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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TL;DR: The age, growth and body condition of the big-scale sand smelt population of Lake Trasimeno were investigated and analysis of back-calculated lengths indicated the occurrence of a reverse Lee’s phenomenon.
Abstract: Key-words: Population dynamics, Lee’s phenomenon, fishery management, introduced species, Lake Trasimeno The age, growth and body condition of the big-scale sand smelt (Atherina boyeri) population of Lake Trasimeno were investigated. In total, 3998 specimens were collected during the study and five age classes (from 0+ to 4+) were identified. From a subsample of 1017 specimens, there were 583 females, 411 males and 23 juveniles. The equations between total length (TL) and weight (W) were: log 10 W = −2.326 + 3.139 log 10 TL for males and log 10 W = −2.366 + 3.168 log 10 TL for females. There were highly significant differences between the sexes and for both sexes the value of b (slope of the log (TL-W regression) was greater than 3 (3.139 for males and 3.168 for females), indicating positive allometric growth. The parameters of the theoretical growth curve were: TLt = 10.03 cm; k = 0.18 yr −1 , t0 = −0.443 yr and Φ � = 1.65. Monthly trends of overall condition and the gonadosomatic index (GSI) indicated that the reproductive period occurred from March to September. Analysis of back-calculated lengths indicated the occurrence of a reverse Lee’s phenomenon. This could be a symptom of predation or competition, with consequences for young specimens with slower growth and smaller size.
17 citations
Cites background from "Native and exotic fish species in t..."
...With regard to fish fauna, the introduction of exotic species together with the fluctuating hydrological regime of the lake and the impact of fisheries have probably contributed to severe alteration of the native fish community (Mearelli et al., 1990; Lorenzoni et al., 2006)....
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...09p2 With regard to fish fauna, the introduction of exotic species together with the fluctuating hydrological regime of the lake and the impact of fisheries have probably contributed to severe alteration of the native fish community (Mearelli et al., 1990; Lorenzoni et al., 2006)....
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TL;DR: In this article, the authors analyzed the degree of diet overlap between European perch and ruffe in Lake Piediluco by using data on the stomach contents of 275 European Perch and 328 Ruffe.
Abstract: The abundance of European perch in Lake Piediluco has significantly dwindled in the last few years. The present study on diet overlap between perch and ruffe was prompted by the rapid expansion of the ruffe stock in the lake. This species was first found in the lake in 1996 and has since become one of the most abundant. The degree of diet overlap between the two species was analyzed by using data on the stomach contents of 275 European perch and 328 ruffe. Results are expressed as abundance (%N), occurrence (%S), weight percentage (%W) and index of predominance (I p ). The diet overlap index (α) was calculated by means of Schoener’s formula using the %W of each food item. As an estimate of the diet width of both species, we used Levins’ indexes of niche breadth (B) and standardized measurement of niche breadth (B A ). Both species are strictly carnivorous, feeding mainly on invertebrates: the most important diet components were dipterans and crustaceans, but the European perch also feeds on fish. In the perch, the Levins index was greater (B=4.332) than that calculated for the ruffe (B=2.262). During the ontogenesis of the European perch, there is a rather pronounced diet shift: dipterans form the largest portion of the diet at all ages, though in older perch fish-eating becomes increasingly evident. Benthic crustaceans tend to be consumed in greater quantities by the 3+ age-class, though they are also found in the stomachs of specimens of all ages. Ruffe, by contrast, do not display a pronounced ontogenetic diet shift. The index of diet overlap between the two species was rather high, the maximum α value being 0.853; values indicate a high degree of diet overlap in the younger ageclasses (1+, 2+ and 3+), with a greater differentiation between the diets of the two species emerging as the age of the perch increased. Our research also clarified some of the biological characteristics of the European perch in Lake Piediluco, namely, theoretical growth in length, weight at length and relative weight. These analyses enabled us to compare the growth characteristics of the European perch during periods when ruffe stocks differed in terms of abundance. All of the results indicate that the growth conditions of the European perch population in Lake Piediluco are steadily worsening. This provides indirect confirmation of a negative interaction with the ruffe.
16 citations
TL;DR: In this article, the psychological and structural determinants of deliberate fish restocking in Italy were investigated through structured questionnaires administered to a sample of recreational anglers in the Arno river basin (Central Italy).
Abstract: Italian freshwater ecosystems were strongly affected by biological invasions during the last few decades. Recreational angling contributed to this, through the widespread use of invasive alien species for fish restocking. To date, no research is available about the psychological and structural determinants of deliberate fish restocking in Italy. This work aims to fill this research gap, through structured questionnaires administered to a sample of recreational anglers (n = 276) in the Arno river basin (Central Italy). A predictive model for fish restocking, based on a quasi-binomial logistic regression, was fit and multi-model inference was drawn, to highlight the most significant predictors. Respondents, who expected that most anglers practiced restocking and who believed restocking could create closer fishing spots, were more prone to illegally restock fish. Our findings indicate that expectations about illegal fish restocking might exist among specialized segments of anglers. Targeted communication campaigns must be enforced as soon as possible to change them. Furthermore, fish restocking is supposed to reduce the travel costs for angling: future research about this is needed to model invasion hotspots.
16 citations
Cites background from "Native and exotic fish species in t..."
