STUDIES ON THE ECOLOGY AND CONTROL OF TYPHA SPECIES

(A CASE STUDY OF HADEJIA-NGURU WETLANDS, NIGERIA)

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Author

Presented To

Department of Education

ABSTRACT
Aspects of ecology and management of Typha species in Hadejia - Nguru wetland were studied for a period of twenty-four months between January 2010 to December 2011.The aim was to identify the resident species of Typha, physico-chemical parameters, soil and sediment associated with proliferation of Typhaspecies, profer Management solutions to Hadejia-Nguru wetlands community. The Hadejia Nguru wetland has an area of about 58,100 hectares of which35,000 hectares were infested by Typha species.Typha proliferation causes a number of ecological problems which include transformation of aquatic environments into terrestrial ones, interference with various methods of catching fish,blockade of river channels and impeding navigation.Generally they became a nuisance by affecting social and economic well- being of the people who ultimately depend on the wetlands for their livelihoods. It also alters the biodiversity of aquatic ecosystems as well as a reduction in light penetration within the aquatic system.The study involved dividing the wetlands into three segment Upper, Middle and Lower courses.Typha species, water,soil and sediment samples, were collected in these segments and impact of Typha species on fish catch and distribution was evaluated by dividing each segment into two, Typha un-infested and Typha infested area. For the biological control; each segment was divided into four each containing 2000 species of Typha inter plant with 50kg, 25kg, 10kg and without Phragmites karka respectively. Manual control each segment was divided into six as cutting Typha 15 cm, 10cm, 5cm below and15cm, 10cm 5cm above water. For physical control each segment was divided into four using single black tarpaulin, double, triple and without black tarpaulin.Typha latifolia and Typha angustifolia accounted for 64-70% and 30% of the Typha species of the wetlands respectively. The physico-chemical parameters of water and sediment of the wetlands showed significant variations, in water PO4-P, NO3-N and Mg;ranging from 3.5-13.5 mg/l, 3-13mg/l and 1-10mg/l respectively. The sediment values showed that phosphate-phosphorus viii rangedfrom 6.5-16mg/kg, Nitrate-nitrogen 6-14mg/kg and Organic matters concentration 4-12mg/kg.The further result indicated that, water PO4-P, NO3-N and Mg concentration favour the growth and proliferation of Typha. A similar trend was exhibited by sediment Phosphate-Phosphorus, Nitrate-Nitrogen and organic matter concentration. The concentration of water PO4-P, NO3-N, Mg and sedimentPO4-P, NO3-N, and Organic matter along the three segments showed that the upper course had greater, concentration than the middle and that of the middle is greater than the lower course. The same trend was observed in the distribution of Typha latifolia and Typha angustifolia. The result of impact on fish catch and distribution showed that open water has the highest number and weight of fish caught than Typha infested area, ranging between83,167 to 173,026kgand 14,402 to 59,355kg respectively. The control of Typha proliferation involved biological, manual and physical techniques. The use of Phragmites karka for Biological control reduced Typha species proliferation by 25%, Manual cutting at 15cm below water level accounted for 95% of total control. The use of shade with black tarpaulin reduced Typha proliferation by 54%. The best control method was that of cutting at 15cm below the water surface.The findings recommended that,farmers should be sensitized on appropriate farming system particularly the involving the use of manure instead of inorganic fertilizer and the best time to control Typha, when their density is low which is at the peak of the wet season