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Journal ArticleDOI

Native and exotic fish species in the tiber river watershed (umbria - italy) and their relationship to the longitudinal gradient

01 Jan 2006-Bulletin Francais De La Peche Et De La Pisciculture (EDP Sciences)-Iss: 382, pp 19-44

TL;DR: The preliminary results suggest that characteristics of fish community alterations depend on the type of river sector involved; the small rivers of the basin are a refuge zone for the native community and are currently of fundamental importance for maintaining biodiversity.

AbstractIn this study we examine the spatial variations in the fish communities in the Tiber River watershed, including both native and exotic species. Its main objectives were to assess the quality of fish communities of this area and to verify if factors of fish community disturbance are constant over the basin or if they change along the river gradient. The level of degradation was evaluated according to the ratio between the number of native fish species and total number of species (ZIC = Zoogeographic Integrity Coefficient). A total of 37 fish species was found, 13 native and 24 exotic (64.86%). Cyprinid is the prevailing family with 15 species (7 native, 8 exotic). The species most frequently introduced are cyprinids, followed by salmonids (4 species) and gobids (3 species). Of the 24 exotic species only 11 (45.83%) can be considered intentionally introduced by man: the proportion of intentionally introduced transplanted species (66.67%) is considerably higher than the translocated species (33.33%). There is a correlation between the longitudinal gradient of the river, the morphological evolution of the riverbed and decline in water quality. High ZIC values were related to higher elevation, greater slope and better water quality. As the size of the river increases the fish communities appear to be ever-more dominated by species of exotic origin, whose number progressively increases with the worsening of the water quality and downstream movement. The number of native species is the greatest in the middle reaches of the rivers, and decreases both upstream and downstream. Compared to the introduced species, the native species tend to stay upstream and are often the only species found in the headwaters. The number of introduced species increases downstream. We have also found differences among translocated and transplanted species: the first ones tend to favor the middle reaches of the rivers, while transplanted species seem to prefer the downstream sectors. In almost all cases, the sampling station immediately below an impoundment has the lowest ZIC values in comparison to the river stretches above the dam. Our preliminary results suggest that characteristics of fish community alterations depend on the type of river sector involved; the small rivers of the basin are a refuge zone for the native community and are currently of fundamental importance for maintaining biodiversity.

Topics: Introduced species (60%), Global biodiversity (52%), Biodiversity (51%)

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Citations
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Journal ArticleDOI
TL;DR: It is concluded that reservoirs promote taxonomic homogenization at multiple spatial scales, while the community-level effects of species introductions and local extinctions within river basins have been sparsely analyzed.
Abstract: Most studies analyzing patterns in biotic homogenization of fish communities have used large-scale approaches, while the community-level effects of species introductions and local extinctions within river basins have been sparsely analyzed. In this article, we examine patterns in freshwater fish α- and β-diversity in relation to the presence of reservoirs in a Mediterranean river (Guadiana river; Iberian Peninsula). We used fish samples from 182 river localities and 59 reservoir ones to address two main questions: (i) do reservoirs favor the establishment of invasive fish species?; and (ii) do reservoirs bear taxonomically homogenized fish communities? Although total species richness was not different between rivers and reservoirs, the latter had more invasive species and less native ones. Fish species found in reservoirs tended to be larger ones, but invasive species of any size showed higher preferences for reservoirs. Native species that were rare or absent in reservoirs were those that showed higher sensitivity to invasive species in rivers. Reservoir fish communities were taxonomically homogenized in relation to river ones, both when considering all fish species and using only natives or only invasive ones. Our results suggest that invasive species occupying reservoirs constitute an ecological filter excluding most native species from such systems. Invasive species in the study area are often widely introduced elsewhere, while native species found in reservoirs are congeneric and ecologically similar to those found in other Iberian studies. Thus, we conclude that reservoirs promote taxonomic homogenization at multiple spatial scales, while could also be promoting the functional homogenization of Iberian fish communities.

91 citations


Cites background from "Native and exotic fish species in t..."

  • ...For example, most of the invasive species listed in Table 1 are frequently found in homogenized rivers in Italy (Lorenzoni et al. 2006) or North America (Moyle and Mount 2007)....

