Environmental factors contributing to the invasion of &lt;em&gt;Najas marina&lt;/em&gt; L.in Madu Ganga estuary, a Ramsarwetland in Sri Lanka

Silva, T. M. S. D. G.; Wijeyaratne, M.J.S.

doi:10.4038/sljas.v22i2.7540

Cited by 2 publications

(2 citation statements)

References 2 publications

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“…Total phosphorus levels recorded in the Anawilundawa reservoir during the present study are higher than those recorded for the Madu Ganga estuary (Silva and Wijeyaratne 2017), which is another Ramsar wetland rich in avifauna. The reasons for this may be the absence of nutrient input by cattle as well as the lotic nature of this estuary.…”

Section: Discussioncontrasting

confidence: 78%

Water quality parameters contributing to the invasion of water hyacinth (<em>Eichhornia crassipes</em>) in the Anawilundawa reservoir in Sri Lanka

Lekamge

Wijeyaratne

Dahanayaka

2020

Sri Lanka J. Aquat.

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Eichhornia crassipes has been found to invade the Anawilundawa reservoir located within Ramsar wetland in the northwestern region of Sri Lanka. Present study was carried out to determine the water quality parameters that could contribute to its invasion and identify an effective control measure. During the study period of March-November 2017, mean values for Secchi depth, water depth and nitrate content in areas where E. crassipes was present (7.9 cm, 12.4 cm and 475 µg L-1 respectively) were found to be significantly lower (p<0.05) than in areas where it was absent (9.0 cm, 14.0 cm and 726 µg L-1 respectively). In areas where E. crassipes was present, low nitrate content may be due to its absorption and low Secchi depth may be due to trapping of detritus. Principal Component Analysis showed that during the monsoon period, high pH combined with low levels of conductivity, salinity, total dissolved solids and total phosphorus contributed for its invasion. From March to July, coverage of E. crassipes gradually decreased and in August the reservoir was completely dry and E. crassipes was present only as sparsely distributed individual plants rooted to the exposed reservoir bed. In September, with incoming water of inter-monsoonal rains and surface runoff, these plants got uprooted and started floating and by October they were flowering. In June, E. crassipes was confined to an area of about 0.5 ha with a mean depth of 13.3 cm. During this month it can be easily removed manually with a little amount of human labour which can be obtained from the riparian community who use this reservoir for irrigation and domestic purposes. However, if it is to be removed, a suitable indigenous plant species that interact with aquatic avifauna has to be introduced to ensure the continuity of some environmental services provided by this reservoir.

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Section: Discussioncontrasting

confidence: 78%

Water quality parameters contributing to the invasion of water hyacinth (<em>Eichhornia crassipes</em>) in the Anawilundawa reservoir in Sri Lanka

Lekamge

Wijeyaratne

Dahanayaka

2020

Sri Lanka J. Aquat.

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“…According to studies, it develops best in waters with salinity between 2 and 20‰ [SILVA, WIJEYARATNE 2017].…”

Section: Discussionmentioning

confidence: 99%

Journal of Water and Land Development

2022

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The increasing salinity of water in reservoirs is caused by climate change. On the other hand, an increase in salinity promotes the group species, halophytes that tolerate or need NaCl for growth. The aim of this study was to identify the response of facultative halophytes' photosynthetic apparatus efficiency (PE) to water salinity. The study covered the spiny water nymph (Najas marina L.) population in four mining subsidence reservoirs. Najas marina is a facultative halophyte which means that it can occur in both fresh and salt water. This plant has the characteristics of the species invasive, such as rapid biomass growth, and wide ecological tolerance. Water salinity, described by conductivity, in the reservoirs ranged from 646 to 3061 µS•cm -1 . PE was expressed in terms of chlorophyll a fluorescence parameters, which were collected in situ using a Pocket PEA device. Water parameters using a YSI ProDSS probe were identified. Data analysis was performed using OJIP test and s the non-parametric Spearman's rank test (p ≤ 0.05). The relationship between chlorophyll a fluorescence parameters and water parameters showed that conductivity, salinity, water clarity, and nitrate content statistically significantly affected PE (p <0.05). Generally, the higher salinity e.g. more than 3000 µS•m -1 , supports PE of facultative halophyte at the stage of optimum development in the vegetation season.

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Environmental factors contributing to the invasion of <em>Najas marina</em> L.in Madu Ganga estuary, a Ramsarwetland in Sri Lanka

Cited by 2 publications

References 2 publications

Water quality parameters contributing to the invasion of water hyacinth (<em>Eichhornia crassipes</em>) in the Anawilundawa reservoir in Sri Lanka

Water quality parameters contributing to the invasion of water hyacinth (<em>Eichhornia crassipes</em>) in the Anawilundawa reservoir in Sri Lanka

Journal of Water and Land Development

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