The importance of water regimes operating at small spatial scales for the diversity and structure of wetland vegetation

1. In most cases, the most important determinant of wetland vegetation is the water regime. Although water regime is usually described and managed at the scale of whole wetlands, the patterning of vegetation is likely to be determined by water regimes that are experienced at much finer spatial scales. In this study, we assess the significance of internal heterogeneity in water regimes and the role that this heterogeneity plays in vegetation patterning. 2. The effects of water regime on wetland plant species richness and vegetation structure were studied at Dowd Morass, a 1500 ha, Ramsar‐listed wetland in south‐eastern Australia that is topographically heterogeneous. Data on plant variables and water depth were collected along 45 (50 m) transects throughout the wetland and related to water regimes assigned individually for each transect. Wetland plants were assigned to plant functional groups (PFG) that describe the response of plants to the presence or absence of water at different life stages. 3. The classification of water depth data indicated four distinct water regimes in the wetland that were differentiated primarily by the duration of the dry period. Representatives of all PFGs co‐existed over small spatial scales where topographical variation was present, and the richness and cover of understorey species declined as transects became more deeply and permanently flooded. Some PFGs (e.g. amphibious fluctuation tolerator‐low growing and amphibious fluctuation responder‐morphologically plastic) were eliminated by extended periods of flooding, which increased the cover but not richness of submerged plants. Species richness and foliage projective cover declined as water regimes shifted from shallow and frequently exposed conditions to regimes typified by deeper and longer inundation. Cover of the structurally dominant woody species was compromised by deeply flooded conditions but vegetative regeneration occurred despite high water levels. 4. Internal topographical variation generates mosaics of water regimes at fine spatial scales that allow plant species with different water regime requirements to co‐exist over small distances. Deep water and an absence of dry periods result in decreased cover of plants and an overall loss of species richness in the understorey. Water regimes are described that promote regeneration and cover of structurally dominant taxa and increased species richness in the understorey. The study demonstrates a strong association between vegetation and the diverse water regimes that exist within a single wetland, a pattern that will be useful for modelling the effects of modified water regimes on wetland vegetation.     

Hydrologic Regime Controls Soil Phosphorus Fluxes in Restoration and Undisturbed Wetlands

Many wetland restoration projects occur on former agricultural soils that have a history of disturbance and fertilization, making them prone to phosphorus (P) release upon flooding. To study the relationship between P release and hydrologic regime, we collected soil cores from three restoration wetlands and three undisturbed wetlands around Upper Klamath Lake in southern Oregon, U.S.A. Soil cores were subjected to one of three hydrologic regimes—flooded, moist, and dry—for 7.5 weeks, and P fluxes were measured upon reflooding. Soils from restoration wetlands released P upon reflooding regardless of the hydrologic regime, with the greatest releases coming from soils that had been flooded or dried. Undisturbed wetland soils released P only after drying. Patterns in P release can be explained by a combination of physical and biological processes, including the release of iron‐bound P due to anoxia in the flooded treatment and the mineralization of organic P under aerobic conditions in the dry treatment. Higher rates of soil P release from restoration wetland soils, particularly under flooded conditions, were associated with higher total P concentrations compared with undisturbed wetland soils. We conclude that maintaining moist soil is the means to minimize P release from recently flooded wetland soils. Alternatively, prolonged flooding provides a means of liberating excess labile P from former agricultural soils while minimizing continued organic P mineralization and soil subsidence.     

Factors influencing macroinvertebrate colonization of seasonal wetlands: responses to emergent plant cover

1. We conducted field experiments to examine factors influencing macroinvertebrate colonization of seasonally flooded marshes. Few macroinvertebrate species were found aestivating in soils within non-flooded wetlands indicating that most taxa colonize these marshes from other flooded habitats.
2. We manipulated amounts of salt grass ( Distichlis spicata ) to examine how emergent plant cover affects aerial colonization by macroinvertebrates. Areas mowed 3 weeks before flooding had low plant cover, areas mowed 5 and 9 weeks before flooding had medium and high plant cover, respectively, and non-mowed control areas had the most plant cover. Macroinvertebrate numbers and biomass were generally higher in mowed treatment areas than in control areas, but overall diversity was generally higher in high plant cover and control areas than in low plant cover areas.
3. Mosquitoes (Culicidae), brine flies (Ephydridae) and hover flies (Syrphidae) were positively correlated with amount of plant cover, and waterboatmen (Corixidae), midges (Chironomidae) and water scavenger beetles (Hydrophilidae) were negatively correlated with plant cover. Species assemblages changed seasonally among treatment areas because these taxa colonize wetlands at different times in the year.
4. These results demonstrate that invertebrate communities may be different within plant stands with heterogeneous amounts of emergent cover, and management practices that alter the structure of wetland vegetation can influence macroinvertebrate communities colonizing seasonal marshes.     

