Flowing Water Habitats Research Articles

Effects of Starve and Shelter Availability on the Group Behavior of Two Freshwater Fish Species (Chindongo demasoni and Spinibarbus sinensis).

In complex environments, fish often suffer from reduced physiological functioning due to starvation, which may have a significant effect on their behavioral adaptive strategies to predator attacks. We selected qingbo (Spinibarbus sinensis, which prefers flowing water habitats) and demasone cichlid (Chindongo demasoni, which prefers still water habitats), to investigate the differences in group distribution and dynamics between the two species when faced with a simulated predation attack under different trophic states (fasted for 2 weeks or fed). We chose to conduct our experiments in a six-arm maze that included a central area and six arms of equal length and width and to obtain evidence of how the fish used the various areas of the maze to respond to simulated predation attacks. We found that the two fish species differed in their responses to simulated predation attacks under different trophic states. The group structure of the two species was relatively stable, and the effect of fasting on the qingbo group was not significant, whereas the demasone cichlid group was more susceptible to the effects of fasting, shelter and a simulated predation attack. In an environment with shelter, both species had the same anti-predator strategy and tended to enter the shelter arm to hide after encountering a simulated predation attack. However, differences in the anti-predator strategies of the two species emerged in the no-shelter environment, with the qingbo tending to enter the arm to hide, whereas the demasone cichlid group chose to enter the central area to congregate, and this phenomenon was more pronounced in the fasted group. In conclusion, our research shows that even group-stable fish may shift their anti-predation strategies (i.e., entering a shelter to hide shifts to aggregating in situ into a shoal) when starved and that the worse the swimming ability of the fish, the more affected they are by starvation.

Assessing the Impacts of Changing Connectivity of Hydropower Dams on the Distribution of Fish Species in the 3S Rivers, a Tributary of the Lower Mekong

Hydropower plants (HPPs) create barriers across rivers and fragment aquatic ecosystems, river reaches and habitats. The reservoirs they create slow the flowing water and convert the riverine into lacustrine ecosystems. The barriers created by HPPs interrupt the seasonal migrations of many fish species, while the reservoirs drive away fish species that are dependent on flowing water habitats. This paper assesses the distribution of fish species in the 3S rivers—Sekong, Sesan and Sre Pok, in Cambodia, Laos and Viet Nam—using IUCN Red List-assessed species distribution by HydroBasin Level 8 from the freshwater reports of the Integrated Biodiversity Assessment Tool (IBAT) and their connectivity with the Mekong. There are currently 61 commissioned dams in the 3S basins and a further 2 under construction, 23 of which are larger than the 30 MW installed capacity. A further 24 HPPs are proposed or planned in these basins. The changes in connectivity caused by the dams are measured by adapting the River Class Connectivity Index (RCICLASS); the original connectivity of the 3S basin taking into account the two major waterfalls in the Sesan and Sre Pok rivers was estimated at 80.9%. With existing dams, the connectivity has been reduced to 23.5%, and with all planned dams, it is reduced further to 10.9%. The resulting re-distribution of fish species occurring throughout the 3S basins is explored, by focusing on migratory guilds and threatened and endemic fish species. With all dams built, it is predicted that the total numbers of species in HydroBasins above the dams will be reduced by 40–50%. The Threatened Species Index is estimated to fall from over 30 near the confluence of the three rivers to less than 10 above the lowest dams on the 3S rivers. The analysis demonstrates how widely available global and regional datasets can be used to assess the impacts of dams on fish biodiversity in this region.

Thermal tolerance of giant salmonfly nymphs (Pteronarcys californica) varies across populations in a regulated river.

Warming of aquatic ecosystems is transforming the distribution, phenology and growth of the organisms dependent upon these ecosystems. Aquatic insects such as stoneflies are especially vulnerable to warming because the aquatic nymph stage of their life cycle depends on cool, well-oxygenated, flowing water habitat. We tracked thermal effects on available aerobic capacity of the aquatic nymph stage of an iconic and vulnerable stonefly species, the giant salmonfly (Pteronarcys californica), to compare habitat thermal regime measurements for two salmonfly populations from habitats separated by a gradient in summer weekly maximum temperatures. Contrary to expectations, the thermal optima range of the warmer habitat population was cooler than for the cooler habitat population. We posit that this unexpected interpopulation variation in thermal response is more strongly driven by diel and seasonal thermal variability than by the highest summer temperatures experienced within respective habitats. Additionally, we show that summer daily maximum temperatures could result in periodic limits in available aerobic capacity to support work of the warmer habitat nymphs and may be the mechanism underlying reduced abundance relative to the upstream cooler habitat population. Our findings provide insight into potential thermal and metabolic mechanisms that could regulate the success of ecological and culturally important aquatic insect species experiencing global change. We conclude that thermal regimes and thermal variation, not just mean and maximum temperatures, are critical drivers of aquatic insect responses to water temperatures.

