Anthropogenic water bodies that are located in urban and industrial areas can be very important for aquatic fauna and flora, especially in areas where there are no natural water bodies (Gee et al. 1997; Gledhill et al. 2008;Vermonden et al. 2009;Chester & Robson 2013; Hassall 2014; Hill et al. 2016; Martínez-Abraín & Jiménez 2016; Rewicz et al. 2016; Hill et al. 2017). These anthropogenic habitats may be particularly important for rare and threatened species. For example, Lewin & Smoliński (2006) reported the presence of the rare gastropod species
Some anthropogenic water bodies are associated with various technological processes including coal, brown coal, nickel, salt or sand mines (Echols et al. 2009; Jaruchiewicz 2014; Luek & Rasmussen 2017). The activity of mines is connected, among others, with the formation of settling ponds. These water bodies are used for temporary retention of saline mine waters before they are discharged into rivers, and therefore their waters are, among others, contaminated with salt (Echols et al. 2009).
It should be emphasized that until recently research on macroinvertebrate communities in settling ponds has rarely been undertaken. The research focused on the effects of drainage from surface coal mining operations on zoobenthos and indicated that settling ponds may create favorable conditions for various taxa of macroinvertebrates (Canton & Ward 1981). However, research on the saline settling ponds that are associated with underground coal mining has never been undertaken.
Anthropogenic salinization is one of the most important factors responsible for biological changes in aquatic biota (Bäthe & Coring 2011; Kang & King 2012; Arle & Wagner 2013), thus it is particularly important in the case of coal mine settling ponds whose waters are often very saline. It should be emphasized that saline inland water bodies can be unique habitats. Only a few submerged aquatic plants can grow and reproduce in conditions of high salinity. Among the submerged macrophytes,
To date, research on invertebrates that inhabit widgeongrass beds has been carried out in estuaries (e.g. Fredette et al. 1990; Heck et al. 1995; Keats & Osher 2007; Henninger et al. 2009; Barnes & Ellwood 2012), lagoons (e.g. Por 1971; Casagranda et al. 2006), coastal habitats (e.g. Montague & Ley 1993; Boström & Bonsdorff 2000; Leopardas et al. 2014; Bartolini-Rosales et al. 2016) and various inland saline habitats such as streams (Velasco et al. 2006), ponds (Verhoeven 1978, 1980; Guerrini et al. 1998) and lakes (Brock & Shiel 1983; Wollheim & Lovvorn 1995; 1996; Herbst et al. 2013), while such research has never been undertaken in saline coal mine settling ponds.
The objective of the study was to verify whether various microhabitats affect the abundance and composition of macroinvertebrates in a saline settling pond. To test this, the research was carried out on microhabitats that occur in a settling pond such as
The studies were conducted in a settling pond located in the center of the mining town of Knurów in Upper Silesia, southern Poland (Fig. 1). Upper Silesia is one of the most industrialized and urbanized regions in Europe and one of the largest coal basins in the world (Jaruchiewicz 2014). The investigated water body (50°13’09”N, 18°40’11”E) was created in 1974 to drain the salt waters from the “Knurów-Szczygłowice” coal mine (Bielańska-Grajner & Cudak 2014). The waters from the settling pond flow into the Bierawka River through small streams, which in turn flows into the Oder River, the second largest river in Poland.
Location of the study area and investigated microhabitatsFigure 1
The water body surface area is 7185.75 m2. Both the shoreline of the settling pond and its bottom are built of post-mining waste with the size ranging from 0.2 cm to 2.0 cm. Only two species of macrophytes were recorded –
The studies were carried out once a month from June to October in 2016. Three types of habitats in different parts of the pond were selected for the sampling of macroinvertebrates, i.e. the bottom overgrown with
Three microhabitats occurring in the studied settling pondFigure 2
The data on macroinvertebrate communities were processed according to dominance (%), frequency (%) and abundance (individuals m-2). During the sampling of macroinvertebrates, samples of water and bottom sediments were also collected for analyses. Water parameters such as conductivity, pH, total dissolved solids (TDS), dissolved oxygen and temperature were measured in the field using Hanna Instruments portable meters in each month of the survey. Other parameters such as alkalinity, iron, chlorides, nitrates, nitrites, ammonium, phosphates, potassium and sulfates were analyzed in the laboratory according to the standard methods by Hermanowicz et al. (1999). The total organic matter (%) from the place where
One-way analysis of variance (ANOVA) was applied to assess any differences in the mean abundance and biomass of macroinvertebrates and the mean abundance of taxa between the studied habitats. The statistical analyses were performed using Statistica version 12.0. Factors with
The water in the settling pond was well oxygenated and slightly alkaline. It was characterized by a very high conductivity as well as a high content of sulfates, potassium and chlorides (Table 1). The total dissolved solids ranged from 12.9 to 17.1 g dm-3. According to the Hammer scale (1990), the water is classified as hyposaline (TDS = 3.0–20.0 g dm-3).
