Spatial and seasonal distribution of macroinvertebrates in high altitude ...

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Sep 7, 2013 - A highland reservoir in the West Black Sea region of Turkey which belongs to the Mediterranean climatic zone was examined. Both littoral and ...
Chinese Journal of Oceanology and Limnology Vol. 31 No. 5, P. 994-1001, 2013 http://dx.doi.org/10.1007/s00343-013-2313-x

Spatial and seasonal distribution of macroinvertebrates in high altitude reservoir (Beyler Reservoir, Turkey)* Özlem FINDIK** Arts and Sciences Faculty, Molecular Biology and Genetic Department, Nevşehir University, 37150 Turkey Received Dec. 18, 2012; accepted in principle Jan. 22, 2013; accepted for publication May 31, 2013 © Chinese Society for Oceanology and Limnology, Science Press, and Springer-Verlag Berlin Heidelberg 2013

Abstract A highland reservoir in the West Black Sea region of Turkey which belongs to the Mediterranean climatic zone was examined. Both littoral and profundal zones were sampled from October 2009 to September 2010, to determine taxonomic composition, biodiversity and abundance of benthic invertebrates as well as the seasonal variation of these measures. A total of 35 taxa were identified, of which 12 belong to Chironomidae and 10 to Oligochaeta groups. The highest diversity and abundance of benthic macroinvertebrates were found at the littoral stations. Macroinvertebrates showed significant positive correlations with water temperature and NO2 and NO3 concentrations, and negative correlation with dissolved oxygen. Keyword: macrofauna; zoobenthos; community structure; littoral; West Black Sea

1 INTRODUCTION Reservoirs are established for energy production, supplies of drinking and irrigation water, as well as for flood prevention. The reservoir in this study was set up to provide irrigation water. The reservoir, classified as inland water in the region, of ecological importance. In Turkey, there are approximately 200 natural lakes and 120 reservoirs, each with different structural and ecological features (Ahıska, 2009). The number of reservoirs has increased all over the world, and in Turkey, this trend is no different. Reservoirs formed by damming rivers always differ from natural lakes in the shape of their longitudinal profiles (Zang et al., 2012). Water level fluctuation is a physical feature in which reservoirs and lakes differ. Macroinvertebrate density and biomass in reservoirs under regular drawdown regimes can be equal to or greater than those in natural lakes (Furey et al., 2006). Waterleve1 fluctuation should also be considered an important factor in community organization of reservoirs (Prat et al., 1992). Higher water-level fluctuation would enhance the mechanical mixing water column, change the properties of the sediment, influence the habitat of organisms, and affect the

macroinvertebrates. Generally, large water-level fluctuations cause a major decline in both macroinvertebrate abundance and biomass of macrophytes (Zang et al., 2012). It is widely accepted that assessment of the benthic macroinvertebrate communities is an important part of the evaluation of environmental quality of aquatic ecosystems (Stewart et al., 2000). They reflect the combined effects of various stresses influencing water quality in time and space (Timms, 2006). In most reservoirs, the benthic community is composed mainly of chironomid larvae and oligochaetes (Mwaura et al., 2002; Moretto et al., 2003; Pamplin and Rocha, 2007; Shao et al., 2008; Beghelli et al., 2012). Other groups, less rich and abundant, can also be present. The whole community of these organisms is crucial to any aquatic ecosystems, since it plays a role in energy transfer and nutrient cycling (Covich, 1999). Usually, both a greater variety and larger quantities of benthic species exist in the littoral and sub-littoral zones of reservoirs and lakes than in the profundal

* Supported by the Scientific and Technological Council of Turkey, TUBITAK (No. 109Y013) ** Corresponding author: [email protected]

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FINDIK: Distribution of macroinvertebrates in high altitude reservoir, Turkey

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Table 1 Description of stations Stations

Zones

Depth (m)

1

Littoral

0, 5

2

Littoral

0, 5

3

Littoral

0, 2

4

Profundal

5 6

Distance from the shore (m)

Bottom type

Macrophytes (absent or present)

0, 5

Muddy

No

0, 15

Sandy/muddy

No

0, 65

Muddy

Yes

45

16

Silty

No

Profundal

5

3

Muddy

No

Profundal

6

5

Silty

No

zone (Petridis and Sinis, 1993; Wetzel, 2001). The structure of the macroinvertebrate community and the habitat preference of species can be affected by the presence of macrophytes, and different macroinvertebrate taxonomic groups may differ in their habitat preferences (Alonso and Camargo, 2010). The first study for the purposes of determining the benthic fauna in the inland waters of Turkey was conducted by Geldiay (1949) in Çubuk Reservoir and Emir Lake. This study examined the macro and micro fauna of these lakes. Until now, only the metal concentrations of sediment in the reservoir have been investigated (Fındık and Turan, 2012). There is no work, however, regarding the benthic macrofauna of this reservoir. The aim of this study was to determine the species composition, abundance, and seasonal distribution of benthic invertebrates inhabiting the littoral and profundal zones of the Beyler reservoir in the West Black Sea region of Turkey. It will provide information on the current status of the reservoir.

