Vegetation Physiognomy Research Articles

STRUKTUR DAN FISIOGNOMI VEGETASI MANGROVE DI REMPANG CATE KOTA BATAM

Structure and physiognomy of mangrove strongly influenced by the zonation that occurred in the area of mangroves growth. The differences of zona growth will effect to differences in the structure and composition of vegetation. There are three zones in the mangrove area, which is caused by the difference of flooding which also resulted in the difference to the salinity. The differences of growth zone will performed to the type vegetation performance (Physiognomy). This study is aims to prove the mangrove’s physiognomy that taken in the coastal area of Rempang Cate Batam, on March 2014 to June 2014. This study was a survey with data collection using a vertical transect plots 100 m. Based on the research that has been done obtained difference vegetation physiognomy stands for every level of growth in each zone growth. Proximally found 13 species of mangroves in 8 families. The results of the analysis of the vegetation on the trees growth level are, Ceriops decandra have the greatest significance important value 167.55% on sapling (juvenille ) level is dominated by Rhizophora apiculata 120%, and seedling growth level dominated by Rhizophora apiculata 186.80%. Keywords: Structure and physiognomy, mangrove zonation

Do groundwater dynamics drive spatial patterns of tree density and diversity in Neotropical savannas?

AbstractQuestionsWhat are the temporal and spatial variations of groundwater depth along topographic gradients in Neotropical savannas? Are patterns of tree density and species diversity along topographic gradients in Neotropical savannas controlled by water table depth? Do soil and groundwater nutrient concentrations differ along topographic gradients in Neotropical savannas?LocationFire‐protected savannas of central Brazil.MethodsOver 16 mo, we monitored temporal and spatial variations in groundwater levels using automated submersible pressure transducers installed in ten wells located along two topographic gradients (five wells per gradient) of 950 m and 1703 m in length, representing elevations of 47 and 37 m a.s.l., respectively. We located the wells according to changes in vegetation physiognomies from woody savannas at high elevations, to open shrubby grasslands at low elevations. Along each topographic gradient we determined soil and groundwater nutrient concentrations as well as richness, density, basal diameter and height of trees within two plots of 14 × 14 m (392 m2) adjacent to each well.ResultsAlong the two gradients, groundwater levels exhibited larger fluctuations at lower than at higher elevations where the water table was deeper. Richness, density and diversity of trees decreased significantly at lower elevations where soils were waterlogged during the wet season. Soil pH and soil concentrations of carbon, nitrogen and manganese decreased significantly as elevation increased along the topographic gradients, but soil nutrient concentrations of phosphorus, aluminium and iron did not change with elevation. Groundwater samples contained only trace amounts of nutrients and were poorly correlated with elevation along the topographic gradients.ConclusionsIn Neotropical savannas, the minimum distance between the soil surface and water table depth (reached during the wet season) and the relatively large fluctuations in groundwater limit tree density and diversity at low elevations as savanna trees cannot cope with extended waterlogging during the wet season and with low soil water availability during the dry season. Thus, variations of tree density and diversity along topographic gradients are more related to spatial and temporal variations in water table depth than to soil and groundwater nutrient variations in Neotropical savannas.

Vegetation geo-climatic zonation in the rocky mountains, Northern Utah, USA

We developed a vegetation geo-climatic zonation incorporating the zonal concept, gradient and discriminant analysis in Wasatch Range, northern Utah, USA. Mountainous forest ecosystems were sampled and described by vegetation, physiographic features and soil properties. The Snowpack Telemetry and National Weather Service Cooperative Observer Program weather station networks were used to approximate the climate of sample plots. We analysed vegetation and environmental data using clustering, ordination, classification, and ANOVA techniques to reveal environmental gradients affecting a broad vegetation pattern and discriminate these gradients. The specific objective was to assess and classify the response of the complex vegetation to those environmental factors operating at a coarse-scale climatic level. Ordination revealed the dominant role of regional, altitude-based climate in the area. Based on vegetation physiognomy, represented by five tree species, climatic data and taxonomic classification of zonal soils, we identified two vegetation geo-climatic zones: (1) a montane zone, with Rocky Mountain juniper and Douglas-fir; and (2) a subalpine zone, with Engelmann spruce and subalpine fir as climatic climax species. Aspen was excluded from the zonation due to its great ecological amplitude. We found significant differences between the zones in regional climate and landform geomorphology/soils. Regional climate was represented by elevation, precipitation, and air and soil temperatures; and geomorphology by soil types. This coarse-scale vegetation geo-climatic zonation provides a framework for a comprehensive ecosystem survey, which is missing in the central Rocky Mountains of the United States. The vegetation-geo-climatic zonation represents a conceptual improvement on earlier classifications. This framework explicitly accounts for the influence of the physical environment on the distribution of vegetation within a complex landscape typical of the central Rocky Mountains and in mountain ranges elsewhere.

