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The presence of vegetation in rivers, streams and riparian zones affects significantly the flow field and consequently the resistance, pollutant dispersion, sediment transport and ecological habitat. In this paper, a comparative study is undertaken to investigate the effect of an array of simple rigid or compound semi-flexible elements, resembling submerged small plants, on key features of the flow field. . Measurements were taken by means of a 3-D ADV instrument at selected locations within the vegetation array and downstream of it. Vertical profiles of the (temporal mean) velocities and turbulent shear stresses were obtained and compared.

A fluid–structure interaction (FSI) methodology is presented for simulating elastic bodies embedded and/or encapsulating viscous incompressible fluid. The fluid solver is based on finite volume and the large eddy simulation approach to account for turbulent flow. The structural dynamic solver is based on the combined finite element method–discrete element method (FEM-DEM). The two solvers are tied up using an immersed boundary method (IBM) iterative algorithm to improve information transfer between the two solvers. The FSI solver is applied to submerged vegetation stems and blades of small-scale horizontal axis kinetic turbines. Both bodies are slender and of cylinder-like shape. While the stem mostly experiences a dominant drag force, the blade experiences a dominant lift force. Following verification cases of a single-stem deformation and a spinning Magnus blade in laminar flows, vegetation flexible stems and flexible rotor blades are analysed, while they are embedded in turbulent flow. It is shown that the single stem’s flexibility has higher effect on the flow as compared to the rigid stem than when in a dense vegetation patch. Making a marine kinetic turbine rotor flexible has the potential of significantly reducing the power production due to undesired twisting and bending of the blades. These studies point to the importance of FSI in flow problems where there is a noticeable deflection of a cylinder-shaped body and the capability of coupling FEM-DEM with flow solver through IBM.

An analysis of flow was carried out in this study to find the effects of trees on the flow structure in a straight compound open channel. To resemble the vegetation stem, two rows of vertic...

The drag induced by flow through vegetation is affected by the velocity, shape of vegetation stems and wake interference among stems. To account for the interference effects, previous works generally related the bulk drag coefficient of vegetation to the solid volume fraction ϕ of the vegetated zone, and the trends of the results were found to be inconsistent. In this work, a systematic laboratory study has been carried out to investigate the effect of the distribution pattern of vegetation stems on the hydrodynamics of gradually varied flow through emergent blade-type vegetation. The finite artificial vegetation patches of solid volume fractions ranging from 0.005 to 0.121 have been used and the stem Reynolds number ranges from 500–2600. The longitudinal water surface profiles have been measured, and the effect of increasing roughness density with respect to varying longitudinal and lateral spacing under the flow conditions is examined. The momentum equation that relates the vegetation resistant force and water surface profile has been used to obtain the mean bulk drag coefficient C d of the canopy. The results show that C d decreases with increasing stem Reynolds number, decreases with increasing ϕ at fixed lateral spacing due to sheltering effect, and increases with ϕ at fixed longitudinal spacing due to channeling effect. An empirical equation has been obtained relating C d to the lateral and longitudinal spacing instead of ϕ .

This paper develops the virtual cylinder model (VCM) to simulate flows through vegetation canopies at low to medium high Reynolds numbers in wetlands. Using a combined Eulerian and Lagrangian approach, the VCM is capable of simulating the flow field around each vegetation stem (modeled as a cylinder) as well as a bulk of numerous stems in a fluid. Numerical results of flows through regularly and randomly arranged cylinders have been compared with direct numerical simulations. Good agreement has been achieved. This model maintains an excellent balance between accuracy and efficiency in modeling interactions between the fluid and vegetation stems. Simulation results demonstrate that this model is promising for investigating the hydrodynamics and vegetation resilience in wetlands that serve as a first line of defense against the sea level rise, storm impacts and coastal erosion.

Vegetation plays an important role in soil erosion control, but few studies have been performed to quantify the effects of vegetation stems on hydraulics of overland flow. Laboratory flume experiments were conducted to investigate the potential effects of vegetation stems on Reynolds number, Froude number, flow velocity and hydraulic resistance of silt-laden overland flow. Cylinders with diameter D of 2·0, 3·2 and 4·0 × 10−2 m were glued onto the flume bed to simulate the vegetation stems, and a bare slope was used as control. The flow discharge varied from 0·5 to 1·5 × 10−3 m3 s−1 and slope gradient was 9°. Results showed that Reynolds number on vegetated slope was significantly higher than that on bare slope because of the effect of vegetation stems on effective flow width. All the flows were supercritical flow, but Froude number decreased as D increased, implying a decrease in runoff ability to carry sediment. The mean flow velocity also decreased with D, while the velocity profile became steeper, and no significant differences were found in surface flow velocities among longitudinal sections on all slopes. Darcy–Weisbach friction coefficient increased with D, implying that the energy consumption of overland flow on hydraulic resistance increased. Reynolds number was not a unique predictor of hydraulic roughness on vegetated slopes. The total resistance on vegetated slopes was partitioned into grain resistance and vegetation resistance, and vegetation resistance accounted for almost 80% of the total resistance and was the dominant roughness element. Further studies are needed to extend and apply the insights obtained under controlled conditions to actual overland flow conditions. Copyright © 2015 John Wiley & Sons, Ltd.

Exchange between wetland surface water and the atmosphere is driven by a variety of motions, ranging from rainfall impact to thermal convection and animal locomotion. Here, we examine the effect of wind-driven vegetation movement. Wind causes the stems of emergent vegetation to wave back and forth, stirring the water column and facilitating air-water exchange. To understand the magnitude of this effect, a gas transfer velocity (k600-value) was measured via laboratory experiments. Vegetation-waving was studied in isolation by mechanically forcing a model canopy to oscillate at a range of frequencies and amplitudes matching those found in the field. The results show that stirring due to vegetation-waving produces k600-values from 0.55 cm/hr to 1.60 cm/hr. The dependence of k600 on waving amplitude and frequency are evident from the laboratory data. These results indicate that vegetation-waving has a non-negligible effect on gas transport; thus it can contribute to a mechanistic understanding of the fluxes underpinning biogeochemical processes.

Results of an experimental study on the drag force measurement involving a single stem kept in a channel flow stem array are presented. The data collected herein and those from literature indicate that the stem drag coefficient logarithmically increases with the areal stem density. The stem Reynolds number is noticed to have only a small effect on the stem drag coefficient which was however found to depend on the stem staggering pattern. The drag coefficient is less influenced by the Froude number in subcritical flows but it decreases with the Froude number in supercritical flows. New relationships are proposed for the stem drag coefficient which appear useful in partitioning the total flow resistance of vegetated bed streams into the stem and the bed particle resistances. The bed particle resistance applies to sediment transport through such vegetated flows for which the average flow velocity is available.

Based on the momentum approach, the authors have conducted extensive flume experiments to measure the drag force FD on a smooth surface single stem in an array of stems. A dimensional analysis was ...

We quantified and compared movement and microhabitat use of Eastern Copperheads (Agkistrodon contortrix) in fragmented and unfragmented habitats to determine the effects of fragmentation on movement and habitat use. We used thread bobbins to track movement and calculate straight-line distance (SLD) moved, total distance (TDM) moved, and occupied area for individual snakes. Microhabitat use was characterized by quantifying number of trees, woody vegetation stems, herbaceous vegetation stems, percent grass coverage, and percent canopy coverage at each location a snake was observed, and at an equal number of randomly selected locations. Neither SLD nor TDM differed between fragmented and unfragmented habitats. Overall average SLD moved was 24.1 m and TDM was 39.6 m over 48 h. Although SLD and TDM did not differ between sites, mean occupied area ± standard error was significantly greater at the unfragmented (2,310.9 ± 272.7 m) compared with the fragmented site (1,025.9 ± 314.9 m). Microhabitat features were similar between the fragmented and unfragmented sites, and herbaceous vegetation and high canopy cover were associated with locations where snakes were observed at both sites. It is likely that Eastern Copperheads can persist in a variety of habitats in the southeastern United States because their preferred microhabitat features are widely distributed and common in both fragmented and unfragmented environments, demonstrating that they retain characteristics of a habitat specialist within heterogeneous environments suitable for generalists.

For shore protection under extreme wave climates, a simple platform, vegetation stems, and vegetation roots were used to assemble a new type of vegetated platform breakwater. To study the interaction of a solitary wave with it, a 2-D numerical model was conducted using a macroscopic approach based on the OlaFlow solver. The numerical model was well-validated using the experimental data in the literature. The simulated results indicate that the simple platform plays a significant role, and the vegetation plays a supporting role in wave damping. The vegetation roots tend to perform better than stems in reducing wave transmission. However, the roots always contribute to diminishing the wave elevation oscillation and sub-peak in the undulating tails. In addition, the velocity distributions of the green water and underflow above and below the platform are investigated to determine the individual drag coefficients for vegetation stems and roots, respectively. In detail, the effects of the relative incident solitary wave height, relative stem height and root height, vegetation density, and relative platform width on the hydrodynamic coefficients of vegetated platforms are discussed. Finally, empirical equations are proposed for predicting the wave transmission and reflection for a solitary wave propagating over the simple platform and the vegetated platform.

