Environmental Management (2010) 45:856–867 DOI 10.1007/s00267-010-9450-1
Application of Two Quality Indices as Monitoring and Management Tools of Rivers. Case Study: The Imera Meridionale River, Italy Giuseppe Bonanno • Rosa Lo Giudice
Received: 3 March 2008 / Accepted: 31 January 2010 / Published online: 4 March 2010 Ó Springer Science+Business Media, LLC 2010
Abstract On the basis of the European Water Framework Directive (2000/60), the water resources of the member states of the European Community should reach good quality standards by 2015. Although such regulations illustrate the basic points for a comprehensive and effective policy of water monitoring and management, no practical tools are provided to face and solve the issues concerning freshwater ecosystems such as rivers. The Italian government has developed a set of regulations as adoption of the European Directive but failed to indicate feasible procedures for river monitoring and management. On a local scale, Sicilian authorities have implemented monitoring networks of watersheds, aiming at describing the general conditions of rivers. However, such monitoring programs have provided a relatively fragmentary picture of the ecological conditions of the rivers. In this study, the integrated use of environmental quality indices is proposed as a methodology able to provide a practical approach to river monitoring and management. As a case study, the Imera Meridionale River, Sicily’s largest river, was chosen. The water quality index developed by the U.S. National Sanitation Foundation and the floristic quality index based on the Wilhelm method were applied. The former enabled us to describe the water quality according to a spatial–temporal gradient, whereas the latter focused on the ecological quality of riparian vegetation. This study proposes a holistic view of river ecosystems by considering biotic and abiotic factors in agreement with the current European regulations. How the combined use of such indices can guide sustainable management efforts is also discussed. G. Bonanno R. L. Giudice (&) Department DACPA, Division of Plant Biology and Ecology, University of Catania, Via Valdisavoia 5, 95123 Catania, Italy e-mail:
[email protected]
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Keywords Environmental assessment River management Water quality index Floristic quality index Imera Meridionale River Italy
Introduction Many countries are concerned with different types of problems related to the presence, utilization, and management of water resources. The assessment of water quality has become a sensitive issue, especially due to the awareness that freshwater will be a scarce resource in the future. In particular, water quality is a major issue when dealing with problems of human health, eutrophication, harmful algal blooms, fish kills, seagrass loss, and even marine mammal and seabird mortality (Herrera-Silveira and others 2004). Because of the constant growth of the world population, the demand for freshwater is increasingly high, especially in the developing countries. At the beginning of 2000, it was estimated that over 1 billion people had no direct access to potable water, and 40% of the world population could not afford freshwater for minimum personal hygiene (UNDP 2003). According to the World Water Development Report (UNESCO 2003), per capita water availability will decrease by 30% in the next two decades. In order to prevent possible water crises, the European Community enacted a set of regulations known as the European Water Framework Directive (WFD 2000), according to which ‘‘water is not a commercial product like any other but, rather, a heritage that must be protected, defended and treated as such.’’ The urge for such regulations came in 1995 when the report of the European Environmental Agency on the state of the environment confirmed the need for action to safeguard Community waters, both quantitatively and qualitatively. This Directive
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is the main European reference in the field of water policy whose purpose is to establish a framework for the protection of inland surface waters, transitional waters, coastal waters, and groundwater that (1) prevents further deterioration and protects and enhances the status of aquatic ecosystems; (2) promotes sustainable water use based on a long-term protection of available water resources; (3) aims at enhanced protection and improvement of the aquatic environment through specific measures for the progressive reduction of polluting discharges; (4) contributes to mitigating the effects of floods and droughts; and (5) contributes to the provision of the sufficient supply of good quality surface water and groundwater as needed for sustainable, balanced, and equitable water use. According to the WFD, water resources should reach good quality standards through sustainable management and integrated protection of aquatic ecosystems by 2015, and strategies for water protection should be based on preventive actions and rectification of environmental damage at the source. However, the WFD does not provide practical tools to describe water quality of rivers and to guide management efforts. Italian law 152/2006 was conceived as a national implementation of the above-mentioned European Directive but it failed to delineate feasible procedures for water monitoring and management. On a local scale, the government of Sicily has implemented an environmental monitoring network aimed at collecting information on the ecological conditions of watersheds. These monitoring campaigns led to the development of special reports known as PAI (2004), which depicted the general situation of the rivers by considering different aspects such as water quality, geomorphology, anthropogenic disturbances, or presence of fish and plant endemism. However, although the PAI provide useful information on the status of rivers, they can be considered as only a preliminary step in assessing environmental quality of rivers. Therefore, the need for a feasible procedure based on practical tools able to apply the guidelines described by European regulations (WFD) is of major importance. Rivers are complex ecosystems that require an integrated analysis of biotic and abiotic factors in order to implement suitable procedures of monitoring and management. The status of rivers depends not only on the chemical and physical quality of the water, but also on other variables such as wildlife habitat, species diversity, and connectivity to other surface waters or habitats (Mitsch and Gosselink 1993). Controlling only chemical and physical water quality does not always assure the integrity of water resources. In turn, biological criteria can offer a way to measure the end result of water quality management efforts and successfully protect surface water resources (Yoder 1991). Biological criteria are also necessary as tools for assessing the quality of water ecosystems because they