The distinct foliar physiognomy of the Late Cretaceous forests of New Zealand — Probably deciduous

Three features of leaf physiognomy: craspedodromous venation, compound teeth and a lobed leaf outline, figure prominently in the Late Cretaceous vegetation of southern New Zealand. These make it distinctly different from typical extant, predominantly evergreen forests and some deciduous vegetation. The physiognomy of the Late Cretaceous vegetation at the assemblage level shows more similarity with predominantly deciduous forests of the Northern Hemisphere, in terms of the proportions of these characters in the flora. At the taxon level, combinations of characters found in fossils are very similar to and in some cases restricted to, widespread extant Northern Hemisphere deciduous taxa, but also to rarer components of evergreen forests. It may not be possible to categorically determine whether any one fossil was deciduous. The distinctly different assemblage-level foliar physiognomy implies a distinctly different “lifestyle” for the New Zealand forests that bordered Gondwana in the Late Cretaceous. It is highly likely that this physiognomy reflects an important deciduous component. This is unexpected as for at least part of this time New Zealand was apparently below (north of) the Polar Circle with a temperate and everwet climate.

Alpine Steppe Vegetation Patterns in the Koyondu Valley, Kyrgyz Republic

As a part of an ecological research project on wild animals, alpine steppe vegetation in the Koyondu Valley, the Sarychat-Ertash State Reserve, in the northern Tian Shan Mountains of the Kyrgyz Republic was surveyed. Horses and sheep were kept as livestock, while wildlife such as Marco Polo sheep (argali) and wolves also inhabited the region. Information regarding wildlife, weather conditions and the livelihood of human inhabitants within the region was scarce and difficult to obtain. In May 2011, 21 releve plots from 5 types of vegetational physiognomy were established at elevations ranging from ca. 3,400 to 3,600 m. In each plot, coverage, sociability and height of each plant species were measured. As a result, vegetation physiognomy of type IV plots (grassland with accumulated detritus) proved to have by far the greatest coverage and v-values of all physiognomy types. Seven varieties of plant community (A1 to A4 and B1 to B3) were recognized based on differing combinations of 4 differential plant species. Varieties of plant community did not exactly correspond to types of vegetation physiognomy, and type IV plots displayed the most variability. Distribution patterns of each community in relation to elevation and slope direction appeared similar on both the left (facing southwest) and right (facing northeast) banks of the valley, but exceptions were observed more frequently on the left bank than the right. When v-value was plotted against the total number of plant species present, the majority of plots fell within a successive transition. Type IV plots, however, were out of this transition and possessed exceptionally abundant vegetation.

Pedogenesis Steppe Soils of The Tlemcen (Western Algeria)

Soil genesis is closely related to climatic conditions.The low rainfall reduces the phenomenon of leaching and does in no way fertilization. This work shows that the evolution of soils of the steppe region of Tlemcen is not only the fact of a soil and climate but also the nuances of microstationnels factors (vegetation, slope and altitude). To this end, we found it necessary to make the physical and chemical analyzes combined with a statistical-Principal Component Analysis (PCA) - soils of the steppe region of Tlemcen, to identify characteristics and edaphic see their actions on the distribution and physiognomy of vegetation. Pedogenesis in steppe soils remains our primary concern, for their present condition is a certain imprint on these steppe ecosystems, the limit of their ecological rupture (desertisation).

Do woody and herbaceous species compete for soil water across topographic gradients? Evidence for niche partitioning in a Neotropical savanna

Savannas are characterized by sparsely distributed woody species within a continuous herbaceous cover, composed mainly by grasses and small eudicot herbs. This vegetation structure is variable across the landscape, with shifts from open grassland to savanna woodland determined by factors that control tree density. These shifts often appear coupled with environmental variations, such as topographic gradients. Here we investigated whether herbaceous and woody savanna species differ in their use of soil water along a topographic gradient of about 110m, spanning several vegetation physiognomies generally associated with Neotropical savannas. We measured the δ2H and δ18O signatures of plants, soils, groundwater and rainfall, determining the depth of plant water uptake and examining variations in water uptake patterns along the gradient. We found that woody species use water from deeper soil layers compared to herbaceous species, regardless of their position in the topographic gradient. However, the presence of a shallow water table restricted plant water uptake to the superficial soil layers at lower portions of the gradient. We confirmed that woody and herbaceous species are plastic with respect to their water use strategy, which determines niche partitioning across topographic gradients. Abiotic factors such as groundwater level, affect water uptake patterns independently of plant growth form, reinforcing vegetation gradients by exerting divergent selective pressures across topographic gradients.