The present study addresses the drag owing to the presence of vegetation and turbulent characteristics in a mobile bed channel, characterized by fully submerged vegetation formed by nonuniform vegetation densities. The influence of seepage on the velocity profiles, Reynolds stress, and turbulence intensities is discussed. Experimental results show that vegetation density is one of the important parameters that affect the flow resistance. It is found that higher vegetation density when placed at the downstream side leads to a reduction in velocity, Reynolds stress, and turbulent intensities. Downward seepage increases the near bed velocity, Reynolds stress, and turbulent intensities. Moment analysis shows that there is an increase in the inrush of flow, and sediment particles are transported more toward the streamwise direction with the application of seepage. The dominance of sweep events over ejection events increases more sediment transport. However, high vegetation density when placed at the downstream portion slightly decreases the dominance of sweep event. Drag coefficient decreases near the vegetation top and increases near the bed. Downward seepage decreases the effect of drag offered by the vegetation stems. The reduction in flow characteristics, viz., velocity, Reynolds stress, turbulent intensities, in the downstream portion of lesser spacing vegetation stems is attributed an increased drag coefficient.

A numerical model based on the double-averaged (spatial and ensemble averaged) method has been developed to simulate vegetated free surface flows. The classical $$k - \varepsilon$$ model is modified by including additional turbulence generation and dissipation terms. These new terms consider the large-scale turbulence generated by shear flows near the flow-vegetation interface and the small-scale wake turbulence generated by the flow separation behind vegetation stems. A new damping function is introduced in the turbulence closure model to suppress the wake turbulence inside the vegetation domain if the shear-generated turbulence is dominant. A series of dense emergent and submerged vegetated flows experiments have been conducted and the velocities have been measured by ADV (Acoustic Doppler Velocimetry) and PIV (Particle Image Velocimetry) at different locations. The experimental results show that the turbulence characteristics near each stem in a group of cylinders are similar to that of a single cylinder, even when the vegetation is dense. The measured data are then used to calibrate the new turbulence closure model. The numerical model is further validated against other published laboratory data of both dense and sparse emergent, submerged and floating vegetated flows. The comparisons show that the new model provides consistently better predictions for mean velocity and turbulence kinetic energy than those by using the existing models.

Numerous studies focus on flow and mixing within cylinder arrays because of their similarity to vegetated flows. Randomly distributed cylinders are considered to be a closer representation of the natural distribution of vegetation stems compared with regularly distributed arrays. This study builds on previous work based on a single, fixed, cylinder diameter to consider non-uniform cylinder diameter distributions. The flow fields associated with arrays of randomly distributed cylinders are modeled in two dimensions using the ANSYS Fluent Computational Fluid Dynamics software with Reynolds Stress Model turbulence closure. A transient scalar transport model is used to characterize longitudinal and transverse mixing (Dx and Dy) within each geometry. The modeling approach is validated against independent laboratory data, and the dispersion coefficients are shown to be comparable with previous experimental studies. Eight different cylinder diameter configurations (six uniform and two non-uniform) are considered, each at 20 different solid volume fractions and with seven different transverse positions for the injection location. The new dispersion data cover a broad range of solid volume fractions, for which simultaneous estimates of Dx and Dy have not been available previously. There are no systematic differences in non-dimensional Dx and Dy between uniform and non-uniform cylinder diameter distributions. When non-dimensionalized by cylinder diameter, both dispersion coefficients are independent of solid volume fraction. When non-dimensionalized by cylinder spacing, both longitudinal and transverse dispersion can be described as linear functions of the ratio of cylinder diameter to cylinder spacing.

The sediment transport capacity plays a pivotal role in erosion research, and is usually predicted using hydraulic variables. The transport capacity and hydraulic variables are affected by vegetation cover. Our understanding of the effect of vegetation cover, including the size, density, and arrangement of vegetation stems, on the relationship between the sediment transport capacity and hydraulic variables were rather limited. The objectives of this study were to investigate the effect vegetation stem cover on the relationship between hydraulic variables and the sediment transport capacity and to derive an equation for predicting the sediment transport capacity in the presence of vegetation cover. Five data sets from 288 flume experiments with a wide range of discharge (0.25–2 × 10−3 m3 s−1), slope (8.8–42.3%), median sediment diameter (0.11–1.16 × 10−3 m), stem cover (0–30%), stem diameter (2–36 mm), and stem arrangement (bead, tessellation, zigzag, random, and banding) were compiled for this study. Extensive regression analysis has shown that the sediment transport capacity could be expressed as a power function of flow velocity, shear stress, stream power, or unit stream power. Predictors of the sediment transport capacity were ranked from the unit stream power as the strongest, followed by the stream power, flow velocity, and the shear stress. Vegetation stem cover had no apparent and direct effect on the relationship between hydraulic variables and the sediment transport capacity so long as the unit stream power or stream power was used as its predictor. Vegetation cover became a significant factor only when the shear stress was used to predict the sediment transport capacity. Finally, a new equation involving the slope gradient, flow velocity, and median sediment diameter in a nondimensional form was shown to be a superior predictor of the sediment transport capacity with the Nash–Sutcliffe coefficient of efficiency of 0.92. The product of slope and flow velocity, that is, the unit stream power, captures the effect of vegetation stem cover and surface roughness and was shown to be an effective predictor of the transport capacity in the presence of vegetation cover.

A set of laboratory experiments were conducted to study the impact of vegetation on bed form resistance and bed load transport in a mobile bed channel. Vegetation stems were simulated by using arrays of emergent polyvinyl chloride (PVC) rods in several staggered configurations. The total flow resistance was divided into bed, sidewall, and vegetation resistances. Bed resistance was further separated into grain and bed form (i.e., ripples and dunes) resistances. By analyzing experimental data using the downhill simplex method (DSM), we derived new empirical relations for predicting bed form resistance and the bed load transport rate in a vegetated channel. Bed form resistance increases with vegetation concentration, and the bed load transport rate reduces with vegetation concentration. However, these conclusions are obtained by using experimental data from this study as well as others available in the literature for a vegetated channel at low concentration.

Vegetation cover can effectively prevent soil erosion and plays an important role in soil and water conservation. Accurate estimation of the sediment transport capacity (Tc) is critical for soil erosion models. Tc data for different levels of vegetation cover, however, are quite limited. The objectives of this study were to evaluate the influence of stem basal cover, slope gradient and discharge on the transport capacity of overland flows for Tc prediction. A non-erodible flume (5 m long and 0.37 m wide) was used in this study. The discharge ranged from 0.5 × 10−3 to 2 × 10−3 m3 s−1, the slope gradient was from 8.8% to 25.9% and an artificial stem basal cover of 0, 1.25%, 2.5%, 5%, 10%, 15%, 20%, 25% and 30% was used to represent the natural vegetation. Stems 2 mm in diameter were randomly arranged. The sediment size for the experiment ranged from 0.25 to 0.59 mm with a median diameter of 0.35 mm. The results show that the measured Tc decreased exponentially as the stem basal cover increased, and the rate of decrease was far greater than what has been reported in the literature. The transport capacity was affected more by the stem basal cover than by slope and discharge when the cover exceeded approximately 2–3%. The research shows that the surface or stem basal cover plays a critical role in reducing the transport capacity of overland flows.

This study presents an experimental study on bed-load transport in the presence of emergent vegetation, which is simulated using uniformly sized circular cylinders arranged in a homogeneous distribution. The spatial variability of bed-load fluxes in vegetated flows is first examined. Then a model is proposed for evaluating the bed-load transport rate based on the scour holes that form around the vegetation stems. The influences of spatial variability and intensified turbulence on sediment transport are finally considered by relating the dimensionless transport rate and flow intensity to the stem size and vegetation density. The derived formula for predicting the bed-load transport rate in vegetated flows is applicable for weak to moderate transport conditions. Nanyang Technological University Published version The first author would gratefully acknowledge the financial support from the NTU Research Scholarship. The authors would also gratefully acknowl-edge the financial support from the National Natural Science Foundation of China (Grant No. 51979242) and tech-nical support from State Key Laboratory of Hydraulics and Mountain River Engineering at Sichuan University.