Vector snail fauna and Schistosoma haematobium transmission patterns in freshwater systems of Ishielu Local Government Area, Ebonyi State, Nigeria

Freshwater snails are widespread in tropical and temperate regions of the world where they serve as intermediate hosts for larval stages of parasitic trematodes which cause schistosomiasis that is endemic in Nigeria. Snail fauna and patterns of Schistosoma haematobium transmission were determined in flowing water habitats (FWH) and stagnant water habitats (SWH) in Ishielu, Local Government Area, Ebonyi State, Nigeria. Snail collection was done using scoop-net and hand-picking techniques. Bulinus species collected were exposed to sunlight/light-induced in laboratory for cercarial shedding. Cercariae were then observed under microscope. 923 snails were collected, 67.7% Lymnaea natalensis, 23.1% Bulinus globosus and 9.2% Bulinus truncatus. Their relative abundance was significantly different (P<0.05). 31.6% Bulinus snails from FWH were infected by S. haematobium whereas 18.5% from SWH were infected. Infectivity of Bulinus spp in each habitat group was not significantly different but was when compared the two groups of habitats (P<0.05). Highest infectivity (45.8%) occurred during dry season peaking in February (45.8%) for FWH and for SWH, highest infectivity occurred during rain peaking in July (26.8%). The transmission potential (T.P) was very high during dry season (93.0%) peaking in February (34.9%) in FWH and very low (0%) for SWH. During rain, the T.P was very high (100%) peaking in July (50%) in SWH and very low (7.0%) for FWH. Pools and rivers in Ishielu are suitable habitats for vector snails wherein season and habitat type influence snail abundance and transmission of Schistosomiasis, the findings of which can help in establishing programmes for proper health awareness and snail control.

Dynamics of a reaction-diffusion-advection model with two species competing in a flow reactor

This paper deals with a reaction-diffusion-advection model arising from a flowing water habitat. In this habitat, two species grow while competing for a single-limited resource. By regarding advection rates of two species as variable parameters, we mainly study the effects of advection rates on extinction and survival of species. More precisely, for the weak-strong competition cases, it turns out that there exists a critical advection rate $ q^{\star}_{1} $ or $ q^{\star}_{2} $, which classifies the global dynamics of the system into two scenarios: (ⅰ) persistence of the species with a strong growth capacity; (ⅱ) extinction of both species. For the evenly matched competition cases, there always exist two critical curves $ \Upsilon_{1} $ and $ \Upsilon_{2} $ for $ q\in(0,q^{\star}_{1}) $ in the $ q-m_{2} $ plane, which may separate competition outcomes into competitive exclusion, bistability and coexistence. These interesting findings indicate that advective movements of species have important biological influence on their competition outcomes in a flowing water habitat.

Fish resources of the early life history stages in the Fuling section of the Three Gorges Reservoir and their responses to hydrological and thermal characteristics