Delving into the variations in tree species composition and richness across South American subtropical Atlantic and Pampean forests

Aims We analyse here the variations in species composition and richness and the geographic ranges of the tree species occurring in South American subtropical Atlantic and Pampean forests. Our goals were to assess (i) the floristic consistency of usual classifications based on vegetation physiognomy, climate and elevation; (ii) the leading role of temperature-related variables on the variations in species composition and richness; (iii) the predominance of species with tropical–subtropical ranges, possibly as a result of forest expansion over grasslands after the Last Glacial Maximum (LGM); (iv) the restriction of most subtropical endemics to stressful habitats as a possible result of past forest refuges during the LGM. Methods

Overview of Biotope Types of Socotra Island

Abstract The study describes main biotopes of Socotra Island. The biotopes were distinguished and described during complex field observations on more than 250 localities of Socotra between years 1999-2004. Classification of biotopes is based on differences in physiognomy, structure and species composition of the vegetation component of present biocoenoses. Groups of biotope types differ, above all, in the physiognomy and structure of vegetation. Biotope types are divided according to composition of dominant species. In this manner, 13 groups of biotopes and 39 biotope types were distinguished and described

Soil modification by termites in a sandy-soil vegetation in the Brazilian Atlantic rain forest

Abstract:Termites play a critical role in the regulation of soil processes, for example, water retention, nutrient cycling, and the formation and maintenance of soil structure. There is a consensus that mound-building termites modify physical and chemical soil properties in clay soils, but there is limited investigation into their influence for sandy soils in the Brazilian Atlantic rain forest. We tested the hypotheses that the termitosphere effectively improves properties of sandy soil, and that the role of termite soil particle selection is of greater importance in soils with higher sand concentration and lower nutrient status. The work was conducted in three vegetation physiognomies: woodland, savanna and grassland. In the woodland physiognomy we sampled in the border and in the interior, totalling four studied areas. We described a soil profile and collected five samples of termitaria and surface soil in each area. Also, in three 100-m2 plots allotted in each area, termite-mound density and volume were estimated, and termites were collected for taxonomic identification. Soil samples were submitted to physical and chemical analysis, and regression models were employed to analyse termite particle selection ability in different soil conditions. In most areas, the concentrations of nutrients, organic carbon and clay-size particles were significantly higher in termite mounds than in surface soils. On a weight basis, termite mounds had up to 32 times more nutrients, 12 times more organic carbon, and five times more clay than surrounding soils, however, aluminium toxicity was lower in termite mounds. Regression models demonstrated that the role of termites in soil particle selection is of greater ecological importance with decreasing soil nutrient status and increasing sand concentration. Therefore, termites greatly improve soil properties, representing truly ecosystem engineers in sandy soils, with an average soil turnover by mound-building activity reaching 10.5 m3 ha−1.

Post-fire recovery occurs overwhelmingly by resprouting in the Chaco Serrano forest of Central Argentina

In fire-prone landscapes, differences in post-fire regeneration by resprouting between species or sites could be far more important in explaining vegetation physiognomy and composition than seed regeneration. This is the first study exploring the relative contribution of tree resprouts and seeds to post-fire crown volume in the Chaco Serrano forest of South America. Additionally, we compare the resprouting response among species and quantify post-fire changes in tree composition among sites. We established 290 permanent plots distributed in three sites affected by wildfires in 2005. For all tree species in all plots we recorded survival of every individual 1 year after the fire; at the plot level, we recorded the above-ground tree volume before and 3 years after the fire. Resprouting from the base was the main resprouting type. Survival varied between species from 73% to 100% for native species and from 7% to 100% for non-natives. Before the fire, crown volume was similar in the three sites, and was completely lost after the fire in 92% of the plots. Three years after the fire, between 8% and 58% of crown volume was recovered. The ratio of crown recovery because of resprouts and seedlings was 1562:1. Tree composition exhibited few changes because of the high post-fire survival of most native species. We conclude that in the semiarid Chaco Serrano ecosystem tree species regenerate mainly by resprouting. This regeneration mode should be taken into account to better understand post-fire successional pathways of these forests, their management and the restoration of burnt forest areas.

