Finding of Aphelocheirus Aestivalis Fabricius 1794 in the River Chiese, Villanuova Sul Clisi (Brescia, Italy)
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Journal of Life Sciences 6 (2018) 183-188 doi: 10.17265/1934-7391/2018.04.003 D DAVID PUBLISHING Finding of Aphelocheirus aestivalis Fabricius 1794 in the River Chiese, Villanuova sul Clisi (Brescia, Italy) Patrizia Giordano Environmental Consultancy in Via Colle Eghezzone 1, Lodi 26900, Italy Abstract: The finding of Aphelocheirus aestivalis in River Chiese, in a residential area of Villanuova sul Clisi (BS), during a monitoring, gave an occasion for a research about ecology of species, particularly rare in Italy. The research purpose was to inquire about distribution of A. aestivalis in Italy and in Europe, about its ecology and habitats, about possible relation between the finding and the ecological peculiarities of Chiese. The record is particularly unexpected because, although the abundance in the site and good water quality as results from dissolved oxygen and electric conductivity, the macroinvertebrate assemblage has a very low diversity and total absence of particular species and the prevalence of tolerant species, its preferred preys. A. aestivalis was found, according to the most of fragmentary and sporadic studies in Italy, just in reduced flow watercourses and it is not clear if there is a connection between its ecological needs and its finding in the site, with not optimal ecological conditions. The reflection is about the role of Aphelocheirus in biological monitoring, independently of low specific diversity, potentially associate to others environmental factories (for example, the geology of watercourse basin) and the necessity of conservation in itself for the sites that host Aphelocheirus aestivalis. Key words: Monitoring, Aphelocheirus aestivalis, indicator. 1. Introduction diffusion [4]. Because of its ecology and its particular breathing, Aphelocheirus aestivalis Fabricius, 1794 (Fig. 1), A. aestivalis requires well oxygenated waters [5] and (Heteroptera Nepomorpha) [1], is the only species of it is possible to find it on the bottom of slow flow and Ahelocheiridae in Europe, except for Iberian shallow valley floor rivers. It is a predator species, peninsula, where we found A. murcius e A. preferring especially Chironomid and Trichoptera occidentalis Nieser et Millan 1989 [2, 3]. I found this (caddisflies) larvae [2]: during the reproductive cycle, species during a monitoring in the River Chiese, in it is located in very running waters and it migrates, in province of Brescia (Italy), in December 2015. the late summer season, to very deep river areas [6], A. aestivalis is a benthonic invertebrate and it is where A. aestivalis winters. This condition needs the distinguished by a plastron breather that uses very cohabitation on site of these two microenvironments. efficaciously dissolved oxygen in surface water, In Italy, there is reporting of the species, occasional obtaining it just for diffusion and, so, allowing it and infrequent, in Piedmont, in Lombardy, in to not reach the surface to breath: its cuticle is Trentino-Alto Adige, in Veneto, in Emilia - Romagna, covered almost entirely by a pile of small hairs, in Tuscany, in Umbria, in Lazio, in Abruzzi and that capture an air film, directly connected to Campania [7]. In the rest of Europe, because of its tracheal spiracles. Once exhausted the air film, the rarity and the decreasing populations in many renewal of oxygen reserve is guaranteed just for countries, it is included in national Red List, as in Czech Republic [8]. Corresponding author: Patrizia Giordano, PhD, ecologist of surface waters, expert in environmental impact assessment, environmental monitoring. 184 Finding of Aphelocheirus aestivalis Fabricius 1794 in the River Chiese, Villanuova sul Clisi (Brescia, Italy) 3. Results We performed the monitoring point-like in the River Chiese on December 7, 2015, after a period of prolonged absence of rain and temperatures higher than seasonal average. We used the Surber Sampler to collect the samples, according to the sampling protocol: individuals number of A. aestivalis was 13 in total. A. aestivalis has been collected on bottom with little stones and pebbles. The result of biological monitoring is included in Fig. 1 Aphelocheirus aestivalis Fabricius 1794 (drawing of Table 1, where we referred individuals number, taxa Stefano Agostini). and families found during the samples. 