Mangrove Keys 3l1d3h

Mangrove keys

From the Wet paper book

Mangroves in Focus (Out of print)

by Dave Claridge (dec) and John Burnett

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Identification activities Activity 1 Identifying mangroves Brief description This activity describes a number of keys that can be used to identify mangroves. What to do

Use the keys 1.1 to 1.6, to identify mangroves in your local area. You may wish to construct your own or use reference books. Notes ●

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Key 1.1 is a general key which can be applied in most situations. Key 1.2 is a key based on easily observable characteristics such as roots, leaves and sap. Key 1.3 is a key based on mangrove fruit of some species. Key 1.4 is a key based on mangrove root systems. Key 1.5 is based on the belief that local field or environmental studies centres can generate their own keys. This key has been reproduced with kind permission of the Jacobs Well Environmental Education Centre in Queensland. The teachers there looked for easy-to-identify features and combined these with other characteristics from more general keys to come up with their own. Key 1.6 is a home-made key based on whole tree characteristics. The advantage of this is that students may be able to identify the whole tree and not wait till flowers or leaves appear.

Fig 4.13 Diagram courtesy Australian Littoral Society

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Key 1.1 Note See glossary for explanation of

This key is based on one developed by Lear and Turner (1977). It is reproduced with permission of the University of Qld Press. In order to use the key start with number 1, select which of the two given statements best describes the species you wish to identify, follow the numbers carefully, repeating as necessary until the identification is complete. Characteristic

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.

13. 14. 15. 16. 17.

Genus / species

palm frond Nypa fruticans not a palm go to 2 leaf blades usually>120 mm long go to 3 leaves usually<120 mm long go to 4 prop roots/knee roots present go to 5 no prop or knee roots go to 6 compound leaves go to 7 simple leaves go to 8 aerial/prop roots from branches Rhizophora sp. no prop roots from branches Bruguiera sp. buttresses present (large) Heritiera littoralis buttresses absent Camptostemon schultzii symmetrical leaflets Xylocarpus sp. asymmetrical leaflets Cynometra iripa leaves opposite go to 9 leaves alternate go to 14 underside of leaves grey Avicennia sp. not grey go to 10 stipules present Scyphiphora hydrophylacea no stipules go to 11 gland at base of leaf stalk Sonneratia sp. leaf stalk lacks gland go to 12 finely toothed upper leaf margin Osbornia octodonta spiney teeth on leaf margin Acanthus ilicifolius leaf margin complete go to 13 terminal shoots spearhead shaped Ceriops sp. not so Bruguiera sp. leaf underside grey Camptostemon schultzii not grey go to 15 white latex(milky sap) present Excoecaria agallocha no latex present go to 16 gland at leaf apex Lumnitzera sp. no gland at leaf apex go to 17 petiole sheathing of stem Aegialitis annulata stem not sheathed Aegiceras corniculatum 3

Key 1.2 Roots, leaves and sap This key is based upon easily observable characteristics which should enable simple field identification. It covers twelve of the fifteen genera which are found in area 3 (see Figure 1.5) and all species on the eastern coast of Australia south of Hervey Bay. This key has been used successfully by secondary students in field work. Characteristic

Genus / species

1. Roots

Pneumatophores pencil conical Prop roots Knee roots Buttress roots—small, multiple Buttresses—vertical plate-like

Avicennia marina Xylocarpus mekongensis Rhizophora stylosa Bruguiera gymnorrhiza Ceriops tagal Xylocarpus granatum

2. Leaves

Crushed leaf aromatic/small Gland at leaf apex Leaf margins spiney Leaves alternate, heart-shaped/large Leaves ovate, sheathing stem Leaves obovate, stem not sheathed

Osbornia octodonta Lumnitzera racemosa Acanthus ilicifolius Hibiscus tiliaceus Aegialitis annulata Aegiceras corniculatum

3. Sap

White latex

Excoecaria agallocha

This key may well be added to, to enable use in other areas. Notes on genera with more than one species ● ● ● ● ● ● ● ● ● ● ●

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Avicennia marina: leaves ovate; bark is finely fissured, greyish A. eucalypifolia: leaves lanceolate; bark smooth, greenish Sonneratia alba: flower petals white or reddish at base S. caseolaris: flowers dark red Lumnitzera littorea: flowers red L.racemosa: flowers white Xylocarpus granatum: meandering, plate-like buttress roots; smooth bark X. mekongensis: conical pneumatophores; rough fissured bark Rhizophora sp. Bruguiera sp. refer to the fruit and root diagrams on Figures 4.14 and 4.15 Ceriops sp.

