Aquatic Macrophyte Species Research Articles

High floral trait diversity of aquatic plants in the Pantanal reveals different pollination strategies

This research brings novel information regarding the floral traits and pollinator groups of aquatic macrophytes. Classifying functional traits and pollinator groups contributes to understanding reproductive processes, community structuring, and ecosystem functioning. Based on an extensive survey of information on 524 species of aquatic macrophyte angiosperms from the Pantanal wetland, we classified the floral traits of these species to identify their potential group of pollinators and how these traits are distributed throughout the botanical families of aquatic plants. We classified their life forms, floral traits (flower type, color, and resource), and main pollinator groups. We also investigated trends, plotting the occurrence of species throughout the phylogeny of angiosperm families, and using a network of interactions, we verified how interactions with different groups of pollinators are distributed within species traits. As a result, the species of aquatic macrophytes in the Pantanal are well distributed within the phylogeny, indicating that they may be more related to ecological than phylogenetic factors. We found a high diversity of floral traits and pollinator groups, predominating white flowers, providing nectar as a resource, and bees as their primary pollinators. Although bees were the main group of pollinators, we also found abiotic interactions linked to the species richness in Poaceae and Cyperaceae, with pollination system mainly performed by wind. Our research represents a first step towards identifying key information gaps. Future studies should focus on understanding in loco traits to fill this gap, besides information on ecological interactions with potential pollinators and species phenology.

Diversity of Aquatic Macrophyte Species of Pardi Wetland, Valsad District, Gujarat, India: Social-economic and Ethnobotanical importance

Wetlands, which serve as a transition between land and water, are a source of concern across the world in terms of resource evaluation and use, environmental protection, pollution control, eco-restoration, biodiversity conservation, and so on. Wetlands are an important aspect of human civilization because they provide drinking water, food, improved water quality, sediment retention, flood storage, transportation, recreation, and climate stabilization, among other things. Despite their numerous advantages, wetlands are increasingly subjected to anthropogenic pressures and are rapidly disappearing. Valsad district is the developing district of Gujarat state, located between 20°37'48.00" N and 72°55'48.00" E, making it one of Gujarat's rainiest districts and having many wetland ecosystems with great aquatic biodiversity. The present investigation aimed to list, find, and investigate wetlands, with a focus on macrophyte species, because of their high socioeconomic and ethnobotanical relevance. The current study identified a total of 43 macrophyte species, which are organized into 35 genera and 24 different families. Out of the 43 macrophyte species, 40 were recorded as angiosperms, 02 as pteridophytes, and 01 as macroalgae. In the present investigation, existing macrophyte species were evaluated based on their ecological classification, life form classification, and their wetland indicator status. This research not only showed the diversity of indigenous macrophytes but also discusses the utilization of aquatic plants for socioeconomic and ethnobotanical purposes, which enhance the traditional medicinal knowledge about the macrophytes.

Floristic survey of aquatic macrophytes in eastern Maranhão, Brazil: richness, biological forms and three new records.

The aim of this study was to carry out a floristic survey of aquatic macrophytes in the municipality of Chapadinha, eastern Maranhão, and classify their biological forms. The study was done between September 2021 and September 2022. A total of 31 families, 49 genera and 72 species of aquatic macrophytes were catalogued, of which 65 are angiosperms. Among them, Bacopa stricta (Plantaginaceae), Staurogyne diantheroides (Acanthaceae), and Xanthosoma aristeguietae (Araceae) are new records for the flora of Maranhão, with the last two new records for Northeast Brazil. The richest family was Cyperaceae, with 11 species, followed by Plantaginaceae (seven taxa), Fabaceae (five taxa) and Lentibulariaceae (five taxa). Six biological forms were recorded, amphibious (27 taxa) and emergent (26 taxa) being the most common. The aquatic environments of Chapadinha are home to a considerable number of species, families, and life forms of macrophytes. The results show that due to the lack of surveys, evidenced by the new records presented, the state aquatic flora is still underestimated. Further studies in poorly explored areas are suggested, especially in the eastern part of the state, to improve understanding of species richness.

