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Environmental DNA (eDNA) analysis can facilitate surveillance of invasive aquatic plant's distribution. However, it is still questionable how accurately eDNA concentration reflects and predicts aquatic plant abundance. Although previous studies investigated relationships between aquatic plant eDNA concentration and their abundance in freshwater environments, the conclusions were not consistent between the studies. Here, a systematic literature search was conducted to summarize previous findings and meta-analyze the relationships between eDNA concentration and aquatic plant abundance. Hierarchical random-effect meta-analyses showed significant positive, but weak, relationships between them (r = 0.45 in average), meaning that eDNA concentration accounted for approximately 20% of the observed variation in plant abundance. Additionally, the relationships tended to be rather stronger in the field than in the laboratory environments, which may be attributed to limited quantifiability and species specificity of plant coverage as abundance metrics, heterogeneous dispersion of plant eDNA particles, and phenology-dependent eDNA production from plant bodies. The finding indicates that aquatic plant eDNA particles could reflect more regional (but not local) abundance, and thus, eDNA-based abundance estimation might be more appropriate at a broader scale (i.e., lower spatial resolution). Further studies focusing on various environmental parameters and plant ecotypes are needed to clarify the relationship. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess aquatic plant distribution patterns in a Mediterranean temporary pond network (Doñana National Park, SW Spain). We analyzed differences in species composition employing multivariate ordination techniques; we specifically examined the importance of hydroperiod and physical and chemical variables in the five geomorphological areas across which the pond network is spread. The ponds significantly segregated along a north-south gradient, matching the segregation pattern of the aquatic plant assemblages. Ponds in the three northernmost areas showed higher levels of species richness than ponds in the two southernmost areas. In the north, ponds were present at higher densities, spanned a broader hydroperiod range, and had lower conductivity levels; these features were associated with the presence of wet-meadow species and larger numbers of submerged and emergent species. In the south, alkaline waters were mainly associated with different charophyte species, and the predominance of long-hydroperiod ponds helped in increasing the number of floating species. Managed ponds, which had been artificially deepened, contributed to increase pond heterogeneity and hydroperiod breadth across the entire network. At present, such ponds are key to the preservation of Doñana's rich and unique aquatic plant community. [ABSTRACT FROM AUTHOR]

In the Mississippi River Delta, the common wetland grass, Phragmites australis, displays high genetic diversity, as several genetically distinct populations are co-occurring. Differences in salinity tolerance may be an important factor determining these populations' distribution in the delta. Our study investigated the salt tolerance of four genotypes exposed to 0, 10, 20, 30, and 40 ppt salinity. The growth rate, biomass, and the light-saturated photosynthetic rate were stimulated at 10 ppt salinity and inhibited at salinities higher than 20 ppt, compared to controls. Increased concentrations of Cl and Na were found in the roots and older leaves of plants exposed to high salinities. Salt tolerance levels differed between genotypes. High salinity tolerance was mainly achieved by reduced water uptake and vacuole compartmentalization of toxic ions. The most tolerant genotype sustained biomass and photosynthesis even at 40 ppt, whereas the most sensitive genotype did not survive salinities higher than 20 ppt. Our findings show that the observed occurrence of different genotypes in the Mississippi River Delta is correlated to genetically determined differences in salinity tolerance. Further investigations are needed to better understand the role that salinity tolerance plays in the invasion of certain introduced P. australis genotypes. [ABSTRACT FROM AUTHOR]

Levins's asymmetrical α index quantifies between species overlap over resources more realistically than similar-purpose single-value indices. The associated community-wide $$\bar \alpha$$ index expresses the degree of 'species packing'. Both indices were formulated upon competing animal (i.e., mobile) organisms and are independent of population densities. However, overlap over resources for nonmobile organisms such as plants may have an impact even below carrying capacity. The proposed $$\hat \alpha$$ index, based on Levins's α index, quantifies spatial overlap for plants integrating information on species spatial distribution and crowding conditions. The $$\hat \alpha$$ index is specifically designed for plant distribution data collected in discrete plots with density expressed as percent coverage (%cover) of substratum. We also propose a community-wide $${\hat \alpha_{\text{c}}}$$ index, conceptually analogous to $$\bar \alpha$$ , but furnished with a measure of dispersion ( se $${\hat \alpha_{\text{c}}}$$ ). Species importance within the community is inferred from comparisons of pairwise $$\hat \alpha$$ 's with $${\hat \alpha_{\text{c}}}$$ . The $$\hat \alpha$$ and $${\hat \alpha_{\text{c}}}$$ indices correlate closely and exponentially with plant density, and correct apparent over- and underestimations of interaction intensity at low and very high crowding by Levins's α and $$\bar \alpha$$ , respectively. Index application to aquatic plant communities gave results consistent with within-community and general ecological patterns, suggesting a high potential of the proposed $$\hat \alpha$$ and $${\hat \alpha_{\text{c}}}$$ indices in basic and applied macrophyte ecological studies and management. [ABSTRACT FROM AUTHOR]

Tillaea aquatica (Crassulaceae) is considered as annual wetland species threatened by changes in land use and progressing eutrophication in large part of its European distribution range. We summarised the historical and recent data on this species, and analysed its distribution and associated habitat changes in the Czech Republic. We used permanent plots as well as seed bank and seed dispersal studies to obtain better insight into the plant's survival strategy. During the second half of the twentieth century T. aquatica disappeared from most historical localities situated mainly in large fishponds. After 1999, altogether 18 new populations were found in small fry ponds and other fish-farming ponds. The largest populations of Tillaea were found in ponds with long-term bottom exposure where the vegetation of perennial herbs was eliminated by herbicides or grazing. Propagules easily dispersible by water, on gumboots or tyres of vehicles, and long-term soil seed bank also might contribute to persistence of the species in the habitats, diminishing the chance of extinction. As the fishpond management has changed, and so have done the original habitats of Tillaea, the species could survive in habitats different from those in the past. In this article, we suggest management measures aimed at promoting survival of Tillaea under new circumstances. [ABSTRACT FROM AUTHOR]