Key 1.3 Mangrove fruit This key is based on matching the fruit with the species name below. Common fruit are shown here and are presented as an example of what could be done.

Note that collecting fruit for identification purposes requires a permit.

Bruguiera exaristata

Bruguiera gymnorrhiza

Ceriops tagal var australis

Rhizophora stylosa

Rhizophora mucronata

Aegiceras corniculatum

Avicennia marina Ceriops tagal var tagal Fig 4.14 Common mangrove fruit (not drawn to scale)

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Key 1.4 Mangrove root systems This key is based on matching the root system with the species name below.

Heritiera littoralis Heritiera littoralis

Ceriops and Bruguiera Bruguiera gymnorrhiza

Aerial roots

Main stem Mud

Rhizophora stylosa

Fig 4.15 Common mangrove root systems (not drawn to scale)

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Rhizophora stylosa

Key 1.5 Make your own key This is based upon a key developed by Jacobs Well Environmental Education Centre and is an example of a local key which you can make.

Key for the identification of local mangroves (Based on a key from a local environmental education centre)

Mangrove

Leaves alternate

Milky mangrove Exoecaria agellocha

Leaves opposite

Are the leaves grey on the underside?

Is sap milky?

Yes

No

River mangrove Aegiceras corniculatum

Yes

Yes

Grey mangrove Avicennia marina

No

Are salt crystals present on the leaf surface and length to width ratio about 2:1?

Does the trunk have aerial prop roots, black or brown spots on Yes underside of leaves?

Spotted mangrove Rhizophora stylosa

No No (Only occasional spots on underside of leaves)

Black mangrove Lumnitzera racemosa

No salt crystals are present on leaves. Yes Length to width ratio about 4:1 to 6:1.

Is the bark papery and the trunk buttressed? Yes

Yellow mangrove Ceriops tagal

No No

Is the bark hard and often fissured? Are their knob roots? The tree you are trying to identify is not common to Moreton Bay

No

Yes

Orange mangrove Bruguiera gymnorrhiza

Fig 4.16 Jacobs Well Environmental Education Centre common mangrove root systems local key. (Reproduced with permission) 7

Key 1.6 Whole tree This key is based on matching the shape of the whole tree with the species name below.

Rounded leaves covered with salt crystals

Thick leathery leaves

Dark rough scaley trunk Tiny white dots on trunk

Knobbly ‘knee’ roots

Multi trunks

River mangrove

Orange mangrove

Thick leathery leaves with tiny spots underneath

Yellowish leaves

Buttressed roots with papery bark

Prop roots

Yellow mangrove Stilted mangrove The Australian Littoral Society is a national organisation of Australians who care about life In our rivers, coastal waters and coral reefs. One of the most important roles of the society is to provide information to help people better understand the conservation problems affecting aquatic life. ALS produces its own bimonthly bulletin as well as special publications on important topics like the Great Barrier Reef and wetlands conservation, and management of river systems. The Moreton Bay Resource Kit mentioned here has been developed specifically to fill the gap in the availability of resource material about Moreton Bay and its islands for teachers, students and the interested public. It is accompanied by a set of twenty slides of aerial and landscape scenes and marine life, and multi-discipline teaching units for primary and secondary schools. For more information about the kit or the society, write to: ALS Secretary P.O. Box 49, MOOROOKA Q 4105.

Leaves shiny and dark and dirty green and dull underneath

Hollow branches Pencil-like roots (pneumatophores)

Grey bark with lots of lichens

White or grey mangrove

Fig 4.17 Illustrations are from the Australian Littoral Society Moreton Bay Resource Kit and are reproduced with permission. 8