Parameters of the water in the investigated settling pond
Parameter
n
Minimum
Maximum
Mean
Standard deviation
Conductivity (μS cm-1)
5
26 000.0
34 400.0
30 944.0
2948.1
pH
5
7.1
8.5
7.7
0.5
Alkalinity (mg CaCO3 dm-3)
5
150.0
250.0
185.8
45.1
Total dissolved solids (g dm-3)
5
12.9
17 .1
15 .4
1.5
Dissolved oxygen (mg O2 dm-3)
5
10.2
17.6
13.4
2.9
Chlorides (mg Cl- dm-3)
5
7840.0
14 650.0
10 782.5
2463.8
Iron (mg dm-3)
5
0.07
0.26
0.14
0.1
Nitrates (mg
5
3.1
11.96
6.2
3.6
Nitrites (mg
5
0.0
1.04
0.67
0.4
Ammonium (mg dm-3)
5
1.08
6.97
2.4
2.3
Phosphates (mg
5
0.001
1.2
0.24
0.5
Potassium (mg dm-3)
5
40.8
68.0
54.3
13.6
Sulfates (mg dm-3)
5
902.0
1530.0
1197.3
315.7
Temperature (°C)
5
13.8
25.1
21.1
4.7
The organic matter content in the sediments of all the habitats was small. It ranged from 0.08% to 0.17% in the bottom overgrown with
A total of 15 191 individuals representing 11 macroinvertebrate families were collected. The abundance of invertebrates was higher on
The most dominant invertebrate species on all the habitats was the amphipod
Seasonal changes in the abundance of Figure 3
Although the total abundance and biomass of the family Corixidae were not significantly different between the habitats (
Structure of macroinvertebrate communities on the microhabitats in the coal mine settling pond
Higher taxa
Family
Species
Bottom sediments
D (%)
F (%)
D (%)
F (%)
D (%)
F (%)
Diptera
Chironomidae
1.8
80
2.3
80
2.5
100
Stratiomyidae
0
0
0
0
0.03
20
Lepidoptera
Crambidae
0
0
0.02
20
0
0
Heteroptera
Corixidae
3.2
100
0.2
80
40
80
Veliidae
0.1
40
1.9
20
0.4
0.1
Odonata
Coenagrionidae
0.04
20
0.1
20
0.03
20
0.1
20
0
0
0
0
Libellulidae
0.03
20
0
0
0.01
0
Araneae
Cybaeidae
0
0
0.02
20
0
0
Amphipoda
Gammaridae
94.7
100
94.5
100
96.5
100
Oligochaeta
Naididae
0
0
0.02
20
0.03
20
0
0
0.1
20
0
0
0.02
20
0.7
60
0.5
80
Gastropoda
Hydrobiidae
0
0
0.1
20
0.1
60
Seasonal changes in the abundance of Corixidae on different microhabitatsFigure 4
The biomass of macroinvertebrates associated with
The results of one-way ANOVA indicated that the impact of the microhabitat type on the abundance and biomass of macroinvertebrates and the abundance of particular taxa was insignificant (
Because there are no data on the fauna of anthropogenic saline ponds, it is impossible to compare our results. It should be emphasized that the studies to date have focused primarily on the influence of water salinity on benthic invertebrates in rivers and streams. These studies have indicated that increased salinization results in the elimination of freshwater taxa and the replacement of sensitive species by eurytopic species and species that are resistant to high salt concentrations, including invasive non-native species (e.g. Braukmann & Böhme 2011; Petruck & Stöffler 2011; Arle & Wagner 2013; Cañedo-Argüelles et al. 2014).
Our studies have shown that the euryhaline amphipod
In addition to
In the studied settling pond, we also observed the non-native gastropod species
The results of our study are consistent with the findings of Hutchinson (1937), who stated that salt-tolerant species of the family Corixidae were much more abundant on widgeongrass beds compared to other aquatic macrophytes. We observed that their abundance was the highest in the first month of the study (June) and decreased by the end of the survey (Fig. 4). The reverse trend was determined for
An unexpected result of our study was the relatively low seasonal variability of the macroinvertebrate richness on all the habitats. Similar results were observed by Wenner & Beatty (1988), Heck et al. (1995) and Boström & Bonsdorff (2000). The lack of taxa associated with a particular habitat suggests that the type of substrate is not a major determinant in the diversity of benthic assemblages and that these taxa showed no specific habitat preferences. One reason may be the mobility of the species (dominant taxa are good swimmers) and the degree of their aggregation (Wilson & Koutsagiannopolou 2014).
The results of our research on the macroinvertebrate biomass are consistent with the study by Kornijow et al. (1990), who noted that the biomass of zoobenthos was lower on
Because there are no data on the fauna of saline coal mine settling ponds, it is important that the future research will focus on the biodiversity of macroinvertebrates, the rate of colonization by alien species and the relationships between taxa and habitat conditions.