M (Environmental Management), North-West University, Potchefstroom Campus Aquatic ecosystems are vital for all life on earth as, without water, there would be no life. It is therefore important that this vital resource is protected, properly managed and that all measures are taken to ensure that it is used in a sustainable manner. As water moves through towns and cities of a region, the water resources are impacted by the anthropogenic activities within these regions. Poor waste management is one such example of an impact that pollutes water resources all over the world. The poor municipal waste management services and the challenges and gaps identified within the waste management legislation, has led to events of illegal dumping. Illegal dumping has been identified as a global problem and not only a local environmental problem in South Africa. The effects caused by illegal dumping are not only limited to where the location of the dumping site is but extends rather to a much greater footprint. Some of the effects caused by illegal dumping include health, social, environmental and economic impacts. Studies have indicated that illegal dumping is more common in the rural communities where there is very limited access to basic services such as potable water, sanitation services and municipal waste collection. This study aimed to assess the impact that illegal dumping has on water quality, through the use of diatoms as a bioindicator of the health of the aquatic ecosystem. Diatoms are known as primary producers that play a significant ecological role in the aquatic ecosystems with their dynamic position at the bottom of the trophic food web. Their specific environmental requirements make them sensitive to any changes within their environment and therefore they are regularly used in aquatic ecosystem studies to assess the anthropogenic impacts and the ecosystem health of aquatic ecosystems. The study was conducted at several surface water bodies within the Ikageng and Promosa suburbs of Potchefstroom in the North-West Province of South Africa. These water bodies form part of a larger drainage system which drains into the Mooi River. The Mooi River is a very important water resource as it is the only source supplying water to the Potchefstroom city. Eight sampling sites were selected for the study at which once-off water and diatom samples were collected during the late summer rainfall month between 15 to 16 February 2019. These sites are located along the drainage lines/streams and dams which all eventually feed into the Mooi River system. The sites were selected as they were representative of the area and the water resources of the area during the time of sampling. Site 8 was used as a reference site to determine the anthropogenic impacts at the other sites and the effect of the illegal dumping on the water quality of those sites. In situ water quality variables were measured at each sampling site and water samples were collected to The effect of illegal dumping on surface water quality using diatoms as a bioindicator measure the physicochemical variables of the water at each site. The samples were analysed for nitrites, nitrates, ammonium, phosphate, sulphate and chloride. The water quality results determined for each site was then compared to the South African water quality guidelines volume 7 specified for aquatic ecosystems to determine if the anthropogenic impacts such as illegal dumping affected the water quality at the different sites. During the diatom sampling, two sets of diatom samples were collected for the live and fixed diatom analysis. Diatoms were sampled from submerged aquatic vegetation stems at each site and prepared and analysed according to the prescribed method of Taylor et al. (2004). The water quality results analysed for the sites raised concern as some of the variables far exceeded the specified concentration range within the water quality guidelines specified for aquatic ecosystems. The inorganic nitrogen (nitrate, ammonium and phosphate) concentrations measured for the sites were very high and indicated the sites to be of a eutrophic/hypertrophic ecological state. These eutrophic conditions at the sites are problematic as it can cause excessive growth of aquatic plants and blue-green algae blooms of which some species could be toxic and harmful to the livestock, humans and wildlife within the area. The chloride concentrations for all sites far exceeded the chronic and the acute effect value. The pH level measured at Site 3 was extremely low and indicated that the system was very acidic, with pH values within the recommended range measured for all the other sites. From the diatom results analysed for the study area, a total of 56 diatom species were identified over the eight sampling sites. The dominant species identified at the sampling sites indicated that all the sites (except sites 1 and 8) are eutrophic as these are species that prefer nutrient-enriched waters and are commonly identified in waters known to be eutrophic and heavily to extremely polluted. The diatom results corresponded with the measured physicochemical water variables which also indicated these sites as nutrients enriched and affected by some sort of pollution. The diatom indices calculated (Specific Pollution sensitivity Index and Generic Diatom Index) also indicated that the sites had poor to bad water quality and was classified as eutrophic ecological state. The Percentage Pollutant Tolerant Valves scores for sites 2 and 3 (fixed) indicated that these sites were heavily contaminated with organic pollution which could be as a result of wastewater discharge from the surrounding areas causing organic pollution. The fixed and live diatom samples had a similar trend for some of the index scores for most of the sites while Site 3 had little resemblance in the index trend for the live and fixed samples. The effect of illegal dumping on surface water quality using diatoms as a bioindicator These results, therefore, indicate that the ecosystem is enriched with nutrients which correlates with the water quality and dominant diatom species. The presence of the illegal dumping at these sites definitely contributed to the elevated nutrient concentrations as previous studies have indicated illegal dumping to be a contributing factor in certain elevated water quality variables such as nutrients. The hypothesis of the study is therefore supported as it can be concluded that the illegal dumping of waste near water sources does negatively influence the water quality of these water resources by altering the water quality parameters which has led to eutrophic polluted conditions. It was concluded that illegal dumping together with various other sources (such as waste water and agricultural runoff) does have an impact on the quality of the selected water resources within the Ikangeng and Promosa area. Masters

River vegetation radically modifies the flow field and turbulence characteristics. To analyze the vegetation effects on the flow, most scientific studies are based on laboratory tests or numerical simulations with vegetation stems on smooth beds. Nevertheless, in this manner, the effects of bed sediments are neglected. The aim of this paper is to experimentally investigate the effects of bed sediments in a vegetated channel and, in consideration of that, comparative experiments of velocity measures, performed with an Acoustic Doppler Velocimeter (ADV) profiler, were carried out in a laboratory flume with different uniform bed sediment sizes and the same pattern of randomly arranged emergent rigid vegetation. To better comprehend the time-averaged flow conditions, the time-averaged velocity was explored. Subsequently, the analysis was focused on the energetic characteristics of the flow field with the determination of the Turbulent Kinetic Energy (TKE) and its components, as well as of the energy spectra of the velocity components immediately downstream of a vegetation element. The results show that both the vegetation and bed roughness surface deeply affect the turbulence characteristics. Furthermore, it was revealed that the roughness influence becomes predominant as the grain size becomes larger.

The monitoring of inundation phenomena through synthetic aperture radar (SAR) data on vegetated areas can be improved through an integrated analysis of different spectral bands. The combination of data with different penetration depths beneath the vegetated canopy can help determine the response of flooded areas with distinct types of vegetation cover to the microwave signal. This is useful especially in cases, which actually constitute the majority, where ground data are scarce or not available.The present study concerns the application of multi-temporal, multi-frequency, and multi-polarization SAR images, specifically data from the Sentinel-1 and PALSAR 2 SAR sensors, operating in C band, VV polarization, and L band, HH and HV polarizations, respectively, in synergy with globally-available land cover data, for improving flood mapping in densely vegetated areas, such as the Zambezi-Shire basin, Mozambique [1], characterized by wetlands, open and closed forest, cropland, grassland (herbaceous and shrubs), and a few urban areas.We show how the combination of various data processing techniques and the simultaneous availability of data with different frequencies and polarizations can help to monitor floodwater evolution over various land cover classes. They also enable detection of different scattering mechanisms, such as double bounce interaction of vegetation stems and trunks with underlying floodwater, giving precious information about the distribution of flooded areas among the different ground cover types present on the site.This kind of studies are expected to assume increasing importance as the availability of multi-frequency data from SAR satellite constellations will increase in the future, thanks to initiatives such as the EU Copernicus program L-band satellite mission ROSE-L [2], and their tight integration with Sentinel-1 as well as with other national constellations such as ALOS 2, or SAOCOM.References[1] Refice, A.; Zingaro, M.; D’Addabbo, A.; Chini, M. Integrating C- and L-Band SAR Imagery for Detailed Flood Monitoring of Remote Vegetated Areas. Water 2020, 12, 2745, doi:10.3390/w12102745.[2] Pierdicca, N.; Davidson, M.; Chini, M.; Dierking, W.; Djavidnia, S.; Haarpaintner, J.; Hajduch, G.; Laurin, G.V.; Lavalle, M.; López-Martínez, C.; et al. The Copernicus L-band SAR mission ROSE-L (Radar Observing System for Europe). In Active and Passive Microwave Remote Sensing for Environmental Monitoring III; SPIE: Washington, DC, USA, 2019; Volume 11154, p. 13.

Flood detection and monitoring is increasingly important, especially on remote areas such as African tropical river basins, where ground investigations are difficult. We present an experiment aimed at integrating multi-temporal and multi-source data from the Sentinel-1 and ALOS 2 synthetic aperture radar (SAR) sensors, operating in C band, VV polarization, and L band, HH and HV polarizations, respectively. Information from the globally available CORINE land cover dataset, derived over Africa from the Proba V satellite, and available publicly at the resolution of 100 m, is also exploited. Integrated multi-frequency, multi-temporal, and multi-polarizations analysis allows highlighting different drying dynamics for floodwater over various land cover classes, such as herbaceous vegetation, wetlands, and forests. They also enable detection of different scattering mechanisms, such as double bounce interaction of vegetation stems and trunks with underlying floodwater, giving precious information about the distribution of flooded areas among the different ground cover types present on the site. The approach is validated through visual analysis from Google EarthTM imagery. This kind of integrated analysis, exploiting multi-source remote sensing to partially make up for the unavailability of reliable ground truth, is expected to assume increasing importance as constellations of satellites, observing the Earth in different electromagnetic radiation bands, will be available.