Activity 2 Identifying crabs Crabs are of the phylum Arthropoda and belong to the class Crustacea. This is due to their exoskeleton which is quite hard and inflexible. The hard shell is unable to grow, so the crab will shed it by moulting. This involves crawling out of the old shell and growing a new one. At this point of time the crab is vulnerable, especially to attack from predators. For this reason the five pairs of legs that they possess are well ted and highly adapted to their environment. Crabs will use their legs to move, usually in a sideways motion, for speed and easy access into their burrows. Crabs make up a rich part of the overall fauna of the unique mangrove environment. They are distributed throughout the environment, depending on the tidal movement, the structure of the mud and the salinity of the area. Since most crabs have their own burrow in the mud, they seldom move far from its entrance. If the crab is removed from its immediate territory then it must either rob another crab of its burrow or excavate a new burrow. This is a dangerous time for the crab as it is exposed to both dehydration and attack by one of the numerous mangrove predators. The mud crab (Scylla serrata) are found along the banks of mangrove-lined rivers and creeks, remaining in their burrows until nightfall when they come out to feed on small fish, other crustaceans, molluscs and anything they can scavenge. A distinctive noise often heard in the mangroves is the clicking sound of the snapping shrimp (Alpheus sp., see Figure 4.18). The sound is produced by the snapping together of the finger sections of the enlarged chelae, which contain a unique peg and socket arrangement. These shrimps live in the wetter regions of the mangrove, especially around the base of mangrove trees and under logs and rocks. Pillbugs (Sphaeroma) and other isopods live in the rotting logs and vegetation as do the various hoppers (Amphipoda) which are quite common in the mangrove environment.

Mangrove crabs and other crustaceans The most common of the mangrove crabs in southern Australia is Helograpsus, a crab that lives in the upper tidal zone in sandy areas. Other mangrove crabs are found in New South Wales. These are represented by a larger range of different Sesarma species, including erythrodactyla (Red fingered marsh crab) and Macrophthalmus crassipes (Sentinel crab). Crabs in the northern Australia come from the two main families, Ocypodidae and Grapsidae (crabs with short eye stalks). The most well known from the Ocypodidae family is the fiddler crab (Uca sp.) with the distinctive single large claw of the male. Other predominant crab species include sentinel crabs on the lower mud banks and further up the banks the semaphore crab (Heloecius cordiformes) with its large purple claws. Both these crabs burrow in the intertidal zone and appear in large numbers as the tide recedes to feed on the algae , microbes and organic matter. In the soft mud under trees and at the back of the mangroves, the red crab ( Sesarma smithii) will burrow, leaving a large and distinctive hole. The crab is nocturnal, leaving its burrow only to go feed on fallen mangrove leaves. Crabs from the Grapsidae family are generally found around pools and rotting logs within the mangrove environment. The crabs in this family include Cleistostoma mcneilli, several species of Sesarma and the quick moving Metopograpsus frontalis.

Fig 4.18 The large ‘clicking’ cheliped of the snapping prawn Alpheus sp, displaying the peg and socket arrangement (after Hale 1976). 9

Make an order specific key This key is based upon one developed by Jacobs Well Environmental Education Centre and is presented as outlines from which local ones can be made.

What crab is it?

Eyes close together on long stalks.

Eyes on short stalks.

Hairy-clawed crab

Yes

Are the claws blue (with orange nippers)?

Are the claws blue (with orange nippers)?

No

Mud crab

Yes

Red-fingered marsh crab

Yes

Yes

Hairy-clawed crab

Yes

Fiddler crab (male)

Yes

Long eyed crab

Yes

Semaphore crab (adult)

Yes

Semaphore crab (young)

Yes

Semaphore crab (possibly female)

No

Is the last pair of legs flatterned like paddles?

Is only one claw big?

No

No

Are the nippers on the claws orange or red and the claws yellow or brown?

Are the claws dirty brown? No

No

Yes

Hairy crab

Are the claws purple?

Are the legs very fuzzy (hairy) on the tops? Is the crab brown all over with no other colours?

No Are the claws pink?

No

Mottled shore crab

Yes

Does the crab have mainly whitish claws with darkly coloured 'arms'?

No Does the crab have a couple of whitish stripes in front (behind its claws)?

No

Red crab

Yes

Are the claws red and do the black eyes have a white spot on top of each? No No

Red rock crab

Yes

Most likely a female fiddler crab Are the claws red or reddish? No

Most likely a shore crab

Fig 4.19 A crab order key based on local knowledge. After Jacobs Well Environmental Education Centre field key (Reproduced with permission). 10

Make an area specific key The flowing key was made from the Jacobs Well Environmental Education Centre and is presented as outlines from which local keys can be made. Each area will have its own characteristic species and this is presented as an outline guide only. What crab is it?

Does the crab have a round shell with blue and white markings on it?

Yes

Soldier crab

Yes

Horn eyed ghost crab

No

Does the crab have pointy eyes and spiky claws that are white? No

Does the crab have pretty patterns on the shell and did you find it in the water on the surf area of the beach without a burrow? Did it dig into the sand very quickly when you found it?

Yes

Sand burrowing crab

No

Is the crab only 10 mm long and white all over? Did you find it on a sand dune?