...…al., 2009; Copp et al., 2009), Cyprinus carpio (Vilizzi, 2012; Vilizzi et al., 2015), Micropterus salmoides (Garcia-Berthou et al., 2000) and Zander lucioperca (Lorenzoni et al., 2006; Kopp et al., 2009), Page 2 that can deeply reshape these ecosystems (Ribeiro and Leunda, 2012; Marr et al., 2013)....
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TL;DR: In this article, the authors assess the distribution, abundance and growth of the non-native topmouth gudgeon Pseudorasbora parva that was recorded for the first time in the Tiber River Basin (central Italy) in 1994.
Abstract: The aim of this research was to assess the distribution, abundance and growth of the non-native topmouth gudgeon Pseudorasbora parva that was recorded for the first time in the Tiber River Basin (central Italy) in 1994. The competitive interaction of P. parva with four native fish species was also investigated. The study area comprised 92 watercourses of the Umbrian section of the Tiber River Basin. Demographic and environmental data were collected during the period 1990−2014 in 171 sampling sites. The results of this study showed a wide distribution of P. parva in the study area, with records from 23.39% of all sampling sites (40 out of 171). This species inhabits the downstream reaches, where the presence of many non-native species and the poor environmental quality are associated with a decrease in native fish species. A total of 5570 specimens of P. parva were collected and five age classes (0+ to 4+ ) were identified. The equation for the total length-weight relationship of P. parva was W = 0.021T L 2.673±0.015 . For the chub Squalius squalus , the Tiber barbel, Barbus tyberinus, and the roach, Rutilus rubilio, the average values of the relative weight were significantly higher in the sites where P. parva was absent. The results of the present study suggest the need to undertake proper strategies for native biodiversity conservation.
13 citations
Cites background from "Native and exotic fish species in t..."
...The body condition estimates for the indigenous species that inhabit the middle and lower reaches of the Tiber River Basin was particularly useful in assessing the negative impact of P. parva on native species (Giannetto et al., 2012)....
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...These results suggested that in Lake Trasimeno the environmental conditions (i.e. habitat conditions, food availability) may be more favourable than in the watercourses of the Tiber River Basin....
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...The study area is the Umbrian section of the Tiber River Basin (8412 km2) (Figure 1) (Lorenzoni et al., 2006)....
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...Waterways that run through predominantly impermeable lands, such as the Nestore River, show very marked flow rate fluctuations (Lorenzoni et al., 2006); in times of drought the modest flow rates produce a greater concentration of pollutants....
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...The Nestore River presents a broad variation in conductivity and EBI, with the latter fluctuating between III and IV water quality classifications, that indicate very high pollution levels (Lorenzoni et al., 2006)....
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TL;DR: The results of the study showed significant differences in the ecological preferences of the two species: the S. lucumonis showed predilection for smaller watercourses characterised by a lower number of species and a higher degree of integrity of fish community than S. squalus.
Abstract: Key-words: endemic species, Squalius lucumonis, Squalius squalus, longitudinal gradient, fish assemblage Squalius lucumonis (Bianco, 1983) is an endemic species restricted to three river basins in central Italy and listed as endangered according to IUCN Red List. The aim of this research was to increase the information on ecological preferences of this species and to focus on its differences with S. squalus (Bonaparte, 1837). Data collected in 86 different watercourses throughout Tiber River basin were analysed in the research. For each of the 368 river sectors examined, the main environmental parameters and the fish community were considered. The information were analysed by means of the Canonical Correspondence Analysis (CCA) while the differences in ecological traits between S. lucumonis and S. squalus were compared by ANOVA. The results of the study showed significant differences in the ecological preferences of the two species: the S. lucumonis showed predilection for smaller watercourses characterised by a lower number of species and a higher degree of integrity of fish community than S. squalus This information allowed to increase the basic knowledge on population biology and ecology of S. lucumonis that could be very useful for the management and conservation of this Italian endemic species.
12 citations
Cites background or result from "Native and exotic fish species in t..."
...endemic species, Squalius lucumonis, Squalius squalus, longitudinal gradient, fish assemblage Squalius lucumonis (Bianco, 1983) is an endemic species restricted to three river basins in central Italy and listed as endangered according to IUCN Red List....
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...Summarising, the preliminary results of this research allowed to investigate the role of the environmental variables in the fish communities of Tiber River basin and confirmed the significant function of the small watercourses as refuge zones for the native community as well as their important function for the conservation of fish biodiversity (Lorenzoni et al., 2006)....
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...Despite it conservational value, the information on ecology and biology of S. lucumonis are limited (Giannetto et al., 2012b), probably because this species was often assimilated with S. squalus (Bonaparte, 1837) a cyprinid endemic in Italian peninsula and Balkans (Kottelat and Freyhof, 2007) and one of the most widespread freshwater fish in Italy (Pompei et al., 2011)....
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...> STUDY AREA The investigated area was the portion of the Tiber River basin (central Italy) located in Umbria region (9413 km2) (Figure 1) The Tiber is the third-longest river in Italy (405 km) and its watershed is the second-largest; besides Umbria it extends also into the Italian Regions Lazio, Emilia Romagna, Tuscany, Marche, Molise and Abruzzo with a total extension of 17375 km2 (Giannetto et al., 2012a)....
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...It is one of the rheophilic cyprinid species inhabiting the secondary water courses (i.e brooks, creeks, small streams) within the “barbel zone” (Mearelli et al., 1995) which is characteristic of the intermediary sectors of the river basins in central Italy (Lorenzoni et al., 2006)....
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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