The distribution, abundance and habitat characteristics of an alien species, Elodea canadensis, were surveyed in watercourses in Slovenia. The accompanying plant community was also examined. Distribution and abundance of macrophytes were assessed in reaches of different length, and habitat assessment is based on 12 parameters of the Riparian, Channel, and Environmental (RCE) Inventory. E. canadensis thrived in 132 out of 1,227 reaches examined and in 12 of the 39 watercourses surveyed. It grew in the company of a variety of species, most frequently with different species of Potamogeton. It was rarely found as the prevailing, and never as the only species in any reach. Canonical correspondence analysis (CCA) of reaches with E. canadensis revealed that the presence of detritus, retention structures and properties of the riparian zone explained most of the variance in community composition. Habitat analysis of well-established stands of E. canadensis showed that its preferred habitats were watercourses flowing through agricultural landscape, with a narrow, more or less disturbed riparian zone, with moderate presence of retention structures, and with sediment that was a mixture of gravel, sand and silt with either coarse or fine organic matter. It was not found in the parts of streams with the most dynamic flow, and was absent from watercourses in the karst region, due to the frequent and extreme water level fluctuations. The alien species E. canadensis did not express its invasive character in heterogeneous watercourses with rich macrophyte communities. [ABSTRACT FROM AUTHOR]

The aim of this paper is to study the relationships between the physical features of rivers and the distribution of macrophyte vegetation. Field work was undertaken at 207 stations along the Scorff River and its tributaries, a salmon river system in southern Brittany (western France). The physical features were considered using a principal component analysis (PCA). Stepwise multiple regression models made it possible to assess their relationships with the botanical data. The first five axes of the physical PCA (used as explicative variables) were initially linked to the most frequently surveyed species, then to their eco-morphological types, and, finally to Arber’s (1920. Water Plants. A Study of Aquatic Angiosperms. Cambridge Univ. Press, Cambridge, 414 pp) morphological classification. It was concluded that plant morphology was closely related to these environmental factors. This could contribute to the development of predictive models for plant distribution and could increase the knowledge of reference vegetation related to bioindication systems. [ABSTRACT FROM AUTHOR]

The aquatic plant communities in two Irish canals were examined between 1990 and 1994 to investigate the factors that influence plant species distribution and community structure. Four main aquatic plant groups were identified by TWINSPAN. Two groups were characterised by bankside vegetation, including Carex sp., Juncus bulbosus and Scirpus lacustris. Large mixed assemblages of emergent, floating leaved, free floating and submerged plant species characterised the third group. The fourth group was species poor and was dominated by Cladophora sp. Canonical Correspondence Analysis identified weed control history, total oxidised nitrogen, water colour, distance from feeder stream and distance from summit as the factors that potentially influenced the distribution of plant species. The results indicated that ongoing management practices did not significantly alter the overall structure and abundance of the plant communities during the study period. [ABSTRACT FROM AUTHOR]

Macrophytes were monitored in 48 headwater rivers in Flanders (Belgium). Only 26 sites had macrophyte vegetation, which was used to calculate five different indices and scores. These indices originated from UK, France, Czech Republic and Germany. Macrophytes were significantly correlated with a number of habitat variables, such as transect size, river width, slope, Huet zonation, distance to source, shadowing and average depth. For the substrate there were significant negative correlations with the fine particle sizes and a positive correlation with the coarse particles. A multivariate analysis of the macrophytes in these headwaters showed three groupings, essentially separated on basis of water hardness and pH. [ABSTRACT FROM AUTHOR]

Three species of Elodea ( Elodea canadensis Michaux, E. nuttallii St John and E. ernstiae St John) have colonized Europe from the American continent. All three arrived in the Alsatian Rhine floodplain (north-eastern France) soon after their arrival in Europe, i.e. in the mid-19th century for E. canadensis, and in the mid-20th century for E. nuttallii and E. ernstiae. The paper investigates the present distribution of Elodea spp. in the floodplain by quantifying the species’ respective occurrences and by describing their habitats. The study further focuses on E. nuttallii which is presently colonizing other parts of Europe. It analyses whether it has continued to expand in the Alsatian Rhine floodplain during recent decades, and it checks whether changes in the abundance of E. nuttallii have had an impact on species richness of water plant communities. E.␣nuttallii has been found to be at present one of the most dominant and most frequent aquatic plant species in the study sector, while E. canadensis and E. ernstiae are less abundant. The species’ distributions differ with regard to water chemistry and water temperature: E. canadensis occurs in oligo-mesotrophic, rather stenothermic habitats, whereas E. nuttallii and E. ernstiae can be encountered in meso- to eutrophic sites with little or no arrival of stenothermic ground water. By comparing successive vegetation relevés from the same sites the study revealed further that the distribution of E. nuttallii has been stable in recent decades, despite local fluctuations in abundance. No relationship could be established between those fluctuations and changes in species richness or type of local plant communities. The sum of the results suggests that the expansion of E. nuttallii in the Alsatian Rhine floodplain had been completed prior to the study period. The species’ present distribution in the study sector as well as its position in local plant communities might therefore be considered a model for what can be expected to happen in areas where E.␣ nuttallii has only recently arrived. [ABSTRACT FROM AUTHOR]