Impact of flooding on potential and realised grassland species richness

In order to reduce flood risk, river management policies advise floodplain restoration and the recreation of water retention areas. These measures may also offer opportunities for the restoration of species-rich floodplain habitats through rewetting and the restoration of flood dynamics. The potential to enhance biodiversity in such flood restoration areas is, however, still subject to debate. In this paper we investigate whether flooding along a small altered lowland river can contribute to the potential and realised species richness of semi-natural meadows. We compare the seed bank and vegetation composition of flooded and non-flooded semi-natural meadows and test the hypothesis that flooding contributes to an input of diaspores into the meadow seed banks, thereby promoting seed density and potential species richness. Furthermore we hypothesise that, where habitat conditions are suitable, flooding leads to a higher realised species richness. Results showed that seed densities in flooded meadows were significantly higher than in non-flooded meadows. The seed banks of flooded meadows also contained a higher proportion of exclusively hydrochorous species. However, the seed bank species richness, as well as the species richness realised in the vegetation did not differ significantly between flooded and non-flooded meadows. Finally, the seed bank and standing vegetation of flooded sites showed larger differences in species composition and Ellenberg nitrogen distribution than non-flooded sites. From these results we conclude that, although flooding does contribute to the density and composition of the seed bank, most imported seeds belong to only a few species. Therefore, it is unlikely that flooding substantially enhances the potential species richness. Furthermore, even if new species are imported as seeds into the seed bank, it seems unlikely that they would be able to establish in the standing vegetation. However, it is unclear which factors impede the establishment of imported species in the vegetation. The implications of our findings for flood meadow restoration are discussed.     

Hydrologic control of litter decomposition in seasonally flooded prairie marshes

The effect of seasonal inundation on the decomposition of emergent macrophyte litter (Scolochloa festucacea) was examined under experimental flooding regimes in a northern prairie marsh. Stem and leaf litter was subjected to six aboveground inundation treatments (ranging from never flooded to flooded April through October) and two belowground treatments (nonflooded and flooded April to August). Flooding increased the rate of mass loss from litter aboveground but retarded decay belowground. Aboveground, N concentration decreased and subsequently increased earlier in the longer flooded treatments, indicating that flooding decreased the time that litter remained in the leaching and immobilization phases of decay. Belowground, both flooded and nonflooded litter showed an initial rapid loss of N, but concentration and percent of original N remaining were greater in the nonflooded marsh throughout the first year. This suggested that more N was immobilized on litter under the nonflooded, more oxidizing soil conditions. Both N concentration and percent N remaining of belowground litter were greater in the flooded than the nonflooded marsh the second year, suggesting that N immobilization was enhanced after water-level drawdown. These results suggest different mechanisms by which flooding affects decomposition in different wetland environments. On the soil surface where oxygen is readily available, flooding accelerates decomposition by increasing moisture. Belowground, flooding creates anoxic conditions that slow decay. The typical hydrologic pattern in seasonally flooded prairie marshes of spring flooding followed by water-level drawdown in summer may maximize system decomposition rates by allowing rapid decomposition aboveground in standing water and by annually alleviating soil anoxia.     

COMPARISON OF THE VEGETATION OF THREE LOUISIANA SWAMP SITES WITH DIFFERENT FLOODING REGIMES

Net primary productivity and community structure were studied at three adjacent swamp sites that were all once subject to seasonal flooding. Because of man-related activities one is now permanently flooded, and a second is managed on a summer-fall dry period and a winter-spring flooded period. In the permanently flooded area such flood-intolerant trees as green ash are dying while shrubs and aquatic plants are increasing. Competition among overstory trees is reduced, enhancing growth of existing baldcypress and water tupelo trees. Total areal production, however, is low (887 g/m²/yr) because of fewer trees. Productivity in the managed area is high (1,780 g/m²/yr). The baldcypress-water tupelo community is being replaced by a swamp maple-ash community typical of bottomlands. In the natural swamp forest, baldcypress and water tupelo have remained dominant. Canopy closure has limited understory and aquatic growth but has also increased competition among overstory trees, resulting in a slow increase in basal area. Productivity is about 1,166 g/m²/yr. It is suggested that the flooding regime is an important controlling factor in each of the areas.     