Assessing Natural and Anthropogenic Variability in Wetland Structure for Two Hydrogeomorphic Riverine Wetland Subclasses

The hydrogeomorphic approach (HGM) to wetland classification and functional assessment has been applied regionally throughout the United States, but the ability of HGM functional assessment models to reflect wetland condition has limited verification. Our objective was to determine how variability derived from anthropogenic effects and natural variability impacted site assessment variables within regional wetland subclasses in central Oklahoma. We collected data for nine potential assessment variables including vegetation physiognomy (e.g., tree basal area, herbaceous cover, canopy cover, etc.) and soil organic matter at wetlands of two HGM riverine subclasses (oxbow and riparian) in May and June, 2010. Using Akaike Information Criteria, we identified limited relationships between landscape disturbance metrics and assessment variables within subclasses. The high degree of natural variability from climatic and hydrologic factors within both subclasses may be masking the impact of landscape disturbance on the other measured assessment variables. Precipitation had significant effects on assessment variables within each of the subclasses. To reduce natural climatic variability, the reference domain may need to be further subdivided. The approach used in this study provides fairly rapid and quantitative methods for evaluating the effectiveness of using HGM assessment variables in assessing wetland condition regionally.

Linking vegetation structure and bird organization: response of mixed-species bird flocks to forest succession in subtropical China

As forests undergo natural succession following artificial afforestation, their bird assemblages also change. However, interspecific avian social organization associated with forest succession has not been fully understood, particularly for mixed-species bird flocks. To disentangle how mixed-species flocks change as a function of local forest structure, we analyzed flock characteristics (particularly species richness, flocking frequency and propensity) and vegetation physiognomies along a presumed successional series (early, middle, and advanced) simultaneously in subtropical forests in southern China. As hypothesized, monthly point counts demonstrated that complexity of flocks increases with the progression of natural forest succession at a local scale. Advanced forests differed significantly from pioneering plantations with respect to vegetation structure, flock characteristics and constituents (especially for understory specialists). Importantly, forest succession affected flock patterns particularly in relation to the flocking propensity of regular species, and the frequency of nuclear species (Huet’s fulvetta Alcippe hueti), which in turn determined flocking occurrence at different successional stands. Canonical correspondence analysis indicated that understory flocking species (mainly Timaliidae babblers) were significantly associated with intact native canopy cover, complex DBH diversity, as well as high densities of dead trees and large trees, representing a maturity level of successional stands. Our study reveals that the effect of natural forest succession on mixed-species bird flocks is species-specific and guild-dependent. From a conservation perspective, despite a high proliferation of pine plantation in southern China, priority should be placed on protecting the advanced forest with a rich collection of understory flocking specialists.

Arboreal Ant Assemblages Respond Differently to Food Source and Vegetation Physiognomies: a Study in the Brazilian Atlantic Rain Forest

This study aimed to analyze assemblages of arboreal ants in different vegetation physiognomies within the Tropical Moist Forest (Atlantic Rain Forest) domain. The study was carried out at the Michelin Ecological Reserve, State of Bahia, Northeast of Brazil. We used sardine (protein resource) and honey (carbohydrate resource) baits to collect ants foraging in three vegetation types: (1) preserved native forest, (2) forest in regeneration (capoeira) with many invasive plants and (3) a mixed agroystem of rubber and cocoa tree plantation. We recorded 69 ant species attracted to the baits, 21 of them exclusive to honey bait and 25 exclusive to the sardine baits. The vegetation physiognomies preserved forest and rubber/cacao agrosystem showed higher species richness in relation to the forest in regeneration (capoeira), suggesting that rubber tree plantations can be a good matrix for the maintenance of some ant species typical of the forest matrix. The type of resource used is important for the structuring of the arboreal ant assemblages. The ants that were attracted to protein resources showed a guild composition that is more differentiated between vegetation types that of ants attracted to glucose resources.

