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  • 1
    Electronic Resource
    Electronic Resource
    Macrophyte functional variables versus species assemblages as predictors of trophic status in flowing waters (1999)
    Springer
    Hydrobiologia 415 (1999), S. 131-138 
    Details
    ISSN: 1573-5117
    Keywords: phosphate ; modelling ; eutrophication ; aquatic plants ; rivers ; irrigation channels
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A series of models was developed using functionally-derived variables (mainly based on morphological attributes of freshwater macrophytes) to predict the trophic status of river and associated channel systems. The models were compared with an existing species-assemblage based procedure for predicting British river trophic conditions (the Macrophyte Trophic Ranking scheme, MTR). We compared sites in cooler temperate conditions (in Scotland) and warmer, sub-tropical conditions (in Egypt). In total, we made measurements of 13 traits from 〉600 individual plant specimens of 33 species growing at 42 sites (divided into independent input and test site datasets). N status (as annual mean concentration in water of total oxidised nitrogen, TON) was only very poorly predicted by this approach. However, P (as annual mean concentration in water of soluble reactive phosphate, SRP) was better predicted: both by a model based on MTR (r = −0.585, p〈0.001), and by models using functional attributes of the macrophyte vegetation. River Trophic Status Indicator (RTSI) models based on ranked plant functional group relationship to river water P concentrations (RTSIFG), or field-measured trait sets of the plants (RTSITR) could also individually explain up to about 34% of the variation in P, both for the total dataset and for subsets from Egypt or Scotland alone or for high v. low-flow sites. Combining both types of RTSI measure produced the most powerful predictive model (r = 0.72, p〈0.001), explaining just over half the variability in P.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003833419359
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  • 2
    Electronic Resource
    Electronic Resource
    Foreword (1994)
    Springer
    Hydrobiologia 290 (1994), S. vii 
    Details
    ISSN: 1573-5117
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00008944
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  • 3
    Electronic Resource
    Electronic Resource
    Response of Elodea canadensis Michx, and Myriophyllum spicatum L. to shade, cutting and competition in experimental culture (1996)
    Springer
    Hydrobiologia 340 (1996), S. 219-224 
    Details
    ISSN: 1573-5117
    Keywords: weed control ; competition ; disturbance ; Elodea canadensis ; Myriophyllum spicatum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Elodea canadensis Michx. and Myriophyllum spicatum L. are widespread nuisance aquatic plant species. Their ecology is regarded as similar. Both species have been previously classified in terms of established-phase survival strategy as ‘competitive disturbance-tolerant’ species. Experimental data are presented to show that although this broad categorisation of strategy is probably correct for the two species, it is possible to demonstrate significant differences in terms of response to disturbance and competition. Less difference was discernible in their comparative response to stress. The drawbacks of applying broad descriptive terminology when dealing with two species of similar strategy are addressed. The results help explain reports of variable success in attempting to manage these two species using disturbance-based weed control measures, and suggest that Elodea is even less susceptible to such measures than Myriophyllum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00012758
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  • 4
    Electronic Resource
    Electronic Resource
    Euhydrophyte communities of the River Nile and its impoundments in Egyptian Nubia (1991)
    Springer
    Hydrobiologia 218 (1991), S. 35-47 
    Details
    ISSN: 1573-5117
    Keywords: macrophytes ; community ecology ; River Nile ; Egypt
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The River Nile and its two impoundments, the Aswan Reservoir and Lake Nasser, are important habitats for submerged and floating-leaved freshwater macrophytes (euhydrophytes) in the desert region of Egyptian Nubia. Ordination and classification analysis of survey data collected during the period 1980–1986 suggested that the Aswan High Dam forms a man-made vegetational boundary, delineating two basic macrophyte community types. In Lake Nasser a community dominated by Najas spp. is present. In the Aswan Reservoir and the R. Nile downstream of the old Aswan Dam the euhydrophyte community is dominated by a Potamogeton crispus — Ceratophyllum demersum association. Differences between the two community types appear to be related to differences in physical factors (e.g. water level fluctuation and flow regime), and water chemistry, to phenological factors, and to the differing successional ages of the macrophyte communities of the Nile system upstream and downstream of the Aswan High Dam. There is some evidence for depth zonation of the submerged macrophyte community in both lake and river habitats. Strategy analysis of the euhydrophyte communities present upstream and downstream of the High Dam, over the period 1963–89, indicated that successful established-phase strategy types were similar on both sides of the dam. In the long term there seems little to prevent euhydrophyte species at present confined to below the High Dam from crossing this boundary to colonise Lake Nasser.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00006416
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  • 5
    Electronic Resource
    Electronic Resource
    Submerged plant survival strategies in relation to management and environmental pressures in drainage channel habitats (1996)
    Springer
    Hydrobiologia 340 (1996), S. 191-195 
    Details
    ISSN: 1573-5117