Plant Establishment from the Seed Bank of a Degraded Floodplain Wetland: A Comparison of Two Alternative Management Scenarios

There has been little research examining the soil seed banks of degraded floodplain wetlands and their contribution to wetland rehabilitation in Australia. Our aim was to assess the establishment of plants from the seed bank that may occur following the delivery of an environmental water allocation to Kanyapella Basin, a 2950 ha wetland located on the floodplain of the Goulburn and Murray Rivers in northern Victoria, Australia. Two hypothetical water regimes were investigated (flooded and dry) in a glasshouse experiment, where plants were left to establish from the seed bank over a period of 124 days. Differences in the establishment of plants from the seed bank indicated that the return of a flooding regime is likely to have a significant effect on the composition of the wetland vegetation. Mapping of the distribution of plant species indicated that propagules were highly dispersed across the wetland for the majority of taxa, in contrast to the localised distribution of many of the plant species represented in the extant vegetation. Inundation favoured the establishment of native wetland and floodplain plants, although many areas of Kanyapella Basin that are currently ‘weed-free’ have the potential to become colonised and potentially dominated by introduced plants if the wetland is not managed appropriately. Overall, results supported the aim of management to reestablish a wetting and drying regime through use of an environmental water allocation. This study presents a significant example of the application of seed bank investigations in wetland ecology and management.     

塔里木河中游洪水漫溢区荒漠河岸林实生苗更新

以塔里木河中游荒漠河岸林为研究对象,2008年6月至2009年8月,对洪水漫溢区河漫滩裸地、林下及林隙三种生境植物一年生实生苗进行了调查。结果表明：实生苗更新主要依赖洪水漫溢,在非漫溢区没有发现实生苗存在;洪水降低了漫溢区的土壤盐度,更重要的是其提供了宝贵的水分条件,在时间和水量上都有效地满足了胡杨等植物种子萌发和幼株生长的水分需求;河漫滩是河岸林种子实生苗产生的基地,洪水漫溢后的河漫滩种子实生苗密度显著大于其余两生境内实生苗密度,同时该生境内物种多样性也显著高于林下和林隙生境;光照决定着漫溢区实生苗能否成林,光照不同的空间样点上,实生苗发生数量和个体生长均存在显著差异,光照强的河漫滩,实生苗发生数量较多且幼苗能保持较高的生长活力和较多的生物量积累。     

Stonefly predation along a hydraulic gradient: a field test of the harsh—benign hypothesis

SUMMARY. 1. Microhabitat preferences of predatory stoneflies and four prey taxa were assessed by taking benthic samples along a hydraulic gradient in a Black Forest stream in West Germany. Densities of predator and prey species were estimated at twenty-one hydraulic regimes.
2. Enclosures containing the stonefly, Dinocras cephalotes , and control cages with no predators were placed in the substrate at hydraulic regimes favourable and unfavourable to predators. Cages received initial prey communities that were obtained from benthic samples taken at hydraulic regimes matching those intended for each cage.
3. Population densities of the two most numerically important prey taxa, the mayfly. Baetis rhodani , and the Chironomidae, were reduced in the presence of Dinocras , but only when enclosures were placed in the hydraulic regimes favourable to the predator. Thus, predation effects increased as the hydraulic regime became more benign to the predators.
4. Densities of two other prey species rare in the diets of Dinocras ( Hydropsyche instabilis and Gammarus fossarum ) were generally unaffected by predators regardless of the hydraulic regime.
5. These data provide support for the hypothesis that perception of the abiotic regime as harsh or benign to predators is a good predictor of predator impact on densities of preferred prey species. In harsher abiotic regimes, impact will be low, while impact will be high in benign abiotic regimes.     