三峡水库调度运行改变了库区江段的水文情势,影响漂流性卵苗在库区江段内的时空分布特征。在水库低水位运行时,具有流水生境特征的库中和库尾江段是产漂流性卵鱼类在整个三峡库区内重要的产卵江段。了解三峡库中和库尾江段产漂流性卵鱼类的早期资源状况及其对水文和水温特征的响应关系,对于采取适宜的保护措施促进鱼类早期资源的恢复具有重要的意义。本文通过2017-2020年5-7月在库中涪陵断面进行的逐日早期资源监测,了解三峡库中和库尾江段产漂流性卵鱼类早期资源的种类组成、产卵规模、产卵场分布及其年际变动特征,并采用随机森林(RF)模型,分析鱼类逐日产卵规模变动与水文、水温格局及其过程的关系,辨识影响不同种类产卵规模变动的关键水文及水温要素。结果表明:2017-2020年共采集到漂流性鱼卵21种,包括长江上游特有鱼类鱼卵3种;以圆筒吻鮈Rhinogobio cylindricus、蒙古鲌Chanodichthys mongolicus、贝氏Hemiculter bleekeri等6种鱼类的鱼卵为主,占总采集鱼卵数的88.76%;各年的鱼卵规模分别为83.04×10⁸、14.29×10⁸、20.43×10⁸和22.83×10⁸ 粒;涪陵以上干流江段分布有6个鱼类的集中产卵场,是圆筒吻鮈、长鳍吻鮈R. ventralis、长薄鳅Leptobotia elongata等长江上游特有鱼类重要的产卵场所;逐日产卵规模主要受产卵时透明度及流量大小、产卵前流量或水位上涨过程以及产卵前积温大小的影响,且影响不同鱼类自然繁殖的关键水温、水文因素在不同种类间存在差异。研究结果可为三峡库区鱼类资源保护措施特别是生态调度措施的实施提供科学依据。;Reservoir operation resulting from river damming has altered the flow regimes of the river sections of reservoirs, inducing profound impacts on the spatiotemporal distribution of the early resources of fish species that spawn drifting eggs (FSDE) in the river sections of reservoirs. During the period of low water-level operation stage of the reservoir, the river section with flowing-water habitats is an important spawning river section compared those other sections of the reservoir. Fully understanding the status of early resource of FSDE and their response to hydrological and thermal characteristics in a reservoir's middle and tail reaches is of great significance for the restoration and promotion the scale of early resource. This paper intended to reveal the inter-annual variation in the species composition of eggs and larvae collected, as well as the spawning scale and distribution of fish spawning grounds in the middle and tail reaches of the Three Gorges Reservoir (TGR), through the daily sampling for eggs and larvae being conducted at the Fuling section from May to July in 2017-2020. The random forest model was further performed to clarify the relationships between the variations in the daily spawning scales and the hydrological, thermal patterns and process conditions, aiming to identify the key hydrological and thermal factors affecting the variations of spawning scales of different species. The results showed that: 1) 21 species of eggs were collected, including 3 species of fish eggs that endemic to the upper reaches of the Yangtze River, and the amounts of eggs of 6 fish species, including Rhinogobio cylindricus, Chanodichthys mongolicus, and Hemiculter bleekeri, etc., were dominant, which accounted for 88.76% of total number of eggs collected. 2) The scale of fish eggs each year was 83.04×10⁸ ind., 14.29×10⁸ ind., 20.43×10⁸ ind., and 22.83×10⁸ ind., respectively. 3) There were 6 main spawning grounds distributed in the upstream of Fuling sampling site in the TGR, where is an important spawning place for endemic fish species (e.g. R. cylindricus, R. ventralis, and Leptobotia elongata) in the upper reaches of the Yangtze River. 4) The daily spawning scales were mainly affected by the amounts of transparency and flow discharge during spawning, as well as flow or water level rising rate and accumulated water temperature before spawning, and the key hydrological and thermal factors that affect the natural reproduction were different among different species. This research provides data support for the implementation of fish resource protection measures, especially ecological regulation measures, in the TGR.

Coupling field-scale and watershed models for regulatory modeling of pesticide aquatic exposures in streams.

Estimating exposure in receiving waterbodies is a key step in the regulatory process to evaluate potential ecological risks posed by the use of agricultural pesticides. The United States Environmental Protection Agency (USEPA) currently uses the Variable Volume Water Model (VVWM) to predict environmental concentrations of pesticides in static waterbodies (ponds) that receive edge-of-field runoff inputs from the Pesticide Root Zone Model (PRZM). This regulatory model, however, does not adequately characterize potential pesticide concentrations in flowing water systems (streams and rivers) drained from watershed areas. This study aims at addressing this gap by coupling the regulatory PRZM model with a watershed-level hydrological model, the Soil and Water Assessment Tool (SWAT), to predict pesticide concentrations in flowing water habitats for aquatic organisms. This coupled PRZM-SWAT model was applied in a test watershed (~HUC12), a headwater watershed of Goodwater Creek in Missouri, and simulation results at the outlet of this watershed were compared to daily and near-daily measured streamflow and atrazine concentration data from a decade-long sampling campaign. Overall, the PRZM-SWAT model captured (1) the general magnitude and temporal trend of daily atrazine concentrations, (2) the observed high-end of exposure levels (>3 ppb) of atrazine concentrations, and (3) the 90th centile annual maximum for various exposure durations (1-, 4-, 7-, 21-, and 60-day rolling average), which are important exposure metrics used in assessing the potential ecological risks posed by the application of pesticides. The PRZM-SWAT model is expected to expand the utility of the field-scale regulatory model to include pesticide exposure prediction capability in flowing waterbodies from agricultural watersheds. Integr Environ Assess Manag 2022;18:1678-1693. © 2022 SETAC.

