Mangroves plants are salt tolerant plants of tropical and subtropical intertidal regions of the world. These highly adapted plants have many peculiar features than their terrestrial and aquatic counterparts. The word ‘mangrove’ can also be used to describe the habitat as well as the plants. Mangroves are distributed in the tropical countries of the world. The mangrove ecosystem covers only 0,037 per cent of the world's surface or 0.12 per cent of the Earth’s land are

Asokan, P K

Kaladharan, P

CMFRI Digital Repository

MANGROVES OF KERALAp. K a ladharan and P.K. A sokanCahcut Research Centre  o f  CMFRI.. W es t H i l l  PO, Kozh ikode-673005Mangroves plants are salt tolerant plants of tropical and subtropical intertidal regions of the world. These highly adapted plants have many peculiar features than their terrestrial and aquatic counterparts. The word ‘mangrove’ can also be used to describe the habitat as well as the plants. Mangroves are distributed in the tropical countries of the world. The mangrove ecosystem covers only 0,037 per cent of the world's surface or 0.12 per cent of the Earth’s land area.Mangroves in India account for about 5 pe rcen t o f the world ’s mangrove vegetation and are spread over an area o f about 4,500 km 2 along the coastal States/UTs of the country.Sunderbans in West Bengal accounts for a little less than half o f the total area under mangroves in India.In Kerala, only Kannur district has good natural patches. There were approximately 755 hectare of mangrove forest in K annur However, it has now become reduced to 17 km I  Forest Survey of India (FSI, 2003) furti'ier showed that mangrove vegetation in Kerala is now restncted largely to river mouths and tidal creeks and that there has been no significant mangrove cover to the south of Cochin,TABLE 1 List o f Mangrove vegetation found in KeralaS.No Family G en u s S p e c ie s Loca l name1 Myrsinaceae A e g ice ro s co rn icu la tum pookanda l2 Acanthaceae A v icenn ia offic inalis uppottiAcanthaceae A v icenn ia m anna cheruuppoUi4 Acanthaceae A c a n th u s ilicifolius chuil ikanda l5 Rhizophoraceae Rhizophora apicu la ta K aya ka n d a l/6va ll ikanda lRhizophoraceae R hizophora m ucrona ta P eekanda l7 Rhizophoraceae Kandelia cande l Cherul<andal/8 Goodeniaceae Scaevo la (accadaeziiuthar^ikanda!9 Lythraceae Sonnera tia alba nakshalrakandal'in Lythraceae Sonnerat/a caseo lar is chakarakanda l11 Rhizophoraceae C eriops tagal Manja kanda!V Euphorbiaceae E x co e ca r ia agallocha kannam pott i13 Rhizophoraceae Brugu iera gym norh iza kuttikandal14 Rhizophoraceae Brugu iera Cylindrica kuttikandal15 Combretaceae Lum n ilze ra racem osaAssociates1 Fabaceae D err is thfollata ponnum va lly2 Fabaceae D err is scandens poon jam va llyPteridophyteVerbenaceaeA c h ro s t ic h u m aureum machintholu4 C le rodend rum innerm e puzhamullafS Acanthaceae C erebra odollum odalanga6 Rubicaceae M orinda citrifloliumcherumanjanathi7 Anonaceae A nona glabraA liga to r  apple, kadalatha8 Barringtoniaceae Barhngton ia racem osasamudrachampa1. A eg /c e ro s  corniculatumCommon name Vernacular names HabitDistributionLeavesFlowersFruitsF a m ily : WlyrsinaceaeBlack m angrove, River mangrove or Khalsi P o o ka n d a l  (Malayalam)Shrubs to small trees, branches horizontally spreading, bark smooth, no aerial roots, stipules absent,Palakode, Kunjim angalam, Kumbala estuaries glabrous both sides Pentam erous, red coloured Curved shape, red colouredCommon name Vernacular names HabitDistributionLeavesFlowersFruitsIndian mangrove. Grey mangrove C/ppofJ/(IVIalayalam)L a rg e  tre e s , 2 0 -  30  m h e ig h t, p e n c il like pneumatophores, Bark is smooth, slightly fissured and does not flake, found sporadically on the banks of rivers and rarely found near the sea. It prefers clay soil and usually found inland.Occur in all major estuaries in KeralaElliptic, oblong, dorsal side green and ventral side pale green, apex rounded , g row  in oppositeLargest among the A v icenn ia  species (diameter of 6 to 10 mm after anthesis). Petals - orange yellow to lemon yellow in colour, Zygomorphic,Sessile, Cymes, Tetramerous: Heart shaped, flattened, testa shiny and pubescent3. Avicennia marinaCommon name Vernacular names HabitF am ily : Verbenaceae/ Av icenna iaceaeGrey mangrove, white mangrove C heruuppott i (Malayalam)Shrubs, less than 5 m height, pencil like pneumatop­hores, Bark is whitish to greyish