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Journal ArticleDOI
TL;DR: Findings show that T-RFLP of 16S rRNA genes can be used to compare vaginal microbial communities and gain information about the numerically dominant populations that are present, and are largely invariant over time.
Abstract: To define and monitor the structure of microbial communities found in the human vagina, a cultivation-independent approach based on analyses of terminal restriction fragment length polymorphisms (T-RFLP) of 16S rRNA genes was developed and validated. Sixteen bacterial strains commonly found in the human vagina were used to construct model communities that were subsequently used to develop efficient means for the isolation of genomic DNA and an optimal strategy for T-RFLP analyses. The various genera in the model community could best be resolved by digesting amplicons made using bacterial primers 8f and 926r with HaeIII; fewer strains could be resolved using other primer-enzyme combinations, and no combination successfully distinguished certain species of the same genus. To demonstrate the utility of the approach, samples from five women that had been collected over a 2-month period were analyzed. Differences and similarities among the vaginal microbial communities of the women were readily apparent. The T-RFLP data suggest that the communities of three women were dominated by a single phylotype, most likely species of Lactobacillus. In contrast, the communities of two other women included numerically abundant populations that differed from Lactobacillus strains whose 16S rRNA genes had been previously determined. The T-RFLP profiles of samples from all the women were largely invariant over time, indicating that the kinds and abundances of the numerically dominant populations were relatively stable throughout two menstrual cycles. These findings show that T-RFLP of 16S rRNA genes can be used to compare vaginal microbial communities and gain information about the numerically dominant populations that are present.

54 citations


Journal ArticleDOI
05 May 2015
TL;DR: There is no consensus on the reasons for the absence of self-sustaining populations of rainbow trout across much of Europe, but knowledge of the mechanisms involved is limited, while the data collected here shed new light on the invasion biology of the species.
Abstract: The rainbow trout (Oncorhynchus mykiss) is probably the most widely introduced fish species in the world. Since the first translocation outside of the range of its natural distribution, the species has been introduced into at least 99 countries and has established reproducing populations in many different parts of the world. The present review aims to synthesize the existing information on these translocations, with special emphasis on self-sustaining populations in Europe, where continuous introductions have in general not led to naturalization. Our survey produced a list of more than 130 confirmed or potential self-sustaining populations across 16 European countries. The highest abundance of such populations was observed in the Alpine foothills of central Europe where naturalization is not limited to modified waters less suitable for native salmonids but also occurs commonly in pristine and near-natural waters. There is no consensus on the reasons for the absence of self-sustaining populations of rainbo...

53 citations


Journal ArticleDOI
Abstract: The aim of the research was to test relative weight (W r ), a condition index which allows evaluation of fish well-being, as a tool to investigate the impact of the presence of non native species (NNS) on the condition of the key native species (NS) of the Tiber River basin (Italy): Barbus tyberinus Bonaparte, Leuciscus cephalus (Linnaeus), Leuciscus lucumonis Bianco, Rutilus rubilio (Bonaparte) and Telestes muticellus (Bonaparte). By means of Canonical Correlation Analysis, data from 130 sampling sites, distributed throughout Tiber River basin, were examined. W r of NS was related to densities of NNS and to environmental variables. Moreover, the correlation between W r of NS and density of NNS was investigated through linear regression analysis and covariance analysis. Preliminary results encourage the use of W r as a tool to assess the relationship between NS and ecological factors (such as the presence of NNS) and to explain the changes that occur along the longitudinal gradient of a river.

28 citations


Journal Article
TL;DR: Preliminary results encourage the use of W r as a tool to assess the relationship between NS and ecological factors and to explain the changes that occur along the longitudinal gradient of a river.

28 citations


Cites background from "Native and exotic fish species in t..."

  • ..., 1995), which is the most represented in Umbria waterways (Lorenzoni et al., 2006), were chosen to analyze the effect of the NNS on the indigenous fauna: B....

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  • ...Nevertheless, the cause-effect relationship frequently remains hypothetical, given the limited information that is available about the status of native species prior to the introduction (Lorenzoni et al., 2006; Gaygusuz et al., 2007)....

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  • ...…species, characterizing the fish communities of the “barbel zone” (Mearelli et al., 1995), which is the most represented in Umbria waterways (Lorenzoni et al., 2006), were chosen to analyze the effect of the NNS on the indigenous fauna: B. tyberinus; L. cephalus, L. lucumonis, R. rubilio…...