Using environmental parameters we studied the distribution of two endangered species, Hydrocharis morsus-ranae L. and Rumex hydrolapathum Huds., in a low-lying marshland of the Swiss Plateau, a region in which aquatic vegetation is particularly threatened. A large part of the study site is regularly mown by a machine for site management purposes. The caterpillar mower digs ruts, which are especially pronounced along the tracks used to reach the mown compartment. To assess the effects of site management on these species, we have tested six environmental parameters (vegetation unit, water conductivity, water supply indicated by altitude, time elapsed since the last cut, distance from major ruts and disturbance of major ruts) that can potentially influence plant distribution. All the plots of these two species have been found in mowed compartment, which seems to indicate a correlation between site management operations and occurrences. The other factors driving the distribution of these plants are vegetation unit, distance from major ruts and water supply. [ABSTRACT FROM AUTHOR]

Temporal and spatial changes of viral and bacterial abundance were examined in relation to environmental factors and hydrography at five stations between May 2000 and July 2001 in the brackish lake of Ganzirri (Sicily, Italy). Virioplankton abundance ranged from 5.26 × 104 to 7.54 × 108VLP ml-1 (on average 1.38 × 108particles ml-1) and was significantly higher at the three eutrophic stations located in the lake of Ganzirri (Stations 1, 2, and 3) than in the channel connecting the lake with the Straits of Messina. The virus-to-bacterium abundance ratio (VBR range, 0.4-117; average:14) showed the highest values in channel connecting the lake of Ganzirri with the meromictic lake of Faro. VBR values<1.0 were found in summer 2000 in relation with peculiar hydrographic constraints. Virioplankton distribution was dependent on salinity, and on dilution of the oligotrophic waters flowing from the Straits. Virioplankton was closely related with bacterioplankton indicating a close coupling between viruses and host cell abundance. [ABSTRACT FROM AUTHOR]

Kandelia candel, a dominant plant species in Hong Kong mangroves, had different growth strategies during its seedling stage for acclimation to various soil types. Leaves of the seedlings grown in sandy soils (coarse texture) were significantly thicker than those in loamy-sandy and silty soils (fine texture). However, leaf weight per unit leaf area of seedlings grown in sandy soils was similar to that in loamy-sandy soils and was 1.60 times that in silty soils. These indicate thatK. candelin sandy soils had developed a more loose leaf structure and a xerophilous characteristic during its seedling stage for acclimation to the features of coarse textured soils, which were low water holding capacity and low mineral content. In addition, for young seedlings grown in sandy and loamy-sandy soils, more biomass was allocated to roots than in silty soils, indicating thatK. candelseedlings in sandy soils developed stronger roots for anchorage and water absorption; another xerophilous characteristic to acclimate to loose and coarse textured soils. As the plants became more mature, no significant difference in leaf thickness of the saplings was found between loamy-sandy and sandy soils. In order to acclimate to the low water holding capacity in sandy soils,K. candelseedlings had lower physiological activities including lower chlorophyll content; lower activities of root oxidase, nitrate reductase, peroxidase and superoxide dismutase but higher malonaldehyde contents than those in silty soils. Canopy shade is an important factor affecting the growth and physiology ofK. candel. The seedling grew worse under the mangrove canopy than that in the open gap, with smaller leaf area, specific leaf area, leaf number and biomass. The seedlings under the canopy eventually died and no saplings were found under canopy shade, implyingK. candelis a shade intolerant species and canopy shade might “force” its newly recruited individuals to expand out of the forest. [ABSTRACT FROM AUTHOR]

Historical changes (1961-2002) in the distribution of herbaceous wetland plant associations were inferred from the hydrological regime of Lake Saint-Pierre, a 312 km2 broadening of the St. Lawrence River (Quebec, Canada), to assess the cumulative effects of human interventions and climatic variability. Relative abundance index (height × percent cover) of wetland plants in 630 field quadrats sampled at 13 sites (1999-2002) were used to derive a model predicting the occurrence of nine herbaceous plant classes with a 71% (24-84%) accuracy. Wetland types included seasonally dry (meadows), mudflats and wet (low marshes and submerged) assemblages. Over the 1961-2002 period, the total surface area of Lake Saint-Pierre herbaceous wetlands ranged between 11 (in 1972) and 128 (in 2001) km2 and was negatively correlated (Spearmanr= -0.86,p<0.0001) to average water level during the current growing season. Within-season variability and level conditions over the previous season defined 5 marsh assemblages characterized by different species composition, relative abundance and diversity. Significant hydrological variables included quadrat elevation, water depth, number of days flooded and depth variability experienced over the current and/or previous growth seasons. The hydrological model suggests that for a given level, wetland plant assemblages differed markedly whether the multi-year sequence of water levels was rising or falling. Lake Saint-Pierre alternated between three broad-scale wetland configurations, dominated by meadows and open marsh with floating-leaved vegetation (in the 1960s), scattered tallScirpusmarshes (in the 1970s and early 1980s) and closed marsh with aggressive emergents (since 1996). The strong response of Lake Saint-Pierre wetlands to hydrological conditions in the current and previous growth seasons underlines their vulnerability to future water level variations resulting from regulation and climate variability. [ABSTRACT FROM AUTHOR]

Examines the distribution of the floating-leafed Nymphacea lotus in irrigation canals and ricefields in Lake Manzala, Egypt. Average density of lotus in irrigation canals and ricefields; Ratio of vegetative to sexual reproduction; Impact of the presence of lotus in ricefields on the growth and grain yield of the crop.