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can be used to characterize various chemical, physical, and biological impacts and detect cumulative impacts. As a result, the European Directive indicated that the quality elements defining the ecological status in rivers should be both biological and physicochemical. In particular, the role of aquatic macrophytes in assessing river ecological conditions is highlighted. In this study, in order to describe objectively and comprehensively the ecological status of river ecosystems, two quality indicators were applied: a water quality index (WQI) and a floristic quality index (FQI). The common denominator of all WQIs is the following basic principle: a WQI must synthesize data such as analytical results by means of a simple quality vector. The WQI is a numerical device used to transfer large water quality data sets into a single cumulatively derived value expressing a given level of water quality (Miller and others 1986). This method makes the information more easily and rapidly interpretable than a list of numerical values. As a consequence, a given index is a powerful communication tool for transmitting information and addressing general questions. The users of this information can range from being directly involved to being distantly connected to the issue such as general public, politicians, scientists, managers, and engineers (Sˇtambuck-Giljanovic´ 1999; Bordalo and others 2006). One of the first WQIs is the WQINSF developed by the U.S. National Sanitation Foundation (Brown and others, 1970, 1972), which is based on the analysis of nine parameters: turbidity, total suspended solids, dissolved oxygen (DO), pH, total phosphates, nitrates, temperature, fecal coliforms, and biochemical oxygen demand (BOD5). WQINSF score ranges from 0 to 100, where 100 represents perfect water conditions (Bordalo and others 2001, 2006; Chang and others 2001). In this paper, the WQINSF was adopted as an assessment tool of water conditions because it incorporates critical environmental variables that affect the quality of aquatic bodies as a function of soil use and land cover. Therefore, this nine-parameter index was chosen to infer the effects of the anthropogenic disturbance such as farming and urbanization. Floristic quality assessment is an evaluation technique that uses characteristics of the existing vegetation termed ‘‘conservatism’’ to infer ecosystem integrity. The result is a unitless index called the ‘‘floristic quality index,’’ higher values of which indicate greater floristic quality and ecosystem integrity (i.e., FQI should be negatively correlated with degree of anthropogenic disturbance and positively correlated with plant diversity indices). The FQI based on the Wilhelm method was adopted as a tool to assess the quality of riparian species naturalness (Swink and Wilhelm 1979; Wilhelm and Ladd 1988). It allows for an objective numerical comparison of two or more unrelated plant
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community types and reflects numerically the impact of human disturbance. The ability to evaluate floristically and assign a repeatable quantitative value can be used in assessing restoration projects and in designing appropriate monitoring actions (Andreas and Lichvar 1995). As a case study, the Imera Meridionale River, Sicily’s largest river, was chosen. To date, scarce data are available on the water quality and riparian vegetation of this river. On the basis of a 2-year monitoring, this study proposes the integrated use of two quality assessment indices that aim to describe the ecological condition of Sicily’s largest river and to guide management efforts.
Materials and Methods Study Area The Imera Meridionale River is the longest Sicilian river (144 km), which originates on the northern side of the island at the Madonie Mountains and empties into the Straight of Sicily near the town of Licata (40,000 inhabitants), on the southern coast (Fig. 1). The watershed drains 2120 km2 of territory, which accounts for 8% of Sicily’s total surface. Annual rainfall ranges from more than 1000 mm (source) to less than 500 mm (mouth), and the annual mean temperature is 18°C. Discharges are variable because they are affected by the Mediterranean climate, which is characterized by summer drought. The annual mean discharge is 5 m3/s, but during the rainy season,
Stations 1 - Portella Manderini 2 - Blufi 3 - Resuttano 4 - Ponte Cinque Archi 5 - Ponte Capodarso
6 - Pietraperzia 7 - Borgo Braemi 8 - Monte Drasi 9 - Monte Petrulla 10 - Licata
Tyrrhenian Sea Imera Meridionale River 1 2 3 4
Strait of Sicily
8
6 7
5
Ionian Sea
9 N
10 0
W
25
50
75
E
100 Km S
Fig. 1 The Imera Meridionale watershed (Sicily) and the location of the sampling sites
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generally winter, the river may cause unexpected floods along the valley stretch, where discharges can reach 1000 m3/s. No dams are built along the Imera Meridionale River, but the flow is indirectly influenced by three dams on the main tributaries. From a geological point of view, the Imera basin is characterized along the upper course by sandstone and conglomerate of the Middle–Lower Miocene and sandstone, marl, shale, and limestone of the Paleogene. The middle and lower stretches are characterized mainly by the ‘‘Gessoso-Solfifera Formation’’ (evaporitic rocks such as chalk and halite) of the Upper Miocene, sand and conglomerate of the Pliocene, and shale and marl of the Middle–Lower Miocene. The Imera Meridionale River is also called ‘‘Salso’’ for its high salinity. The main activity of the areas that the river runs through is farming; in particular, greenhouses are widespread along the final course. As a result, the waters are especially affected by agricultural chemicals due to herbicide runoff rather than industrial pollutants. Several towns are near the river but only one is crossed by it (Licata, at its mouth). Water Quality Index The WQINSF is a nine-parameter index that can indicate the health of water courses at various points and can be used to analyze and document changes over time. The parameters of the WQINSF include turbidity, total suspended solids, DO, pH, total phosphates, nitrates, temperature, fecal coliforms, and biochemical oxygen demand (BOD5). The WQINSF is calculated according to the following equation: WQI ¼
9 X
w i qi
i¼1
where WQI is a number between 0 and 100 indicating the water quality index; qi is the water quality score of a given parameter, a number between 0 and 100; and wi is the weighting factor of the i parameter, a number between 0 and 1, attributed as a function of its importance for the global quality (Brown and others 1970). Five class ratings of water quality were considered: excellent (91–100), good (71–90), reasonable (51–70), polluted (26–50), and very polluted (0–25; Mitchell and Stapp 1995). The chemistry of freshwaters can be quite variable. Natural spatial variation is determined mainly by land use in its watershed, the type of rocks available for weathering, how wet or dry the climate is, and the composition of rain, which in turn is influenced by proximity to the sea. All these factors provide the opportunity for substantial local variation in river chemistry. However, these heterogeneities tend to average out as a river proceeds downstream (Livingstone 1963).