Most of the existing works on vegetated flows are based on experimental tests in smooth channel beds with staggered-arranged rigid/flexible vegetation stems. Actually, a riverbed is characterized by other roughness elements, i.e., sediments, which have important implications on the development of the turbulence structures, especially in the near-bed flow zone. Thus, the aim of this experimental study was to explore for the first time the turbulence anisotropy of flows through emergent rigid vegetation on rough beds, using the so-called anisotropy invariant maps (AIMs). Toward this end, an experimental investigation, based on Acoustic Doppler Velocimeter (ADV) measures, was performed in a laboratory flume and consisted of three runs with different bed sediment size. In order to comprehend the mean flow conditions, the present study firstly analyzed and discussed the time-averaged velocity, the Reynolds shear stresses, the viscous stresses, and the vorticity fields in the free stream region. The analysis of the AIMs showed that the combined effect of vegetation and bed roughness causes the evolution of the turbulence from the quasi-three-dimensional isotropy to axisymmetric anisotropy approaching the bed surface. This confirms that, as the effects of the bed roughness diminish, the turbulence tends to an isotropic state. This behavior is more evident for the run with the lowest bed sediment diameter. Furthermore, it was revealed that also the topographical configuration of the bed surface has a strong impact on the turbulent characteristics of the flow.

A finite element vegetation model is presented for predicting the dynamic interaction of ground vehicles with vegetation. The purpose of the model is to predict ground vehicle mobility over vegetation covered terrains. The types of vegetation can range from small diameter highly compliant stems to large stiff trees. Those include various types of vegetation such as grass, crops, shrubs/bushes, small trees, and large trees. Mobility measures which can be predicted include maximum safe vehicle speed along a specified path, tire slip, and fuel consumption. The ground vehicles are modeled using high-fidelity multibody dynamics models. The vegetation stems are modeled using an arrangement of thin and/or thick beam finite elements. The thin beam model uses the torsional spring beam formulation for small flexible vegetation and only includes the axial and bending beam responses. The thick beam model includes axial, bending, torsional, and shear beam responses and uses a lumped parameter beam element which connects two rigid body type nodes. The vegetation model includes the effects of normal contact and friction with the vehicle and between stems, stem breaking, and stem aerodynamic forces.

The glacier recession and the runoff variation on the Qinghai-Tibet plateau conducted by the global warming is changing the regional hydrological and ecological processes. Although there is great need for the knowledge of the runoff evolution and biogenic substances migration and transformation for developing strategies for adaptive utilization of runoff, progress in study on these hydrological questions lags behind because of lack of observation dataset under harsh plateau cold conditions.In order to understand the critical zone ecohydrological dynamics and evaluate the runoff components in the Qinghai-Tibet Plateau, a series of observation and research were carried out in the Niyang River watershed, a tributary of the Yarlung Zangbo River. Four basins embed in a larger basin (1500 km2) were monitored and sampled at altitudes between 3667 to 6140 m. More than 500 samples from rain, snow, river water, spring water, glacier ice, vegetation stem, and soil were collected, with which theδ2H, δ18O, K, Ca, Na, Mg, Sr, Si, F, Cl, N, and S in the water are examined. 5 automatic hydrometric stations were established, and the water level data was sent back by Beidou satellite. The 3D laser scanning and RTK technologies were used to obtain detailed geomorphological information near the 5 current measurement section, based on which a hydrodynamic model is able to be calibrated for the discharge estimation.The δ2H and δ18O of the precipitation proposed a local meteoric water isotope line, which is parallel to the WMWL but higher in the δD~δ18O graph. The river water isotopes suggest its source is the precipitation, which are similar to the spring ground water (but the geochemical elements are quite different between the surface and ground water). The vegetation stems water and soil water (by cryogenic vacuum extraction) isotope values suggest the attribute of the river/precipitation sources, but a few observation data appear different implying using water formed by the multiple precipitation events or supplied by the higher place under a significant evaporation influence.The time series of the runoff and the snow cover and glacier variation results show that the base flow is varied obviously relate to the temperature which influence the melting processes of the glacier and frozen earth from March to August, and the rain runoff events control the flood peek. It suggests that the concentration time should be less than 10 days in the interested watershed.The tempo-spatial variation characteristics of the geochemical elements are analyzed and mapped in the interested area, which suggested relative steady water components signals contributing to the runoff. Based on which, a set of overdetermined equations are established to evaluate the quantities of different runoff components.This study could help to evaluate runoff components quantitively in Tibet where lack of data. Monitoring and studing is still going on, which is included in the 2nd comprehensive scientific investigation into Qinghai-Tibet Plateau since 2019.Funded by the NSFC project 91647111 and 91647203 included in the Runoff Change and its Adaptive Management in the Major Rivers in Southwestern China Major Research Plan.

Sediment transport capacity (Tc) is an essential parameter in the establishment of the slope soil erosion model. Slope type is an important crucial factor affecting sediment transport capacity of overland flow, and vegetation can effectively inhibit soil loss. Two new formulae of sediment transport capacity (Tc) are proposed of brown soil slope and vegetation slope in this study and evaluate the influence of slope gradient (S) and flow discharge (Q) on sediment transport capacity of different slope types. Laboratory experiments conducted using four flow discharges (0.35, 0.45, 0.55, and 0.65 L s-1), four slope gradients (3, 6, 9, and 12°), and two kinds of underlying surface (Brown soil slope, Vegetation slope). The soil particle size range is 0.05–0.5mm. The vegetation stems were 2mm in diameter and randomly arranged. The results show that the sediment transport capacity was positively correlated with the flow discharge and slope gradient. The vegetation slope’s average sediment transport capacity is 11.80% higher than the brown soil slope that same discharge and slope gradient conditions. The sensitivity of sediment transport capacity to flow discharge on brown soil slope is higher than that of slope gradient. The sensitivity of sediment transport capacity of vegetation slope to slope gradient is more heightened than flow discharge. The sediment transport capacity was well predicted by discharge and slope gradient on brown soil slope (R2 = 0.982) and vegetation slope (R2 = 0.993). This method is helpful to promote the study of the sediment transport process on overland flow.

Experimental observations in a tilting flume having a bed covered with rice plants (Oryza sativa) are used to analyse the flow characteristics of flexible emergent vegetation with downward seepage. The flow velocity for no-seepage and with seepage is reduced by, on average, 52% and 33%, respectively, as the flow reaches the downstream end with vegetation. Higher Reynolds stress occurs at the start of the vegetation zone; hence, bed material transport occurs in this region. The results indicate that the bed is no longer the primary source of turbulence generation in vegetated flow; rather it is dominated by turbulence generated by the vegetation stems. The local effect of the presence of vegetation causes variations in the hydrodynamic characteristics along the vegetated portion of the channel, which leads to erosion and deposition in the vegetation zone. The experiments show that vegetation can provide considerable stability to channels by reducing channel erosion even with downward seepage.

In order to fully exploit robot motion capabilities in complex environments, robots need to reason about obstacles in a non-binary fashion. In this paper, we focus on the modeling and characterization of pliable materials such as tall vegetation. These materials are of interest because they are pervasive in the real world, requiring the robotic vehicle to determine when to traverse or avoid them. This paper develops and experimentally verifies a template model for vegetation stems. In addition, it presents a methodology to generate predictions of the associated energetic cost incurred by a tracked mobile robot when traversing a vegetation patch of variable density.

Дослідження проводилося на території гідрологічного заказника «Гнила Липа», розташованого в Горохівському районі Волинської області з метою вивчення екологічних і етологічних особливостей бобра річкового на території заказника. У ході дослідження використовувалися маршрутний метод, облік шляхом виявлення поселень, обчислення кількості тварин за кількістю погризів дерев на території, фотографування нір, гребель, хаток. На території гідрологічного заказника «Гнила Липа» сліди діяльності бобрів виявлені на двох ділянках: поблизу стариці річки Гнила Липа і заболоченому березі річки Липа біля пагорба «Катеринські гори». Біля стариці річки Гнила Липа виявлені 3 жилі нори і 4 заселені хатки, а також 5 нежилих хаток. Це поселення має хорошу кормову базу, оскільки поруч розташовані зарості верби козячої і вільхи. Біля пагорба «Катеринські гори» виявлено 2 нежилі хатки і 2 нежилі нори. Це поселення тварини покинули через зменшення кількості деревно-кущової рослинності і обміління меліоративних каналів в посушливі 2015 – 2016 роки. Серед типів житла у виявлених бобрових поселеннях переважають хатки, які тварини спорудили на низьких заболочених ділянках (стариця Гнилої Липи, берег Липи). Нори бобри будують в берегах меліоративних каналів. На меліоративних каналах обстеженої території нами виявлено 5 гребель з п’ятьма ставками і два «транспортувальні канали» на стариці Гнилої Липи. Такі канали бобри споруджують для транспортування кормів від місця заготівлі до свого житла. За нашими даними, на досліджуваній території проживає приблизно 28 особин бобра річкового. Оптимальна чисельність цього виду для території заказника – 10 особин. З огляду на співвідношення заселених і нежилих нір і хаток, аналіз стану кормової бази та зростання посушливості в весняно-літній період, можна припустити, що тенденція до подальшого зменшення кількості бобра річкового на території заказника «Гнила Липа» збережеться. Основними кормами бобрів досліджуваної території влітку є трав’яниста рослинність, стебла і кореневища лепехи, осоки та сільськогосподарські культури. Взимку тварини харчуються, переважно, заготовленими восени гілками і частинами стовбурів верби, вільхи, осики, тополі. The research was carried out on the territory of the hydrological reserve "Gnya Lypa" is located in Horokhiv district of Volyn region. The purpose of the work is to establish ecological and ethological features of the сastor fiber on the territory of the reserve. The study used the route method, accounting by identifying settlements, calculating the number of animals in the number of stripping in the territory, photographing nails, dams, huts. On the territory of the hydrological reserve "Gnya Lypa" traces of castor fibers’ activity were found on two sites: near the dead arm of river Gnyla Lypa and the swampy bank of the Lypa River near the "Katerynsky Hory" hill. Nearby of the dead arm of river Gnyla Lypa 3 habitable holes and 4 inhabited huts, as well as 5 uninhabited huts, were discovered. This settlement has a good forage base, as thickets of goat’s almonds and alder can be found nearby. Near the hill "Katerynsky Hory" found 2 uninhabited huts and 2 non-habitable holes. This settlement of the animals left because of the decrease in the number of shrubs and washing of reclamation channels in the arid 2015, 2016 years. Among the types of house in the identified beaver settlements are dominated by huts, which animals erected on low marshy areas (the dead arm of river Gnyla Lypa, the bank of the Gnyla Lypa). Beavers build the holes on the banks of ameliorative channels. At the ameliorative channels of the surveyed area, we identified 5 dams with five tables and two "transport channels" on the dead arm of river Gnyla Lypa. Such channels beavers constructed for transporting feed from the place of harvesting to their homes. According to our data, about 28 species of сastor fiber live on the studied territory. The optimal size of this species for the territory of the reserve is 10 individuals. Taking into account the ratio of inhabited and non-habitable holes and huts, analysis of the condition of the forage base and the increase of aridity in the spring-summer period, one can conclude that the trend towards further decrease of the amount of beaver in the territory of the "Gnyla Lypa" reserve will be preserved. The main food of the castor fibers in the study area in the summer is a herbaceous vegetation, stems and rhizomes calamus, sedges and the crops. In winter, animals feed on, mainly, harvested in the fall branches and parts of trunks of willow, alder, aspen, and poplar

