Effects of submergence in water on seed germination and vigor of the Copaifera lucens (Fabaceae) seedlings

et al. 2017

Ecological Research

The reverse seasonal flooding that resulted from the construction of the Three Gorges Project has induced a drastic degradation of draw-down zone vegetation and the seed bank in the reservoir. The composition and distribution of seed banks and their similarities to standing vegetation were determined through field investigations and germination experiments on the vegetation as well as soil seed bank data collected from three restoration sites in Zigui county, Wanzhou city, and Zhongxian county to uncover the effects of vegetation restoration on seed bank development in the Three Gorges Reservoir region. The results showed the soil seed banks were composed of 44, 43, and 50 herbaceous species, and an average seed density of 9418.79 ± 804.92, 4283.44 ± 427.89, 6539.28 ± 432.22 seeds/m 2 , respectively. The soil seed bank was mainly composed of annual and perennial herbaceous plants. Most of the dominant species of soil seed banks came from introduced species. Reverse seasonal flooding induced the spatial variation of species diversity and seed density of the soil seed bank. The species diversity in the upper part of the draw-down zone was higher than that in the middle and lower parts. The highest seed density occurred in the middle upper parts of the drawdown zone, followed by the lower part. The similarity coefficient between the soil seed bank and the extant vegetation community was 0.495, 0.526, and 0.550 at Zigui, Wanzhou, and Zhongxian restoration sites, respectively.

Section: Spatial Variation Of the Soil Seed Banks At Vegetation Restomentioning

confidence: 99%

The soil seed bank of a rehabilitated draw‐down zone and its similarity to standing vegetation in the Three Gorges Reservoir Area

Zhang

et al. 2017

Ecological Research

“…The results of the current experiment showed that the soil seed bank of B. ichangensis, D. chinense and C. paucinervis would still be able to germinate during the next spring after one flooding cycle in the drawdown zone. However, seed viability and germination ability differ after flooding because different plant species have different flood-resistance abilities (Walls et al 2005;Vidal et al 2014). The seeds of B. ichangensis and D. chinense were best adapted to short-term flooding, and the seeds of C. paucinervis are even adapted to long-term flooding.…”

Section: Discussionmentioning

confidence: 99%

Effects of flooding on seed viability and nutrient composition in three riparian shrubs and implications for restoration

Journal of Freshwater Ecology

et al. 2018

2018) Effects of flooding on seed viability and nutrient composition in three riparian shrubs and implications for restoration, Journal of Freshwater Ecology, 33:1, 449-460, ABSTRACTConstructions of large reservoirs (all over the world) have resulted in the degradation of riparian vegetation. The coverage and species biodiversity of riparian communities in the Three Gorges Reservoir area have dramatically decreased since the completion of the Three Gorges Project. The responses of three shrub seeds to flooding time were examined to investigate the potential use of soil seed banks for the ecological restoration of the drawdown zone in the Three Gorges Reservoir Area. The effects of flooding time on seed viability and seed nutrient composition for the riparian shrubs Buxus ichangensis, Cornus paucinervis and Distylium chinense were tested by simulating 0, 5, 6, 7, 8 and 9 month flooding periods under a controlled experiment. Results showed that seed viability decreased with the length of flooding treatment. Seeds of all three shrubs displayed relatively high viability and remained viable after six months of flooding. However, seed viability significantly decreased after seven months of flooding. After nine months of flooding, the seed viability of B. ichangensis, C. paucinervis and D. chinense decreased by 86.14%, 24.03% and 43.43%, respectively, compared with a non-flooded control. The protein, starch and soluble sugar content of seeds from the three shrubs decreased with flooding time. The seed bank samples of D. chinense and B. ichangensis showed the highest tolerance against short-term flooding, while the seeds of C. paucinervis exhibited the strongest tolerance against long-term flooding. ARTICLE HISTORY

“…For wetland soil seed banks, appropriate submersion favours seed germination and improvement of plant species diversity (Ge, Liu, & Wang, ; Goodman et al, ). However, long‐term submersion can cause changes in soil oxygen content, water content, and temperature, which in turn affect seed germination in soil seed banks (Vidal, Andrade, Andrade, & Mielke, ; Wang, Jiang, Lu, & Wang, ). Plant seeds maintain their own physiological activities under submerged conditions through anaerobic respiration, often consuming a large amount of nutrients, which is relatively inefficient relative to aerobic respiration (Gomes & Garcia, ; Kestring, Klein, & Rossi, ).…”

Section: Discussionmentioning

confidence: 99%

“…For wetland soil seed banks, appropriate submersion favours seed germination and improvement of plant species diversity (Ge, Liu, & Wang, 2013;Goodman et al, 2011). However, long-term submersion can cause changes in soil oxygen content, water content, and temperature, which in turn affect seed germination in soil seed banks (Vidal, Andrade, Andrade, & Mielke, 2014;Wang, Jiang, Lu, & Wang, 2013).…”

Section: Effects Of Reversal Seasonal Submersion On the Germinationmentioning

confidence: 99%

“…Plant seeds maintain their own physiological activities under submerged conditions through anaerobic respiration, often consuming a large amount of nutrients, which is relatively inefficient relative to aerobic respiration (Gomes & Garcia, 2013;Kestring, Klein, & Rossi, 2009). The vitality of plant seeds decrease and their germination capability is gradually lost after prolonged submersion (Dixon, 2003;Vidal, et al, 2014). Finally, the number of germinated plant species and their seeds in the seed bank is declining, thereby resulting in the degradation of the soil seed banks (Nicol, Ganf, & Pelton, 2003;Robertson & James, 2007).…”

Section: Effects Of Reversal Seasonal Submersion On the Germinationmentioning

confidence: 99%

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Effects of reverse seasonal submersion on the germination and persistence of soil seed banks in hydro‐fluctuation belts

et al. 2018

Ecohydrology

The construction of the Three Gorges Dam has resulted in the occurrence of reverse seasonal water‐level fluctuations. The species composition and quantity of riparian soil seed banks collected from four hydro‐fluctuation belts were assessed by simulating different submersion cycles to determine the effects of reverse seasonal water‐level fluctuations on the germination and persistence of soil seed banks in the Three Gorges Reservoir Region. Results showed the number of species that germinated from the soil seed bank decreased with submersion. The number of germinated seeds in soil seed banks after submersion for 7 months in Xingshan, Zigui, Wanzhou, and Zhongxian decreased by 60%, 53%, 57%, and 57%, respectively, relative to the control. The species diversity index and seed density of germinated seeds in soil seed banks also significantly decreased with prolongation of submersion time. Seed density decreased by 93%, 83%, 76%, and 72%, respectively, after 7 months of submersion. Species composition and dominance within the soil seed bank changed over time due to submersion. In general, reverse seasonal submersion negatively impacts the germination and persistence of soil seed banks. The response of soil seed bank germination and persistence to reverse seasonal submersion became the key factor determining the heterogeneity in the spatial distribution of the soil seed bank in hydro‐fluctuation belts due to the large differences in submersion time between areas at various elevations.