or yellow-green in colour, smooth, often powdery and scaly. The grey mangroveDistributionLeavesFlowersFruitsI  Acanthus ilicifoliusCommon name Vernacular names HabitDistributionLeavesFlowerscan experience stunted growth in water conditions that are too saline, but thrive to their full height in waters where  both salt and fresh water are present. The species can to lerate high salinity by excreting salts th rough  its leavesS e a w a rd  a re a s ,  Kun jim angalamo f T h a la s e r ry ,  K a n n u r  andThick, Elliptic, yellow ish-green and hairless above and s ilver-grey below  with pointed tip. Underside of the leaf has specia l g lands fo r secreting excess salt.F lowers are small. 0.3 to 0.5 cm across, sessile, fragrant, pa le -ye llow  in co lou r Zygom orph ic , Sessile, Cymes. Tetramerous, Peta ls orange/ yellowFru it is hea rtshaped , rounded o r som etim es shortly beaked; outer skin is greyish with fine hairsand inside is radiant g reen o r russet brownF a m ily : A can tha ce aeHolly-leaved acanthus. Sea Holly or Holy Mangrove C h u ll ikan  da/ (M a I ay a I a m )Shrubs, occurs in w a te r fro n t areasO ccur in all m a jo r estuaries in KeralaLarge, spiny m arg ins and tip, deccusate phyllotaxiTerm ina l in flo rescence  , Spikes, Light blue to violet f lowers, w ith tw o  persistant bractioles, Zygomorphic, Sym peta lousCommon name Vernacular names HabitDistributionLeavesFlowersFruitsOrange mangrove Kutt ikanda l  (Malayalam)Tall tree, spreading, Trunk and branches are marked with leaf and stipule scars. Aerial roots are short or shallow buttress like, Trunk base is thick and robust, Bark is pale grey or brown, thick, hard and rough Pneumatophores knee shapedPuthuvypu, KumbalanzhiElliptic, oblong acute apex, coriaceous, margin entire, more than 12 cm long , tip acute, opposite arrangement, leathery, dark green coloured with 2-5 cm long petiolesSolitary, axillary, cam panulate large. Calyx- claw like tip acute, deep red to scarlet coloured. Petals -Orange brown coloured, tip acute with tassels (appendages)Hypocotyl cigar shaped, 15 to 25 cm in length, 1.5 to 2 cm in diameter, stocky with blunt narrowed apex and calyx persistent.B. Bruguiera cylindricaCommon name Vernacular names HabitFam ily : R h izo ph o race a eOrange mangrove ku tt ikanda l (Malayalam)A  small, erect, evergreen tree 6 to 10 m tall with knee­like above-ground breathing roots. Bark smooth, greyDistributionLeavesFlowersFruitswith few  ienticells, or shallow buttress like aerial roots, T runk base is thick .robust and scaly at the bottomValapatanam, Puthuvypu & KumbalanzhiSimple, Oblong, lanceolate rarely elliptic, tip acute, bluntly pointedInflorescence is three-flowered cyme. White in colour. Calyx- greenish, Sepals eight lobed, greenish yellow coloured, stout, upto 5 mm pers is ten tto  fruit forming cap like structure above the propogules,Petals-3-4 m m  longupto 1.5 cm , conical. Hypocotyl - calyx persistent, spindle shaped, 10 to 15 cm long, 0.5 to 1 cm in d iam e te r.DistributionLeaves7. Ceriops tagalCommon nameVernacular names HabitF a m ily : R h izo p h o ra ce a eYellow  m angrove, spurred mangrove or Tagal MangroveM an ja  k a n d a !  (Maiayalam)Evergreen small to moderate tree. Canopy conical Aerial roots- shallow  buttress and form flange like plank roots at the base o f the  trunk. Bark is pale grey to reddish brown in co lo u r smooth in young trees, deeply fissured in old ones and flaky at the bottom.Valapatnam, KunjimangalamSimple opposite, size smaller than Bruguiera , Obvate to oblong A pex rounded , glabrous, blades dark green in shade, shiny, bright greenish yellow in full sun, upsidedown egg-shaped.FlowersFruitsVery small, in axillary cyme, Calyx 5 lobed, persistent but dried, less prominenet, Petals white, shorterthan sepals, five petals, white in colour turns brown soon.Slightly conical 1 .5-2.0  cm long, pointed apex, hypocotyl ridged calyx persistent, but dried. Outer surface of the propagules are warty and ridged.Uses The trunk is used fo r house building. One of the best firewood sources and the bark is excellent for tanning. The fruit is som etim es eaten.8. Excoecaria agaUochaCommon nameVernacular names HabitDistribution LeavesFlowersFam ily: E u p h o rb iaceaeMilky mangrove, B lind-your-eye mangrove or River poison treeK annam po tty  (Malayalam)Medium sized tree up to 15 m height, partialiy deciduous. Latex poisonous. Bark