    Keywords: Submerged plants ; survival strategies ; drainage channels ; aquatic weeds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The abundance of submerged weeds, in relation to management regime and environmental factors, was surveyed during 1992 and 1993 in drainage channels located in four geographically-distinct areas of Britain. The aim of the study was to ascertain, using a multivariate approach, the degree to which species survival strategy and vegetation could be related to disturbance and stress pressures on plant survival. Indices of disturbance and stress were constructed from combined environmental data for each site. A species ordination using Canonical Correspondence Analysis showed that the combined disturbance variable explained more of the variability that did stress. Two main groups of species could be distinguished. The larger group scored low on the disturbance gradient and these species, with different tolerances to stress (especially light-limitation), appeared to be those better-adapted to habitats with low disturbance (e.g. Potamogeton pectinatus and Potamogeton lucens). The smaller group comprised species which tended to occur in sites with higher disturbance (e.g. regular cutting) such as Callitriche stagnalis. Using the terminology of strategy theory, most of the dominant species could be classed as ‘competitive/disturbance tolerators (CD)’ or variants of this established-phase strategy. The limitations are discussed of applying the strategy approach at species level in a defined habitat-type which shows a high degree of uniformity between sites, such as artificial drainage channels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00012754
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  • 6
    Electronic Resource
    Electronic Resource
    Seasonal changes in phytoplankton community structure in relation to physico-chemical factors in Loch Lomond, Scotland (1997)
    Springer
    Hydrobiologia 350 (1997), S. 63-79 
    Details
    ISSN: 1573-5117
    Keywords: phytoplankton dynamics ; lake ; waterchemistry ; plant community
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An intensive seasonal sampling programme at twocontrasting sites in Loch Lomond, the largest lake inBritain, showed the 1992–93 status of the loch to bemesotrophic in the shallow south basin andoligotrophic in the deeper north basin. There isevidence for an increase in both phytoplanktonproduction and reactive phosphorus concentrations inthe loch during the two decades up to 1993. CanonicalCorrespondence Analysis (CCA), plus classification (by Two-Way Indicator Species Analysis: TWINSPAN) ofthe dataset of time-position samples from the lochrevealed that seasonal factors (particularly thethermal regime of the loch, and associated variables)remain more important than non-seasonal environmentalvariables in predicting changes in phytoplanktoncommunity composition. As in the 1970s, the communityremains dominated by a diatom-desmid assemblage, but cyanobacteria blooms, albeit at fairly low abundance,are becoming a frequent phenomenon in the south basinof the loch.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003037012226
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  • 7
    Electronic Resource
    Electronic Resource
    Freshwater and wetland plant communities of Loch Lomond (1994)
    Springer
    Hydrobiologia 290 (1994), S. 63-74 
    Details
    ISSN: 1573-5117
    Keywords: aquatic vegetation ; wetland vegetation ; Loch Lomond ; lake ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Information on the aquatic and wetland vegetation of Loch Lomond, Scotland, is summarised for the period 1957–90. Aquatic macrophyte growth is estimated to occupy about 1% of the loch's total surface area, being limited to the 0–10 m euphotic zone, and probably excluded from much of this area by wave disturbance and unsuitable substrates. Aquatic vegetation is however abundant in sheltered bays and less-exposed shorelines, particularly in the South Basin of the loch. Although Littorella uniflora (L.) Aschers is the commonest, ubiquitous, submerged plant of the loch, three separate euhydrophyte communities have been identified within the loch. One of these is characterised by abundant stands of Elodea canadensis Michx., which appears to have invaded Loch Lomond some time between 1967–88, and has rapidly spread throughout the loch.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00008954
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  • 8
    Electronic Resource
    Electronic Resource
    Interrelationships of fish and channel environmental conditions with aquatic macrophytes in an Argentine irrigation system (1998)
    Springer
    Hydrobiologia 380 (1998), S. 15-25 
    Details
    ISSN: 1573-5117
    Keywords: Macrophytes ; irrigation and drainage channels ; turbidity ; Cyprinus carpio ; South America
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This study examines the relationships between fish, environmental variables and submerged macrophytes within the irrigation system of the lower valley of the Río Colorado in southern Argentina. Using Canonical Correspondence Analysis (CCA), the strongest environmental gradients detected were conductivity and carp ( Cyprinus carpi) biomass per unit area of channel cross-section. These variables were positively associated with each other and also with water turbidity. Sites scoring high on these gradients were mainly drainage channels; those scoring lowest were irrigation channels. The main fish species associated with high carp biomass, high turbidity and high conductivity were carpa ( C. carpio), pejerrey ( Odontesthes bonariensis), madrecita ( Jenynsia lineata lineata) and lisa ( Mugil liza). Dientudo ( Oligosarcus jenynsi) and mojarra ( Astianax eigenmanniorum) were more strongly associated with clearer water, with low carp biomass. In all CCA analyses macrophytes were arranged in similar order along the main conductivity-turbidity-carp biomass gradient. Lowest on this main environmental gradient, and scoring very close to each other, were Potamogeton pectinatus and Chara contraria. Salinity-tolerant species