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  • ...The Extended Biotic Index (EBI) (Ghetti, 1986), which is a biotic index used to evaluate the overall water quality based on the sensitivity of some key groups of macrobenthic fauna to pollution (Lorenzoni et al., 2006), was assessed on the same day or within several days of the fish collections....

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  • ...In the Tiber River basin, the streams are being seriously degraded due to the stocking programs that have modified their native fish fauna: of the 47 fish species currently present only 13 are native (Lorenzoni et al., 2006)....

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References
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Book
01 Jan 1992
Abstract: Set your standards with these standard methods. This is it: the most widely read publication in the water industry, your all-inclusive reference tool. This comprehensive reference covers all aspects of USEPA-approved water analysis methods. More than 400 methods - all detailed step-by-step; 8 vibrant, full-color pages of aquatic algae illustrations; Never-before-seen figures that will help users with toxicity testing and the identification of apparatus used in the methods; Over 300 superbly illustrated figures; A new analytical tool for a number of inorganic nonmetals; Improved coverage of data evaluation, sample preservation, and reagant water; And much more!

78,276 citations


Journal ArticleDOI
TL;DR: It is hypothesized that producer and consumer communities characteristic of a given river reach become established in harmony with the dynamic physical conditions of the channel.
Abstract: From headwaters to mouth, the physical variables within a river system present a continuous gradient of physical conditions. This gradient should elicit a series of responses within the constituent...

8,581 citations


"Native and exotic fish species in t..." refers background in this paper

  • ...Fish assemblage composition varied along the Tiber River according to environmental variables, a common feature of stream fish communities (HUET, 1949, 1954, 1962; VANNOTE et al., 1980; MINSHALL et al., 1985; CHANGEUX, 1995)....

    [...]

  • ...Habitat controls the longitudinal distribution of fish, and changes in habitat characteristics are often associated with changes in the composition of the fish assemblage (HUET, 1949, 1954, 1962; VANNOTE et al., 1980; MINSHALL et al., 1985; MORIN and NAIMAN, 1990; CHANGEUX, 1995; BELLIARD et al., 1999; ARUNACHALAM, 2000; BUNN and DAVIES, 2000)....

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  • ...…of fish, and changes in habitat characteristics are often associated with changes in the composition of the fish assemblage (HUET, 1949, 1954, 1962; VANNOTE et al., 1980; MINSHALL et al., 1985; MORIN and NAIMAN, 1990; CHANGEUX, 1995; BELLIARD et al., 1999; ARUNACHALAM, 2000; BUNN and DAVIES, 2000)....

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Journal ArticleDOI
TL;DR: Alkalinity measurements are used in the interpretation and control of water and wastewater treatment processes and can be interpreted in terms of specific substances only when the chemical composition of the sample is known.
Abstract: 1. Discussion Alkalinity of a water is its acid-neutralizing capacity. It is the sum of all the titratable bases. The measured value may vary significantly with the end-point pH used. Alkalinity is a measure of an aggregate property of water and can be interpreted in terms of specific substances only when the chemical composition of the sample is known. Alkalinity is significant in many uses and treatments of natural waters and wastewaters. Because the alkalinity of many surface waters is primarily a function of carbonate, bicarbonate, and hydroxide content, it is taken as an indication of the concentration of these constitutents. The measured values also may include contributions from borates, phosphates, silicates, or other bases if these are present. Alkalinity in excess of alkaline earth metal concentrations is significant in determining the suitability of a water for irrigation. Alkalinity measurements are used in the interpretation and control of water and wastewater treatment processes. Raw domestic wastewater has an alkalinity less than, or only slightly greater than, that of the water supply. Properly operating anaerobic digesters typically have supernatant alkalinities in the range of 2000 to 4000 mg calcium carbonate (CaCO3)/L. 1