Current distribution, trends, abiotic and biotic preferences of two Elodea species in Bulgaria

Two invasive aquatic macrophyte species from the genus Elodea and their distribution in Bulgaria were studied. The research was based on 653 field surveys from the period 2009-2022. Elodea records constitute to only 6% of the database. Between the two species studied, E. nuttallii exhibited a wider distribution both in rivers and lakes (natural and artificial). Several instances of invaders? dominance were observed, with E. nuttallii showing dominance patterns mainly in lakes, and E. canadensis in rivers. Both species were distributed in aquatic habitats with a wide variation in abiotic characteristics, except for the dominant substrate. E. nuttallii showed a more significant altitudinal range reaching above 1500 m. Such altitudinal variations resulted in diverse ecological habitats in terms of abiotic factors such as temperature and light intensity. The studied aquatic macrophyte communities demonstrated average species richness. Ceratophyllum demersum and Myriophyllum spicatum were the most commonly recorded representatives of the native aquatic flora. Canadian waterweed demonstrated the ability to form dense communities in rivers, while Nuttall?s waterweed retained average values of abundance. A case of natural disappearance within the Elodea species has been documented. The systematised information covering a 13-year period could serve to identify strategic areas for monitoring aquatic IAS and their management.

Quantitative Assessment of Macrophytes Diversity and their Status in Wetlands of Guru Ghasidas Vishwavidyalaya, Bilaspur, Chhattisgarh (India)

The most significant and taxonomically varied biotic element in every aquatic environment is aquatic macrophytes. They play a vital role in maintaining the ecosystem's structure and functionality. Additionally serving as bioindicators of the general health of a water body are macrophyte kinds, variety, density, and depth. In present study, the quantitative diversity of aquatic macrophytes was assessed from different wetlands of Guru Ghasidas Vishwavidyalaya which is a central university and holds four important water bodies in Bilaspur district of Chhattisgarh state, India. A total of 33 aquatic macrophytes species were identified belonging to 21 families from wetlands of Guru Ghasidas Vishwavidyalaya. These macrophytes were grouped as floating, submerged and emergent mainly dominated by emergent macrophyte species followed by floating and submerged i.e., 23, 8 and 2 species respectively. The highest species diversity was observed in Pond 1 and 4 with 26 species each and highest species richness was observed in Pond 4 with 158 individual counts, the highest IVI was achieved by emergent Ipomoea carnea (16.492) and the highest occurring family was found to be Cyperaceae (12.12% of total species). Other diversity indices were calculated as 3.451, 0.042, 33 and 0.946 for Shannon-Wiener Index (H’), Simpson's Index (D), Species Richness (R), and Evenness (E) respectively. However, for the conservation and sustainable utilization of aquatic ecosystems, it is necessary to understand the status and importance of macrophytes to the ecosystem and its functioning.

PEMULIHAN PERAIRAN TERCEMAR MENGGUNAKAN MAKROFITA AIR

Indonesia possesses a potential and diverse biodiversity of plants that can be utilized as phytoremediation agents. One of the ecosystems frequently encountering pollution is the aquatic ecosystem. Therefore, this research is conducted to identify the diversity of aquatic macrophytes with the potential for water remediation efforts. The method employed is qualitative descriptive based on literature review. The literature study revealed 30 species of aquatic macrophytes, with 15 species prominently utilized for environmental remediation. Among these, Ipomea aquatica and Scirpus grossus emerge as the most widely employed aquatic macrophytes.

