Number Of Macrophyte Species Research Articles

Inter-linkages between in-stream plant diversity and macroinvertebrate communities

Evidence of freshwater biodiversity decline, species extinction and severe alterations in the biological structure and function of freshwater ecosystems is accumulating. Here we explore the role of macrophyte diversity in lowland streams for the abundance, taxon richness and composition of macroinvertebrate communities also including the abundance of different functional feeding groups. We applied a controlled in situ experiment in four small lowland stream reaches situated in rural landscapes in Denmark. We were able to explain a major fraction of the variability in the macroinvertebrate communities by differences in total macrophyte surface areas among treatments, but the number of macrophyte species in the experimental treatment also played a highly significant role (i.e. one, two or three plant species) for both the abundance, richness and composition of the macroinvertebrate community. We strongly encourage managers to protect plant diversity in streams, not only because the plants themselves constitute an important part of the biodiversity, but also because they positively affect the macroinvertebrate community. Moreover, macrophyte-friendly management can be seen as a nature-based solution to mitigate the degraded physical conditions characterising many streams in agricultural catchments.

Spatial and temporal changes in occupancy frequency distribution patterns of freshwater macrophytes in Finland.

A useful method for characterizing biological numerous assemblages at regional scales is the species occupancy frequency distribution (SOFD). An SOFD shows the number or proportion of study sites each species occurred. Species that occur at only a few sites are termed satellite species, while species that occur at many sites are termed core species.This study is the first to document and assess SOFD patterns in aquatic macrophytes. It characterizes SOFD patterns of freshwater macrophyte assemblages in Finland at two spatial and two temporal scales. For this, I analyzed three published datasets on freshwater macrophyte distributions: two from studies conducted at a local scale and the third from large national surveys. One local study and the national study also included data on temporal variation in species occupancy frequencies.In the national study, the number of core and satellite species varied slightly between the older and the newer survey, respectively. Among the 113 waterbodies surveyed as part of the national study, the SOFD followed a unimodal satellite pattern. However, for the older dataset (from the 1930s), a bimodal symmetric pattern also fit the SOFD data well. At the local scale, I observed geographical variation in SOFD patterns. The dataset from southern Finland followed a unimodal satellite SOFD pattern; data from central Finland instead displayed a bimodal symmetric SOFD pattern, although they also fit equally well with a bimodal truncated pattern. Moreover, temporal patterns in central Finland seemed to demonstrate a shift from a bimodal symmetric to a bimodal asymmetric SOFD probably.Geographical variation in the SOFD pattern may be due to variation in the regional species pool. The temporal changes in SOFD pattern may be due to lake eutrophication and anthropogenic disturbance around waterbodies, which may increase number of macrophyte species.

To the analysis of the flora of water bodies and watercourses of the city of Tobolsk (Tyumen region) and cities of the Vyatka-Kama Cis-Urals

The flora of water bodies and watercourses of the city of Tobolsk is composed of 266 species of macrophytes, including both higher plants and macroalgae. This indicator is higher than the number of macrophyte species in the previously studied cities of the Vyatka-Kama Cis-Urals, while the ratio of ecological groups remains the same. The taxonomic richness and ecological diversity of the hydrophilic component of urban floras depends on a number of factors: 1) the presence and diversity within the urban landscape of habitats inhabited by aquatic and semi-aquatic plants; 2) the position of the city’s territory in the system of regional land subdivisions within the physical-geographical country; 3) the age of the city. The composition of macrophytes is not affected by the size of the urban area and the geographical position of the city within a region.

Динамика зарастания нерестовых участков Псковского озера на примере залива Анохово

The dynamics of overgrowing of spawning grounds in the southern area of Peipsi-Pihkva Lake complex is considered, based on 28 years of observations from Anokhovo Bay. The history of the study of the water area is analyzed in detail, the species and syntaxonomic composition of plant associations in the littoral areas of the bay is described, and the dominant species are established. Over the entire observation period, the total number of macrophyte species increased by almost 2.5 times, and the number of plant associations increased approximately twofold. The area of the bay overgrown with macrophytes increased by 9.5%, with a simultaneous increase in the overgrowth density. The dominant species are common reed Phragmites australis, lakeshore bulrush Schoenoplectus lacustris, and yellow water-lily Nuphar lutea.