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Floristic Quality Index The FQI is an index of conservatism, based on the native flora of a region. A numerical quality rating, called ‘‘coefficient of conservatism,’’ is assigned to each plant. Each numerical value is an expression of the taxon’s autoecological value with respect to all other taxa in the flora. The higher the numerical rating, the more conservative the taxon. Species conservatism reflects the ecological specialization that a plant displays to a specific habitat or set of environmental conditions. Therefore, the natural quality of an area is reflected by its richness in conservative species. In this study, the FQI was adopted as a vegetative metric system tailored specifically to the riparian flora of the Imera Meridionale River.
Prior to the computation of the FQI, a floristic checklist was compiled at each sampling station. In total, 279 plant species were listed (data partially shown in Table 1). The assignment of the coefficients of conservatism to each species was based on authors’ extensive field experience with the flora of Sicily and descriptions of habitat preferences in local and regional manuals. The coefficients of conservatism were determined according to Andreas and Lichvar (1995) and Fennessy (1995). Plants were given numerical ranks (coefficients of conservatism) between 0 and 10, and only native species were considered in the FQI computation. The ranking of 0 was given to all those taxa that, primarily as a result of human disturbance, have become opportunistic invaders of natural areas, often creating extensive monocultures. The ranking of 0 was also
Table 1 Macrophyte list with the corresponding coefficients of conservatism (CC) Species
CC
Species
CC
Acanthus mollis L.
0
Melilotus siculus (Turra) All.
0
Agrostis stolonifera L. subsp. stolonifera
0
Nasturtium officinale R. Br.
Alisma plantago-aquatica L.
6
Osmunda regalis L.
Alnus glutinosa (L.) Gaertn.
8
Paspalum distichum L.
0
Apium nodiflorum (L.) Lag.
5
Phalaris paradoxa L.
0
Arisarum vulgare Targ.-Tozz.
3
Phragmites australis (Cav.) Trin. ex Steud.
0
5 10
Arum italicum Mill.
3
Polypogon maritimus Willd.
5
Arundo donax L.
0
Populus alba L.
8
Populus nigra L. Potamogeton natans L.
8 9
Rumex conglomeratus Murray
3 6
Asparagus acutifolium L. Athyrium filix-femina (L.) Roth Bolboschoenus maritimus (L.) Palla
3 10 6
Carex pendula Huds.
8
Salix alba L. subsp. alba
Carex remota L.
8
Salix alba subsp. vitellina (L.) Arcang.
8
Calystegia sepium (L.) R. Br.
2
Salix pedicellata Desf.
8
Cerinthe maior L.
0
Salicornia europea L.
6
Conium maculatum L.
0
Sarcocornia fruticosa (L.) A. J. Scott
6
Cyperus longus L.
6
Schoenoplectus lacustris (L.) Palla subsp. lacustris
6
Dipsacus fullonum L.
0
Sonchus oleraceus L.
0
Dittrichia viscosa (L.) Greuter
3
Sparganium erectum L.
6
Elymus panormitanus (Parl.) Tzvelev
8
Spartium junceum L.
3
Epilobium hirsutum L.
3
Tamarix africana Poir.
6
Fraxinus angustifolia Vahl.
8
Tamarix gallica L.
6
Galium aparine L.
0
Typha angustifolia L.
5
Glyceria spicata (Biv.) Guss. Hordeum marinum Huds.
5 0
Typha latifolia L. Ulmus glabra Huds.
4 8
Juncus acutus L.
5
Ulmus minor Mill.
6
Juncus maritimus Lam.
6
Veronica anagallis-aquatica L.
5
Juncus effusus L.
3
Veronica beccabunga L.
6
Juncus subulatus Forssk.
6
Zannichellia obtusifolia Talavera, Garcı´a Mur. & H.Smith
9
Lemna trisulca L.