The distribution and taxonomic composition of Rotifera in Southeast Asia is reviewed. For some countries, records are poor: Brunei, Cambodia and Laos are almost terra incognita for rotifers (<10 taxa recorded), while the Thai rotifer fauna is the best documented (ca. 310 taxa on record). However, analysis of the available data is impeded by fuzzy taxonomy and the questionable reliability of many records. Most studies focus on the pelagic or littoral of freshwater habitats. Other habitats are largely ignored. Similarly, few studies deal comprehensively with illoricate Monogononta, sessile Flosculariacea and Collothecacea and, especially, Bdelloidea. The genera Lecane, Brachionus and Trichocerca are the best represented, with littoral taxa predominant. Fisheries-related studies dealing with highly productive pelagic environments tend to over report the contribution of Brachionus. Most taxa are thermophilic character, exemplified by the dominance of tropic-centred Lecane and Brachionus. Some cold-water taxa have been recorded, but the relative climatological homogeneity of the region and low number of studies on high-altitude environments prevent the discrimination of clear latitudinal or altitudinal variation in the distribution of rotifers within Southeast Asia. The majority of Southeast Asian rotifers are widely distributed, including true cosmopolites and thermophilic taxa. There are several local or Oriental endemic Rotifera, mostly Lecane. The American Brachionus havanaensis and Keratella americana appear to have been introduced to the region. The taxonomy of some Rotifera described from the region is commented upon; Brachionus murphyi Sudzuki is recognised as senior synonym of B. niwati Sanoamuang et al. (syn. nov.). Some cases of geographical and/or ecological vicariant species-pairs are suggested. The Southeast Asian rotiferfauna contains a sizeable fraction of taxa occurring in the tropicalregions of the Old World, most of which also occur in tropical Austral [ABSTRACT FROM AUTHOR]

The Rotifera from four peat-swamps in the provinces Suratthanee (Kra-Jood and Kun-Thu-Lee peat-swamps), Nakhonsri-thammarat (Khuan-Kreng peat-swamp) and Yala (Lan-Kway peat-swamp) in southern Thailand were examined by the study of qualitative samples collected on three occasions during July, October and November, 1998. A total of 96 species was identified, seventeen of which are new to the Thai rotifer fauna. The most diverse genera were Lecane (40.6%), followed by Lepadella (8.3%) and Trichocerca (7.3%). The most diverse rotifer fauna was foundin Kra-Jood peat-swamp (61 species), followed by Kun-Thu-Lee (57 species), Lan-Kway (41 species) and Khuan-Kreng (24 species) peat-swamps, respectively. [ABSTRACT FROM AUTHOR]

The species composition of the rotifer fauna of Lake Kud-Thing, NongKhai Province, northeast Thailand was investigated in a monthly sampling program from January to December 1998. A remarkably rich rotifercommunity consisting of 183 taxa was recorded, including 32 new records to the Thai fauna. The most diverse genera were Lecane (23.5%), followed by Trichocerca (16.9%) and Lepadella (11.5%). Lecane isanensis n. sp. is described and figured. Thirteen species (Aspelta circinator, Collotheca tenuilobata, Lecane nelsoni, Lepadella benjamini, Lepadella eurysterna, Sinantherina ariprepes, Testudinella cf. insinuata,Trichocerca abilioi, Trichocerca inermis, Trichocerca montana, Trichocerca orca, Trichocerca rosea and Trichocerca simonei) are new to the Oriental region. Notably, the record of Trichocerca orca is the first since its discovery in New Zealand in 1913. The rotifers can be classified into three groups based on duration of appearance; (1) common, perennial; (2) uncommon, perennial; and (3) uncommon, sporadic species. The high species richness of rotifers, particularly members of the genera Lecane and Trichocerca, but low diversity of Brachionus together suggest that the lake is probably not eutrophicated. [ABSTRACT FROM AUTHOR]

We studied the distribution of Lepadellidae (Rotifera) in freshwaterhabitats in the floodplain of the River Rusizi in northwest Burundi.Twenty-three species belonging to Colurella Bory de St. Vincent, 1824 (3 species), Lepadella Bory de St. Vincent, 1826 (18 species) and Squatinella Bory de St. Vincent, 1826 (2 species) are recorded, 22 of them are new to Burundi. One of the taxa encountered probably represents an unnamed species. Lepadella arabica Segers & Dumont, 1993 is recognised as junior subjective synonym of Lepadella eurysterna Myers, 1942 (syn. nov.). Most of the taxa recorded are cosmopolitan or tropicopolitan, two are restricted to the tropical regions of the Old World and Australia, and one, Squatinella lunata Segers, 1993 is an Ethiopian endemic. [ABSTRACT FROM AUTHOR]

Knowledge of rotifers from Greenland is poor. Those from marine and other saline waters have especially been poorly investigated. The authors have studied meiofauna from different saline localities at DiskoIsland, West Greenland on several occasions from 1990 to 1999. Samples from the intertidal zone, rock pools and a saline, radioactive spring contained 16 rotifer species. Six of these are new to Greenland. The radioactive salt spring has previously been suggested to contain marine relicts dating back to a warmer period with a higher sea level. The samples from the spring, however, did not yield any marine rotifers. It did contain the euryhaline Cephalodella gracilis. A description of its trophi adds to the known variability of this species. The trophi of Notholca striata and N. psammarina are studied in detail using light and scanning electron microscopy for the first time, and aspects of their taxonomy are discussed. [ABSTRACT FROM AUTHOR]