Distribution of macrophyte species and habitats in South African estuaries

This study investigated the area coverage and species composition of different habitat types in all estuaries and bioclimatic regions along the coast of South Africa. Estuary habitat covers a total area of 95,657ha. Reeds and sedges (14,732.6ha) were the dominant habitat type overall. Supratidal salt marsh was dominant in the cool temperate region (4869.7ha), intertidal salt marsh in the warm temperate region (2509ha) and reeds and sedges in the subtropical region (10,484ha). In the cool temperate, warm temperate and subtropical regions, the estuaries with the largest areas were the Berg (6799ha), Knysna (2038.7ha) and St Lucia estuaries (40,832.8ha), respectively. The number of macrophyte species per estuary varied from one to 53. Macrophyte species richness was higher in estuaries of the cool and warm temperate zone than that in the subtropical zone. Macrophyte species are distributed in 47 families and the dominant families are the Cyperaceae (18), Chenopodiaceae (14), Juncaceae (5), while 15 other families had only one representative species. The number of species in temporarily open/closed estuaries (TOCEs) and permanently open estuaries (POEs) was higher than that found in other estuary types (river mouths, estuarine bays and lakes). Only Juncus kraussii and Phragmites australis occurred in more than half of South African estuaries. The data are collated in an estuary botanical database that can be accessed for monitoring and conservation planning purposes. These findings have already found application in the management of estuaries in South Africa, the National Biodiversity Assessment and the National Estuary Biodiversity Plan.

A test of the Lake Habitat Survey method in Cleveland Reservoir and Lake Chivero (Manyame River Basin, Zimbabwe)

The Lake Habitat Survey (LHS) method has only been applied once in a tropical African reservoir and could potentially be a useful tool for hydromorphological impact assessments. This study (October 2012) tested the application of the LHS method to two Zimbabwean reservoirs, Cleveland and Chivero, which are impacted differently by human activities within their catchments with varying levels of physical impacts and lakeshore use. The Lake Habitat Quality Assessment (LHQA) and Lake Habitat Modification Score (LHMS) were used to assess the habitat quality and the magnitude of human impact on the reservoirs. Cleveland Reservoir LHQA (78 out of 112) and LHMS (16 out of 42) scores are indicative of relatively low human pressure (e.g. angling and canoeing). Results show that although Cleveland Reservoir is coming under increasing anthropogenic pressure, it does not appear to suffer from major alien plant invasion as compared to Lake Chivero, which scored 62/112 and 32/42 for the LHQA and LHMS, respectively. There were no significant differences between the numbers of vegetation layers in the riparian vegetation of the two reservoirs. However, there were significant differences in the number of macrophyte species and shoreline/riparian pressures between the two reservoirs. In conclusion, the use of the LHS can better enhance quality and reliability of lake hydromorphological assessments in tropical systems, where such an investigation is required to support decision making, after adaptations of the method have been made, i.e., inclusion of catchment impacts on lakes and reservoirs in LHS scoring metrics.

Effect of habitat complexity attributes on species richness

Habitat destruction is a leading cause of biodiversity loss worldwide. Destruction involving structural simplification tends to be a large contributing factor to this loss as many studies have reported a positive relationship between habitat complexity and taxonomic richness. However, the aspects of complexity that are most important for this relationship are still unclear. We tested whether several attributes of complexity contribute significantly to the effects of habitat complexity on macroinvertebrate richness. We sampled macroinvertebrates associated with several species of macrophytes covering a wide complexity gradient in freshwater coastal wetlands. Macrophyte complexity was quantified by measuring vertical and horizontal interstitial distances. Multiple regression was used to assess the relative importance of complexity attributes including the overall complexity as a space size/frequency index, space‐size heterogeneity as the variation in space sizes, as well as the more commonly used macrophyte biomass, number of stems and the number of macrophyte species. Our results indicate that space‐size heterogeneity is a more important contributor to taxonomic richness than overall complexity and the other complexity attributes examined. The results of this study have implications for the use of this concept in habitat restoration by the enhancement of habitat structures.

Drainage ditching at the catchment scale affects water quality and macrophyte occurrence in Swedish lakes

Summary1. We have limited knowledge of the effects of land use in general and of drainage ditching in particular on macrophyte communities in lakes. I quantified catchment land use, including drainage ditching, as well as water quality and the number of macrophyte species in 17 Swedish lakes in summer 2005.2. Land use within 1 km of the studied lakes was analysed in a geographic information system. The following variables were included: areas of forests, mires, agricultural land and urbanization, length of drainage ditches (classified according to the use of the land they drained), and shortest distance from lake to an urban area. To extract and analyse general trends in the data sets, redundancy analysis was used.3. Water quality was explained mainly by three land‐use related variables: the lengths of agricultural, forest and mire ditches. The length of agricultural ditches was positively correlated with lake water conductivity, total dissolved solids, Ca, N and total organic carbon (TOC). The lengths of forest and mire ditches were positively correlated with lake water characteristics, especially TOC.4. The number of species representing different macrophyte life forms was explained by three environmental variables: conductivity, and lengths of forest and agricultural ditches. The numbers of isoetids, nymphaeids, elodeids and total obligate hydrophytes were negatively correlated with length of forest ditches. In contrast, the number of lemnids and helophytes was positively correlated with conductivity and length of agricultural ditches. Furthermore, the number of isoetids was exponentially related (negatively) to lengths of agricultural and forest ditches, indicating a threshold response to drainage ditch length.5. The results suggest that effects on water quality and macrophyte communities result from drainage ditching in the lake catchments rather than from land use itself. Given the total area of drainage‐ditched land worldwide (millions of ha in Scandinavia alone), drainage ditching should be considered when evaluating environmental impacts on lake water quality and macrophyte occurrence and when determining reference conditions for catchment land use.