9
Zannichellia palustris L. subsp. palustris
9
Xanthium strumarium L. subsp. italicum (Moretti) D.Lo¨ve
3
Limonium optimae Raimondo
10
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860
assigned to species that are typically part of a ruderal community. Rankings of 1–10 were assigned to plants based on their degree of fidelity to a range of synecological parameters. Plants found in a variety of communities, including disturbed sites, were assigned rankings of 1–3. Rankings of 4–6 were applied to taxa typically associated with a specific plant community that tolerate moderate disturbance. Rankings of 7–8 were applied to those taxa associated with a plant community in an advanced successional stage that has undergone minor disturbance or taxa that are typical of stable conditions. Those plants with a high degree of fidelity to a narrow range of synecological parameters were assigned a value of 9–10. Rare plants considered threatened or endangered were given a coefficient of conservatism ranging from 7 to 10. Following Swink and Wilhelm (1979) and Wilhelm and Ladd (1988), the coefficients of conservatism can be used to arrive at a numerical value expressed by the FQI. This numerical value provides a floristic-based assessment of the natural area related to the degree of artificial disturbance indicated by the presence of non-native or opportunistic native taxa. The FQIs from different types of vegetation can be objectively compared. The index value does not imply that one type of vegetation is ‘‘better’’ than another; it simply provides a way of measuring the degree of naturalness of the species found there. The FQI is also useful in comparing how vegetation changes over time, either from natural succession or from management. The equation of FQI is R FQI ¼ pffiffiffiffi N where FQI is the floristic quality index, R is the sum of the coefficients of conservatism for all plants recorded in the area, and N is the number of native species recorded. Because N does not include non-native species, the FQI could be biased if native and non-native species coexisted. A high biotic index due to a few good species and many non-native species is possible from a computational point of view, but it is ecologically very rare to find such opposite biological conditions because non-native species tend to replace native plants. Sampling Water sampling was carried out monthly during 2006 and 2007. Ten sampling sites were chosen and their locations are shown in Fig. 1. Stations were located approximately every 15 km (Table 2). Water samples were collected with 1 l sterilized bottles and during similar weather conditions. Collection days were sunny, without previous rain. All of the parameters were analyzed in the laboratory the day after the collection except DO, pH, and temperature, which
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were measured in situ. Water parameters were determined according to APHA Standard Methods (2005). Portable instruments were calibrated prior to use according to the manufacturers’ directions. All quantifications were carried out in triplicate, and the results are expressed as averages. For the determination of water quality, European Standards (EU 1975) were used as reference in each case. Field teams sampled the vegetation of the study sites every 2 months during 2006–2007. The vegetation sampling units were 1 9 1-m2 quadrats that were established along randomly located transects. At least one 200-m transect was taken in each site and a target number of quadrats was determined prior to vegetation sampling. Depending on the complexity of the vegetation, these surveys took from one to several hours to complete. The focus of the survey was to identify aquatic and riparian plant taxa. All species were recorded and assigned a coefficient of conservatism. Unknown species were collected and taken to the floristic laboratory for identification. Plant keys used for identification and nomenclature of plant species followed Greuter and others (1984–1989), Tutin and others (1964–1993), and Giardina and others (2007). Statistical Treatment A one-way analysis of variance (ANOVA) was conducted. Before the ANOVA was performed, data were checked for their normality and homogeneity of variance. A post hoc Tukey test was used, and the significance level chosen was 0.05. Statistical processing was performed using R software, version 2.6.2.
Results The mean values of the WQINSF and the corresponding parameters are shown in Table 3. During the study period Table 2 Stations surveyed along the Imera Meridionale River Name
Elevation ASL (m)
Portella Manderini
Yearly average flow, 2006–2007 (m3/s)
1206
0.40
Blufi
580