Structure and species richness of low-diversity floodplain forest on the Rio Tapajós, Eastern Amazonia, Brazil

Rivers in the Amazonian region have annual water level fluctuations varying from 6 to 20m, and the flooding period ranges from 50 to 270 days between the rising and falling phases. Along the rivers there are many different types of vegetation which are annually flooded. In order to study the variation of the species composition and structure of a forest that is seasonally flooded by a clear water river in Brazilian Amazonia 20km SW of Santarém, Pará State, Brazil, we surveyed three hectares, each divided in ten randomly placed rectangular quadrats (10×50m). The number of species per hectare ranged from 21 to 30. The number of trees varied from 242 to 741. Total basal area ranged from 0.70 to 10.9m2. Leguminosae was the most abundant and dominant family in the three hectares sampled. Couepia paraensis (Chrysobalanaceae), Campsiandra laurifolia (Leguminosae) and Leopoldinia pulchra (Palmae) were the most abundant species in the hectares sampled. Similarity indexes at species level varied from 46 to 60% between the three hectares sampled. The hectares studied have the lowest species richness observed in igapó floodplain forest of the Brazilian Amazonia. This may be correlated with the water type, soil condition and proximity of savanna.     

Response of wild mammals to seasonal shrinking-and-expansion of habitats due to flooding regime of the Pantanal, Brazil.

The Pantanal is a large savanna wetland (138,183 km2 in Brazil), important for its wildlife, fed by tributaries of the upper Paraguay River, center of South America (Brazil, touching Bolivia and Paraguay). Uplands are plateaus (250-1,200 m high, 215,000 km2 in Brazil) and flatland is the Pantanal (80-150 m high, 147,574 km2 in Brazil). Rivers are slow moving when they meet the flatland (slope 0.3-0.5 m/km east-west; 0.03-0.15 m/km north-south), periodically overflowing their banks, creating a complex seasonal habitat range. Recurrent shallow flooding occupies 80% of the Pantanal; during the dry season flooded areas dry up. Fluctuating water levels, nutrients and wildlife form a dynamic ecosystem. A flooding regime forms distinct sub-regions within the Pantanal. A mammal survey was carried out in the sub-region of the Rio Negro from April, 2003 through March, 2004 to study the diversity and abundance of terrestrial mammals during the dry and flooding seasons. A total of 36 species were observed in the field. The capybara Hydrochaeris hydrochaeris was the most frequent species, followed by the crab-eating-fox Cerdocyon thous and the marsh deer Blastocerus dichotomus. The highest abundance of species was observed during the dry season (August and September), when there is a considerable expansion of terrestrial habitats, mainly seasonally flooded grassland. Animal abundance (in terms of observed individual frequencies) varied during the dry and wet seasons and the seasonally flooded grassland was the most utilized habitat by mammals in the dry season.     

Expression of Tolerance for Meloidogyne graminicola in Rice Cultivars as Affected by Soil Type and Flooding

The effects of different water regimes on the pathogenicity of Meloidogyne graminicola on six rice cultivars were determined in two soil types in three greenhouse experiments. Two water regimes, simulating continuous flooding and intermittent flooding, were used with five of the cultivars. All cultivars were susceptible to the nematode, but IR72 and IR74 were more tolerant than IR20 and IR29 under intermittent flooding. All were tolerant under continuous flooding. UPLRi-5 was grown under multiple water regimes: no flooding; continuous flooding; flooding starting at maximum tillering, panicle initiation, or booting stage; and flooding from sowing until maximum tillering or booting. In sandy loam soil, M. graminicola reduced stem and leaf dry weight, root dry weight, and grain weight under all water regimes. In clay loam soil, the nematode reduced root weight when the soil was not flooded or flooded only for a short time, from panicle initiation, or booting to maturity, and from sowing to maximum tillering. In clay loam soil, stem and leaf dry weight, as well as grain weight, were reduced by the nematode under all water regimes except continuous flooding or when the soil was flooded from sowing to booting stage. These results indicate that rice cultivar tolerance of M. graminicola varies with water regime and that yield losses due to M. graminicola may be prevented or minimized when the rice crop is flooded early and kept flooded until a late stage of development.     

Linking hydroperiod and vegetation response in Carolina bay wetlands

Hydrology filters propagule bank expression in herbaceous Carolina bays, but the strength of this filter’s effects on community composition at different points along the hydrologic gradient of these southeastern U.S. depressional wetlands is unknown. We used an experimental approach to determine the pattern of vegetation expression from propagule banks of Carolina bays exposed to different hydrologic conditions and gradients. Propagule banks of sediment cores collected from six Carolina bays were placed in bins, each of which was allocated to one of three hydrologic treatments: moist soil (MS), mid-summer drawdown (DD), or flooded (FL). After one season of vegetation development (1995) in the hydrologic treatments, half of the bins were left flat and the remaining were sloped to produce a finer moisture gradient within each bin. We compared taxa richness, community composition based on cover, and cover patterns of eight abundant species that developed in bins over the season (1996) after sloping. Species richness was significantly higher in the moist soil treatment and in sloped bins. Community composition, however, was affected by the hydrologic treatment only and not the finer-scale flooding gradient produced by sloping. Under flooded conditions, floating-leaved and submerged aquatics had higher cover; vegetation converged on simpler, less variable communities dominated by obligate wetland species, with species exhibiting different patterns of abundance over small changes in water depth. Emergent species typically had higher cover in moist soil and drawdown treatments. These results confirm a tight mechanistic link between hydrology and vegetation patterns within Carolina bays, but suggest that the strength of this link is not uniform across the gradient. The linkage weakens with drier conditions as both facultative wetland and upland species recruit into the standing vegetation.     