Yes

Dune ghost crab

No Sand bubbler crab

Fig 4.20 A crab specific key developed by Jacobs Well Environmental Education Centre field key (Reproduced with permission). 11

More crab identification information Hairy clawed crab Lump of mud in middle of each blue claw (actually hairs!), pale eyes, white stripes at front behind claws, orange nippers.

Fiddler crab Has one large claw (almost as big as its body) and one tiny claw to feed with, there are three different types— one has a big white claw, another has a mainly orange claw with white nippers, while the third has a whitish upper nipper and an orange lower nipper on its big claw. Female fiddler crabs have two tiny equal-sized claws.

Long eyed crab The crab is a brownish colour all over, has long eyes and hairy or fuzzy legs.

Semaphore crab Adults have purple claws with whitish nippers, young ones have pink or orange claws with whitish nippers. They all have vertical white stripes on their front behind the claws. Legs and body dark.

Mud crab Green, orange and brown colours on claws and shell. The largest crab you are likely to see during your visit. Will usually only be found in water. Sharpish ‘spikes’ around edge of shell. Last pair of legs flattened like paddles.

Red fingered marsh crab Nippers always orange or red; adults have a green or bluish shell. Young ones can have a brown or black and green shell. Lots of tiny hairs on the legs.

Hairy crab Orange-brown all over with no other colours. The top of the leg is shaggy/hairy and holds the mud. Ends of legs (feet) are very pointy and thin.

Mottled shore crab Shell is dark with white speckles, mainly towards the bottom. Whitish claws with dark 'arms'.

Red crab Red claws with pale tips to the nippers. Blackish body. Tiny hairs over legs and body. White spot on top of each eye. Textured fly screen-like surface on body behind claws (at the front).

Red rock crab Reddish or orange-brown claws. Smooth, slightly flattened, dark body.

Shore crab Yellow or orange claws on the adults with brown body. Brown claws and brown body on young ones. Usually four or six tiny pale spots on the back of its smooth shell. Fig 4.21 More crab identification information (after Jacobs Well Environmental Education Centre) 12

Crab Identification Key A 1a 1b 2a 2b 3a 3b 4a

Long-stalked eyes Short or no stalked eyes Claws equal size Claws not equal size (males only) Has hairs on legs or claws Has no hair on legs Orange-brown colour; hair also on carapace; one tooth on claw 4b Blue claws; hairs between claws 5a Elongated body, very long eye stalk, two fine notches on side 5b Squarish body; purple claws 6a Rear leg segments pointed 6b Rear leg segments paddle-like 7a Spines along top of claws 7b No spines along top of claws 8a Hair on legs; honey yellow colour 8b No hair on legs 9a Red fingers and claws fine ridges on top and side of carapace 9b White fingers, purple claw 10a Has three spots on its back 10b Does not have spots 11a Greenish carapace; strong claws 11b Blue mottled carapace; blue legs

go to 2 go to 6 go to 3 Fiddler crab Uca sp. go to 4 go to 5 Hairy crab Cleistostoma mcneilli Hairy clawed crab Australoplax tridentata Sentinal crab Macrophthalmus crassipes Semaphore crab Heloecius cordiforis go to 7 go to 10 Red crab Neosarmatium smithii go to 8 Mottled shore crab Metapograpsus frontalis go to 9 Red fingered marsh crab Sesarma erthrodactyln Shore crab Helograpsus hanwellianus Red spot crab Portunus sanguinolentus go to 11 Mud crab Scylla serrata Blue swimmer crab Portunus pelagicus

Crab Identification Key B 1a 1b 2a 2b 3a 3b 4a

Long-stalked eyes Short or no stalked eyes Claws equal size Claws not equal size (males only) Has hairs on legs or claws Has no hair on legs Orange-brown colour; hair also on carapace; one tooth on claw

go to 2 go to 6 go to 3 Uca sp. go to 4 go to 5 (Hairy crab) Cleistostoma mcneilli (Hairy clawed crab) Australoplax tridentata

4b Blue claws; hairs between claws 5a Elongated body, very long eye stalk, two fine notches on side (Sentinal crab) Macrophthalmus crassipes 5b Squarish body; purple claws (Semaphore crab) Heloecius cordiforis 6a Rear leg segments pointed go to 7 6b Rear leg segments paddle like go to 10 7a Spines along top of claws (Red crab) Neosarmatium smithii 7b No spines along top of claws go to 8 8a Hair on legs; honey yellow colour (Mottled shore crab) Metapograpsus frontalis 8b No hair on legs go to 9 9a Red fingers and claws fine ridges on top and side of carapace (Red fingered marsh crab) Sesarma erthrodactyln 9b White fingers, purple claw (Shore crab) Helograpsus hanwellianus 10a Has three spots on its back (Red spot crab) Portunus sanguinolentus 10b Does not have spots go to 11 11a Greenish carapace; strong claws (Mud crab) Scylla serrata 11b Blue mottled carapace; blue legs (Blue swimmer crab) Portunus pelagicus Fig 4.22 Crab identification keys