0.73
Resuttano
450
1.44
Ponte Cinque Archi
350
2.03
Ponte Capodarso
290
2.65
Pietraperzia
220
3.20
Borgo Braemi
160
3.52
Monte Drasi
80
4.66
Monte Petrulla
50
6.47
0
9.08
Licata
43.19 ± 2.82 0.07 0.08 0.10 0.10 0.10 0.11 0.11
44.83 ± 3.55
0.17 Weighting factor
0.16
71.25 ± 24.12
63.09 ± 20.64 7.4 ± 0.4
10.21 ± 1.71 7.7 ± 0.2
9.17 ± 1.75 3.57 ± 1.44
4.20 ± 1.29 8.16 ± 0.18 18.25 ± 5.71 0.18 ± 0.04
8.10 ± 0.20 16.18 ± 5.04 0.17 ± 0.05 5542 ± 1386
6462 ± 1426
21.17 ± 9.84
18.00 ± 8.68
Monte Petrulla
Licata
49.22 ± 3.56
51.29 ± 3.05 49.71 ± 18.12
57.00 ± 20.73 7.1 ± 0.6
6.5 ± 0.4 7.90 ± 1.45
8.43 ± 1.67 2.52 ± 0.66
2.31 ± 0.68 0.15 ± 0.05
0.19 ± 0.03 7.96 ± 0.20 9.22 ± 0.84
7.85 ± 0.20 8.96 ± 1.10 2243 ± 875 36.59 ± 5.71
29.54 ± 11.30 3134 ± 1299
Borgo Braemi
Monte Drasi
60.81 ± 4.63
54.27 ± 3.52 6.15 ± 0.4 48.25 ± 13.38 5.85 ± 1.31 1.96 ± 0.66 0.13 ± 0.04 7.87 ± 0.17 8.02 ± 1.32 41.33 ± 5.97 Pietraperzia
1542 ± 664
62.10 ± 4.78 5.75 ± 0.3 36.75 ± 11.33
5.96 ± 0.3 38.54 ± 9.97 5.20 ± 0.73
4.91 ± 0.62 1.13 ± 0.49
1.38 ± 0.46 0.18 ± 0.05
0.17 ± 0.07 7.57 ± 0.08 6.45 ± 1.54
53.88 ± 7.65
7.48 ± 0.08 6.93 ± 1.44
930 ± 406
1070 ± 660
Ponte Cinque Archi 59.33 ± 9.65
Ponte Capodarso
73.44 ± 6.08 65.10 ± 4.25
81.93 ± 3.34 5.0 ± 0.01 16.25 ± 7.53
5.40 ± 0.4 25.63 ± 6.65 5.65 ± 0.2 33.88 ± 10.06 2.05 ± 0.86 4.10 ± 0.80
0.68 ± 0.31 0.01 ± 0.001
0.78 ± 0.57 1.15 ± 0.52 0.16 ± 0.08 0.18 ± 0.08
0.23 ± 0.11 7.77 ± 0.26 1.98 ± 0.59 213 ± 190
259 ± 183 749 ± 287
83.04 ± 5.45
77.92 ± 8.38 68.63 ± 8.00
Portella Manderini
Blufi Resuttano
7.56 ± 0.27 3.09 ± 1.39 7.73 ± 0.20 5.55 ± 1.29
Turbidity (NTU) Difference in Total phosphates (mg L-1) Nitrates temperature (°C) (mg L-1) BOD5 (mg L-1) Oxygen Fecal coliforms pH saturation (%) (cfu 100 mL–1) Station
Table 3 Average values ± SD for the nine parameters considered and WQINSF scores during 2006–2007, along with weighting factors
2006–2007, water quality steadily decreased along a spatial gradient according to which water conditions were good, reasonable, and polluted in the upper, middle, and lower courses, respectively. The stretch with good quality accounted for 10% of the total course, whereas the stretches with reasonable and polluted conditions accounted for 47 and 43%, respectively (Table 4). The 2 study years showed the same percentage of stretch with good quality (10%) but water quality degradation occurred in the middle and lower courses in 2007 (Table 4). The mean water quality was 60.37 ± 12.69 in 2006 and 56.86 ± 12.42 in 2007. Both years exhibited similar spatial trends (P \ 0.05; Fig. 2), indicating that water quality declines from the source to the mouth, with no recovery. After an initial decrease, water conditions were almost stable from 30 to 60 km (WQINSF = 60–65). From Ponte Capodarso, water quality started sharply decreasing. The concentration of DO was high near the source (83.04%), mainly because the river goes through a nature reserve where human disturbance is very low. The DO scores were still acceptable up to Resuttano (68.63%), 30 km downstream. After Resuttano, DO ranged from 60 to \20% (18%, Licata, mouth; Table 3). DO declined from the source to the mouth, with no recovery, and such a decrease was sharper whenever an area between two sites had urban settlements. In this particular case, DO concentration decreased by roughly 10% as seen between Blufi and Resuttano and between Ponte Capodarso and Pietraperzia. The quantity of fecal coliforms at the mouth was 30 times greater than in the source area, and it was probably due to the domestic effluents of Licata. In turn, the quality of the river is good with respect to pH (values range from 7.48 to 8.16), because the pH of most natural waters is between 6 and 9 (USGS 1993). The degree of acidification is very important and depends on both inputs and buffering capacity. Biological communities are affected by diverse pathways, and taxa differ in their susceptibility. Freshwaters can vary widely in acidity and alkalinity, and extreme pH values (much below 5 or above 9) are harmful to most organisms. Regarding BOD5, the Imera Meridionale River was moderately polluted down to Pietraperzia (8.02 mg L-1), 75 km from the source. From Pietraperzia to Monte Drasi, the increase in BOD5 was modest. On the contrary, at the last two sites, the concentration of BOD5 doubled. The difference in temperature was on average less than 0.2°C and its influence on water quality was minimal. Total phosphates and nitrates started increasing where farming became the dominant activity (middle course). Turbidity and suspended solids increased steadily downstream. Similar temporal trends were found in both years (P \ 0.05; Fig. 3): water quality was stable during the period January–March, declined from April to July, and steadily increased from August onward. This trend reflects