Numerous studies have focused on flow and mixing within cylinder arrays because of their similarity to vegetated flows. Randomly distributed cylinders are considered to be a closer representation of the natural distribution of vegetation stems compared with regularly distributed arrays. In this study the flow fields associated with two arrays of regularly and randomly distributed cylinders are modelled in two dimensions, using ANSYS Fluent 16.1. The RSM turbulence model is used to model the turbulence closure, and all the variables are discretized using the second order upwind method. The resulting flow fields are used to run the solute transport model to characterize mixing within each geometry. For the same stem diameter and solid volume fraction, greater dispersion is evident in the random cylinder array compared with the regular array. Dispersion coefficient values are compared with those reported in the literature and a good agreement is shown. Turbulence length scales estimated from the velocity profiles and optimized dispersion coefficients are close to the cylinder diameter, which is in agreement with theories in the literature.

Coastal communities around the world face increasing risk from flooding as a result of rising sea level, increasing storminess, and land subsidence1–2. Salt marshes can act as natural buffer zones, providing protection from waves during storms3–7. However, the effectiveness of marshes in protecting the coastline during extreme events when water levels are at a maximum and waves are highest is poorly understood8,9. Here, we experimentally assess wave dissipation under storm surge conditions in a 300-meter-long wave flume tank that contains a transplanted section of natural salt marsh. We find that the presence of marsh vegetation causes considerable wave attenuation, even when water levels and waves are highest. From a comparison with experiments without vegetation, we estimate that up to 60% of observed wave reduction is attributed to vegetation. We also find that although waves progressively flatten and break vegetation stems and thereby reduce dissipation, the marsh substrate remained stable and resistant to surface erosion under all conditions. The effectiveness of storm wave dissipation and the resilience of tidal marshes even at extreme conditions suggests that salt marsh ecosystems can be a valuable component of coastal protection schemes.

Surface water flow controls water velocities, water depths, and residence times, and influences sediment and nutrient transport and other ecological processes in shallow aquatic systems. Flow through wetlands is substantially influenced by drag on vegetation stems but is also affected by microtopography. Our goal was to use microtopography data directly in a widely used wetland model while retaining the advantages of the model’s one-dimensional structure. The base simulation with no explicit treatment of microtopography only performed well for a period of high water when vegetation dominated flow resistance. Extended simulations using microtopography can improve the fit to low-water conditions substantially. The best fit simulation had a flow conductance parameter that decreased in value by 70 % during dry season such that mcrotopographic features blocked 40 % of the cross sectional width for flow. Modeled surface water became ponded and flow ceased when 85 % of the cross sectional width became blocked by microtopographic features. We conclude that vegetation drag dominates wetland flow resistance at higher water levels and microtopography dominates at low water levels with the threshold delineated by the top of microtopographic features. Our results support the practicality of predicting flow on floodplains using relatively easily measured physical and biological variables.

The presence of aquatic vegetation changes the flow characteristics in a channel. The impact of the presence of submerged, flexible vegetation in a channel with an additional parameter such as downward seepage is analyzed in the present work. Two patterns, staggered and uniform, and two different vegetation spacing, 15 and 10 cm center–center, were adopted. Experiments were conducted for the case of no seepage, 10% seepage, and 15% seepage. Velocity profiles show the presence of an inflection point near the top of the vegetation where maximum Reynolds stress is achieved. The velocity profiles measured in the unobstructed region of uniform pattern are higher compared to the velocity measured in line with the vegetation stems. Downward seepage increases the velocity, Reynolds stress, and turbulent intensities in the average range of 10–15% as compared to the no-seepage case. Higher-order turbulent statistics such as moment analysis, quadrant analysis, and turbulent kinetic budget are derived through...

Kaur, J., Percival, D., Hainstock, L. J. and Privé, J.-P. 2012. Seasonal growth dynamics and carbon allocation of the wild blueberry plant ( Vaccinium angustifolium Ait.). Can. J. Plant Sci. 92: 1145–1154. Field studies were conducted at the Wild Blueberry Research Station, Debert, NS, to examine the carbon allocation dynamics within the wild blueberry (Vaccinium angustifolium Ait.). This was achieved with biweekly measurements of dry weight, soluble sugar and starch levels of the rhizomes, roots, stems/leaves and berries of plants in the vegetative (i.e., sprout phase) and cropping phases of production. Non-structural carbohydrate levels were determined using high-performance liquid chromatography (HPLC). Growth parameters included phenology, stem height, dry weights of the above-ground vegetation (stems and leaves), berries, rhizomes and roots. Interestingly, root growth was observed prior to upright shoot emergence and dry weight for rhizome remained higher compared with stems and leaves. The rhizomes acted as a carbohydrate source during stem and root growth. The developing berry crop appeared to be a strong sink for photo-assimilates, as berries were found to import sucrose and convert it to fructose and glucose during maturation, and HPLC studies further confirmed the increasing levels of fructose and glucose. Given the phenology of the wild blueberry, the results exemplify the importance of the rhizomes as a strong carbohydrate source, especially in the early stages of a growing season when the carbohydrate production is limited.

The open-channel flow with submerged vegetation shows distinct features in two separate regions, namely upper and vegetation layers. In the upper layer, the flow is akin to the open-channel flow, while the flow in the vegetation layer is relatively uniform with suppressed turbulence due to vegetation stems. This paper presents laboratory experiments to investigate the characteristics of turbulent flows and suspended sediment transport in open-channel flows with submerged vegetation. An open-channel facility, 0.5 m wide and 12 m long, was used for laboratory experiments. Various discharges were employed with depth ratios of 2~3, and wooden cylinders were used for vegetation. To make equilibrium suspension, sediment particles of median diameter of 75 were fed until capacity condition. Laser Doppler velocimeter was used to measure instantaneous velocity, and direct sampling with vinyl tube was used to measure the concentration of suspended sediment. Using the sampled data, the mean flow and turbulence structures were provided and characteristics of suspended sediment concentration with Rouse number were presented.

The potential of reed beds to act as biofilters of pathogenic and environmental mycobacteria was investigated through examination of the fate of mycobacteria in a constructed reed bed filtering effluent from a large captive wildfowl collection. Particular emphasis was placed on the presence and location of Mycobacterium avium - the causal agent of avian tuberculosis (ATB) - in an effort to clarify the potential role of reed beds in the control of this disease. Water, sediment, and stems and roots of common reed (Phragmites australis) and greater reedmace (Typha latifolia) were taken from 15 locations within the reed bed plus sites upstream and downstream. Samples were analysed for mycobacteria using PCR and specifically for M. avium using nested PCR. Environmental mycobacteria were found throughout the entire reed bed but M. avium was not found downstream of the first vegetation growth. The reed bed was found to effectively remove M. avium from the water through a combination of sedimentation and adsorption onto vegetation stems. The results of this study show that constructed reed beds composed of a settlement lagoon and one or more vegetation beds can act as valuable and ecologically friendly tools in the environmental control of ATB.