Species richness pattern of aquatic vascular macrophytes along elevation gradients in Nepal Himalayas

Abstract. Siwakoti EA, Nepali B, Mandal TN, Baniya CB. 2023. Species richness pattern of aquatic vascular macrophytes along elevation gradients in Nepal Himalayas. Biodiversitas 24: 5179-5190. Aquatic vascular macrophytes constitute an important component of aquatic ecosystems. This study aims to determine the species richness pattern of aquatic vascular macrophytes along elevation gradients (100-4900 m asl) in the Nepal Himalayas. We used available published literature on elevational ranges of aquatic vascular macrophytes in Nepal to interpolate the species elevational ranges, thereby providing species richness estimates for 100 m elevational bands. A total of 113 species of aquatic vascular macrophytes belonging to 66 genera under 35 families were recorded from Nepal. Among these macrophytes, dicots were represented by 21 families, monocots with 10 families and pteridophytes with 4 families. Regarding the geographical divisions, the total number of aquatic vascular macrophytes recorded was 76 from the east, 90 from the central and 67 from the west, conclusively central Nepal showed the maximum number of macrophytes. The highest species richness was contributed by Hydrocharitaceae followed by Potamogetonaceae, Plantaginaceae, Lentibulariaceae and Nymphaeaceae. So far, the functional types of macrophytes are concerned, free-floating species were 15, submerged species were 36, floating-leaved species were 18 and emergent species were 44 along elevation gradients in the three geographical divisions in Nepal. The Generalized Linear Model (GLM) was applied to find out the relation between the species richness of aquatic vascular macrophytes with elevation. It showed a statistically significant monotonic declining pattern with increasing elevation. The occurrence of this model was further verified by aquatic vascular macrophyte richness at every 200 m elevation which converged with the general pattern. The study conducted along one of the world’s longest bioclimatic elevational gradients led to support the monotonic declining pattern of aquatic vascular macrophytes richness indicating the difference in richness pattern among aquatic and terrestrial ecosystems. It also emphasizes the importance of conserving aquatic ecosystems with their vegetation.

Aquatic macrophyte growth season in Central and Northern European Union and the implications for aquatic macrophyte risk assessments for herbicides.

Under current European Union regulation, the risks to aquatic organisms must be assessed for uses of plant protection products (PPPs) that may result in exposure to the environment. For herbicidal PPPs, aquatic macrophytes are often the most sensitive taxa. For some herbicidal modes of action, macrophytes may be affected only while they are actively growing. For the risk assessment, it is therefore useful to know whether application timings would result in surface water exposure during periods when aquatic macrophytes are actively growing (therefore potentially resulting in effects). Toxicity endpoints, which are based on studies with active growth, may be overconservative in cases where exposure of PPPs will not co-occur with active macrophyte growth. A comprehensive literature search was performed, using systematic and manual approaches, with the aim of identifying the main active growth period for macrophytes in natural freshwater bodies in climates relevant to the Central and Northern zones of the European Union. The results of the searches were screened initially to identify all potentially relevant references, for which a full evaluation was then performed. Reliability was assessed using the principles of the Klimisch scoring system. As part of the full evaluation, growth periods were identified for each macrophyte species studied. Finally, the extracted growth periods were considered together to determine an overall active growth period for aquatic macrophytes representative of the Central and Northern EU zones. Based on this literature review, the active growth period identified for most aquatic macrophyte species representative of the Central and Northern EU zones is April to September. Relating to the regulatory implication of these results, it may be possible to conclude a low risk for aquatic macrophytes if the predicted surface water exposure period for certain PPPs is demonstrated to be outside the periods of active growth. Integr Environ Assess Manag 2024;20:1125-1139. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Introduce invasive alien macrophytes species in Indonesia national priority lakes (study case: lake Rawa Pening, Sentarum, Tempe, Tondano, Sentani)

