has not187

yet been studied. The faunal diversity and spatialorganization of such habitats represent significant gaps
in our understanding of the structure of mangrove ecosystems.
Macrobenthos are important functional components
in mangrove swamps through their feeding or burrowing
activities. Litter grazing by grapsoid crabs and snails canenhance nutrient processing and contribute to ecosystem
function. Burrowing activities by crabs can also bebeneficial for mangrove plants. Such positive interactions demonstrate the importance of these animals formaintaining mangrove ecosystems. This knowledge is ofprime importance for the conservation and restoration ofmangrove ecosystems, which are being degraded and lostworldwide.

Acknowledgements
I am grateful to two anonymous reviewers for theirvaluable comments for improving the manuscript.
References
Adachi, K., K. Toriyama, T. Azekura, K. Morioka, P. Tongnunui
and K. Ikejima (2012) Potent cellulase activity in thehepatopancreas of mangrove crabs. Fisheries Science, 78:
1309-1314.
Ashton, E.C. (2002) Mangrove sesarmid crab feeding experiments
in Peninsular Malaysia. Journal of Experimental Marine Biology and Ecology, 273: 97-119.
Beever III, J.W., D. Simberloff and L.L. King (1979) Herbivory
and predation by the mangrove tree crab Aratus pisonii.
Oecologia, 43: 317-328.
Berry, A.J. (1963) Faunal zonation in mangrove swamps. Bulletinof the National Museum, St. Singapore, 32: 90-98.
Bertness, M.D. (1985) Fiddler crab regulation of Sparina
alterniflora production on a New England salt marsh. Ecology,
66: 1042-1055.
Boneka, F.B. (1994) Coexistence of Littoraria scabra andLittoraria pallescens (Gastropoda: Littorinidae) in northern
Sulawesi, Indonesia. Phuket Marine Biological Center, Special
Publication, No. 13: 147-151.
Camilleri, J. (1989) Leaf choice by crustaceans in a mangrove
forest in Queensland. Marine Biology, 102: 453-459.
Cannicci, S., D. Burrows, S. Fratini, T.J. Smith III, J. Offenberg
and F. Dahdouh-Guebas (2008) Faunal impact on vegetation
structure and ecosystem function in mangrove forests: A review.
Aquatic Botany, 89: 186-200.
Cannicci, S., S. Ritossa, R.K. Ruwa and M. Vannini (1996) Treefidelity and hole fidelity in the tree crab Sesarma leptosoma(Decapoda, Grapsidae). Journal of Experimental Marine Biology and Ecology, 196: 299-311.
Chen, G.C. and Y. Ye (2008) Leaf consumption by Sesarma plicata
in a mangrove forest at Jiulongjiang Estuary, China. Marine
Biology, 154: 997-1007.
Chen, G.C. and Y. Ye (2010) Changes in properties of mangrove
sediment due to foraging on Kandelia obovata leaves by crabs
Parasesarma plicatum (Grapsidae: Sesarminae). Marine Ecology Progress Series, 419: 137-145.
Dahdouh-Guebas, F., M. Giuggioli, A. Oluoch, M. Vannini and S.
Cannicci (1999) Feeding habits of non-ocypodid crabs from two
mangrove forests in Kenya. Bulletin of Marine Science, 64:
291-297.
Day, J.H. (1974) The ecology of Morrumbene estuary,

188

K. WADA

Moçambique. Transactions of the Royal Society of South Africa,
41: 43-97.
Ellison, A.M. and E.J. Farnsworth (1990) The ecology of Belizean
mangrove root-fouling communities: I. Epibenthic fauna arebarriers to isopod attack of red mangrove root. Journal of
Experimental Marine Biology and Ecology, 142: 91-104.
Ellison, A.M. and E.J. Farnsworth (1992) The ecology of Belizean
mangrove root-fouling communities: patterns of epibiont
distribution and abundance and effects on root growth.
Hydrobiologia, 247: 87–98.
Ellison, A.M., E.J. Farnsworth and R.R. Twiley (1996) Mutualism
between red mangrove and root-fouling sponges in Belizean
mangal. Ecology, 77: 2431-2444.
Emmerson, W.D. and L.E. McGwynne (1992) Feeding andassimilation of mangrove leaves by the crab Sesarma meinertide Man in relation to leaf-litter production in Mgazana, a
warm-temperate southern African mangrove swamp. Journal of
Experimental Marine Biology and Ecology, 157: 41-53.
Fratini, S., V. Vigiani, M. Vannini and S. Cannicci (2004)
Terebralia palustris (Gastropoda; Potamididae) in a Kenyan
mangal: size structure, distribution and impact on the consumption of leaf litter. Marine Biology, 144: 1173-1182.
Frith, D.W., R. Tantanasiriwong and O. Bhatia (1976) Zonation ofmacrofauna on a mangrove shore, Phuket Island. Phuket Marine
Biological Center, Research Bulletin, 10: 1-37.
Giddins, R.L., J.S. Lucas, M.J. Neilson and G.N. Richards (1986)
Feeding ecology of the mangrove crab Neosarmatium smithi(Crustacea: Decapoda: Sesarmidae). Marine Ecology Progress
Series, 33: 147-155.
Kristensen, E. (2008) Mangrove crabs as ecosystem engineers;emphasis on sediment processes. Journal of Sea Research, 59:
30-43.
Lee, S.Y. (1998) Ecological role of grapsid crabs in mangrove
ecosystems; a review. Marine and Freshwater Research, 49:
335-343.
Macnae, W. (1966) Mangroves in eastern and southern Australia.
Australian Journal of Botany, 14: 67-104.
Malley, D.F. (1978) Degradation of mangrove leaf litter by thetropical sesarmid crab Chiromanthes onychophorum. Marine
Biology, 49: 377-386.
Micheli, F. (1993) Feeding ecology of mangrove crabs in North
Eastern Australia: mangrove litter consumption by Sesarma
messa and Sesarma smithii. Journal of Experimental Marine
Biology and Ecology, 171: 165-186.
Nakasone, Y. (1977) Crab zonation in the Yuhi River, Okinawa
Island. Japanese Journal of Ecology, 27: 61-70.
Niiyama, T. and H. Toyohara (2011) Widespread distribution ofcellulase and hemicellulase activities among aquatic invertebrates. Fisheries Science, 77: 649-655.
Nishihira, M. (1983) Grazing of the mangrove litters by Terebralia
palustris (Gastropoda: Potamididae) in the Okinawan mangal:
preliminary report. Galaxea, 2: 45-58.
Nordhaus, I. and M. Wolff (2007) Feeding ecology of the mangrove crab Ucides cordatus (Ocypodidae): food choice, foodquality and assimilation efficiency. Marine Biology, 151:
1665-1681.
Nordhaus, I., M. Wolff and K. Diele (2006) Litter processing andpopulation food intake of the mangrove crab Ucides cordatus ina high intertidal forest in northern Brazil. Estuarine, Coastal and
Shelf Science, 67: 239-250.
Ohgaki, S. (1992) Distribution and movement of the mangrove
Littoraria (Gastropoda) on Ishigaki Island, Okinawa. Venus, 51:
269-278.
Perry, D.M. (1988) Effects of associated fauna on growth andproductivity in the red mangrove. Ecology, 69: 1064-1075.
Proffitt, C.E. and D.J. Devlin (2005) Grazing by the interidal
gastropod Melampus coffeus greatly increases mangrove leaf
litter degradation rates. Marine Ecology Progress Series, 296:
209-218.