Coastal wetlands are among the natural features with the capability to dissipate wave energy and reduce storm damage. Inadequate representation of wave and vegetation characteristics in numerical models may reduce their capability in predicting wave processes over wetlands. Previous numerical wave models have typically applied simplifications on vegetation behavior. For instance, vegetation stems were usually assumed to be rigid or semi-flexible and thus extreme stem deflections could not be captured. In this study, a time-domain nonlinear numerical model based on extended Boussinesq formulation is developed and coupled with a numerical model for vegetation blade dynamics that allows for arbitrary flexibility. Comparison with analytical and laboratory experiments show that the coupled model can adequately predict flow as well as vegetation blade dynamics without the need for any parameter tuning. The model is then used to obtain wave-induced forces on a stem and vegetation blade orientation. Model results indicate that the variation of the vegetative drag coefficient with wave frequency is non-monotonic.

A large population of Sphodros rufipes (Latreille 1829) was discovered in a municipal park in Memphis, Tennessee. We examined potential stem diameter preference, frequency of web attachment to available tree species and the spatial distribution patterns of spiders and potential attachment structures. A wide range of structure diameters were utilized for web attachment. The association of pursewebs to tree taxa was independent of the frequency of tree taxa occurrence. The spacing of vegetation stems and trunks was approximately random, but spiders exhibited a nonrandom, aggregated distribution, which was more pronounced in subadults than adults. The factors influencing S. rufipes to occur in aggregations cannot be explained by the spatial proximity of potential attachment structures in the forest.

In this study, an array of rigid cylindrical rods was used to simulate emergent vegetation stems that were subject to unidirectional open channel flows. The instantaneous drag force experienced by the rods was measured with a load cell. In addition, the particle image velocimetry (PIV) technique was applied to sample the flow information in a horizontal plane, and wave gauges were used to record the fluctuation in the water-surface elevation. The results show that the drag fluctuation normalized by the mean value may reach as high as 133% when the Reynolds number (defined based on the stem diameter) varied in the range from 400 to 1,100. High fluctuations were also observed in the flow velocity and flow depth under similar flow conditions. Accepted version

