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The Effects Of Flooding On Survival And Recovery Growth Of Riparian Plant Species Salix Variegata Franch. And Arundinella Anomala Steud. In Three Gorges Reservoir Region

Posted on:2009-11-16Degree:MasterType:Thesis
Country:ChinaCandidate:Y LiFull Text:PDF
GTID:2120360242496873Subject:Ecology
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Owing to the largest dam construction of the world in Three Gorges in China, some low-elevation areas along the river bank will be submerged as long as 6 months. Flooding adversely affects the plant growth and some other aspects, so some plant species in the water-level-fluctuation zone can not survive, which leads to a series of ecological problems, such as soil erosion, destruction of the eco-environment. To restore the damaged vegetation and to improve the environmental quality in this region, riparian vegetating is an important measure of all possibilities. For riparian vegetating, selection of appropriate plant species which are adapted to frequent flooding is crucial.To evaluate the tolerance of two riparian plants Salix variegata Franch. and Arundinella anomala Steud. in Three Gorges reservoir region, a long-term simulation experiment was conducted and the survival and recovery growth of S. variegata and A. anomala were analyzed. The results of the experiments showed that:The effects of flooding on survival and recovery growth of the riparian plant Salix variegata Franch. in Three Gorges reservoir regionThe results showed that: The flooding had little effects on the survival of S. variegata. All plants subjected to belowground submergence can surive 180d inundation, but the survival decreased to 0 after 180d submergence with 2m water depth. The S. variegata plants were still able to start recovery growth after flooding, and showed strong recovery capability even though the recovery growth was different due to the different intensities of water submergence. With the increase in duration of flooding, the time S. variegata needed to start recovery growth increased. However, all flooded plants could recover in one week when flooding was ended. Under the condition of the same flooding duration, the plants subjected to belowground submergence and 2m water depth submergence had higher RGR than the control plants. After 40d, 60d and 90d inundation, The RGR of the plants submerged with 2m water depth were 57.8%, 143.4%, 130.4% higher than that of the control plants, respectively. In the experiment, it was shown that the growth of S. variegata varied with flooding intensity. The aboveground biomass of the plants subjected to belowground submergence was not significantly different from that of the control plants, but the plants submerged with 2m water depth had lower aboveground biomass than the control plants. After 2 months growth following flooding termination, the variation pattern in aboveground biomass among plants subjected to treatments of different flooding depth was similar to that of plants when flooding was just ended. The research demonstrates that S. variegata has high survival and good recovery growth after long-term flooding, and it showed good tolerance to flooding and could be applied in revegetation of water-level-fluctuation zone in Three Gorges reservoir region.The effects of flooding on survival and recovery growth of the riparian plant Arundinella anomala Steud. in Three Gorges reservoir regionIt was found that the continuous flooding and intermittent flooding had little effects on survival of A. anomala in 90d submergence, but it could not survive 180d submergence. In 90d submergence, flooding also had little effects on the recovery growth of A. anomala. During the recovery period, the increase in tiller number, leaf number and RGR were significantly higher than that of the control plants, and the RGR of the submerged plants remained the same for all flooding duration. We also found that under 90d submergence, the effects of continuous flooding and intermittent flooding on recovery growth of A. anomala did not have significant difference, specifically, there is no significant difference between the ratio of RGR following the continuous flooding and that following the intermittent flooding. The results demonstrated that long-term flooding that exceed 90d submergence would affect the survival and recovery growth of A. anomala, but it had high survival and good recovery growth after 90d flooding, and it showed good tolerance to flooding.Research on dynamics of the recovery growth of Arundinella anomala Steud. and Salix variegata Franch. in Three Gorges reservoir region after flooding The results showed that: (i) After short-term flooding, the increase rate of tiller number and leaf number of A. anomala remained the same during the whole recovery period. Tiller number and leaf number of A. anomala subjected to 90d flooding increased quickly during the early recovery period, and it decreased during the late recovery period, although the rate of increase was still higher than that of the control plants. The aboveground biomass of A. anomala would be inhibited by long-term flooding, but it increased quickly during recovery period, (ii) The first branch number of S. variegata subjected to short-term flooding increased quickly during the early reovery period, and it decreased during the late recovery period. The first branch of the plants subjected to long-term flooding did not increase during the whole recovery period, which was similar to the control plants. The variation pattern of leaf number during the recovery period was contrary to that of the first branch number. The leaf number of the plants subjected to short-term flooding did not increased significantly during the early recovery period, but the increase rate in late recovery period increased and was higher than that of the control plants. After long-term flooding, the leaf number increased quickly during the early recovery period, but the increase rate decreased in late recovery period. Similar to A. anomala, the long-term flooding would inhibite the aboveground biomass of S. variegata, but it increased quickly during recovery period. The results demonstrated that A. anomala and S. variegata still had recovery capability after flooding and they both showed good tolerance to flooding.
Keywords/Search Tags:Flooding, Three Gorges reservoir region, Salix variegata Franch, Arundinella anomala Steud, survival, recovery growth
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