Using a polyclonal antibody against the mate recognition pheromone (MRP) of Brachionus rotundiformis Koshiki strain, we investigated the behavioral reproductive isolation and the similarity of MRP among geographically and temporally isolated B. rotundiformis strains. Males of the Koshiki strain did not discriminate in mating attempts among females of the Koshiki strain and those of conspecific allopatric strains from Hamana, Fiji, Thailand and Spain. Likewise, Koshiki males attempted mating with statistically indistinguishable frequency with Koshiki females and B. plicatilis strains. However, copulation was not consummated between Koshiki males and B. plicatilis females. The amount of anti-MRP binding to three allopatric B. rotundiformis strains was similar to that of the Koshiki strain, but binding to Hamana and the B. plicatilis strain was significantly lower. Four temporally separated B. rotundiformis populations were hatched from resting eggs collected from 0, 5, 10 and 15 cm depth in the sediment of Kai-ike pond in Koshiki island, Japan. Sediment age was determined using the 210Pb method, allowing us to estimate that resting eggs from 15 cm depth were produced 65 years ago. Results of mating assays and anti-MRP binding showed that no behavioral reproductive isolation existsamong the four temporally isolated Koshiki strains. B. rotundiformisappears to be reproductively isolated from B. plicatilis, but heterospecific matings are still attempted between B. plicatilis and B. rotundiformis, suggesting that the MRP remains sufficiently similar to elicit circling behavior. [ABSTRACT FROM AUTHOR]

During the austral summer 1997/98, a survey was made of a series of freshwater bodies on the Kerguelen Islands, Subantarctica (49 deg. S-69 deg. E), in the area of Port-aux- Francais and Val Studer. The rotifer fauna from plankton of 17 lentic freshwaters is listed and commented upon. Species richness (39 taxa) and species diversity are fairly low. Only 6 taxa are euplanktic, the others are facultative plankters or littoral/benthic species. Three of the true plankters found are restricted to the Southern Hemisphere, whereas the rest of the rotifers (apart from two unidentified monogononts) shows a wide-spread or cosmopolitan distribution. Thirty-three taxa are new to the Kerguelen archipelago. A comparison is made with the rotifer assemblages observed on other Subantarctic islands. Taxonomic notes on little known species are added. The validity of Cephalodella gibba microdactyla asseparate subspecies is rejected, and Filinia terminalis kergueleniensis is recognized as junior synonym of F. pejleri. [ABSTRACT FROM AUTHOR]

One hundred and sixteen species of Rotifera are recorded from seven floodplain lakes of the Brahmaputra basin (northeastern India), the highest rotifer biodiversity recorded from these biotopes in the Indian subcontinent to date. The Australasian Brachionus dichotomus reductus and Lecane batillifer; the Oriental Keratella edmondsoni, Lecane blachei and L. acanthinula; the Palaeotropical Lecane braumi, L. lateralis, L. unguitata, Trichocerca tropis, Testudinella greeni and T. brevicaudata; the Pantropical Brachionus donneri and a rather widely distributed Horaella brehmi represent taxa of biogeographical interest.Three species are new additions to the Indian rotifer fauna and eight are new to the N.E. region. Lecanidae > Brachionidae = Colurellidae> Trichocercidae > Testudinellidae comprise the largest fraction (68.0%) of the examined fauna. Comments are made on the general nature and composition of the rotifer taxocoenosis as well as on acidophilic elements, ecology of various taxa and on the species richness of different lakes. [ABSTRACT FROM AUTHOR]

Invertebrates at 20 sites on 19 Campbell Island streams were sampledover the Austral summer of 1996/97. Twelve of the 16 benthic invertebrate taxa known from the island were collected. The most abundant group was the Crustacea, which included an isopod (Notidotea lacustris)and two amphipods, one belonging to the family Eusiridae and one to the suborder Gammaridea. Five species of Diptera were found (three chironomids; Orthocladiinae sp., Chironominae sp. and Maoridiamesa insularis, as well as an empidid and a simuliid Austrosimulium campbellense). One trichopteran, the hydroptilid caddis Oxyethira albiceps and two plecopteran species Rungaperla campbelli and R. longicauda and unidentified Oligochaetes were also collected. In general, Campbell Island streams are stable, deeply incised, have unusually high salinity from wind-blown sea spray and a unique benthic invertebrate fauna. With the exception of high altitude streams with large boulders which had invertebrate communities dominated by Crustacea and the endemic stonefly of the genus Rungaperla, none of the measured environmental variables or geographic location could explain the distinctive communities found. The species-poor stream fauna and the absence of many invertebrate families commonly found on mainland New Zealand appears to be related to the extreme isolation and geological history of the island. [ABSTRACT FROM AUTHOR]

Twenty-five samples from 18 terrestrial and/or freshwater habitats in the eastern part of Korea yielded 38 new records of bdelloid rotifers, 22 of which are new to the Asian fauna. Among these Korean new records, Dissotrocha aculeata reversa Berzins and Habrotrocha plana Milne were recorded outside their type localities for the first time, and Macrotrachela bullata (Murray) was reported only from two countriesafter its description. Bradyscela granulosa de Koning, Habrotrocha gracilis gracilis Montet, Macrotrachela latior Donner, Philodina duplicalcar (de Koning) and P. rugosa coriacea Bryce are recorded outside Europe for the first time. The taxonomy and distribution of these rare species are discussed. [ABSTRACT FROM AUTHOR]