4. SOLANUM EVOLVULIFOLIUM Greenm., Bot. Gaz. 37: 211. 1904. ���TYPE: COSTA RICA. San Jos��: La Palma, 1,460 m, Sep 1898 (fl, fr), A. Tonduz 12615 (lectotype, here designated: GH���GH00077489!; possible isolectotypes: CR���12615, K���K000449423!, K���K000449424!, M���M0111204!, NY���NY00138984!, US ��� US 00027570!). Vine, sometimes shrubby, climbing tree trunks or other vegetation. Stems slender, woody, glabrous to densely pubescent, the trichomes typically ca. 1 mm or longer, occasionally in distinct lines along stem. Sympodial units plurifoliate. Leaves simple, the arrangement distinctly distichous, the blades 0.5���5 �� 0.3���3 cm, 1���3 times as long as wide, ovate to oblong-ovate, chartaceous to coriaceous, sand-punctate, glabrous to densely pubescent on the leaf blade adaxially and abaxially, pubescent on midvein adaxially with hairs 0.2���0.5 mm, discolored, occasionally reddish below; venation pinnate, with 3���4 pairs of secondary veins, the veins densely sand-punctate; base truncate to cordate, often oblique; margins entire to undulate, revolute; apex rounded and apiculate to acute, sometimes acuminate; petioles nearly absent to 0.5 cm, glabrous to densely pubescent, densely sand-punctate. Internodes 0.5��� 1.5(���3.5) cm. Inflorescences 1���15 cmlong, unbranched, nearly leaf-opposed to extra-axillary, with 2���80 flowers (scars), the axes glabrous to pubescent with simple, uniseriate, curled hairs; peduncle 0.6���1.5 cm; rachis 1���14 cm; pedicels 4��� 10 mm in flower, green to pink, 10���15 mm in fruit, glabrous to densely pubescent, spaced nearly contiguously to 8 mm apart. Calyx 1.5���3 mm long, conical, the tube 1���2.5 mm long, the lobes 0.5���1.5 �� 0.8���1.5 mm, deltate, rounded and minutely apiculate at tips to acute, the margins somewhat thickened, glabrous to sparsely pubescent along margins, more dense at tips of the lobes, pale green to pink; fruiting calyx minutely accrescent. Corolla 1���2 cmindiameter, 5���8 mm long, stellate, membranous, greenish, white, pink, to bluish-purple, sometimes mottled, the lobes 5���11 �� 2���3 mm, lanceolate, acute at apices, glabrous adaxially and abaxially, the margins ciliate.Stamens withfilamentsca. 1 mm long, glabrous; anthers 2���3 �� 0.8���1.5 mm. Ovary glabrous; style 4���6 �� ca. 0.25 mm, cylindrical to somewhat clavate, minutely papillose in lower 2/3; stigma truncate to somewhat capitate. Fruit 0.6���1.5 �� 0.6���1 cm, globose to ovoid, slightly flattened, rounded to acute at apex, glabrous, red to reddish-brown when ripe. Seeds 1.5���2 mm in diameter, rounded, tan, the surface rugulose. Figure 1H���I. Habitat and Distribution��� Solanum evolvulifolium occursin Costa Rica, Panama, Colombia, Venezuela, Ecuador, and Peru as an epiphyte on tree trunks in rain and cloud forest habitats; (200���) 800���2,600 m in elevation (Fig. 6). Phenology��� Flowering and fruiting apparently occurs yearround. Etymology��� The epithet evolvulifolium refers to the similarity of the leaves of this species to some species of Evolvulus (Convolvulaceae). Notes��� Solanum evolvulifolium , a climbing species, is recognizable by its characteristic distichous leaf arrangement (Fig. 1H) and branching pattern. The main stem of this species is most often encountered climbing on tree trunks, attached with adventitious roots at the nodes; secondary branches extend away from the main stem. Higher order branches are typically distichous and arise at ca. 45�� angles, often giving the plant a characteristic, flattened appearance. The leaves often diminish in size along a branch, occasionally to a branching point or inflorescence, and then increase in size again. The pedicels, calyx and corolla are frequently pinkish-white to greenish-pink. This species can be distinguished from other simple leaved, viny members of sect. Herpystichum by the uniformly short internodes, somewhat coriaceous leaves (instead of chartaceous or somewhat fleshy), and the flattened aspect of the branches that results from the distichous leaves branches. South American collections are more variable than those from Central America in leaf shape and, especially, the degree of pubescence. The calyx lobes of Central American collections are broadly ovate and rounded apically, whereas the lobes of most South American collections are deltoid in shape and acute apically. These calyx characters, however, are not sufficiently uniform, nor are they correlated with other characters that might justify segregation of S. evolvulifolium into one or more additional species. Several extreme forms from South America are included here, and these include especially robust forms from Colombia and Ecuador and an especially pubescent form from Ecuador. It is possible that the differences merit specific status, but both forms are represented by only a few collections and are thus included within a broadly defined and variable, yet easily identifiable S. evolvulifolium. Furthermore, the three sequenced accessions of S. evolvulifolium, including one accession of the robust form and two of the standard form, form a monophyletic group together with S. crassinervium and S. loxophyllum (Fig. 4). The robust form of S. evolvulifolium is strongly supported as sister to Central American accessions of S. evolvulifolium lending support for its inclusion in a morphologically variable, yet easily recognizeable S. evolvulifolium. There is some confusion about the numbering and collector of the lectotype collection of S. evolvulifolium. Greenman���s protologue states that the collector and number is Pittier 7413. However, the handwritten labels on the K specimens give the collector as Tonduz. They do not have a collector number, but they do have a ���herb. nat. Cost. number 12615 (Herbario del Museo Nacional de Costa Rica). Nevertheless, there is sufficient overlap of label information on different specimens to determine that they are all clearly part of the same collection. All labels list Tonduz��� name and the herb. nat. Cost. number. Furthermore, it seems that Tonduz was the actual collector, but that Pittier distributed the specimens under his own set of numbers (Dauphin L��pez 2009; B. Hammel, pers. comm.). For these reasons, we refer to the collection as Tonduz 12615. Greenman cited two syntypes, Tonduz 12615 (as Pittier 7413) and Werckl�� 11599, in his original description of S. evolvulifolium. Tonduz 12615 is chosen as the lectotype because this collection has many duplicates, whereas only a single specimen is known of the Werckl�� collection. The GH specimen of Tonduz 12615 is chosen as the lectotype because Greenman was at GH in 1904 and this is likely the specimen that he used in his description of S. evolvulifolium. Furthermore, the GH specimen gives the altitude as 1460 m, the altitude stated in the protologue. The rest of the Tonduz 12615 collections report an altitude of 1,542 m and therefore they are listed above as possible isolectotypes. Representative Specimens Examined��� COSTA RICA. La Palma, 1,500 m, Nov 1897 (fr), K. Werckl�� 11599 (GH). Alajuela: Reserva Biol��gica Monteverde, 10��19���N 84��43���W, 820 m, 22 Oct 1988 (fl), E. Bello 468 (F, MO); Reserva Forestal de Arenal, 10��18���N 84��42���W, 850���900 m, 28 Feb 1990 (fl), E. Bello 1961 (MO); San Carlos, La Forma, Finca El Jilguero, 10��25���25���N 84��42���05���W, 800 m, 22 Nov 1992 (fl), G. Herrera 5696 (MO); 12 km NNW of San Ram��n by road on way to San Lorenzo, 1 km Sof Balsa, 10��10���N 84��29���W, 1,100 m, 25 Apr 1983 (fl), R. L. Liesner & E. Judziewicz 14936 (MO, WIS). Cartago: Beside R��o Villegas, valley of R��o Grande de Orosi, 9��42���N 83��47���W, 1,620 m, 11 Jan 1970 (fl), R. W. Lent 1849 (F, MO, U); Monumento Nacional Guayabo, 9��58���N 83��41���W, 26 Jan 1993 (fl), G. Rivera 2054 (F, K); growing in dense upland rain forest about 5 km SW of Tapanti, 9��47���N 83��55���W, 1,500 m, 17 Aug 1967 (fr), J. Taylor & C. Taylor 4472 (MO, NY). Heredia: Vicinity of Colonia Virgen del Socorro, 10��17���N 84��10���W, 900 m, 10 Aug 1975, (fl), J. Utley & K. Utley 2824 (F); Parque Nacional Braulio Carrillo, 10��15���50���N 84��05���W, 1,200 ���1,400 m, 13 Nov 1986 (fl), M. Grayum & G. Herrera 7881 (MO). Limon: Gu��piles, Los Angeles, San Miguel, 10��04���20���N 83��50���40���W, 1,300 m, 21 Feb 1990 (fl), A. Chac��n et al. 744 (MO); Parque Nacional Cordillera de Talamanca, 9��22���30���N 83��14���10���W, 1,700 m, 24 Mar 1993 (fl), A. Fern��ndez 818 (BM, MO); El Progreso, 9��47���20���N, 83��07���30���W, 1,600 m, 24 Apr 1989 (fl), G. Herrera & A. Chac��n 2771 (F, MO, NY); San Jose: road between Alto La Palma and Bajo La Hondura, 1,400 m, 24 Feb 1978 (fl), F. Almeda & K Nakai 3913 (MO); P��rez Zeled��n, Savegre, 9��31���N 83��51���W, 1,900 m, 3 Aug 1994 (fl, fr), G. Herrera et al.7253 (K); woods near Quebrada Vargus, Alto La Palma, 10��04���N 83��59���W, 1,400 m, 31 Mar 1974 (fl), R. W. Lent 3852 (AAU, F, MO). PANAMA. Bocas del Toro: Nslope of Cerro Horqueta, 8��49���24���N 82��26���54���W, 6,000 ���7,000 ft, 5 Aug 1947 (fr), P. H. Allen 4995 (F, G, U); along road from Fortuna Dam, towards Chiriqu�� Grande, 2.2 miles Nof the continental divide, 8��45���N 82��15���W, 800 m, 12 Mar 1985 (fl), G. McPherson 6815 (MO, WIS). Chiriqui: Boquete, Bajo Chorro, 8��50���N 82��29���W, 6,000 ft, 12 Jan 1938 (fl) M. E. Davidson 112 (GH, F, US). Chiriqu��/Bocas del Toro: Zona Protectora Palo Seco, along continental divide, 8��47���N 82��13���W, 1,100 ���1,300 m, 11 Aug 2000 (fl), S. Knapp & J. Mallet 9178 (BR, MO). COLOMBIA. Antioquia: R��o Caldera, 5��58���N, 74��58���W, Jan 1953 (fl), Bro. Daniel 4498 (US). Caldas: La Finca, Quind��o, 4��27���N 75��40���W, 3,200 m, Feb 1937 (st), E. Dryander 2136 (US); Santa Cecelia, Cordillera occidental,vertiente occidental, 5��18���N 76��13���W, 800 m, 29 Dec 1945 (fl), K. von Sneidern 5524 (F). Cauca: El Tambo, Parque Nacional Munchique, 2��36���40���N 74��54���10���W, 2,570 m, 20 Jul 1993 (fl, fr), G. Lozano et al. 6961 (COL, MA); El Cairo, Cerro del Ingl��s, Cordillera Occidental, 4��45���N 76��13���W, 2,260 m, 5 Jan 1987 (fl), F. A. Silverstone Sopkin et al. 2967 (NY); El Tambo, La Costa, 4��4���N 77��1���W, 1,500 m, 25 Mar 1938 (infl), K.von Sneidern 1663 (F, G, S, US). Choc��: San Jose del Palmar, Hoya del Rio Torito, Finca Los Guaduales, 5��02���N 76��22���W, 630 m, 6 Mar 1980 (fl), E. Forero et al. 6793 (COL, MO); 6 km Eof R��o Pato, ca. 48 km Wof Las Animas on the Pan American Highway, 5��20N 76��49���W, 250 m, 11 Jan 1979 (fl, fr), A. H.Gentry & A. Renteria 24016 (AAU, MO). Nari��o: Cordillera Occidental, Finca La Planada, near Chucunes, 1��11���N 77��58���W, 1,950 m, 13 Jan 1981 (fr), A. H. Gentry et al. 30549 (COL, MO, NY); Junin-Barbacoas road, 2���10 km. Nof Junin, 1��30���N 78��10���W, 900 m, 26 Jul 1986, (st), A. H. Gentry et al. 55333 (MO). Putumayo: Villagarz��n, Carretera a Pto. Asis, 4 May 1994 (st), J. L. Fern��ndez 11431 (COL); Punto de Buenos Aires, Cerro Portachuelo, 0��22���N 75��01���W, 2,080 m, 27 Jul 1964 (fl), D. D. Soejarto 1139 (GH). Risaralda: Ap��a, Vereda La Cumbre, 5��8���42N 76��0���46���W, 2,285 m, 24 Feb 1983 (fl), J.H.Torres 2216 (COL); Pereira, La Pastora, 2,500 m, 20 Jan 1998 (fl), G. Vargas 4472 (COL). Valle: Cordillera occidental, Hoya del R��o Digua, La Elsa, 3��15���N 70��51���W, 1,000 ���1,200 m, 9 Nov 1943 (fl, fr), J. Cuatrecasas 15313 (F, US). VENEZUELA. M��rida: Rivas D��vila, 22���27 km Sof Tovar along rd. to Canagu��, 8��14���N 71��45���W, 2,100 ���2,256 m, 16 Apr 1984 (fl, fr), J. L. Luteyn et al. 9960 (NY). ECUADOR. Carchi: Mira, Norte del Carmen, Camino a Chical, 0��17���N 78��13���W, 2,000 m, 10 Feb 1992 (fl), W. A. Palacios et al. 9753 (MO); Tulcan, Reserva Ind��gena Aw��, 0��53���N 78��25���W, 1,800 m, 17 Aug 1992 (fr), G. Tipaz et al. 1923 (MO). Carchi / Esmeraldas: Near Lita, 0��52���N 78��27���W, 600 m, 19 May 1987 (fl). H. Van der Werff et al. 9493 (MO). Cotopaxi: Sigchos, Triunfo Grande, 0��32���22���S 78��58���59���W, 2,349 m, 6 Aug 2003 (fl, fr), J. E. Ramos Perez et al.7061 (NY); Pujil��,Reserva Biol��gica Los Ilinizas, 0��58���45���S 79��06���53���W, 1,725 m, 10 Aug 2003 (st), F. A. Silverstone Sopkin et al. 10027 (MO, NY). Esmeraldas: Road Lita-Alto Tambo, ca. km 17.8, 0��51���N 78��29���W, 850 m, 28 Sep 1991 (fl), B. Ollgaard 99154 (AAU). Loja: Cerro de Celica, Celica - Guachanam��, km 2.7, 4��05���46���S 79��56���45���W, 2,250 m, 12 Apr 1994 (fl, fr), P. M. Jorgensen et al. 93 (NY). Napo: Parque Nacional Sumaco y Comunidad de Pacto Sumaco, 0��38���56���S 77��35���49���W, 1,550 ���1,700 m, 26 Apr 1997 (fr), A. Alvarez et al. 2017 (MO); Quijos, Cosanga, Yanayacu Biological Station and Center for Creative Studies, 0��35���55���S 77��53���22���W, 2,200 m, 18 Aug 2005 (fl), J. L. Clark et al. 9438 (BM, NY, US); Km 2, carretera nueva Cotundo ��� Coca, 0��42���N 77��42���W, 1,130 m, 5 Aug 1984 (fl), C. H. Dodson et al. 15031 (NY, MO).Pichincha:Reservaecol��gica R��o Guajalito, km 59 delacarretera antigua Quito-St. Domingo de los Colorados, 0��13���53���S 74��48���10���W, 1,800 ��� 2,000 m, 4 May 2000 (fl, fr), I. Tapia 1254 (SEL). Sucumbios: El Reventador, colecciones en ��mbas m��rgenes del Rio Reventador, 0��02���N 77��41���W, 1,850 m, 6 Oct 1990 (st), J. Jaramillo & E. Grijalva 12933 (AAU, NY). PERU. Amazonas: Monte Virgen, 50 m frente la comunidad de Caterpiza, 3��55���S 77��42���W, 200 m, 30 Aug 1979, (fl, fr), V. Huashikat 268 (MO)., Published as part of Tepe, EJ & Bohs, L, 2011, A revision of Solanum section Herpystichum, pp. 1068-1087 in Systematic Botany 36 (4) on pages 1077-1079, DOI: 10.1600/036364411X605074, http://zenodo.org/record/6327846, {"references":["Donnell Smith, J. 1904. Undescribed plants from Guatemala and other Central American Republics. XXV. Botanical Gazette (Chicago, Ill.) 37: 208 - 214.","Dauphin Lopez, G. 2009, March 8. Tonduz el desconocido. Nacion. Available from http: // wvw. nacion. com / ancora / 2009 / marzo / 08 / ancora 1894941. html."]}