861
Suspended solids WQINSF (mg L-1)
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862
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Table 4 Extension of the stretches according to quality classes in 2006 and 2007 Year
Quality class Good
Reasonable
Polluted
Extension (km)
Percentage of total course
Extension (km)
Percentage of total course
Extension (km)
Percentage of total course
2006
15
10%
75
52%
54
38%
2007
15
10%
60
42%
69
48%
2006–2007
15
10%
68
47%
61
43%
90
2006
80
2006
70
2007
2007
60
70 50
WQINSF
WQINSF
60 50 40 30
40 30 20
20
10
10 0
0
0
15
30
45
60
75
90
105
J
120 144
F
M
A
M
J
km
the monthly distribution of discharges, which significantly decrease until July, followed by a recovery in August (P \ 0.05; Fig. 4). A positive correlation between water quality and discharges was also found. Water quality improvement may have been due to high dilution during rainy periods (Al-Ani and others 1987). The floristic analysis of the riparian species is shown in Table 5. The decreasing FQI values indicate that riparian vegetation was affected by a progressive loss of naturalness. This qualitative reduction of species was largely due to the increasing number of invasive, non-native, and ruderal taxa such as Phragmites australis and Galium aparine. WQINSF and FQI showed similar decreasing trends along the river. According to Pearson’s coefficient (r = 0.9720, P \ 0.001), WQINSF and FQI scores had a positive correlation. The Imera Meridionale River is also a stressed ecosystem in terms of salinity resulting from several factors such as geology, semiarid climate, and nutrient runoff. Whether the high salinity in rivers is harmful to the organisms is unclear, although biotic changes unquestionably occur in the brackish water of estuaries (Allan and Castillo 2008). Salinity is often considered to be a major factor in the replacement of native riparian species by invasive species (Busch and others 1992; Glenn and others 1998). By contrast, Shafroth and others (1995) concluded that salinity played only a minor role in the replacement of Populus
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A
S
O
N
D
N
D
Months
Fig. 3 WQINSF monthly trend in 2006 and 2007
10.00 2006
9.00
Discharges (m3/s)
Fig. 2 WQINSF spatial trend in 2006 and 2007
J
2007
8.00 7.00 6.00 5.00 4.00 3.00 2.00 1.00 0.00 J
F
M
A
M
J
J
A
S
O
Months Fig. 4 Monthly average flow trend in 2006 and 2007
(native) by Tamarix (invasive) along the Rio Grande because both plants showed equal germination and seedling growth in salt concentrations up to five times normal river-water salinity (2.5 g L-1). On the basis of literature data (INEA 2001) and in situ measurements, the salinity trend of the Imera Meridionale River was graphed (Fig. 5). Salinity follows three main patterns: initially, salinity rises up to 45 km from the headwaters (6.23 g L-1); a declining trend occurs along the middle stem up to 105 km (3.23 g L-1); and the final stretch shows a dramatic increase (7.54 g L-1). The lack of a single salinity trend may be due to the initial water contamination by salty ores, followed by
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Table 5 Floristic quality index (FQI) and corresponding parameters for the period 2006–2007 Station
Species recorded
Sum of the coefficients of conservatism
FQI
Portella Manderini
165
947
73.72
Blufi
178
902
67.61
Resuttano Ponte Cinque Archi
187 198
895 891
65.45 63.32
Ponte Capodarso
218
853
57.77
Pietraperzia
194
784
56.29
Borgo Braemi
212
752
51.65
Monte Drasi
183
653
48.27
Monte Petrulla
195
619
44.33
Licata
215
592
40.37
8 7 Salinity (g L-1)
6 5 4 3 2 1 0 0
15
30
45
60
75
90
105
120
144
km
Fig. 5 Salinity trend along the Imera Meridonale River
a mitigation due to a different rock composition (Onaindia and others 1996; Lacoul and Freedman 2006). In the lower course, the sharp increase in salinity may be caused by the combined effects of primary and secondary salinization due to high rates of evaporation and discharges of nutrient chemicals (Jin 2008). According to the salinity/FQI relationship, the floristic quality trend of riparian plant communities does not reflect significantly the saline nature of the Imera Meridionale River along the first 105 km (r = –0.523, P [ 0.05), probably because of the salinity fluctuation. Instead, the high correlation found between salinity and FQI in the lower course (r = –0.862, P \ 0.01) is likely to be due to natural and anthropogenic salinities, the latter caused mainly by the massive use of nitrates and phosphates in farming activities.