Species Composition of Termites (Isoptera) in Different Cerrado Vegetation Physiognomies

Little is known about the termite fauna of the different vegetation physiognomies in the Cerrado biome. It is suggested that the species compositions in grassland and savanna areas are closely related to each other, and quite distinct from those of forests. This study compared the species composition from five different physiognomies of Cerrado, and tested the hypothesis that the termite faunas of savannas and grasslands form a distinct group from that of forests. The study was conducted in the Parque Estadual da Serra de Jaraguá, state of Goiás, Brazil. Termites were sampled from two physiognomies of savanna, one natural grassland, one pasture, and one gallery forest. A transect with 10 parcels of 5x2 m was established in each physiognomy. The relative abundance was inferred by the number of encounters, termites were classified in feeding guilds, and the dissimilarity in the species composition between the physiognomies was calculated. A total of 219 encounters, of 42 species of two families were recorded. The most abundant feeding guilds were the humivores (98) and xylophages (55). The physiognomies with the largest number of species were rupestrian cerrado (23 species) and cerrado sensu stricto (21). The physiognomies had a similar species composition (less than 55% dissimilarity), mainly the natural open areas. The hypothesis of a distinct fauna of termites in forest vegetation was refuted. The termite fauna of gallery forest is very different from that of pasture, but most species also occur in natural open areas. The impact of pasture on the diversity and composition of termites seems to be significant, but the impact is even greater on the proportion of the feeding guilds, reducing the proportion of xylophages and intermediates.

Soil physical conditions limit palm and tree basal area in Amazonian forests

Background: Trees and arborescent palms adopt different rooting strategies and responses to physical limitations imposed by soil structure, depth and anoxia. However, the implications of these differences for understanding variation in the relative abundance of these groups have not been explored. Aims: We analysed the relationship between soil physical constraints and tree and palm basal area to understand how the physical properties of soil are directly or indirectly related to the structure and physiognomy of lowland Amazonian forests. Methods: We analysed inventory data from 74 forest plots across Amazonia, from the RAINFOR and PPBio networks for which basal area, stand turnover rates and soil data were available. We related patterns of basal area to environmental variables in ordinary least squares and quantile regression models. Results: Soil physical properties predicted the upper limit for basal area of both trees and palms. This relationship was direct for palms but mediated by forest turnover rates for trees. Soil physical constraints alone explained up to 24% of palm basal area and, together with rainfall, up to 18% of tree basal area. Tree basal area was greatest in forests with lower turnover rates on well-structured soils, while palm basal area was high in weakly structured soils. Conclusions: Our results show that palms and trees are associated with different soil physical conditions. We suggest that adaptations of these life-forms drive their responses to soil structure, and thus shape the overall forest physiognomy of Amazonian forest vegetation.

Seed germination from lowland tapir (Tapirus terrestris) fecal samples collected during the dry season in the northern Brazilian Amazon

This study evaluated the potential of lowland tapirs as seed dispersers in the northern Brazilian Amazon. The study analyzed the viability of seeds after passage through the gut. Fecal samples were collected from 6 different vegetation physiognomies in Viruá National Park during the dry season. The samples were then kept in a greenhouse for 16 months to allow the seeds to germinate. The seedling species were identified and classified according to the type of fruit, plant habit, seed size and type of ingestion. Of the 111 fecal samples, 94 (84.7%) had viable seeds of 75 species. Melastomataceae was the most frequent family with viable seeds in the fecal samples (69.1% of samples, N= 18 species). The data suggest that the importance of the lowland tapirs as dispersers is not restricted to the species consumed actively by frugivory but also extends to species accidentally consumed during browsing. The occurrence of both large and small viable seeds in the fecal samples as well as a number of large drupes, which probably cannot be transported via endozoochory by any other animal species, provide evidence of the ecological importance of lowland tapirs to the dynamics of the forest-campinarana vegetation mosaic in the region.

Floristic and vegetation structure of a grassland plant community on shallow basalt in southern Brazil

Few studies have adequately described the floristic and structural features of natural grasslands associated with shallow basalt soils in southern Brazil. This study was carried out on natural grazing land used for livestock production in the municipality of Santana do Livramento, in the Campanha region of the state of Rio Grande do Sul, Brazil. The aim of the study was to describe the floristic and structural diversity of the area. The floristic list obtained comprises 229 plant taxa from 40 botanical families, with a predominance of the families Poaceae (62), Asteraceae (28), Fabaceae (16) and Cyperaceae (12). The estimated diversity and evenness in the community were 3.00 and 0.874, respectively. Bare soil and rock outcrops accounted for 19.3% of the area, resulting in limited forage availability. Multivariate analysis revealed two well-defined groups among the sampling units. One group showed a high degree of internal aggregation, associated with deep soils, and was characterized by the presence of tussocks, whereas the other was less aggregate and was characterized by prostrate species growing on shallow soil. Ordination analysis indicated a gradient of moisture and of soil depth in the study area, resulting in different vegetation patterns. These patterns were analogous to the vegetation physiognomies described for Uruguayan grasslands. Overall, the grassland community studied is similar to others found throughout southern Brazil, although it harbors more winter forage species. In addition, the rare grass Paspalum indecorum Mez is locally dominant in some patches, behaving similarly to P. notatum Fl., a widespread grass that dominates extensive grassland areas in southern Brazil.