2 METHOD 2.1 Study site Beyler Reservoir, which is an important reservoir for the province of Kastamonu, is located at 41°68′– 41°69′N and 33°79′E, at an altitude of 1 134 m (Fig.1). It was set up to provide irrigation water to the land near the towns of Devrekani and Seyfiler; today, this reservoir provides irrigation water to an area of 5 178 hm. The reservoir is located on İncesu Stream, a tributary of Devrekani Stream between Fakılar and Karayazıcılar villages, 9 km north of Devrekani. The reservoir’s construction was completed in 1993. At normal water level, the volume of the reservoir is 25 hm3, and its surface area is 2.40 km2 (DSI, 2007). The reservoir contains chub, common carp and mirror carp, big-scale sand smelt, and rainbow trout. With the construction of the Beyler Reservoir, fishing

Fig.1 Study area: the Beyler Reservoir with the sampling sites

emerged in the area, as a new line of work. Samples were collected at 6 stations (Fig.1); descriptions of stations are provided in Table 1. Station 1, where sampling was difficult during high water levels, was set up near the embankment, and it had muddy sediments. Macrophytes were found only at Station 3. The sediment at Station 2 was sandy and muddy. Station 3 was established at the point where İncesu stream flows into the reservoir, and it had muddy sediments. Station 5, situated at the east side of the reservoir, 3 m from the rocky shoreline, had hard sediments. Shore vegetation was not observed at this station. Station 6 was located at the northern side of the reservoir, an area surrounded mostly by agricultural land. The sediment here was silty. Station 4 was a profundal station at the center of the reservoir, with a depth of approximately 45 m, had muddy sediments. 2.2 Collection of macroinvertebrate Samplings for macroinvertebrate enumeration were collected from 6 locations in the reservoir, once

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CHIN. J. OCEANOL. LIMNOL., 31(5), 2013

per season (four times per year), between November 2009 and July 2010. Two types of sampling devices were used to collect macroinvertebrates: hand net samplers in shallow regions where the substrate was mostly clay and macrophytes, and Ekman Birge grab samplers for finer sediments and muddy bottoms. At each of the sampling sites, two samples were collected. Macroinvertebrates obtained through the sieving of the collected samples through a sieve of 500 μm and by the use of thin long-nose tweezers, were preserved in 4% formalin. The samples brought to the laboratory were divided into groups and then preserved in 70% ethyl alcohol solution (Welch, 1948). The identification of macroinvertebrate species was attempted to the lowest level possible. In the identification process: Sperber (1950), Brinkhurst and Jamieson (1971), Kathman and Brinkhurst (1998), Timm (1999) and Pinder (2010) were used for Oligochaeta, while Cranston (1982), Wiederholm (1983), Şahin (1991), Merritt and Cummins (1996), Tachet et al. (2000) and Klink and Moller (2003) were used for the other groups. The number of taxa per site, and the abundance of individual taxon per m2 were calculated. 2.3 Water quality Water samples were collected at the 6 stations seasonally. In the field, water temperature and dissolved oxygen were measured using a HANNA (HI 9142) oxygen meter, and the pH was measured using an ORION pH meter. The physicochemistry of the water samples brought to the laboratory was analyzed using standard methods. Total hardness, calcium, and magnesium were analyzed with titrimetrically, using EDTA. Nitrite nitrogen was measured using alphanaphthylamine, nitrate nitrogen using the salicylate method, and phosphate phosphorus using the spectrophotometric method with molybdate. All analyses were done using standard methods (APHA 1992). 2.4 Statistical analysis Statistical analysis of the data was carried out using SPSS 19.0, for Windows. In order to determine statistical differences for the biological data, the F test was applied (Elliot, 1977). Also, differences between seasons (over all stations) of physicochemical data were analyzed with ANOVA. Macroinvertebrate abundance data were transformed by log (x+1) to

Vol.31

Fig.2 Total number of benthic macroinvertebrate taxa in different sampling months in the Beyler Reservoir

make the distributions closer to normal. Correlations between abundance of taxa and environmental variables were made with Pearson correlation coefficients. In order to evaluate the biodiversity of the macroinvertebrates, the Shannon-Wiener diversity index and Margalef richness indices were calculated for each sample station and sample period, in accordance with Magurran (1991). Diversity of the community was described with Shannon-Wiener diversity index (H'): H'=-Σ1n Pi lnPi, where Pi is the relative abundance of the species i; Pi=Ni/N, where Ni is the density of the species i, n is the number of species and N is the total density of the macroinvertebrates. Margalef richness index: R=(S– 1)/loge(N), where S is the number of benthic species and N is the abundance.

3 RESULT A total of 35 taxa were found in the Beyler Reservoir during the studied periods (Table 2). It is important to note, however, that several organisms were not identified at species level. The benthic fauna were represented by 8 groups. The greatest richness was observed in the family Chironomidae, with 12 taxa. It was followed by Oligochaeta, with 10; Ephemeroptera, with 4; Hirudinea, with 3; and Mollusca, with 3. Crustacea, Odonata and Heteroptera were taxonomically poorest, with only one taxa in each group. Higher numbers of taxa were found at the littoral stations (41) than at profundal ones (12). Significant differences were not observed among the sampling stations (F test analysis), in terms of taxon numbers. Statistical differences were observed, however, between the sampling seasons (P