Discussion The integrated application of ecological indices can be useful in establishing river monitoring and management strategies. Rivers can maintain acceptable quality
conditions only if monitoring campaigns consider the multimetric ecological trends resulting from the various effects of human impacts on waters. Comprehensive monitoring based on numerous environmental variables is a key aspect for implementing extensive control networks that integrate different fields of research (Fig. 6). Consequently, management actions should rely on a holistic perspective that adopts multiple criteria to assess the status of rivers and creates suitable financial and legislative conditions within a policy of sustainable development (Fig. 7). A basic aspect of integrated approaches provides the possibility of relying on a wide set of environmental parameters resulting from the application of multimetric indices such as WQINSF and FQI. The advantage of using these indices is the synthetic and objective characterization of chemical, physical, and biological factors that may prompt the application of multimetric quality standards. This study showed that a progressive ecological degradation occurred along the Imera Meridionale River, and riparian vegetation and water quality were adversely demonstrated by both indices decreasing along a spatial gradient. Human actions can have different effects on ecosystems. These may result in point and nonpoint pollution and habitat alteration. WQINSF can be employed as a global and local indicator of water degradation. On a watershed scale, this study showed that the water quality of the river was good in the upper course (10% of total course), reasonable in the middle course (47%), and polluted in the final stretch (43%). However, local influences on water status were also detected. In particular, data showed a significant decrease in those stations close to urban settlements, namely, Blufi, Resuttano, Pietraperzia, and Monte Petrulla-Licata (Table 3). This can be considered indicative of a larger influence of urban pollutants (i.e., nontreated discharges) compared to agricultural chemicals (i.e., pesticide runoff). In turn, the FQI is more suitable for the assessment of habitat alterations (Lopez and Fennessy 2002). Table 5 shows a steady decrease in floristic quality along the whole course of the river. The absence of recovery trends indicates that insufficient measures have been taken to safeguard the naturalness of riparian vegetation from anthropogenic pressure. The decrease in FQI values can be locally interpreted whenever a significant reduction is detected. In particular, between Portella Manderini and Blufi stations (upper course), the worsening of floristic riparian quality is likely due to the change from a nature reserve to an anthropogenically affected area (i.e., grazing, tourism). Previous studies showed that anthropization is the main factor that favors the distribution of alien species, thus impoverishing the naturalness of habitats (Rodgers and Parker 2003). Similarly, the significant decrease in FQI
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RIVER MONITORING
INTEGRATED APPROACH
WQI + FQI
wide set of environmental parameters
monitoring of chemical, physical and biological factors
application of chemical, physical and biological standards
identification of the different effects of human actions
detection of point and nonpoint sources of disturbance
detection of physical habitat alteration
identification of multimetric quality trends
correlation between biotic and abiotic components
integration of biological monitoring and physicochemical monitoring
monitoring at different levels
measures by analytical methods
response of the biological community
extension of monitoring networks
water quality assessment
riparian vegetation assessment
integration of different fields of expertise
coordination among organizations
creation of environmental protection committees
Fig. 6 Scheme of the integrated monitoring based on the indices WQINSF (WQI) and FQI
at the station Ponte Capodarso (middle course) can be explained by the presence of an invasive construction, namely, a 5-km-long viaduct with pillars in the river bed, that may have caused the habitat fragmentation of plant species. In the lower course, the quality of riparian vegetation decreased significantly station to station, namely, from Borgo Braemi to Licata, and factors such as increasing urbanization and intensive agriculture can be the main human activities affecting habitat integrity. The integrated application of two ecological indicators allowed the identification of multimetric quality trends. In particular, through systematic sampling, a significant correlation was established between the biotic (riparian vegetation) and the abiotic (water) components of the Imera Meridionale River (r = 0.9720, P \ 0.001). Physicochemical approaches should not automatically be preferred over biological approaches because both have advantages and shortcomings. Instead, the two approaches should be regarded as complimentary (Chapman 1996). Physicochemical and microbiological monitoring (i.e., WQINSF) has the advantage of the possibility of precise pollutant determination. Another advantage is the possibility of standardization that relies on well-established sampling
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and processing protocols. However, physicochemical monitoring can be affected by sample contamination for some micropollutants (e.g., metals) and high costs are also involved. In turn, biological monitoring (i.e., FQI) measures the loss of naturalness of aquatic habitats and has a good response to minor pollution events but is less valid for pollutant flux studies and standardization is difficult (Chapman 1996). In contrast to water quality, which was measured by analytical methods (WQINSF), the description of riparian vegetation quality (FQI) relied on the response of biological communities to changes in their environment. The quality of living organisms has a longer time dimension (i.e., plants, fish, macroinvertebrates) than water quality because biota can integrate the effects of chemical and hydrological events that may have lasted years (Chapman 1996). Thus, the progressive decline in FQI along the Imera Meridionale River can be the consequence of degradation processes started long before the monitoring was carried out. A major aspect of integrated monitoring is the collection, analysis, and processing of heterogeneous data, resulting in the integration of different fields of expertise (e.g., ecology, botany, environmental engineering). This
Environmental Management (2010) 45:856–867
865
RIVER MANAGEMENT
INTEGRATED APPROACH
WQI + FQI
holistic approach
more complete picture of river conditions
tailored management strategy
multiple criteria of assessment
evaluation of river ecosystems from diverse perspectives
combined proposals to solve multiple issues
rivers as sentinels of environment
description of geographic patterns
evaluation of management efforts
optimization of financial resources
rational allocation of funds
estimation of benefits and costs in river project planning
specific legislative interventions
improvement of existing laws on water quality and biota integrity
indices as guide parameters of environmental quality
sustainable development
integration between water condition and neighboring territory
social and economic impacts
Fig. 7 Scheme of the integrated management based on the indices WQINSF (WQI) and FQI