Relationships between grazing and waterfowl production in the Canadian prairies

AbstractThe survival of waterfowl nests is positively correlated with the amount of grassland on the landscape, and population growth rates of some waterfowl species (e.g., mallards [Anas platyrhynchos]) are sensitive to nest survival rates. Thus, the effect of actions that alter grassland vegetation physiognomy, such as grazing, on waterfowl production is of interest to waterfowl habitat managers. Additionally, grasslands contribute other ecological goods (e.g., forage for livestock and wildlife) and services (e.g., photosynthesis, carbon sequestration), which can be influenced by grazing practices. We address key uncertainties about the linkages between grazing, vegetation physiognomy, and the survival and density of duck nests at study‐site, field, and nest‐site spatial scales. Using data from 2,554 duck nests found in 434 grazed or idled fields (median field size = 48.0 ha) in the Canadian Prairie Pothole Region between 2002 and 2009, we found that vegetation physiognomy affected nest survival at both the field and nest‐site scales, such that nest survival increased with nest‐site vegetation density and late‐season field vegetation density. Nest survival also responded to early‐season within‐field variation in vegetation height in a quadratic manner, such that survival was greatest in fields with moderate variation in vegetation height. Nest survival was negatively related to the intensity of grazing and to the amount of cropland in the surrounding landscape. Both the abundance of wetlands and the average vegetation height in the field had a positive influence on nest density. Fields idled during the breeding season had greater densities of nests than fields grazed either early or late in the breeding season. Leaving lands idled may be the most effective way to increase both waterfowl nest survival and nest density. When management of upland vegetation is required, we recommend grazing at moderate stocking rates (between 2 and 2.5 animal unit months [AUM]/ha) after the waterfowl breeding season is complete and monitoring vegetative characteristics to ensure they remain suitable to attract nesting waterfowl (e.g., leaving vegetation height >28 cm). Where grazing must be carried out during the breeding season, low to moderate stocking rates should be encouraged as these rates appear to have the least negative impact on both waterfowl nest survival and nest density. These stocking rates also will maintain rangeland in good condition to the long‐term benefit of producers. © 2013 The Wildlife Society.

Structure, ecological spectra and species dominance in riparian forests from Benin (West Africa)

This paper investigates the structure of the Benin Riparian Forests (RFs) through different methods: lifeforms, phytogeographic types, diameter class distribution, basal area, and stem density. Field data was collected in 373 phytosociological relevés using the Braun-Blanquet approach. RFs displayed a physiognomy that is highly variable in terms of structural characteristics. RFs in Benin were similar to many dense tropical forests and to the West African ones in particular, in terms of phytogeographical types (higher contribution of Guineo-Congolian basin species) and life forms (high abundance of phanerophytes and lianas, high occurrence of therophytes and medium size trees, low percentage of megaphanerophytes and woody lianas). Diameter class distribution was reserve J type, while values of basal area and stem density varied from 23 to 59 m2/ha, and 253 to 785 trees/ha respectively. Species dominance, in terms of abundance and basal area (i.e. 4.4% of the tree richness contributes 48.5% of overall abundance and 57.4% of the total basal area), was a major characteristic of RFs in Benin. The most dominant and frequent tree species were Pterocarpus santalinoides, Cola laurifolia, Syzygium guineense, Dialium guineense, Berlinia grandiflora, Cynometra megalophylla, Elaeis guineensis, Diospyros mespiliformis, Uapaca togoensis and Parinari congensis. Many stands of RFs are facing various levels of structural and floristic simplification, which include transformations in vegetation physiognomy, from dense pristine stands to sparsely forested waterways banks, riparian scrub, or bare land. Measures have to be taken to conserve the structural complexity of these edaphic and topographic forest ecosystems.Keywords: riparian forests, structure, dominance, Ben