Native and exotic fish species in the tiber river watershed (umbria - italy) and their relationship to the longitudinal gradient
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.
Abstract: In 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.
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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.
30 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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TL;DR: The growth and reproductive biology of the invasive goldfish Carassius auratus auratus were studied in Lake Trasimeno, central Italy; the results revealed that the population is made up of eight age-classes, and the sex ratio proved to be extremely unbalanced.
Abstract: The growth and reproductive biology of the invasive goldfish Carassius auratus auratus were studied in Lake Trasimeno, central Italy The results of the research revealed that the population is made up of eight age-classes The sex ratio proved to be extremely unbalanced (1 : 19 in favour of females) Growth can be deemed rapid, the von Bertalanffy growth in length function being TL = 43019{1-e(-0272(t 0162) )} for the total sample and φ' = 2702 No sexual dimorphism in growth was observed Back-calculation analysis suggested the existence of an inverse Lee phenomenon among 1 year-old specimens The reproductive period covers a broad time-span, from March to June In females, sexual maturity is reached after the second winter of life (2 age-class); however, a small percentage (755%) of females is able to reproduce at the age of 1 year Most of the males attained sexual maturity in the first year (6061%) The reproductive investment of the females is high; the relationship between SL and the number of eggs was Ne = 00041 SL4368 Fecundity varied from 286 to 219104 eggs, with an average relative fecundity of 103 ± 5 eggs g-1; the mean diameter of the eggs was 127 ± 001 mm The reproductive investment of the females was not homogeneous across the ageclasses; in addition to absolute fecundity, relative fecundity and egg diameter were seen to increase with the size of the specimens
29 citations
Cites background from "Native and exotic fish species in t..."
...The fi sh population in Lake Trasimeno, as in the rest of the Tiber River basin, is compromised by the presence of exotic species (Lorenzoni et al. 2006)....
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TL;DR: Overall, a general pattern of species addition from upstream to downstream sections was discovered and is likely related to increased habitat complexity and additions of non-native species in downstream sections.
Abstract: Longitudinal gradients of fish assemblage and habitat structure were investigated in the Kootenai River of northern Idaho. A total of 43 500-m river reaches was sampled repeatedly with several techniques (boat-mounted electrofishing, hoop nets and benthic trawls) in the summers of 2012 and 2013. Differences in habitat and fish assemblage structure were apparent along the longitudinal gradient of the Kootenai River. Habitat characteristics (e.g. depth, substrate composition and water velocity) were related to fish assemblage structure in three different geomorphic river sections. Upper river sections were characterized by native salmonids (e.g. mountain whitefish Prosopium williamsoni), whereas native cyprinids (peamouth Mylocheilus caurinus, northern pikeminnow Ptychocheilus oregonensis) and non-native fishes (pumpkinseed Lepomis gibbosus, yellow perch Perca flavescens) were common in the downstream section. Overall, a general pattern of species addition from upstream to downstream sections was discovered and is likely related to increased habitat complexity and additions of non-native species in downstream sections. Assemblage structure of the upper sections were similar, but were both dissimilar to the lower section of the Kootenai River. Species-specific hurdle regressions indicated the relationships among habitat characteristics and the predicted probability of occurrence and relative abundance varied by species. Understanding fish assemblage structure in relation to habitat could improve conservation efforts of rare fishes and improve management of coldwater river systems. Copyright © 2015 John Wiley & Sons, Ltd.
28 citations
Cites background from "Native and exotic fish species in t..."
...Increased occurrence of non-native fishes has also been reported from upstream to downstream sections of the Willamette River, Oregon (Hughes and Gammon, 1987), and the Tiber River, Italy (Lorenzoni et al., 2006)....
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TL;DR: In this article, the authors used the self-organizing map (SOM) based on fish biomass data to characterize fish assemblages and assess how well they correspond to the landscape classification.
26 citations
TL;DR: The finding that most individuals of the morphologically similar B. plebejus and B. tyberinus have very high assignment probabilities to their respective species suggests that the presented approach may serve as a valuable tool to distinguish morphologically very similar taxa.
Abstract: This integrative study examined the morphological and genetic affinities of three endemic barbel species from Italy (brook barbel Barbus caninus, Italian barbel Barbus plebejus and horse barbel Barbus tyberinus) and of putative hybrid specimens to their species of origin. Two of the species frequently occur together with the non-native barbel Barbus barbus. DNA barcoding indicates that mitochondrial (mt) haplotypes often do not match the species expected from morphology. Linear distance measurements and meristics are not informative for discrimination of the species and putative hybrids, but a discriminant analysis of principal components (DAPC) of geometric landmark data produces reassignments largely in congruence with mt and nuclear genetic data. Cyto-nuclear conflicts confirm the presence of hybridization in B. plebejus and B. tyberinus and identify additional introgressed specimens. A comparison between mixed genotypes and their morphology-based assignment reveals no predictable pattern. The finding that most individuals of the morphologically similar B. plebejus and B. tyberinus have very high assignment probabilities to their respective species suggests that the presented approach may serve as a valuable tool to distinguish morphologically very similar taxa.
20 citations
References
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Book•
01 Jan 1992
TL;DR: The most widely read reference in the water industry, Water Industry Reference as discussed by the authors, is a comprehensive reference tool for water analysis methods that covers all aspects of USEPA-approved water analysis.
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!
78,324 citations
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...
9,145 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)....
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...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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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
7,510 citations
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.
6,195 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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TL;DR: In this article, a new multivariate analysis technique, called canonical correspondence analysis (CCA), was developed to relate community composition to known variation in the environment, where 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.
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.
5,689 citations