According to Presidential Regulation (Perpres) Number 60 of 2021, 15 lakes are classified as Indonesia’s national priority lakes. From 15 lakes, five of them are Tempe (South Sulawesi), Sentarum (West Kalimantan), Rawa Pening (Central Java), Tondano (North Sulawesi) and Sentani (Papua). Aquatic macrophytes are aquatic photosynthetic organisms that can be seen with the naked eye and actively grow periodically or permanently beneath, on, or above the water’s surface. The national priority lakes face upon invasive aquatic macrophytes. Therefore, their presence must be controlled. This research purposed to introduce invasive aquatic macrophytes in several of Indonesia’s national priority lakes. The aquatic macrophytes are recorded using a purposive sampling method with plots square (1x1 m2) and three replications. All aquatic macrophytes were documented, including species, family, population numbers, life forms and origin. The research from these five national priority lakes discovered a total of 10 families and 14 species of invasive aquatic macrophytes. The families were Pontederiaceea, Onagraceae, Polygonaceae, Lentibulariaceae, Araceae, Cyperaceae, Poaceae, Schropulariaceae, Alismataceae, Salviniaceae, and Hydrocharitaceae. The invasive aquatic macrophytes such as Monochoria hastata, Eichhornia crassipes, Persicaria barbata, Ludwigia adscendens, Utricularia aurea, Ludwigia perennis, Pistia stratiotes, Ludwigia peruviana, Cyperus odoratus, Panicum repens, Bacopa floribunda, Limnocharis flava, Salvinia natans, and Hydrilla verticillata. The research result can be used as guidelines for good lakes management.

The effect of lead (Pb) on the growth rates of two aquatic macrophyte species; Limnobium laevigatum (Humb & Bonpl. ex Willd) Heine and Egeria densa Planch. grown in different experimental media

Anthropogenic causes contribute to toxic pollutants in aquatic environments and heavy metal pollution. As a heavy metal, Lead (Pb), is one of the most common causes of pollution in water. Heavy metals must be removed from the aquatic environment because they adversely affect health and all living things in each environment. In this study we aimed to determine the effects of lead (Pb) exposure on the growth rates and biomass of two aquatic macrophyte species, E. densa and L. laevigatum. Plants grown in in two different experimental media. For this purpose, both plants were exposed to 3 different concentrations of lead (1 ppm, 5 ppm, 15 ppm). Samples were measured on the 1st, 4th and 7th days, and the first and last weights of the plants were compared. Bioexperiments were run in triplicate. Positive values were observed in the growth rates of both plants, except for the negative growth rates observed on the 1st day at 1 ppm and 5 ppm lead concentrations in the pond water environment. Both plants showed positive growth in 25% Hoagland medium at all concentrations and days, except for the 1 ppm lead concentration, being observed for E. densa. As a result of our study, lead exposure did not significantly alter the growth rates of E. densa and L. laevigatum in the experimental media used for short-term (up tp 7 days) durations.

Rotifers (Rotifera: Monogononta) Associated with Littoral Macrophyte Habitats in Flooded Neotropical Ponds: A Qualitative Study

Rotifers represent an important component of freshwater zooplankton. The high richness of taxa, particularly in littoral macrophyte zones of water bodies in tropical and subtropical flood-prone areas, is a repeatedly reported fact. However, studies on the composition of periphytic rotifers in the Neotropics are reduced and almost non-existent in some regions. A qualitative study on rotifers (Monogononta) associated with littoral aquatic vegetation and their seasonal variation was carried out in three flood-prone ponds in the “Esteros de Camaguán Fauna Reserve” in the Venezuelan plains. For the selection of the collection sites, the two-stage stratified method with proportional affixation was used. Samples of macrophytes and the water associated with them were taken in littoral zones. The percentages of occurrence and numerical frequency were calculated for each rotifer taxa. The faunal similarities and correlations within and between ponds in the same and different climatic seasons were estimated using the Jaccard and Spearman coefficients (α = 0.05), respectively. In total, 102 rotifer taxa associated with 11 species of aquatic macrophytes were identified. The genus Taphrocampa with two taxa plus ten other taxa, are new records for Venezuela and one of them for South America. The taxocenosis and the geographic distribution of the reported taxa reflect a typical composition of the littoral zones of tropical regions. The total richness of both planktonic associated with aquatic vegetation and periphytic assemblages were similar. The highest richness of rotifer taxa coincided with the rainy season and the lowest with the early rainy season. The rotifer fauna presented low similarity values within and between ponds according to seasonality and, with some exceptions, between planktonic and periphytic environments. The importance of sampling periphytic rotifers and the influence of the flood cycle, and the degree of macrophyte development in the structuring of periphytic rotifer communities, were confirmed.