should imply the coordination among various institutions such as universities and regulatory agencies. This study underlines the need for centralized coordination to simplify river integrated monitoring programs, in accordance with the European Directive, which points out the establishment of special environmental protection committees, whose tasks should be to coordinate monitoring and to encourage a dialogue between institutions and citizens. The monitoring and management of rivers are often difficult when they run through different political entities. However, the Ohio River Valley Water Sanitation Commission (ORSANCO) is an important example of successful sustainable management by an interjurisdictional commission, which consists of representatives of eight states in the Ohio River Valley and the United States Government (Vicory and Tennant 1995). Similarly, in Europe, Germany, France, the Netherlands, Switzerland, and Luxembourg instituted the International Commission for the protection of the Rhine River, which coordinates the monitoring and management efforts to safeguard the ecological integrity of the river (Malle 1996). For too long, people have regarded water as simply a fluid to be used; water unused was water wasted. Water
resource management is still dominated by legal doctrines from a less crowded world, weak implementation of good laws, and a focus on water chemistry (Karr and Chu 2000). But such narrow views do not guarantee the wellbeing of aquatic life and the integrity of water and watershed. In turn, integrated monitoring relying on different quality indices proposes a holistic approach to management decisions. This approach results in a more complete picture of the river ecosystem conceived as an entity, thus guiding the implementation of global tailored management strategies. This study showed that the progressive degradation in water quality and plant communities of the Imera Meridionale River needs different intensities of management efforts according to the level of environmental quality. One of the management actions should be aimed at improving sewage treatment because water quality was significantly affected near urbanized stretches. In particular, according to the temporal changes in water quality (Fig. 3), water purification should be maximized in the summer because of low rainfall, with consequent scarce dilution. Along the most polluted stretches (WQINSF \ 51), if high water treatment is not possible, discharges should be reduced by choosing alternative water bodies. Riparian vegetation
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naturalness showed a particularly significant degradation close to invasive constructions. The presence of hydraulic engineering structures such as dams, concrete banks, or weirs endangers the physical and biological integrity of rivers (Graf 2004). Recovery interventions of the riparian vegetation of the Imera Meridionale River should be aimed at reaching FQI values close to the FQI of the first station, which is considered a pristine site (nature reserve). An important safeguard action should consider the creation of a protection buffer along the river, wider in the lower course, where the FQI drops dramatically. In this buffer, human activities such as grazing, agriculture, and logging should be limited. Because rivers integrate all that happens in their landscapes, their condition reveals much about the consequences of human actions. In this study, the condition of the Imera Meridionale River indicated that much of the river’s rich natural capital has been lost. Rivers can be considered as sentinels of the environment: they give early warning of the risks human activities engender. Society can no longer afford to ignore these risks or behave as if they did not exist. In particular, the description of geographic patterns helps in detecting the signs of river degradation. Sampling sites throughout the Imera Meridionale River showed different levels of water-vegetation integrity. Areas with sharp declines in WQINSF and FQI were associated with towns and extensive agricultural areas. An exhaustive evaluation of management efforts cannot rely only on criteria assessing water quality. Indeed, management decisions should also consider the plant integrity of rivers. For instance, between the Ponte Cinque Archi and the Ponte Capodarso sites, FQI values dropped significantly despite the creation of a huge nature reserve. The poor results in terms of plant recovery are likely due to the presence of a viaduct with pillars built in the river bed. Management actions should consider that areas affected by invasive constructions may be at risk of being damaged forever, thus limiting any kind of safeguard measure. The consequence of this is that even though water quality is reasonable, floristic integrity may be adversely affected, and the whole river ecosystem may be at risk in that stretch. Therefore, for a rational planning of river wellbeing, three scales of river management should be adopted: basin-scale management (i.e., appropriate land use), segment-scale management (i.e., river bank restoration), and reach-scale management (i.e., habitat restoration; Osugi and others 2007). Monitoring in the twentieth century began with a restricted focus (organic pollution, toxic chemicals) but is shifting to a more integrative approach that evaluates the condition of rivers from diverse perspectives (Fig. 6). The application of the WQINSF and FQI is an effective monitoring and management methodology that can implement
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European regulations because it can communicate qualitative physicochemical and biological conditions and provide quantitative assessments for use in legal or regulatory contexts. Society must improve its understanding and measurement of ecological risks. Integrated monitoring and management identify the condition of living systems, which is the best primary end point to assess environmental quality. The systematic study of river conditions helps communities keep the natural assets that support them. It is also a major step toward restoring degraded systems, thus reversing the trend toward resource damage and depletion that has prevailed during the twentieth century.
Conclusions Water ecosystems such as rivers are complex entities that require an in-depth analysis in order to plan effective monitoring and management programs. Such initiatives can provide good results only if supported by a complete picture of ecological data, ranging from abiotic to biotic factors. Monitoring and management are two complementary aspects of environmental protection that should rely on the integrated approach of quality parameters to have a comprehensive perspective of river processes, thus implementing tailored strategies of ecological enhancement. Classical analytical ways of describing water status should not disregard the biological component but, instead, they should be integrated with it. Periodic sampling revealed that water and floristic quality indices could be useful for the monitoring and assessment of rivers and for tracking restoration programs over time. Therefore, the integration of the WQINSF with the FQI could be considered as a valid methodology to better manage and help restore river ecosystems, especially when such water bodies show symptoms of ecological degradation and loss of biodiversity. Acknowledgments This study was partially funded by the Italian Ministry of University and Scientific and Technological Research and is part of a research program into aquatic and terrestrial ecosystems in Sicily (PRA No. 21040101). The authors also wish to thank the Editorial Board, Dr. Dale Robertson, and the two anonymous reviewers for their critically constructive comments.
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