lake victoria, confronting the water hyacinth
DESCRIPTION
This presentation looks at water hyacinth with respect to Lake victoria. It explores the biological classification, the origin, factors for its flourishing and its detrimental effects. It further explores the various control measures and the economic uses of this floating water weed.TRANSCRIPT
LAKE VICTORIA
Confronting The Water Hyacinth
ROBERT BOB OKELLO
Presentation Outline
• Location of L. Victoria
• What is the water hyacinth
• Origin w.r.t L. Victoria
• Factors for its bloom
• Ecological & Economic effects
• Control & Economic benefits
• Conclusion
Location of L. Victoria
• East Africa (Uganda, Tanzania & Kenya)
• Area: 68,800 km²
• Elevation: 1,134 m
• Width: 250 km
• Largest tropical lake in the world
• World's 2nd largest freshwater lake by surface area
What is Water Hyacinth?
• Botanically known as Eichhornia crassipes
• Free-floating perenial aquatic plant (Hydrophyte)
• Native to Amazon
• Highly Problematic & invasive outside native range
• Overall effects of the Water hyacinth are still unknown
What is Water Hyacinth?
Classification
Kingdom: Plantae
(Unclassified): Angiosperms
(Unclassified): Monocots
(Unclassified): Commelinids
Order: Commelinales
Family: Pontederiaceae
Genus: Eichhornia
Species: E. crassipes
How did it get to L. Victoria?
• Introduced in the region by the Belgian colonists to Rwanda
• In the 1980s
• To beautify their holdings
• This slowly advanced to lake Victoria by natural means
• Aid of the River Kagera
• First sighted in 1988
Why Has it Flourished?
• Optimum growth temperatures (25o-30o)
• Optimum PH of 5.0 – 7.5 (L. Vic = Fresh)
• Optimal salinity (<15% of sea water)
• The plant produces numerous viable seeds
• Shallow shores in Uganda with muddy bottoms thus providing perfect growth conditions
• No competitors
Detrimental Effects
• Invasion of fish breeding grounds• Aquatic habitat colonisation (80% of Uganda’s shoreline
infested)• Creates anoxic (total depletion of oxygen) conditions in the
lake• Creates breeding grounds for female anopheles mosquitoes
(malaria)• Fishing dificulties• Navigational challenges for water vessels
Control Measures
1. Chemical Control• Herbicides are used• Expensive on large scale• Have detrimental effects
on the environment• Health related issues
Control Measures
2. Physical Control• Land based machines
(bucket cranes, drag lines/boorm)
• Aquatic based machinery (aquatic weed harvester, dredges, vegetation shredder)
Control Measures
3. Biological Control• Use of water hyacinth eating
pests/insects• Neochetina eichhorniae (mottled
water hyacinth weevil)• Megamelus scutellaris (USD’s
Agricultural research)
Economic Uses
• Bioenergy (1 hec = 70metric tonnes of biogas. 1Kg = 730litres of biogas )
• Phytoremediation (Waste water treatment) – roots naturally absorb pollutants e.g. Lead, mercury
• Food source – it’s a carotene-rich vegetable• Also a source of animal feeds• Medicinal value (Tonic effect) – medicating
horse skin.• Source of organic fertiliser• For making Furniture, hand bags and ropes • Small scale paper production• Job opportunities
References
http://sabahionline.com/en_GB/articles/hoa/articles/features/2013/09/27/feature-02
http://www.economist.com/node/110585
http://en.wikipedia.org/wiki/Eichhornia_crassipes
http://en.wikipedia.org/wiki/Water_hyacinth_in_Lake_Victoria
http://aciar.gov.au/files/node/2292/pr102chapter21.pdf
http://en.wikipedia.org/wiki/Lake_Victoria
http://en.wikipedia.org/wiki/Lake_Victoria#Water_hyacinth_invasion
http://www.businessdailyafrica.com/image/view/-/1308408/medRes/282736/-/maxw/600/-/8hjvc/-
/DnKisumuCounty1607xx.jpg