The potential of reed beds to act as biofilters of pathogenic and environmental mycobacteria was investigated through examination of the fate of mycobacteria in a constructed reed bed filtering effluent from a large captive wildfowl collection. Particular emphasis was placed on the presence and location of Mycobacterium avium--the causal agent of avian tuberculosis (ATB)--in an effort to clarify the potential role of reed beds in the control of this disease. Water, sediment, and stems and roots of common reed (Phragmites australis) and greater reedmace (Typha latifolia) were taken from 15 locations within the reed bed plus sites upstream and downstream. Samples were analysed for mycobacteria using PCR and specifically for M. avium using nested PCR. Environmental mycobacteria were found throughout the entire reed bed but M. avium was not found downstream of the first vegetation growth. The reed bed was found to effectively remove M. avium from the water through a combination of sedimentation and adsorption onto vegetation stems. The results of this study show that constructed reed beds composed of a settlement lagoon and one or more vegetation beds can act as valuable and ecologically friendly tools in the environmental control of ATB.

Emergent instream vegetation influences the transport and deposition of suspended sediment in rivers, and hence their morphology and nutrient dynamics. An experimental laboratory study has shown how emergent vegetation stems promote sediment deposition. The suspended transport and the extent of longitudinal deposits from suspension within emergent stems is enhanced by increased flow depth and reduced by increased sediment grain size and stem density. The shear zone between longitudinal vegetation strips and adjacent unvegetated channel flow induces diffusion of sediment into the vegetated zone. The transverse extent of the resulting deposit is enhanced by increased flow depth and stem density, and reduced by increased sediment grain size. Values of sediment diffusivity for the two experimental situations were inferred by application of two-dimensional formulations of the diffusion-convection equation. These applications indicate that vertical diffusivity is considerably reduced and transverse diffusivity in the shear zone considerably increased by the stems. Water SA Vol. 32(2) 2006: pp.211-218

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T18:42:46Z No. of bitstreams: 1 S1676-06032007000200027.pdf: 207905 bytes, checksum: 6240b67d0625259af59b10cabf18e604 (MD5) Made available in DSpace on 2013-08-22T18:42:46Z (GMT). No. of bitstreams: 1 S1676-06032007000200027.pdf: 207905 bytes, checksum: 6240b67d0625259af59b10cabf18e604 (MD5) Previous issue date: 2007-01-01 Made available in DSpace on 2013-09-30T19:30:21Z (GMT). No. of bitstreams: 2 S1676-06032007000200027.pdf: 207905 bytes, checksum: 6240b67d0625259af59b10cabf18e604 (MD5) S1676-06032007000200027.pdf.txt: 48757 bytes, checksum: 4b1216c6911f97a7bd075fe2a13997d8 (MD5) Previous issue date: 2007-01-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T15:08:20Z No. of bitstreams: 2 S1676-06032007000200027.pdf: 207905 bytes, checksum: 6240b67d0625259af59b10cabf18e604 (MD5) S1676-06032007000200027.pdf.txt: 48757 bytes, checksum: 4b1216c6911f97a7bd075fe2a13997d8 (MD5) Made available in DSpace on 2014-05-20T15:08:20Z (GMT). No. of bitstreams: 2 S1676-06032007000200027.pdf: 207905 bytes, checksum: 6240b67d0625259af59b10cabf18e604 (MD5) S1676-06032007000200027.pdf.txt: 48757 bytes, checksum: 4b1216c6911f97a7bd075fe2a13997d8 (MD5) Previous issue date: 2007-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Os cupins são insetos sociais pertencentes à ordem Isoptera e constituem um dos grupos de invertebrados dominantes em ambientes terrestres tropicais. Atualmente, existem cerca de 2.900 espécies descritas, que estão distribuídas em sete famílias: Mastotermitidae, Kalotermitidae, Termopsidae, Hodotermitidae, Serritermitidae, Rhinotermitidae e Termitidae. A região neotropical engloba 537 espécies, e dessas, aproximadamente 300 ocorrem no Brasil e pertencem às famílias Kalotermitidae, Rhinotermitidae, Serritermitidae e Termitidae. Apesar dos isópteros serem bastante conhecidos pelo seu potencial como praga, o papel ecológico dos térmitas no ambiente é primordial, visto que desempenham o papel de consumidores primários e/ou decompositores nos ecossistemas naturais. Esses insetos participam ativamente na trituração, decomposição, humificação e mineralização de uma variedade de recursos celulósicos. Uma grande diversidade de material orgânico, em vários estágios de decomposição, pode servir de alimento para os cupins, incluindo madeira (viva ou morta), gramíneas, plantas herbáceas, serapilheira, fungos, ninhos construídos por outras espécies de cupins, excrementos e carcaças de animais, liquens e até mesmo material orgânico presente no solo (húmus). Essa vasta gama de fontes alimentares permitiu aos cupins ocuparem quase todas as regiões quentes e temperadas da Terra, ocorrendo em praticamente todos os ambientes terrestres, naturais ou modificados pela espécie humana. Portanto, os isópteros são encontrados nas matas tropicais e temperadas, cerrados, savanas, caatingas, restingas, mangues, campos, culturas, pastagens e cidades. Termites are social insects belonging to the order Isoptera and constitute one of the dominant groups of invertebrates in terrestrial environments of the tropical region. Currently, there are around 2,900 species described in seven families: Mastotermitidae, Kalotermitidae, Termopsidae, Hodotermitidae, Serritermitidae, Rhinotermitidae and Termitidae. The Neotropical region contains 537 species, and from these, approximately 300 occur in Brazil and belong to the families Kalotermitidae, Rhinotermitidae, Serritermitidae and Termitidae. Although the Isoptera has been known by their potential as pest, the ecological role of the termites in the environment is primordial since they play a role as primary consumers and/or decomposers in natural ecosystems. These insects participate actively in the crushing, decomposition, humus production and mineralization of a variety of cellulose-based resources. A great diversity of organic material, in several stages of decomposition, may serve as food for termites, including wood (sound or decayed), grass, herbaceous plants, litter, fungi, nests built by other termite species, dung and carrion, lichen and even organic material present in the soil (humus). This vast range of food sources allowed the termites to occupy almost all the tropical and temperate regions of the Earth, occurring practically in all the terrestrial environments, natural or modified by the human species. Therefore, termites are found in the tropical and temperate forests, cerrados, savannas, caatingas, shallow places, mangrove regions, low vegetation stems, crops, pastures and urban environments. Universidade Estadual Paulista Instituto de Biociências Departamento de Biologia Universidade Estadual Paulista Instituto de Biociências Departamento de Biologia

In 1976-1977, 284 gaps (canopy-opening sizes 1-1490 M2) were sampled (age, size, species composition) from old-growth mesic forests in Great Smoky Mountains National Park, Joyce Kilmer Wilderness Area and Walker Cove Research Natural Area. In 1983, the woody vegetation (stems - 1 cm dbh) of 273 of these gaps was resampled, rates of gap closure by canopy tree branch growth and sapling height growth were estimated, and incidences of disturbances occurring since 1976-1977 were noted. The average yearly crown extension growth rate was 18 cm/yr, with much variation among species and in- dividuals. Some individual crowns grew into the canopy opening as much as 4 m in the 7 yr. Saplings grew an average of 30 cm/yr in height, again with much variation. Overall, taller saplings grew somewhat faster than smaller ones and saplings in large gaps grew faster than those in small gaps. These two rates of gap closure together suggest that most saplings will require two or more gap episodes to reach the forest canopy. For woody vegetation, basal area per unit gap area was originally highest in small gaps, though it increased between sampling dates most in large gaps. Stem density had been highest in small old gaps, but decreased the most in old gaps. Tsuga canadensis, Fagus grandifolia, Acer saccharum, and Halesia carolina were the most important species in the gaps studied. Most species did not change in relative density or dominance between the two sampling dates and showed no significant correlations between those parameters and gap size and age. Overall, Tsuga and Fagus decreased and Acer saccharum increased in importance. High rates of repeat disturbance favor species able to grow in intermediate light levels and to survive several periods of suppression before reaching the canopy.