The three most abundant and species-rich genera of erpobdellid leeches - Erpobdella, Dina and Trocheta - have traditionally been distinguished by their annulation pattern. Erpobdella has five unsubdivided annuli per somite, in Dina the last annulus is widened and subdivided once, and in Trocheta, the last and often also the first annulus is further subdivided. The last two genera are often referred to as the subfamily Trochetinae. The presented molecular phylogenetic analysis, based on mitochondrial 12S rDNA sequences and nuclear ITS2 sequences,has revealed a sister relationship between Trocheta and Erpobdella rather than between Trocheta and Dina. Furthermore, the annulation pattern has proved to be inappropriate for the diagnosis of Dina and Trocheta. The taxon Trocheta bykowskii krasense has been classified on the basis of its Trocheta-like annulation; however, according to the molecular phylogeny, it belongs to the Dina clade. A pair of diagnostic PCR primers were developed to identify unambiguously individuals with intermediate annulation. In summary, (1) the traditional genus diagnosis of Dina and Trocheta is no longer tenable, and the genera are not always morphologically distinguishable by traditional characters;(2) T. b. krasense Sket, 1968, should be re-classified as Dina krasensis; (3) the subfamily Trochetinae should be annulled because it does not represent a monophyletic assemblage. [ABSTRACT FROM AUTHOR]

During an annual cycle, flux rates of oxygen, nitrate, nitrite, ammonium, phosphate and silicate were measured in light and dark bell jars at three sites in Ria Formosa (Algarve, Portugal) enclosing either a natural macrophytic community (macroalgae on sand or mud, a seagrass bed of Zostera noltii) or bare sediments. The results are compared with a preceeding study in which the same bell jar technique has beenapplied in the Sylt-Romo Bay of the northern Wadden Sea. Nitrate flux was mainly directed from the water column to the benthic communities in Ria Formosa, as well as in the Sylt-Romo Bay. However, nitrate uptake was higher in the northern, more eutrophic study area. In Ria Formosa, nutrient concentrations were lower than in the Sylt-Romo Bay possibly due to strong water exchange with Atlantic waters. High temperatures and strong insolation had a greater impact on nitrate fluxesin Ria Formosa than in the Sylt-Romo Bay. Bioturbating macrofauna increased ammonium efflux in the Sylt- Romo Bay while this effect was not as pronounced in the Ria Formosa study sites. Benthic phosphate uptake dominated in the Ria Formosa and was correlated to initial phosphate concentrations in incoming waters. At both study sites, oxygen and nutrient fluxes were correlated with temperature. Additionally, flux rates were strongly influenced by biotic components and levels of eutrophication. A literature survey showed that mainly in temperate regions, material fluxes increase with temperature, whereas in warmer areas, ammonium and phosphate fluxes between sediment and water were generally lower. [ABSTRACT FROM AUTHOR]

The community composition of benthic macroinvertebrates from 870 estuarine sites was examined in order to either confirm or challenge established boundaries of biogeographical provinces along the Gulf of Mexico and western Atlantic coasts of the United States. The objective was two-fold: (1) to demarcate boundaries that separate dissimilar fauna in the Gulf of Mexico, and (2) to compare the Gulf of Mexico biogeographically with other well-known provinces. We segmented the coastline into grid cells with dimensions of 1 deg. latitude and 2-4 deg. longitude. Using the descriptive techniques of cluster analysis andnonmetric multidimensional scaling, we determined the similarities in benthic community composition between sites within grid cells in the Gulf of Mexico and compared the biotic ordinations to natural habitat characteristics such as salinity, sediment type, and depth. We then evaluated the overall community composition within each grid cell in the Gulf of Mexico and established whether or not similarities existed between adjacent grid cells. In this manner, we confirmed that aneast-west gradient existed in estuarine benthic community composition along the Gulf of Mexico coast. This information was combined with our previous work in the western Atlantic coast to discern biogeographical provinces. Based on cluster analyses and an analysis of endemicbenthic species the following provinces are proposed: (1) the Virginian province, from Cape Cod, Massachusetts to Wilmington, North Carolina, (2) the Gulf of Mexico, from Rio Grande, Texas to Cape Romano, Florida, and (3) south Florida, south of latitude 26 deg. N. The region encompassing South Carolina, Georgia and northern Florida represents a transitional area between temperate and tropical provinces. [ABSTRACT FROM AUTHOR]

A hypothesis of phylogenetic relationships inferred from analysis ofplastid-encoded rbcL sequences is presented for members of the Solieriaceae, an economically important family containing carrageenan-typephycocolloids. Previous studies established that the Solieriaceae sensu lato forms a terminal clade in the Solieriaceae complex, a cluster of families sister to the Gigartinaceae complex (Gigartinaceae and Phyllophoraceae). The family Solieriaceae (including the Areschougiaceae) presently contains about 20 genera that are widely distributed in warm-temperate and tropical waters throughout the world. Molecular rbcL and published morphological evidence are consistent with an Australasian origin for the family and a Tethyan distribution for its tropical representatives from west to east as far as the Pacific coast of North and South America. The austral lineages (Callophycus, Rhabdonia, Areschougia and Erythroclonium) are resolved at the base of the tree. The remaining genera , comprising the tropical and subtropical cluster, form a robust terminal clade (100% bootstrap support). This assemblage can be divided into seven groups, most of which receive strong bootstrap support: (1) Sarconema, (2) a Eucheuma group, (3) an Atlantic Solieria group, (4) an Indo-Pacific Solieria robusta group, (5) a Meristiella/Meristotheca group, (6) Agardhiella and (7) a Sarcodiotheca group that includes 'Eucheuma' uncinatum from the Gulf of California. Four clusters of species are recognized in the Eucheuma groupthat correspond to the sections: Eucheuma, Gelatiformia (= Betaphycus), Anaxiferae, and Cottoniformia (= Kappaphycus) proposed by MaxwellDoty. No decision is reached regarding the taxonomic rank appropriate to the eucheumoid taxa. [ABSTRACT FROM AUTHOR]