Factors inhibiting parathion hydrolysis in organic matter-amended soil under flooded conditions

Summary A water-extractable factor that developed in a flooded soil amended with 0.5% glucose or rice straw inhibited the biological hydrolysis of parathion. In glucose-amended flooded soil, the factor was removed by filtration of the standing water through a Millipore filter. Apparently, glucose application enhanced the proliferation of micro-organisms detrimental to parathionhydrolyzing agents. On the other hand, the toxic factor formed in rice straw-amended soil under flooded conditions passed through a Millipore membrane and was not inactivated by steam treatment. The toxicity developed within 36 h after flooding of rice straw-amended soil and persisted for 90 days or more under continued flooding. These studies indicated that a heat-resistant and stable factor with ability to block the hydrolysis of parathion developed in rice straw-amended soil under flooded conditions.     

Distribution and diel migration of macroinvertebrates within dense submerged vegetation

1. We studied vertical and horizontal distribution of macroinvertebrates within a dense stand of Chara spp. in Lake Krankesjön, southern Sweden. Invertebrates were sampled at three depths within the vegetation and at three distances from the vegetation edge during day and night in July and August. Corresponding samples of oxygen content of the water were taken.
2. The densities (number of invertebrates per unit plant biomass) of most invertebrate taxa were generally lower in the upper layers of the vegetation than in the layers close to the sediment. The densities of several taxa ( Asellus aquaticus , Cloëon sp. and Polycentropodidae), as well as total density of invertebrates, were higher at the edge than in the innermost parts of the macrophyte stand, whereas snail densities generally were highest at the innermost sites.
3. Densities of A. aquaticus , Chironomidae larvae and Helobdella stagnalis generally increased at night. These taxa appear to undertake a diel vertical migration within the vegetation, towards, or even down to the sediment in daytime and up into the vegetation, in some cases to the vegetation surface, at night. Factors underlying the diel vertical migration are discussed, as are their ecological consequences.     

Effects of Soil Properties and Flooding on the Mobility and Transformation of Mercury in a Temperate Riparian Wetland

Three fractions of mercury (mobile, semi-mobile, and non-mobile mercury) were detected in the soil of an estuarine wetland in Nansi Lake, which is on the east route of China's South-to-North Water Transfer Project. The correlations between these mercury fractions and soil properties were examined under different levels of toxicity. Furthermore, the effects of two flooding conditions (permanent flooding and seasonal flooding) on mercury mobility were analyzed. Results showed that soil pH was negatively correlated with mobile mercury, whereas semi-mobile mercury was positively correlated with total aluminum, iron, and manganese. Moreover, free alumina was positively correlated with all three fractions of mercury. Our study suggests that high contents of soil acid and free alumina might promote wetlands as “sinks” for mercury sequestration, along with low concentrations of organic matter and manganese. In addition, seasonally flooded wetland might limit the production of toxic mobile mercury more than permanently flooded wetland. Large areas of seasonally flooded wetlands in the watershed are permanently flooded by the water transfer project, which elevates the water level during the dry season. As a result, the potential toxicity of mercury may increase in the watershed during water transfer, which should gain more attention.     

How does the propagule bank contribute to cyclic vegetation change in a lakeshore marsh with seasonal drawdown?

