INVASIVES SPECIES IN REUNION ISLANDS RIVERS AND PONDS Reunion - - PowerPoint PPT Presentation

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INVASIVES SPECIES IN REUNION ISLANDS RIVERS AND PONDS Reunion - - PowerPoint PPT Presentation

Sep 27, 2022 112 likes •422 views

INVASIVES SPECIES IN REUNION ISLANDS RIVERS AND PONDS Reunion Island belongs to one of 34 HOT SPOTS OF BIODIVERISITY in the world Lyce Boisjoly Potier- REUNION ISLAND - FRANCE Isolated Young Few rivers high rate of endemicity Lyce

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Reunion Island belongs to one of 34 HOT SPOTS OF BIODIVERISITY in the world

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

INVASIVES SPECIES IN REUNION ISLAND’S RIVERS AND PONDS

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Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

Isolated Young Few rivers high rate of endemicity

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Identity card of water hyacinth

  • Scientific name :

Eichhornia crassipes

  • Group : Pontederiaceae
  • Living areas : tropical

regions, ponds, soft water

  • Size : around 50cm to 1m

(the roots → 3m)

  • Reproduction : rapid,

vegetative and sexual.

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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2) Introduction in Reunion

Island

When? : 18th century Why? : -To purify the water infested with mosquitoes.

  • To be

used as an ornemental flower. Where? : From Amazonia and the west of Brazil to St Paul pond

St Paul pond

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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3) Current location

Gol pond (St Louis) St Paul pond

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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4) Consequences and solutions

  • Reduces the mineral

nutriment in the water.

  • Too thick for light rays to

get into the water.

  • Reduces dissolved

dioxygen concentration by eutrophication Manual taking. On rainy periods the pond water overflows and the water hyacinth is dispatched towards the sea.

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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Identity card of Water lettuce

  • Scientific name : Pistia stratiotes
  • Family : Aracae
  • Living areas : Pond
  • leaves : around 14cm
  • Reproduction :

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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Introduction in Reunion Island

  • When : ?
  • Why : - Ornament
  • use like filter

Where : from Africa

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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Current Location

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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Consequences and solutions

  • Block light and consume a lot of oxygen in spite of the other species

(fishes or seaweed)

  • Put out of the water

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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The Australian crayfish

(or blue crayfish)

I- Presentation

  • Scientific name : Cherax quadricarinatus
  • Family : Parastacidae
  • Size : 15cm for female and 18cm for male (until 25cm)
  • Average weight : 250g
  • Lifespan : 5 years
  • Feeding : Can adapt its diet .
  • Reproduction : Female lays between 300

And 800 green olive eggs. The incubation takes about 6 weeks .

  • Habitat : Between 15 and 30°c

Australia

Lycée Bois South Africa , Mexico , Jamaica joly Potier- REUNION ISLAND - FRANCE

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. Introduction in Reunion Island Where : This crustacean found in '' l'Etang de Saint Paul's '' pond and it is invasive in this area . Why ? When ?

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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Species threatened by the Australian crayfish ''Bichique'' and small shrimp .

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

Consequences and solutions

Competition and predation behaviour of indigenious fauna which can lead important modifications on aquatic

  • ecosystems. This species is often host to diseases

( virus , bacteria ) .

Fry = baby fish =bichique Cabot bouche ronde = adulte

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Identity card of Managuense

  • Scientific name:

Managuense (Parachromis managuensis)

  • Family: Cichlidae
  • Living areas: Central

America, Honduras, Costa Rica, Reunion Island

  • Size: 50-65 cm
  • Reproduction: spawning of

1000-2000 eggs

  • Food: Eat fishes or micro-

invertebrates

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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Introduction of Managuense in Reunion Island

  • Why: To kill Tilapias (introduced by aquaculture).
  • Where: Introduced in Etang du Gol

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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Current Location

Etang du Gol Etang Saint- Paul

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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Consequences and Solutions

  • Predation and loss of endemic biodiversity.
  • One of the solutions is to fish it ....but battle lost in advance ?

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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  • Scientific name :

Oreochromis niloticus spp

  • Group : Cichlidae
  • Living areas : warm rivers

and ponds

  • Size : 20-30 cm
  • Food : mosquitos,

phytoplancton

  • Colour : silver

Identity card of « Le Tilapia »

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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Introduction in Reunion island

  • When : In 1957
  • Why : Feeding

role

  • Where : From

Madagascar to farming pools

Reunion island Maurit ius

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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Current location

Ponds Rivers Presence

  • f Tilapia

Etang St Paul Bois rouge Etang du Gol Grand étang

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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Consequences and solutions

  • Impacts : taking place of local endemic fishes
  • > disappearance of those species
  • - No real solution … yet

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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Identity card of Chinese turtle

Class : Mauremys sinensis Family : Geoemydidae Length : < 25 cm Food : water plants,fish,snails,worms,insects Breeding : between 5 and 7 years

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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Introduction of Chinese turtle in Reunion Island?

Where does it come from ? Coast provinces of the south of

  • China. North and center of Vietnam.Laos and Taiwan.

How ? Possibly escaped from their breeding space. Why ? To become pets When ? End of 20th century

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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Current location

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

Rivière des Galets and maybe ponds

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consequences-Solutions

Harmful for waterways.

May consume insects and fish.

No real solutions nowadays

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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IDENTITY CARD OF THE AFRICAN COMMON TOAD

Scientific name : Bufo Bufo or Bufo gutturalis Family : Bufonidae Size: 7 to 12 cm Breeding : water Food: other frogs,insects,spiders Class : Amphibia Alternative name : Gutturalis toad

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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Introduction to Reunion Island

When ?1927 Why ?To fight paludism,malaria Where?From southern Africa

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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Current location

in Reunion island : humid areas The gutturalis toad is very adaptable to any environment.

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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Consequences-Solutions

The Bufo bufo is a great predator. Gecko de Manapany Gecko des Hauts

Lycée Boisjoly Potier- REUNION ISLAND - FRANCE

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Lycée Boisjoly Potier- REUNION ISLAND - FRANCE