grey, No aerial roots, sexes seperateCosmopolitan, A lm ost in all the estuariesSimple, Spirally arranged or opposite, pointed apex, Petiole - I to  2 cm iong,Unisexual flowers, in axillary inflorescence, raceme, trilocular ovary, Male and fem ale flowers are present onFruitsMale plant9. Kandelia candalCommon name Vernacular names HabitDistributionLeavesFlowersFruitsseparate trees and inflorescence is spike. Male spike is catkin like in appearance, yellowish and up to 7 cm long. Fem ale spike is shorter than male spike. Flowers are tiny, about 0.2 to 0.3 cm across,Trilobed, Shizocarpic, 1.5 - 2 cm diamFemale plant F a m ily :  R h izopho raceaeNarrow leaved kandalCherukanda l/ Ezhuthani kandal (Malayalam)Small to m ed ium  tree, upto 7 m height, bark smooth greenish o r reddish brown , w ithout any aerial or stilt roots, no pneum atophoresChettuva, Ponnani, Kadalundi, Valapatnam, Payyoli, Kun jim angalam  and Kumbala estuaries.Opposite, oblong, apex obtuse, dark green and glabrousdorsal sideW hite, 1,5 to 2 cm long, axillary cyme pentamerous, P eta ls -b if id , S tam ens-num erous1.5 to 2.5 cm long, hypocotyl s lender and pointed10. Lumnitzera racem osa Fam ily : C om bre taceaeCommon name Vernacular names HabitBlack m angrove  / W hite^flowered Black Mangrove (Malayalam)Grows on the terrestrial edge of the mangroves as a shrub m ore com m only  than as a tree. Above-ground b r e a t h r g  ro o ts  a re  no rm a lly  abse rlt but m mo,St environm ents, small looping lateral roots may develop.DistributionLeavesFlowersFruitsBark is grey in co lour and fissured longitudinally in older trees.Valapatnam, Kunjim angalam  estuaries.Succulent and small (up to 4cm length, 2cm w/idth). The shape is obovate (broadest above the middle of the leaf), the apex is rounded or emarginated (the indent in the tip of the leaf). Petiole is often absent (leaves are thus often sessile). An obvious characteristic is the serrated edge o f the leaf.Flowers are small and erect with green-coloured tube­like calyx, which is divided into five lobes at the tip. Petals are five, white in co lour and arranged alternate to sepals. Stamens are ten in number, free, arranged in two whorls, five stamens at the base of the petal and remaining five at the base of the lobes of the calyx.Fruit is fleshy and fla ttened while on the tree, but fibrous after floating in water. There is no vivipary or cryptovivipary. Fruit is vase- shaped11. Rhizophora mucronata F a m ily : R h izo ph o race a eCommon name Vernacular names HabitRed mangroves P anach ikanda l  (Malayalam)Medium trees, upto 20 m height, branches spreading horizontally Stem with fallen leaf scars. Extensive stilt roots, looping from the base of the trunk and bow shaped, horizontal branches form s very gregarious growth of succulent cylindrical roots. .These stilt roots also function as above-ground breath ing  roots. Bark is brown or reddish, smooth and sometimes scalyDistributionLeavesFlowersFruitsC iie ttuva , Ponnani, Kadalundi, Valapatnam, Payyoli, Kunjim angalam  and Kumbala estuaries.Dark g lossy green, thick and coated with cuticle, 15 cm long and 8 cm width. Apex pointed and mucronate. Ventral surface with cork wartsLarge, axillary cyme, more than 2 flowers, long petioles. Corolla and Calyx hairy, Smooth bract but woody, stigma sessileC oriaceous, 2.5 to 3.5 cm long, Cotyledonary collar absent in the radicle with wanted surface and more pointed tip1 2 . Rhizophora apiculata Family: R h izophoraceaeCommon name Vernacular names HabitDistributionLeavesFlowersFruitsRed mangroves K a y a k a n d a l  (Malayalam)M ed ium  to ta l l trees, upto 20 m height, branches sp read ing  horizontally, Stem with fallen leaf scars, Extensive stilt roots, looping from the base of the trunk and b ow  sh a p e d , h o r izon ta l b ra nch es  fo rm s very gregarious growth of succulent cylindrical rootsPayyoli, and  K un j im anga lam  estuaries.Dark glossy green, large size. Apex pointed. Bracts and midrib reddishAxillary cyme. 2 flowers, Petioles absent or stout, Petals glabrous, hairless, Calyx non reflexed,C oriaceous, 2.5 to 3.5 cm long, Cotyledonary collar present in the  radicle, Radicle- smooth surface.14. Scaevola taccada Family: G o o d e n ia c e a eCommon name: Fan-flowers, Half-flowers Vernacular names: Vella modagam (Malayalam)HabitDistributionLeavesFlowersFruitsEcological significanceShrubs to small diffuse trees, Grows