Relationships between the presence of odonate species and environmental characteristics in lowland ponds of central Italy

A set of 21 ponds was sampled three times for odonate larvae during spring 2002. At the same time 17 environmental variables were recorded including area, wet phase duration, total nitrogen, total phosphorus, aquatic macrophytes and land use. A total of 16 odonate species belonging to Lestidae, Coenagrionidae, Aeshnidae and Libellulidae were recorded, and the total number of species per pond varied from zero to six. The relationships between species richness, assemblages and environmental variables were studied by simple and multiple correlation and by Canonical Correspondence Analysis (CCA). The results showed that permanent ponds were larger, deeper, had more macrophyte species, had more extensive macrophytes cover and lower concentrations of nitrogen and phosphorus than temporary ponds. Multiple regression analysis showed that the number of odonate species was positively affected firstly by the number of macrophyte species, and then by pond depth. However, pond depth appeared to be interchangeable with several others variables, such as pond area and water duration and negatively correlated with nitrogen concentration, variables which are all linked with the permanent or temporary status of the ponds. CCA analysis indicated that odonate species presence was linked with a few environmental variables, showing a tendency of Odonata to avoid ponds with higher nitrogen concentrations, with the exception of Lestes barbarus, a species typical of temporary water in central Italy. At the same time, the majority of species were linked with longer water phase duration and with greater macrophyte species richness. A comparison with previous studies, and in particular with those carried out in central Italy, confirmed the positive influence of macrophytes, water duration, and also the negative effect of nutrient load. However, several other variables, in particular land use, shade, presence of fish, which were influential in other studies, were not significant in this study.

Factors Affecting Macroinvertebrate Communities in Astatic Ponds in Central Italy

ABSTRACT Twenty astatic ponds near Rome were studied in order to define the relationships between physicochemical variables and macroinvertebrate communities. The main abiotic factor differentiating the ponds was the annual hydrologic cycle. Depth, surface area, and sand percentages in the sediment were higher in permanent ponds, whereas silt+clay content was higher in temporary ones. No difference was recorded in pH, conductivity and oxygen content in the water or organic matter in the sediments between the two pond types. Three main ecological assemblages were distinguished: a) generalist taxa common to both pond types; b) taxa associated with and adapted to temporary ponds; and c) taxa which seemed to prefer permanent ponds. Overall, there was no relationship between number of taxa and surface area, except for Odonata and aquatic macrophytes. A positive correlation was observed between number of macrophyte species and macroinvertebrate taxa richness, and particularly of odonates and chironomids, suggesting that an increase in aquatic vegetation species leads to an increase in microhabitats and suitable food, substrate, and/or refuge from predators. Odonata seemed also to prefer more stable and sunny ponds.

Macrophyte Species Changes in the Everglades: Examination along a Eutrophication Gradient

AbstractMacrophyte species distribution in the marsh and slough areas of the northern Everglades were examined along a surface water and soil P gradient to characterize the effects of nutrient enrichment on the macrophyte community changes in the Everglades ecosystem. Macrophyte species distribution and frequency examined at 51 sites located in the Water Conservation Area (WCA‐2A) revealed distinct trends in species changes with P enrichment. Marshes in the unenriched and enriched areas were dominated by Cladium jamaicense and Typha domingensis, respectively. Open water areas were characterized by Eleocharis sp., Utricularia sp., Chara zeylanica, and Nymphaea odorata in the unenriched areas and by floating plants and Polygonum sp. in the enriched areas. We compared the macrophyte species distribution with the soil P contour map of WCA‐2A and derived six major categories of P enrichment (labeled 0–5) that may be used to adequately describe macrophyte species distribution in the WCA‐2A. Soil and surface water P values that correspond to the different P‐enrichment categories and the number of macrophyte species in each category have been estimated. Examination of the relative abundance of the macrophyte species in the six P‐enrichment categories showed a decline in characteristic slough macrophyte species with P enrichment. Increase in P status of the system was also accompanied by the advent and gradual establishment of macrophytes such as Mikania scandens, Sarcostemma clausum, Polygonum sp., Acrostichum danaeifolium, and a variety of floating plants. Characteristic slough macrophyte species such as Utricularia purpurea, Eleocharis elongata, and Eleocharis cellulosa serve as indicators of the unenriched P conditions.