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Activity 3 Identifying shells A useful way to identify shells is to use illustrations to help you. Unfortunately not all shells have common names and it may be difficult to draw them to scale. These two pages are designed to be used as ideas only. The diagrams are not drawn to scale.

Bubble shell (Quibulla sp)

Hercules mud whelk (Pyrazus ebeninus)

Telescope mud whelk (Telescopium telescopium)

Conniwink (Bembecium nanum)

Black nerite shell (Nerita lineata) Mangrove australwink (Littoraria scabra)

Fragile air breather (Salinator salinator fragilis)

Fig 4.23 Common shells of mangrove regions (not to scale)

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Bembecium nanum

Salinator solida

Cerithium cuminji

Salinator fragilis

Australian mud whelk (Velacumantis australis)

Speckled periwinkle (Austracochlea concamerata)

Hairy mussel (Trichomya hirsuta)) Common striped periwinkle (Austracochlea obtusa)

Fig 4.24 Common shells of mangrove regions (not to scale)

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Activity 4 Identifying spiders The following page layout is presented as a guide to spiders. Each local area will have its own varieties. You will have to reconstruct some of this information to suit local conditions. (Illustrations by Glenn Leiper.) General information about spiders ● ● ●

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In most species, the females are larger than the male. In most species, the female is known to eat the male. If a male lives on the same web as the female, he is used as a food locater. When he senses a catch on the web, he notifies the female then gets out of the way while she investigates and feeds. He feeds later. Most spiders have more than two eyes, most have six or eight eyes! These are used for forward vision and upward vision. Spiders can only see a few centimetres. They can sense a creature approaching because they have receptive hairs on their legs which detect air movement. Nocturnal spiders pull down their web after a night's trapping/hunting and then eat it. This provides protein in the diet.

Some local species Golden orb web spiders Nephila sp. ●

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Golden orb spider

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diurnal (day-feeding), building their web during the day males are much smaller than the large female builds a large, strong web—in the Pacific Islands it is used to make fishing nets female wraps up tangled insects in silk, feeds on them then retires; male then moves in and feeds female will eat male if given the chance female spins the web. the web also provides a home for dew drop spiders which the orb spider will chase away if they get in the way, especially while feeding young are carried on the breeze after hatching. Upon landing, they make their own tiny web.

Dew drop spider (Argyiodes anipodimus) Dew drop spider

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Fig 4.25 Common spiders found in mangrove areas (after Leiper 1993)

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silvery and small about 3 to 4 mm across Iives on the orb spider's web will spin only occasional small amounts of silk on this larger web

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cleans up after the orb spider, if allowed

Six spine spider (Gasteracantha minax) ●

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female is orange and black, male is black, about 8-9 mm in size nocturnal spins an orb web each night between low bushes (a wheel pattern) removes web at daytime so that birds can not spot them and eat them, they eat their own web

Six spine spider

Huntsman (Isopoda sp.) ●

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the juveniles (or young) are bright green to match their leafy habitat adult's body colour is black and hairy they protect their egg sacks, some even carry them on their backs they travel by the wind their natural home lies beneath the bark of trees for food they depend on large insects including flies, moths and beetles they will bite humans and produce localised pain

Huntsman spider

Leaf curling spider (Phonognatha graeffei) ● ● ●

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uses a leaf at the centre of its web to disguise its shelter the leaf is dragged up on a silkline off the ground the spider hides in the leaf during the day then rebuilds its web at night eggs are laid in folded leaves and hung some distance from the main web food is mainly insects

Flower spider (Diaea variabilis) ● ● ● ● ●

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found throughout eastern Australia is common in flowers, gardens and in the field uses its colour for camouflage in the flowers eats small insects and other spiders glossy white colour and is only about a centimetre across first and second set of legs same length

References

Flower spider

J. Child, Australian Spiders, Gould League of Victoria Junior Survival Spiders R. Mascord, Australian Spiders, identification chart

Leaf curling spider

"FLICK" spider

Fig 4.26 Common spiders found in mangrove areas (after Leiper 1993) 17