near to sea in sandy beaches, stem hollow or filled with pithCalicut, Thikkodi, Payyoli,Large, spoon shaped, succulent, spira lly arranged , mostly aggregated at the apex of branches, sessile or short petiolesCymes, axillary, bracts and bracteoles small with a tuft o f barbate trichom es in axilsWhite, corolla tube thin and splits during anthesis Pentamerous,Drupe, white ovoid- globose, 2 loculesSand binder and recom m ended for green fence against sea erosion■15. Sonneratia albaCommon name Vernacular names HabitDistributionLeavesFlowersFruitsFamily: LythraceaeSweet-Scented Apple MangroveChakkara kandal (Malayalam)Tall trees, horizontally branchedChettuva. Ponnani, Valapatnam, Payyoli, esturariespale, elliptic to ovate orobovate, base rounded, tip broad, rounded: vyith broad recurved mucroPenta or octo merus. Corolla tube shiny. Calyx stongly tinged red. petals white variably semipetalous to absent. S tamen filaments are white.Fruit is 2-4.5 cm in diameter, about equal to width of floral tube.Vernacular names Habit16. Sonneratia caseolaris  F am ily : LythraceaeCommon name : Apple mangrove, Crabapple mangroveNai<shatra kandal (Malayalam)A  small- to  m edium - sized sized, evergreen tree 8 to 10 m tall w ith open spreading crown, horizontal branches and s le n d e r  tw ig s . A b o ve -g ro u n d  b ranch ing  roots (pneum.atophores) are peg like, 50 to 90 cm tail and up to 7 cm in d iam ete r with spongy outer surface Bark is grey and flaky  in the older trees.Distribution ' Chettuva, Ponnani, Kadalundi, Talaserry, Valapatnam,Kunjim angalam  and Kumbala estuaries.-LeavesFlowersFruitsOpposite, elliptic, oblong with short petioles, midrib often red at baseSolitary, petals slender, reddish, num erous stamens. Flowers open only in the late evening, lasting one night only; nectar is plenty in the calyxF ru it IS round but f la tte n e d , g reen  in co lour, with honzontally extended calyx and persistent long style.ROLE OF KEYSTONE SPECIES IN AQUATIC ECOSYSTEMM.Feroz K h a n ’ , P ree tha  P a n ik k a r ',  A .P .S harm a*', B .C J h a ’ *and  M.E.Vijayakumar*"C e n t ra l  In la n d  F is h e r ie s  R e s e a rc h  Ins t i tu te ,Barrackpore ,  H/es( B en ga l -700120  "R esea rch  Centre  CIFRI, Banga lo re  -  560089Introduction“[Keystone species] im portance convinced managers and consen/ationists alike that the ecological im pact o f single spec ies matters. That is, in order to manage, understand, and restore ecologica l assem blages, the roles of individual species have to be understood and cons ide red .” -  Dr. Robert PainA keystone species is a species that has a disproportionately large effect on its environment relative to its abundance. Such species play a critical role in maintaining the structure of an e c o lo g ic a l  c o m m u n ity ,  a f fe c t in g  m a n y  o th e r  o rg a n is m s  in an ecosystem and helping to determ ine the types and numbers of various other species in the community.The role that a keystone species plays in its ecosystem is analogous to the role of a keystone in an arch. W h ile  the  keystone is under the least pressure of any of the stones in an arch, the arch still co liapses w ithout it. Similarly, an ecosystem may expenence a dramatic shift if a keystone species is rem oved, even though that species was a small part of the ecosystem by m easures o f b iom ass or productivity. It has become a very popular concept in conservation biology.The keystone species concept was coined, in 1969. by the zoologist Robert T  Paine, professor em eritus of the University of W ashington, to explain the relationship between P isa s te ro ch ra ce u s ,  a species o f starfish, and M yti lus  californianus, a speaesof mussel. In his classic 1966 paper. Dr. Robert Paine descnbe sue a ^  klwctnnp Bay in Washington State, This led to his 1969 paper where he proposed the keystone species concept. The concept has been very  popular in conservation, deployed in a range of contexts and m obilized to eng ender support for conservation.Given that there are many historical defin itiohs of the keystohe speoies oohcept^ and without a consensus on its exact defin ition, a list o f examples best illustrates theconcept of keystone species.

Mangroves of Kerala

http://eprints.cmfri.org.in/9778/1/Vulnerable_Threatened_Marine_Ecosystems_Kaladharan_Asokan.pdf

Mangroves of Kerala

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