7,133 citations


Journal ArticleDOI
TL;DR: Given their current scale, biotic invasions have taken their place alongside human-driven atmospheric and oceanic alterations as major agents of global change and left unchecked, they will influence these other forces in profound but still unpredictable ways.
Abstract: Biotic invaders are species that establish a new range in which they proliferate, spread, and persist to the detriment of the environment. They are the most important ecological outcomes from the unprecedented alterations in the distribution of the earth's biota brought about largely through human transport and commerce. In a world without borders, few if any areas remain sheltered from these im- migrations. The fate of immigrants is decidedly mixed. Few survive the hazards of chronic and stochastic forces, and only a small fraction become naturalized. In turn, some naturalized species do become invasive. There are several potential reasons why some immigrant species prosper: some escape from the constraints of their native predators or parasites; others are aided by human-caused disturbance that disrupts native communities. Ironically, many biotic invasions are apparently facilitated by cultivation and husbandry, unintentional actions that foster immigrant populations until they are self-perpetuating and uncontrollable. Whatever the cause, biotic invaders can in many cases inflict enormous environmental damage: (1) Animal invaders can cause extinctions of vulnerable native species through predation, grazing, competition, and habitat alteration. (2) Plant invaders can completely alter the fire regime, nutrient cycling, hydrology, and energy budgets in a native ecosystem and can greatly diminish the abundance or survival of native species. (3) In agriculture, the principal pests of temperate crops are nonindigenous, and the combined expenses of pest control and crop losses constitute an onerous "tax" on food, fiber, and forage production. (4) The global cost of virulent plant and animal diseases caused by parasites transported to new ranges and presented with susceptible new hosts is currently incalculable. Identifying future invaders and taking effective steps to prevent their dispersal and establishment con- stitutes an enormous challenge to both conservation and international commerce. Detection and management when exclusion fails have proved daunting for varied reasons: (1) Efforts to identify general attributes of future invaders have often been inconclusive. (2) Predicting susceptible locales for future invasions seems even more problematic, given the enormous differences in the rates of arrival among potential invaders. (3) Eradication of an established invader is rare, and control efforts vary enormously in their efficacy. Successful control, however, depends more on commitment and continuing diligence than on the efficacy of specific tools themselves. (4) Control of biotic invasions is most effective when it employs a long-term, ecosystem- wide strategy rather than a tactical approach focused on battling individual invaders. (5) Prevention of invasions is much less costly than post-entry control. Revamping national and international quarantine laws by adopting a "guilty until proven innocent" approach would be a productive first step. Failure to address the issue of biotic invasions could effectively result in severe global consequences, including wholesale loss of agricultural, forestry, and fishery resources in some regions, disruption of the ecological processes that supply natural services on which human enterprise depends, and the creation of homogeneous, impoverished ecosystems composed of cosmopolitan species. Given their current scale, biotic invasions have taken their place alongside human-driven atmospheric and oceanic alterations as major agents of global change. Left unchecked, they will influence these other forces in profound but still unpredictable ways.

5,846 citations


"Native and exotic fish species in t..." refers background in this paper

  • ...Another problem is the introduction of exotic species, which is considered as one of the most important but least studied factors that disrupt aquatic ecosystems (MILLS et al., 1993; LEACH, 1995; LODGE et al., 2000; MACK et al., 2000; BYERS et al., 2002)....

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  • ...Literature regarding the impact of exotic species reports numerous examples of the extinction of native species (COWX, 1997; LODGE et al., 2000; MACK et al., 2000)....

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Journal ArticleDOI
01 Oct 1986-Ecology
Abstract: A new multivariate analysis technique, developed to relate community composition to known variation in the environment, is described. The technique is an extension of correspondence analysis (reciprocal averaging), a popular ordination technique that extracts continuous axes of variation from species occurrence or abundance data. Such ordination axes are typically interpreted with the help of external knowledge and data on environmental variables; this two—step approach (ordination followed by environmental gradient identification) is termed indirect gradient analysis. In the new technique, called canonical correspondence analysis, ordination axes are chosen in the light of known environmental variables by imposing the extra restriction that the axes be linear combinations of environmental variables. In this way community variation can be directly related to environmental variation. The environmental variables may be quantitative or nominal. As many axes can be extracted as there are environmental variables. The method of detrending can be incorporated in the technique to remove arch effects. (Detrended) canonical correspondence analysis is an efficient ordination technique when species have bell—shaped response curves or surfaces with respect to environmental gradients, and is therefore more appropriate for analyzing data on community composition and environmental variables than canonical correlation analysis. The new technique leads to an ordination diagram in which points represent species and sites, and vectors represent environmental variables. Such a diagram shows the patterns of variation in community composition that can be explained best by the environmental variables and also visualizes approximately the "centers" of the species distributions along each of the environmental variables. Such diagrams effectively summarized relationships between community and environment for data sets on hunting spiders, dyke vegetation, and algae along a pollution gradient.

5,440 citations