Novel Sampling Methodology for Identifying Presence and Absence of Aquatic Macrophyte Species in Two Lakes in Northern British Columbia, Canada

Aquatic macrophytes provide essential food and habitat for all levels of aquatic life, as well as have a critical role in nutrient cycling. Many aquatic macrophytes are submerged for part or all of their life cycle, which makes them difficult, time-consuming, and expensive to sample. During a study of two lakes, Bednesti and Berman, in northern British Columbia, Canada, we developed a nondestructive, cost-effective, and time-sensitive sampling methodology for aquatic macrophytes. With two people sampling in a single boat, 90 randomly selected sample sites with four transects each were completed over five 4-hr sampling periods. This methodology produced presence/absence data, which would be an effective methodology for monitoring aquatic macrophyte populations in freshwater environments. The technique allowed us to identify aquatic macrophytes at a species level, regardless of emergent or submergent growing patterns. This technique was used to study the impacts of residential development on freshwater aquatic macrophyte communities and provided useful and easily obtainable data for that purpose. Natural resource and conservation fields may find this technique useful to monitor aquatic environments for specific, rare, or invasive aquatic macrophyte species in an efficient and cost-effective manner.

Potential Phytoremediation of Aquatic Macrophyte Species for Heavy Metals in Urban Environments in the Southern Area of Brazil

This research investigated four different species of aquatic macrophytes with natural occurrence in an urban environment highly anthropized in Southern Brazil. The aim of the research was to compare the phytoremediation potential among the species E. anagallis, H. grumosa, H. ranunculoides, and S. montevidensis through Pearson´s correlation analysis and cluster analysis, using the heavy metal content identified through HNO3 - HClO4 and phytoremediation indexes. The results highlighted the bioconcentration factor (BCF) of H. ranunculoides, with outstanding results for Cu BCF = 667.09, Zn BCF = 149.93, Cd BCF = 26.85, Cr BCF = 31.77, Ni BCF = 35.47, and Pb BCF= 126.29. Additionally, H. grumosa and S. montevidensis were also highlighted, considering the potential phytoremoval (g ha−1). Therefore, this study demonstrates the tolerance and potential for removal of heavy metals Cu, Cr, Cd, Pb, Ni, and Zn by the evaluated aquatic macrophyte species and elucidates the outstanding potential of application in phytoremediation purposes.

A Survey of Aquatic Macrophytes in the Akassa Axis of the River Nun, Niger Delta, Nigeria

An ecological study was conducted to measure the diversity of aquatic macrophytes and nutrient levels of the River Nun estuary around Akassa, Niger Delta, Nigeria. This was done to ascertain the current ecological status of the estuary and gauge the ecological health of the water body as a result of anthropogenic additions into the water body. Macrophye and Subsurface samples were collected from three sampling points on the estuary. Macrophyte samples were identified using standard keys while water samples were investigated for pH, Salinity, Nitrates, Phosphates, and Sulphates. Result from the study reveals the presence of 17 species of aquatic macrophytes from 8 families. All nutrient parameters were within the permissible levels. There is no significant difference (P>0.05) in pH, salinity and sulphate between stations. There is a significant difference (P<0.05) in nitrate and phosphate between stations. The diversity of macrophytes was also uniformly high in all stations. The preponderance of macrophytes in this study agrees with the aphorism that marine ecosystems contain a high diversity of living organisms. The River Nun is therefore not under any immediate ecological threat.