such as Ruppia maritima, Zannichellia palustris and Enteromorpha flexuosa tended to score highest, followed by the surface floating Azolla filiculoides and the filamentous alga Cladophora surera. Within the constraints imposed by conductivity, turbidity was a key predictor of both abundance and distribution of the two dominant plants of the irrigation scheme ( P. pectinatus and C. contraria). Turbidity was strongly predicted by biomass of carp per unit channel cross sectional area, when fine sediment particle content was taken into account. The positive association between carp biomass and water turbidity was both substantial and predictable, and was in turn associated with reduction in submerged plant growth. The biomass of the most widespread nuisance-causing plant species in the channels, Potamogeton pectinatus, could best be predicted ( R = 0.592, P 〈 0.05) using a multiple regression model utilising four predictor variables: conductivity, nitrate, phosphate and carp biomass.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003215513435
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  • 9
    Electronic Resource
    Electronic Resource
    Evidence for consistent functional groups of wetland vegetation across a broad geographical range of Europe (1996)
    Springer
    Wetlands ecology and management 4 (1996), S. 51-63 
    Details
    ISSN: 1572-9834
    Keywords: functional group ; competitive ; plant morphology ; strategy ; traits
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We provide evidence for the existence of a general relationship between plant size and survival strategy (sensu Grime 1974) in wetland habitats across a broad geographical range in European riverine wetlands. Between April−October, in 1991 and 1992, data on eight size-related traits were collected for 144 plant populations, drawn from 85 plant species, growing in riverine wetland habitats in Spain, France, Ireland and the UK. Two non-hierarchical techniques were used to classify plant populations, on the basis of these eight traits, into three groups with a good degree of internal cohesion and external isolation. The C-S-D plant strategy model (equivalent to the C-S-R model: Grime (1974)) was used as a summary of the survival strategy of a plant. Prior strategy classifications were available for 98 of the studied populations. UsingX 2 tests the frequency of strategies in the three groups was compared to the overall frequencies of strategies. The frequency of strategies in each of the three groups was significantly different compared to the overall frequencies. Group 1 (G1) contained over 75% of the total C strategists. Group 2 (G2) contained over 80% of all the C-S-D (intermediate) strategists from the total data set and Group 3 (G3) was intermediate between G1 and G2 but contained a stronger D component. These results suggest that size-related traits may be of value in describing the ecological survival strategies of plants, in terms of C-S-D. Statistical analysis revealed no evidence for a common phylogenetic origin of the functional plant groups identified. Plant size, and in particular height, proved to be a trait of particular value in differentiating between groups. Evidence from these data suggests that relationships between the size and the survival strategy of a plant may be generally valid across a wide range of geographical areas in wetland habitats. We provide evidence to suggest that survival strategies prevalent in the three groups could be linked to differences in plant tolerance of hydrological stress/disturbance factors (such as summer water table depth) in riverine wetlands of Europe.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01876135
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  • 10
    Electronic Resource
    Electronic Resource
    The plant biodiversity of the Wadi Allaqi Biosphere Reserve (Egypt): impact of Lake Nasser on a desert wadi ecosystem (1997)
    Springer
    Biodiversity and conservation 6 (1997), S. 1259-1275 
    Details
    ISSN: 1572-9710
    Keywords: desert vegetation ; plant biodiversity ; flood impacts ; phytogeography ; Egypt
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A data set comprising 95 stands of desert vegetation, collected from the Wadi Allaqi Biosphere Reserve and its environs within the South-Eastern Desert of Egypt during 1985–90, was analysed using multivariate procedures (two-way indicator species analysis: TWINSPAN; detrended correspondence analysis: DCA; canonical correspondence analysis: CCA), to produce a classification of plant communities in the area, and to examine the relationships of these plant communities to natural and man-induced features of the physical environment of the area (in particular, the influence of Lake Nasser, a major impoundment of the River Nile formed in 1964). The vegetation classification produced groupings broader, in both floristic and ecological terms, than those found by earlier studies of this area. In total 78 plant species were recorded from four phytogeographic elements. Four principal vegetation groups were identified, of which one is new to the area, and is the result of major environmental changes affecting the downstream part of the Wadi Allaqi system, following periodic flooding of the wadi by Lake Nasser during the past 30 years. This community was indicated by Tamarix nilotica. There was a strongly-zoned (downstream–upstream) pattern to the vegetation within this lower part of Wadi Allaqi, which appears to be a function of the probability of flooding by the lake. The remaining three vegetation groups occur higher in the wadi basin. Groundwater-dependence appeared to be important in defining a group indicated by Acacia tortilis, as well as the Tamarix nilotica group. The two remaining groups, characterized respectively by Acacia ehrenbergiana and Cullen plicatum, represent vegetation groups which are precipitation-dependent, and which tolerate drier conditions within the Allaqi system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/B:BIOC.0000034012.93599.c0
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