Robertson, A.I. (1986) Leaf-burying crabs: their influence onenergy flow and export from mixed mangrove forests(Rhizophora spp.) in northeastern Australia. Journal of Experimental Marine Biology and Ecology, 102: 237-248.
Rodelli, M.R., J.N. Gearing, P.J. Gearing, N. Marshall and A.
Sasekumar (1984) Stable isotope ratio as a tracer of mangrove
carbon in Malaysian ecosystem. Oecologia, 61: 326-333.
Rützler, K. (1995) Low-tide exposure of sponges in a Caribbean
mangrove community. Marine Ecology, 16: 165-179.
Sankolli, K.N. (1963) On the occurrence of Thalassina anomala(Herbst), a burrowing crustacean in Bombay waters, and its
burrowing methods. Journal of Bombay Natural History Society,60: 598-605.
Sasekumar, A. (1974) Distribution of macrofauna on a Malayan
mangrove shore. Journal of Animal Ecology, 43: 51-69.
Shokita, S., J. Sanguansin, S. Nishijima, S. Soemodihardjo, A.
Abdullah, M.H. He, R. Kasinathan and K. Okamoto (1989)
Distribution and abundance of benthic macrofauna in theFunaura mangal of Iriomote Island, the Ryukyus. Galaxea, 8:17-30.
Simberloff, D., B.J. Brown and S. Lowrie (1978) Isopod and insect
borers may benefit Florida mangroves. Science, 201: 630-632.
Slim, F.J., M.A. Hemminga, C. Ochieng, N.T. Jannink, E. Cocheretde la Moriniere and G. van der Velde (1997) Leaf litter removalby the snail Terebralia palustris (Linnaeus) and sesarmid crabs
in an East African mangrove forest (Gazi Bay, Kenya). Journalof Experimental Marine Biology and Ecology, 215: 35–48.
Smith, N.F., C. Wilcox and J.M. Lessmann (2009) Fiddler crab
burrowing affects growth and production of the white mangrove(Laguncularia racemosa) in a restored Florida coastal marsh.
Marine Biology, 156: 2255-2266.
Smith, T.J., III. (1987) Seed predation in relation to tree dominanceand distribution in mangrove forests. Ecology, 68: 266-273.
Smith, T.J., III, K.G. Boto, S.D. Frusher and R.L. Giddins (1991)
Keystone species and mangrove forest dynamics: the influenceof burrowing by crabs on soil nutrient status and forest
productivity. Estuarine, Coastal and Shelf Science, 33: 419-432.
Vannini, M. and R.K. Ruwa (1994) Vertical migration in the treecrab Sesarma leptosoma (Decapoda, Grapsidae). Marine Biology, 118: 271-278.
von Hagen, H.O. (1977) The tree-climbing crabs in Trinidad.
Studies on the Fauna of Curaçao and other Caribbean Islands,
54: 25-59.
Wada, K., A. Komiyama and K. Ogino (1987) Underground vertical distributions of macrofauna and root in a mangrove forest ofsouthern Thailand. Publications of the Seto Marine Biological
Laboratory, 32: 329-333.
Wada, K. and D. Wowor (1989) Foraging on mangrove pneumatophore by ocypodid crabs. Journal of Experimental Marine
Biology and Ecology, 134: 89-100.

Keiji WADA
Keiji WADA is Director of the KYOUSEIScience Center for Life and Nature at Nara
Women’s University. He is interested inbiodiversity of coastal environments including
mangrove swamps, with a focus on behavior,ecology and taxonomy of intertidal crabs. His
main published books are Threatened Animals ofJapanese Tidal Flats: Red Data Book of Seashore Benthos (Tokai
University Press), Ecology of Marine Benthos (Tokai University Press),
Natural History of Tidal Flats (Kyoto University Press), and Guide to
Seashore Animals of Japan, with Color Pictures and Keys, Vol. II(Hoikusha Publishing).

(Received 26 November 2012, Accepted 19 June 2013)