Noise constrains the evolution of call frequency contours in flowing water frogs: a comparative analysis in two clades

BackgroundThe acoustic adaptation hypothesis (AAH) states that signals should evolve towards an optimal transmission of the intended information from senders to intended receivers given the environmental constraints of the medium that they traverse. To date, most AAH studies have focused on the effect of stratified vegetation on signal propagation. These studies, based on the AAH, predict that acoustic signals should experience less attenuation and degradation where habitats are less acoustically complex. Here, we explored this effect by including an environmental noise dimension to test some AAH predictions in two clades of widespread amphibians (Bufonidae and Ranidae) that actively use acoustic signals for communication. By using data from 106 species in these clades, we focused on the characterization of the differences in dominant frequency (DF) and frequency contour (i.e., frequency modulation [FM] and harmonic performances) of mating calls and compared them between species that inhabit flowing-water or still-water environments.ResultsAfter including temperature, body size, habitat type and phylogenetic relationships, we found that DF differences among species were explained mostly by body size and habitat structure. We also showed that species living in lentic habitats tend to have advertisement calls characterized by well-defined FM and harmonics. Likewise, our results suggest that flowing-water habitats can constrain the evolutionary trajectories of the frequency-contour traits of advertisement calls in these anurans.ConclusionsOur results may support AAH predictions in frogs that vocalize in noisy habitats because flowing-water environments often produce persistent ambient noise. For instance, these anurans tend to generate vocalizations with less well-defined FM and harmonic traits. These findings may help us understand how noise in the environment can influence natural selection as it shapes acoustic signals in affected species.

Diversity of dragonflies (Insecta: Odonata) in Ujung Kulon National Park

Ujung Kulon National Park is a lowland tropical forest that was still preserved. There was limited information about the diversity of dragonflies in Ujung Kulon National Park. The purpose of this study was to study species diversity of dragonfly in Ujung Kulon. The research was conducted in Ujung Kulon Peninsula, Banten, Indonesia in five locations and three types of aquatic habitats i.e., natural ponds, streams in forests, and rivers. The transect line method is used to collect adult dragonflies. Thirty-one species of dragonflies belong to two anisopteran families and six zygopteran families were reported in this study. Twenty-two species were as new records based on previous publications. There were different species compositions in all habitat types (R = 1, p = 0.0016, one-way ANOSIM with Bray-Curtis similarity index). Natural ponds have the highest anisopteran species richness compared to other habitats. Eight species Anisoptera only were found in natural ponds. Meanwhile, zygopteran species prefer in flowing water habitat.

Egestion of plant propagules by turtles in a small Massachusetts river

ABSTRACTEvidence from flowing-water habitats has confirmed a role of turtles regarding the effective internal transport and viability of riparian plant seeds. We assessed potential propagule dispersal by Eastern painted turtles (Chrysemys picta) within a small river in Massachusetts and factors that may influence the diversity and abundance of egested propagules. From August–October 2015 and June–October 2016, we captured 69 turtles (28 male and 13 female), recorded standard measurements (sex, size, mass, BCI), and collected their faeces from which we isolated propagules. Propagules, mostly seeds, were observed in a small (28%) group of individuals. Overall, 4808 seeds of four taxa and 62 tubers were recovered. Most turtles (58%) defaecated propagules of just one taxon and number of seeds per turtle was highly variable (1–1506, 253.05 ± 414.55 seeds). Taxon richness, abundance, and Simpson Index of propagules varied significantly by sampling year. Sex-year interaction was also a significant predictor of propagule abundance. No turtle-specific features (sex or BCI) have any significant influence on any of the seeds egested. While our study suggests a minor role for C. picta as mobilisers of river plant propagules, these highly vagile animals may still create intermittent links between spatially isolated populations within and between waterbodies.

Population, sex and body size: determinants of behavioural variations and behavioural correlations among wild zebrafish Daniorerio.