The Phytoremediation using Water Hyacinth and Water Lettuce: Correlation between Sugar Content, Biomass Growth Rate, and Nutrients

Degradation of water quality due to the presence of pollutants in water is an emerging issue in many countries, including Malaysia. Phytoremediation is one of the environmentally friendly, cost-effective conventional technologies that are still used in modern times. However, the selection of plant species is the most important aspect for the application of phytoremediation in wastewater treatment. Nevertheless, there are species of floating aquatic macrophytes that are capable of coping with various pollutants present in wastewater. Among the various floating aquatic macrophyte species, water hyacinth (WH) and water lettuce (WL) have been described as effective phytoremediators in reducing water pollution through bioaccumulation in their body tissues. Hence, WH and WL were chosen in this study as it is easily found, propagated, and cultivated. This paper aims to determine the biosorption capacity of these species in eliminating various pollutants present in wastewater as well as to define the optimum harvesting time for each species. Although these floating aquatic macrophytes are considered the most problematic plants due to their uncontrollable growth in water bodies worldwide, their ability to remove pollutants from wastewater has created a sustainable approach for their use in phytoremediation. In this sense, the use of phytoremediation by implementing the invasive floating aquatic macrophytes can certainly support the sustainable management of wastewater treatment in the future. Based on the results, it was found that WH efficiently removed higher PO43-, NO3- and NO2- concentrations compared to WL from the wastewater. Both WH and WL showed the same trend of correlation between the growth rate and sugar content, where the sugar content increased when the plants reached the highest growth rate. The maximum nutrient uptake occurred in 14-17 days, proving that nutrient availability is critical for plant growth. This study concludes that the sugar content of WH and WL are increased with the biomass growth rate, and both plants species are competent in eradicating the nutrient pollution in wastewater. On top of that, this study infers that the maximum harvesting period for WH biomass is on day 18, while WL biomass is on day 21; based on the highest sugar content and biomass weight of each species.

The influence of macrophyte ecological groups on food web components of temperate freshwater lakes

Aquatic macrophyte taxonomic composition, species abundance and cover determine the physical structure, complexity and heterogeneity of aquatic habitats – the structuring role of macrophytes. These traits influence richness, distribution, feeding and strength of the relationships between food web communities in lakes. The aim of this study was to determine how lakes with different dominating macrophyte ecological groups affect planktonic food web components, emphasising the influence on young of year (YOY) fish and large (≥1 +) fish community. We hypothesised that different dominating macrophyte ecological groups have different structural effects on food web components and YOY fish growth, abundance and feeding. Studied lakes categorised into three different macrophyte ecological groups – lakes dominated by emergent, floating+floating-leaved or submerged vegetation. We found that all dominating ecological groups had a strong influence on plankton communities (except heterotrophic bacterioplankton and nanoflagellates), YOY fish and large fish. Floating-leaved plant dominance was positively related to planktonic food web structure and YOY fish weight, length, abundance and the consumption of zooplankton as a prey of all major species of YOY fishes. Larger fish tended to favour the presence of emergent vegetation. This conclusion has important implications for local managers and conservationists in respect to the maintenance and protection of littoral habitats and fish resources.

Physiological responses and phytoremediation capacity of floating and submerged aquatic macrophytes exposed to ciprofloxacin.

Ciprofloxacin (Cipro) water contamination is a global concern, having reached disturbing concentrations and threatening the aquatic ecosystems. We investigated the physiological responses and Cipro-phytoremediation capacity of one floating (Salvinia molesta D.S. Mitchell) and one submerged (Egeria densa Planch.) species of aquatic macrophytes. The plants were exposed to increased concentrations of Cipro (0, 1, 10, and 100µg.Cipro.L-1) in artificially contaminated water for 96 and 168 h. Although the antibiotic affected the activities of mitochondrial electron transport chain enzymes, the resulting increases in H2O2 concentrations were not associated with oxidative damage or growth reductions, mainly due to the activation of antioxidant systems for both species. In addition to being tolerant to Cipro, after only 96h, plants were able to reclaim more than 58% of that from the media. The phytoremediation capacity did not differ between the species, however, while S. molesta bioaccumulate, E. densa appears to metabolize Cipro in their tissues. Both macrophytes are indicated for Cipro-phytoremediation projects.