The red alga Polysiphonia setacea Hollenberg (=Womersleyella setacea(Hollenberg) R. Norris), described originally from the Hawaiian Islands and later reported for other tropical localities, has recently become widespread in the Mediterranean. In several localities it forms a dense, almost monospecific turf but, despite its abundance, it appears to reproduce only vegetatively; neither sporangia nor sexual reproductive structures have thus far been found. In order to elucidate its life history, plants were cultured in a variety of conditions of temperature, daylength and photon irradiance, and the upper thermal limit was also determined. Isolates of P. setacea grew well in culture,but were more tufted and branched than wild plants. No reproduction by spores or gametes was observed and only an unusual form of vegetative regeneration was found. Some pericentral cells became darker and larger than the others and produced proliferations from which new plants arose. Plants grew best at 15 and 20 deg. C, and relatively poor growth was observed at 10 and 25 deg. C. At 20 deg. C growth was better in long days than in short days. The upper thermal limit was 28deg. C, and plants were able to tolerate a temperature as low as 5 deg. C for 4 weeks without any damage. These observations show that P. setacea is well adapted to the environmental conditions of the western Mediterranean, and there is good agreement with the phenology of the species in the wild. Although this entity has been treated as an introduction from a tropical area, our results suggest that the Mediterranean entity would not be able to survive or grow in surface waters of tropical areas whence this species has been reported. However, the occurrence of thermal ecotypes in P. setacea is a possibility and further studies, based perhaps on molecular data, are necessary to assess the origin of the Mediterranean populations. [ABSTRACT FROM AUTHOR]

The marine benthic algae from North East Herald Cay, Coral Sea, South Pacific, are listed with taxonomic, bibliographic and biogeographicdetails. The checklist includes 66 species of which 23 are green, 2 are brown, and 41 are red algal species. The almost complete absence of brown algae from what is seemingly a typical tropical reef environment on which a true coral cay has developed is noteworthy. All samples were from the lagoon, which forms the concave side of a crescent-shaped reef and which ranges in depth from 0-30 m. The endemic Caribbean green alga Chamaedoris peniculum is recorded for the Pacific for the first time, and a possibly undescribed species of the genus Rhipiliopsis was also discovered. Although only preliminary, the survey shows that the marine flora is seemingly typical of coral cays for the general region of the Great Barrier Reef. [ABSTRACT FROM AUTHOR]

Partial 18S rDNA sequences, including a 102 base pair insertion, were used to infer a phylogeny among 48 samples across all sections in Halimeda Lamouroux, 1812. The phylogeny reveals a separation of the monophyletic section Rhipsalis into a western Atlantic and a western Pacific clade. Consequently, morphologically similar species within this section such as H. monile (Ellis & Solander) Lamouroux (western Atlantic), and H. cylindracea Decaisne (western Pacific), are not sistertaxa. Vicariant events that separated the tropical regions of the Atlantic and Indo-Pacific Oceans can explain the observed biogeographical pattern in section Rhipsalis. [ABSTRACT FROM AUTHOR]

The zoogeographical distribution of branchiobdellidans (Annelida) and temnocephalidans (Platyhelminthes), ectosymbiotic on freshwater crustaceans, is reviewed and revised. In the areas where the Holarctic branchiobdellidans and Gondwanian temnocephalidans overlap, distributions of species and their respective hosts are reviewed in detail. Specimens of the branchiobdellid, Branchiobdella astaci, and the scutariellid temnocephalidan, Bubalocerus pretneri, were allowed to meet in vitro on the dorsal carapace of a crayfish, Austropotamobius pallipes. This usually resulted in the scutariellid being ingested by a branchiobdellid. Specimens of B. astaci were placed in contact with the host of B. pretneri, Troglocaris sp., a cave-dwelling shrimp and the branchiobdellid immediately moved away from the shrimp. [ABSTRACT FROM AUTHOR]

To increase the overall faunistic knowledge of Swedish Clitellata, asurvey was performed in Nationalstadsparken, a mosaic of fresh and brackish waters, parklands alternating with remnants of natural biota,and areas of urban development, within the cities of Stockholm and Solna on the Baltic coast of Sweden (59 deg. N, 18 deg. E). One hundred and twenty-one species (113 Oligochaeta, 8 Hirudinea) were collected at 31 aquatic and 27 terrestrial or littoral localities; 49 species of Oligochaeta were found at the aquatic localities, 70 species atthe terrestrial/littoral sites. Twenty-four species are new records for Sweden, and this urban national park thus features 64% of all non-marine clitellates known from the country. The result is consistent with a view that diversity is enhanced when human activities increasehabitat complexity, even in areas in direct contact with a large city. [ABSTRACT FROM AUTHOR]

A taxonomic revision of the Euglenophyta found exclusively in South America is presented. The taxonomy, geographical distribution and critical analysis of the synonyms are given. More than two hundred species and infraspecific entities from South America are described, many of them recorded several times in different regions. The genus Trachelomonas comprises the highest number of new taxa, reaching more than 100 entities. It is followed by Phacus (48 taxa), Strombomonas (33 taxa), Euglena (15 taxa) Lepocinclis (14 taxa), and Distigma, Entosiphon and Sphenomonas with one new taxon each. [ABSTRACT FROM AUTHOR]

The distribution of four calanoid copepod species of Boeckella in New Zealand are mapped and described. An explanation of their distribution patterns based on panbiogeographic methods is compared to an explanation based on dispersalist concepts. The panbiogeographic explanation is simpler, and is consistent with explanation of distribution patterns among other genera of plants, invertebrates, amphibians and birds. [ABSTRACT FROM AUTHOR]