This study (1) investigated variation among populations and the effects of sex and body size on boldness, activity and shoal-association tendency among wild zebrafish, and (2) tested for existence of correlations between behaviours, controlling for sex and body size. Individuals across four natural populations were tested for general activity in a novel situation, number of predator inspections undertaken and tendency to associate with a conspecific shoal in the presence of predators. Results showed a significant effect of population on boldness with a population from high-predation habitat being bolder than populations from low-predation habitats. Males showed significantly higher tendencies than females to associate with a conspecific shoal in the presence of predators. Further, a negative relationship was found between activity and boldness only within two low-predation populations. Individual body size had a strong effect on the activity–boldness relationship within the low-predation population from flowing water habitat. Smaller fish were bolder and less active while larger fish were more cautious and active. Overall, the results indicated that while population-level behavioural responses might be shaped by predation pressure, state-dependent factors could determine behavioural correlations among individuals within populations.

Mineralogical and geochemical features of bacterial mats and travertines of the Khoito-Gol thermal spring (East Sayan)

The mineralogical and geochemical features of the Khoito-Gol ecosystem (fresh thermal waters-microorganisms-travertines) of the Baikal Rift Zone and the aspects of the interaction among its components were studied. The research has shown that the behavior, distribution, and accumulation of trace elements are determined mostly by the geochemical barriers of geologic and biologic genesis in the flowing-water habitat of bacteria of the Khoito-Gol spring. Formation of biominerals by different functional groups of its bacterial community is considered.

Population persistence in flowing-water habitats: Conditions where flow-based management of harmful algal blooms works, and where it does not

Control of harmful algae in the coves or bays of larger water bodies could be accomplished by hydraulic flushing with algae-free water. This suggestion is examined with a mathematical model of a harmful algal population, parameterized to represent the toxic haptophyte Prymnesium parvum, and its limiting nutrient. A small cove with a hydraulic storage zone and longitudinal advection and dispersion is coupled to a larger lake where ongoing or transient blooms serve as a source for the algal population. This population is transported upstream by dispersion and flushed downstream by advection. Morphometry and hydraulics represent a lake in Texas where blooms of P. parvum have been problematic. When dispersion and hydraulic storage are low to moderate, available pumping technology is predicted to be capable of suppressing the algal population within a variable portion of the cove, under both steady state and transient conditions. This suppression occurs when temperature-dependent algal growth is low. At temperatures high enough to support more rapid growth, flow augmentation carries a risk of stimulating a bloom under some hydraulic conditions. The model presented here complements similar models without population sources, and contributes to theoretical understanding of population persistence in reservoirs and other flowing-water habitats.

Background noise as a selective pressure: stream-breeding anurans call at higher frequencies

Acoustic signals are an important part in the behaviour of many species and may play a key role in speciation. However, little is known about the importance of natural selection on the evolution of such signals. Acoustics signals are the main communication channel for most anuran species, and background noise from streams is a constant source of masking interference for species reproducing in these environments. Herein, we test if the noise of flowing water habitats has favoured advertisement calls with higher dominant frequencies in frogs. Phylogenetic generalized least square model analysis revealed a significant influence of reproductive environment and body size on dominant frequency, with no significant interaction between habitat and body size. While stream breeders call at higher dominant frequencies, this acoustic parameter is inversely correlated with body size in both environments. We discuss the biological consequences of long-term adaptive shift in this acoustic parameter and possible trade-offs with other evolutionary forces.

A PDE system modeling the competition and inhibition of harmful algae with seasonal variations

In this paper, we study a reaction–diffusion–advection system modeling the competition of harmful algae with seasonal variations in a flowing water habitat. We assume that harmful algae produce toxins, which have inhibitory effects on their algal competitors, that is, the produced toxins can inhibit the growth of its competitor. For the single population model, we prove that the algae will be washed out eventually if the trivial periodic state is locally asymptotically stable, while there exists a unique positive periodic state which is globally attractive if the trivial periodic state is unstable. When there is mutual invasibility of both semitrivial periodic solutions of the two-species model, we are able to prove the existence of periodic coexistence state.