2. Materials and Methods In addition to the remarkable finding of A. aestivalis, we observed the totally lack of Plecoptera The river basin of River Chiese is about 409 km2 and Ephemeroptera (except for Baetis, ubiquitous [9]: River Chiese has an appreciable flow watercourse genus) and the prevalent presence of more adaptable (36 m3/s). taxa; above all, we noticed the abundance of taxa The samplings of benthonic invertebrates fauna preferred by A. aestivalis as preies (Chironomida and have been collected in a site localized in a section of Tricoptera Hydropsychidae and Tricoptera River Chiese, running through the Villanuova sul Clisi Rhyacophilidae), besides the species preferentially (BRESCIA) residential area: we collected the samples detritivores. in order to execute a local monitoring. This was part Values of pH, temperature, dissolved oxygen and of a preliminary environmental study connected with a electrical conductivity parameters are referred briefly potential realization of a project (hydropower plant). in Table 2. This sampling was necessary because of the lack of The biological monitoring results give a numerical bibliographic environmental data related to the site in value of Extended Biotic Index (IBE) [11] equivalent question. This singular monitoring was very useful to to 6 (Class of quality III, Judgement: polluted frame the ecological conditions of the River Chiese in environment) and a numerical value of STAR_ICMi that particular site. The method of sampling was equivalent to 0.457 (Class of quality IV, Judgement: carried out with Surber Sampler and measurement of poor). The previous monitoring carried out by surface sampled, according to the multihabitat ARPA 1 Lombardia on long-standing monitoring proportional sampling. sites in River Chiese confirmed our values, found in The software MacrOper.ICM [10] was used to samples of December 2015, and the poor ecological obtain multimetric Index STAR_ICMi. Individuals condition of the River Chiese; the monitoring sites and taxa, collected in the samples, have been counted of ARPA Lombardy are located upstream and the final result is a evaluation of the site compared (Barghe, province of Brescia) and downstream with Extended Biotic Index (IBE) [11] as a quality (Montichiari, province of Brescia) of Villanuova sul class, equivalent to a class of “polluted environment”. Clisi site [12]. During the monitoring, we have measured temperature, pH, dissolved oxygen and electrical conductivity with a multiparametric probe. 1 Agenzia Regionale per la Protezione dell’Ambiente della Lombardia. Finding of Aphelocheirus aestivalis Fabricius 1794 in the River Chiese, 185 Villanuova sul Clisi (Brescia, Italy) Table 1 List of taxa, families and individuals number on site of River Chiese. Taxon Families Systematics unit Individuals number Hydropsychidae Hydropsychidae 53 Trichoptera Rhyacophilidae Rhyacophilidae 21 Ephemeroptera Baetidae Baetis 24 Chironomidae Chironomidae 25 Coleoptera Elmidae Elmidae 1 Triclada Dugesiidae Dugesia 1 Heteroptera Aphelocheiridae Aphelocheirus 13 Oligochaeta Lumbricidae Lumbricidae 12 Bivalvia Pisidiidae Pisidium 3 Gastropoda Ancylidae Ancylus 1 Idracarina 5 Others Gammaridae Gammarus 5 Total systematics unit 9 Total families 12 Total individuals 164 Table 2 Values of pH, temperature, dissolved oxygen and electrical conductivity parameters in sampling, December 2015. Parameters Values pH 7.8 Temperature 12.7 °C Dissolved oxygen 8.3 mg/L Electrical conductivity 266 µS/cm 4. Discussion rainfall of the 2015 last quarter; these conditions have reduced the River Chiese flow and, so, the As referred in Table 2, values of pH, temperature microhabitats occupied by A. aestivalis were visible and dissolved oxygen parameters, measured on site, and accessible. In these circumstances, we could find are all within normal limits; the value of electrical it. Furthermore, about finding of A. aestivalis in River conductivity parameter shows a mineralisation degree Chiese, it is important to underline that, in Lombardy, “appreciable” but not high [11]. bibliographical data about A. aestivalis are known for From the biological point of view, the finding of the River Mincio basin [13], for a few occasional Aphelocheirus aestivalis is interesting for different reports in the River Ticino [14] and other low flow reasons: first of all, the finding connected to the watercourses. season was unusual because A. aestivalis is The finding of A. aestivalis in River Chiese induces preferentially found during the late summer-autumn a few reflections about the rarity of this species in season (September-October). And second, it is Italy, in general, about its ecological preferences and meaningful the localization in the River Chiese, that it about the finding in this particular site. In facts, we is a water body in a “sufficient” ecological condition, could find A. aestivalis in a appreciable flow as it is confirmed in the monitoring stations of Barghe watercourse, River Chiese (the average flow is 36 and Montichiari [12]; for these stations, there are no m3/s), while, on average, the rare reports known in previous of A. aestivalis. The explanation for the A. Italy are referred to low flow watercourses (average aestivalis finding