The genus Eodiaptomus Kiefer contains six species, five of which aredistributed in Asia, and one in Australia and New Guinea. A seventh species, E. sanuamuangae n.sp., is now added from Thailand. It has hitherto been misidentified as E. sinensis (Burckhardt), but can be recognized by various morphologic criteria. In the female, both spines on either wing of the fifth pediger are laterally placed. The third endopodite-segment of P2-P4 has seven, instead of six, setae. The sensory seta on the basis of P5 is extraordinarily long. On the male rightantennule, the spine on segment 8 is much reduced, whereas that on segment 15 is relatively strong; the spinous process on the antepenultimate segment is slender, straight, with a hooked tip and as long as the next segment. Morphologically and geographically, E. sanuamuangaen.sp. links the Asian to the Australian forms. The Australian E. lumholtzi (Sars) is redescribed. A detailed morphological comparison is made of all Eodiaptomus spp. Their taxonomic characters, interspeciesrelationship, and biogeography are discussed. [ABSTRACT FROM AUTHOR]

Six species in two genera of Darwinulidae are here reported from Europe; two of these are known from fossils only. Microdarwinula zimmeri(Menzel) is, in Europe, an interstitial species. Darwinula stevensoni (Brady & Robertson), the type species of the genus, is also the most common darwinulid. Although it abounds in the shallow littoral of lakes, it can also occur in rivers, bogs and springs, both in fresh and saline waters. Darwinula boteai Danielopol is found in interstitialhabitats in Rumania. Darwinula pagliolii Pinto & Kotzian, originallydescribed from Recent South American populations, is reported from fossil, German localities. Darwinula brasiliensis Pinto & Kotzian, originally described as D. africana brasiliensis, also from South America, is here elevated to specific rank. It has been found extant in a bog in southern France and is reported from a museum collection from aScottish lake. The latter species is here reported from Europe for the first time. Finally, Darwinula danielopoli n.sp. is also describedfrom German Holocene (Subrecent) fossils. This species represents the first nominal taxon of a distinctly separate lineage within Darwinula s.1. Global and European distribution, history, ecological tolerance ranges, brooding and clonal taxonomy in this group are discussed. [ABSTRACT FROM AUTHOR]

Thirty-five species of the family Lecanidae are examined from Tripura state in North-Eastern India. Of these, Lecane levistyla and L. scutata are interesting cold-water forms; L. batillifer is an Australasian element; L. acanthinula and L. sinuata are Oriental endemics and L. braumi, L. lateralis and L. simonneae are palaeotropical species. The lecanid fauna also includes the pantropical L. thienemanni and L. sola while the remainder are cosmopolitan and tropicopolitan elements. [ABSTRACT FROM AUTHOR]

Algae collected from an oligotrophic crater lake were identified andcompared with similar regional information. A total of 50 genera and105 infrageneric taxa were identified, mostly Chlorophyta (66%), Cyanophyta (20%) and Bacillariophyta (7 genera: one central and six pennates). Relatively few Chlorococcales were found in this oligotrophic lake. The families most frequently found were Oedogoniaceae (18 species), Desmidiaceae (17), Zygnemataceae (13), Oscillatoriaceae (11), and Chaetophoraceae (9). Two genera of Cyanophyta, seven of Chlorophytaand 59 species are first records for Mexico. [ABSTRACT FROM AUTHOR]

The taxonomy of some Neotropical representatives of the genus Floscularia Cuvier, 1798 (Rotifera: Monogononta) is discussed, based on SEMstudies of trophi and external morphology. Floscularia armata n.sp. and F. bifida n. sp. are described, and F. conifera (Hudson, 1886) isrestored at full species rank. A hypothesis on the functional relevance of differences in trophi morphology for niche segregation is formulated. [ABSTRACT FROM AUTHOR]

The flora of Prespa National Park is composed of 1326 plant species.Among them are 17 Pteridophytes and 1309 Spermatophytes, representedby 11 Gymnosperms, 1057 Dicotyledons and 241 Monocotyledons. The flora is evaluated and categorised into species which can be considered as new for the Greek flora, species under international protection, and rare local species threatened with extinction. Plant species are also categorised according to their ecological requirements, with special reference to the endemic species and their centres of origin in respect to their total percentage (15.4%). [ABSTRACT FROM AUTHOR]

Literature and original information reveals that lakes at any latitude may be expected to lodge +50 spp. of cladocerans, against +150 spp. of rotifers in the temperate, and +210 spp. in the tropical zone. Collector's curves can be used to estimate the number of species present at any point in time in a lake. Hyperbolic regression and Chao's non-parametric estimator were used to extrapolate from species numbersobserved to true numbers present. Estimates for rotifers were better(had lower variances) than for cladocerans, and both were better in the temperate than in the tropical zone, where more species co-exist than in the temperate zone but where many more species are rare. Approximate numbers of samples required to approach true instantaneous species richness were calculated. However, a test in a (sub)tropical lake in Brasil where such an 'asymptotic' number of samples was collected and examined failed to reduce the variance, while recording a number of species higher than predicted. We conclude that seasonal succession was still significant here, and that more research is needed to determine the minimum number of sampling repeats needed for a full census. Lakes with an ATBI (All Taxa Biological Inventory) for rotifersand cladocerans were compared by a complementarity index. This revealed geographic gradients between lakes, strong for cladocerans, but less so for rotifers. It is argued that this mainly reflects a difference in the state of taxonomic advancement between these two groups, and that the theory of cosmopolitanism must be abandoned for both. [ABSTRACT FROM AUTHOR]