A reaction–diffusion–advection model of harmful algae growth with toxin degradation

This paper is devoted to the study of a reaction–diffusion–advection system modeling the dynamics of a single nutrient, harmful algae and algal toxin in a flowing water habitat with a hydraulic storage zone. We introduce the basic reproduction ratio R0 for algae and show that R0 serves as a threshold value for persistence and extinction of the algae. More precisely, we prove that the washout steady state is globally attractive if R0<1, while there exists a positive steady state and the algae is uniformly persistent if R0>1. With an additional assumption, we obtain the uniqueness and global attractivity of the positive steady state in the case where R0>1.

Dynamical analysis of a model of harmful algae in flowing habitats with variable rates

This study considers an advection–dispersion–reaction model of harmful algae in a flowing water habitat. The habitat is selected such that the main channel is coupled with a storage zone. The rates are considered to be time dependent instead of constant, which is more natural. The introduction of variable rates makes the system difficult to study. We prove the well-posedness and boundedness using the evolution semigroup approach. Often, it is difficult to find an analytical solution for a given model, thus approximate solutions are very useful and it is important to study them. In the second part, we use a discretization method to find the approximate solution of our model system.

Community structure and photosynthetic activity of benthic biofilms from a waterfall in the maritime Antarctica

High-energy flowing water habitats such as waterfalls are uncommon in Antarctica, though they may become more regular as temperature increase. Both high spatial and temporal environmental variability is expected on them. The extent of their biological colonization will depend on the amount of ecological strategies displayed by the surrounding biota. We report here a study on phototrophic microbenthic communities inhabiting such environment in a stream on the Byers Peninsula of Livingston Island. Five different biofilms were distinguished by colour, and were located in specific microhabitat types in the waterfall, which flowed down a steep canyon. Photosynthetic pigment content and microscopic observations demonstrated a different assemblage of chlorophytes, cyanobacteria and diatoms among them. Biofilms were not randomly distributed in the stream channel, which may be related to water flow, nutrient availability and moisture. The exopolymeric substances content, stoichiometry and pigment composition varied among biofilms, likely reflecting differences in the water and nutrients availability. The photosynthetic rates were in the range of the observed in previous studies in the site and varied according to the habitat within the stream. Communities dominated by chlorophytes were restricted to the central channel, suggesting adaptation to faster flow regime. However, cyanobacterial biofilms appeared in a great range of environmental conditions. They were rare in the central channel where water flow was greatest, but achieved large biomass stocks on submerged and even exposed sites in the splash zone at the edge of the flowing water. This study shows how Antarctic biofilms can have a large variability in community structure and biomass over short length scales, reflecting the range of microhabitats in this Antarctic waterfall ecosystem, and the potential occurrence of different strategies to overcome fluctuating conditions.

Global dynamics of zooplankton and harmful algae in flowing habitats

This paper is devoted to the study of two advection–dispersion–reaction models arising from the dynamics of harmful algae and zooplankton in flowing-water habitats where a main channel is coupled to a hydraulic storage zone, representing an ensemble of fringing coves on the shoreline. For the system modeling the dynamics of algae and their toxin that contains little limiting nutrient, we establish a threshold type result on the global attractivity in terms of the basic reproduction ratio for algae. For the model with zooplankton that eat the algae and are inhibited by the toxin produced by algae, we show that there exists a coexistence steady state and the zooplankton is uniformly persistent provided that two basic reproduction ratios for algae and zooplankton are greater than unity.

Distribution Pattern of Trees in a Hydrological Gradient below the Paran&amp;#225;-Paraguay River Confluence

Riparian and riverine aquatic plant species have evolved within the context of flowing water habitats for which the flooding and droughts are the forcing factors that shape the community features, either through a positive or negative effect on the ecosystem’s function, according to the timing, frequency and magnitude of such events. In the Paraná floodplain landscape, topographic position is a crude indicator of the position along the complex gradient, but it also includes information about flood/drought periods and trees’ resilience to extreme hydrological phases. We present the occurrence of major tree species in riparian forests of the Paraná River on islands of different topographies in a section of the Paraná River downstream from the confluence with the Paraguay River. Our results suggest that each tree species had a preferred position in the topographic gradient, sites where the observed counts were more frequent. This trees species were more frequent between 2 and 8 m in the topographic position and were affected by 5 and 202 hydrosedimentologic pulses between 1949 and 1999. We suggest that knowledge of the distribution curves of the vegetation species present can help draw possible future scenarios of the river landscape. Future engineering works to alter the hydrological dynamics of Paraná should pay more attention to the distribution of riparian forests because they are indicators of changes at the landscape level and they are the support for the wildlife of the river.