Detecting Water Hyacinth Infestation in Kuttanad, India, Using Dual-Pol Sentinel-1 SAR Imagery

Water hyacinth (Pontederia crassipes, also known as Eichhornia crassipes) is a highly invasive aquatic macrophyte species, indigenous to Amazonia, Brazil and tropical South America. It was introduced to India in 1896 and has now become an environmental and social challenge throughout the country in community ponds, freshwater lakes, irrigation channels, rivers and most other surface waterbodies. Considering its large speed of propagation on the water surface under conducive conditions and the adverse impact the infesting weed has, constant monitoring is needed to aid civic bodies, governments and policy makers involved in remedial measures. The synoptic coverage provided by satellite imaging and other remote sensing practices make it convenient to find a solution using this type of data. While there is an established background for the practice of remote sensing in the detection of aquatic plants, the use of Synthetic Aperture Radar (SAR) has yet to be fully exploited in the detection of water hyacinth. This research focusses on detecting water hyacinth within Vembanad Lake, Kuttanad, India. Here, results show that the monitoring of water hyacinth has proven to be possible using Sentinel-1 SAR data. A quantitative analysis of detection performance is presented using traditional and state-of-the-art change detectors. Analysis of these more powerful detectors showed true positive detection ratings of ~95% with 0.1% false alarm, showing significantly greater positive detection ratings when compared to the more traditional detectors. We are therefore confident that water hyacinth can be monitored using SAR data provided the extent of the infestation is significantly larger than the resolution cell (bigger than a quarter of a hectare).

Aquatic Macrophytes in Southern Amazonia, Brazil: Richness, Endemism, and Comparative Floristics

Southern Amazonia harbors a wide diversity of aquatic macrophyte species because of its diverse wetland habitats and location in the Amazon-Cerrado transition zone, which spans the two largest biogeographic domains in South America. We investigated the taxonomic diversity of aquatic macrophytes in the region with a focus on endemism, species richness, and life forms. We present new records of aquatic macrophyte species and compare our results with other Brazilian phytogeographic domains. We found a high number of species of aquatic macrophytes for the southern Amazon region, comparable to extensive inventories in southern, northeastern, and northern regions of Brazil. We recorded 709 species of aquatic macrophytes in 313 genera and 97 families, which includes 90 species endemic to Brazil and five species endemic to the Brazilian Amazonia. The macrophyte species list of southern Amazonia showed < 25% similarity to inventories in Amazonia and Cerrado. This high diversity of aquatic macrophytes in southern Amazonia, with endemic species and others with restricted ranges, emphasizes the need for conserving these wetlands and vegetation types.

Aquatic Macrophytes Hosting Immature Mansonia (Mansonia) Blanchard, 1901 (Diptera, Culicidae) in Porto Velho, Rondonia State, Brazil.

High abundance of hematophagous mosquitoes of the genus Mansonia Blanchard, 1901 (Diptera: Culicidae) threatens human and domestic animal health and well-being. Knowledge of the biology of nuisance mosquito species is necessary to understand specific ecological and biological factors to enable rapid and effective monitoring measures for sustainable control programs. The establishment and dispersion of Mansonia species are associated with the occurrence of aquatic macrophytes species, which are indispensable for the development of larvae and pupae. To increase knowledge of the host plants for Mansonia immature stages in Porto Velho, Rondonia State, Brazil, specimens of four plant species, which occur across the tributaries of the Madeira River were sampled and inspected for the presence of egg batches, larvae, and pupae. A total of 1,386 larvae and pupae of Mansonia spp. were collected attached to the roots of Eichhornia crassipes (Mart.) Solms (Commelinales: Pontederiaceae), Pistia stratiotes L. (Alismatales: Araceae), and Limnobium laevigatum (Humb. and Bonpl. Ex Willd.) Heine (Alismatales: Hydrocharitaceae). The novel association of Mansonia species with L. laevigatum is presented. Egg batches of Mansonia spp. were found only on Salvinia molesta D.S. Mitch. (Salviniales: Salviniaceae). Possible differences in the roles played by E. crassipes and S. molesta in the reproductive cycle of Mansonia spp. in the surveyed area are discussed. All species of host plants including E. crassipes, P. stratiotes, S. molesta, and L. laevigatum should be considered when planning macrophyte management for the control of Mansonia species.