Lakeshore marshes around Liangzi Lake, in the middle reach of the Yangtze River, China, experience annual changes of water level of c. 1.5 m. During the drawdown period, the vegetation is structured by helophytes and emergents; during the rainy season when the dams are closed (June–September) the marshes are flooded and their vegetation rapidly changes to be come dominated by submerged, floating-leaved and tall emergent species. The species composition and abundance of both the marsh seed bank and the vegetative propagule bank were compared with those of the drawdown and flooded vegetation types. These data provided a test of the predictive power of van der Valk's model of northern temperate seasonal vegetation change in a subtropical, freshwater wetland with cyclic vegetational change. The abundant species were detected in the propagule bank. The seed bank was found to determine the species richness of both types of the vegetation, whereas the vegetative propagule bank consisted of the dominants of the drawdown vegetation. Water depth conditions, and the composition of seed and vegetative propagules banks together determine the structure of the standing vegetation during drawdown and flooding. van der Valk's succession model was found to predict the seasonal vegetation change reasonably well. The Chi-square test showed no significant difference between predicted vegetation and actual vegetation in both drawdown and flooding periods.     

Altered stream-flow regimes and invasive plant species: the Tamarix case

Aim  To test the hypothesis that anthropogenic alteration of stream-flow regimes is a key driver of compositional shifts from native to introduced riparian plant species.
Location  The arid south-western United States; 24 river reaches in the Gila and Lower Colorado drainage basins of Arizona.
Methods  We compared the abundance of three dominant woody riparian taxa (native Populus fremontii and Salix gooddingii , and introduced Tamarix ) between river reaches that varied in stream-flow permanence (perennial vs. intermittent), presence or absence of an upstream flow-regulating dam, and presence or absence of municipal effluent as a stream water source.
Results  Populus and Salix were the dominant pioneer trees along the reaches with perennial flow and a natural flood regime. In contrast, Tamarix had high abundance (patch area and basal area) along reaches with intermittent stream flows (caused by natural and cultural factors), as well as those with dam-regulated flows.
Main conclusions  Stream-flow regimes are strong determinants of riparian vegetation structure, and hydrological alterations can drive dominance shifts to introduced species that have an adaptive suite of traits. Deep alluvial groundwater on intermittent rivers favours the deep-rooted, stress-adapted Tamarix over the shallower-rooted and more competitive Populus and Salix . On flow-regulated rivers, shifts in flood timing favour the reproductively opportunistic Tamarix over Populus and Salix , both of which have narrow germination windows . The prevailing hydrological conditions thus favour a new dominant pioneer species in the riparian corridors of the American Southwest. These results reaffirm the importance of reinstating stream-flow regimes (inclusive of groundwater flows) for re-establishing the native pioneer trees as the dominant forest type.     

Wetlands for northern pike (Esox lucius L.) recruitment in the Baltic Sea

In recent decades, wetlands have been constructed or restored around the Baltic sea to counteract the eutrophication of its coastal waters. Some of these wetlands could also be suitable spawning and nursery areas for anadromous northern pike (Esox lucius L.). We studied juvenile pike production in three coastal wetlands along the south-eastern coast of Sweden that were restored in different ways. Where terrestrial vegetation was temporarily flooded, pike larval/juvenile emigration increased from a few thousand individuals before restoration to over a hundred thousand afterwards. We suggest that vegetation was the key to this successful reproduction, as wetlands where vegetation was removed or reduced saw no similar increase in pike production. Flooded vegetation in shallow waters offers optimal spawning conditions, increased food resources, and refuge from predation. The growth and emigration of larvae and juveniles were followed over time, revealing that 80–95% of individuals left the wetlands within 1 month (at a size <6 cm). This emigration probably represents an adaption to seasonally decreasing water levels but may also be a way to avoid cannibalism.     

河水漫溢对塔里木河下游荒漠河岸林地表植被与土壤种子库的影响

采用种子萌发法,研究了河水漫溢对塔里木河下游荒漠河岸林地表植被与土壤种子库的影响.结果表明：塔里木河下游漫溢区地表植被分属8科13属14种,非漫溢区为10科21属26种植物;与非漫溢区相比,漫溢区地表植被中出现了一些浅根系和喜湿的草本植物;漫溢区单位面积物种数、植被盖度、植株密度、物种多样性指数和丰富度指数均比非漫溢区有明显增加.漫溢区土壤种子库中有物种19种,比非漫溢区增加了5种;漫溢区土壤种子库总密度比非漫溢区增加了3.94倍;与非漫溢区相比,漫溢区1年生草本植物种子的比例增加了23.07%,而灌木植物种子比例减少了20.99%;多年生草本的变化则不明显;河水漫溢提高了土壤种子库的生物多样性.漫溢区和非漫溢区土壤种子库与地表植被的共有物种分别为18和9种,土壤种子库与地表植被的相似性系数分别为0.842和 0.667.