Relationships between physical and chemical factors and aquatic macroinvertebrates in perennial streams in the arid northern mountain basin El Batinah, Oman

Abstract

The relationships between physical properties, water chemistry and aquatic macroinvertebrates were investigated in riffles of four perennial streams in the arid northern Oman. Samples were collected monthly in autumn, winter and spring with a Surber net. Thirty two invertebrate taxa were recorded, most species are widely distributed, but few species with very restricted distribution were also captured. Diptera followed by Pulmonata, Coleoptera and Odonata were the most represented taxa, Trichoptera and Heteroptera were a significant component only in one station (the Fezeh), where the lowest mean water temperature (23°C) was recorded. In the dry months from May to October, aquatic macroinvertebrates were completely absent. In order to summarise the community response some biotic indices were calculated. The highest diversity was observed in the Fezeh station. A seasonal gradient was also observed, with the highest diversity values in January, April, and December. The low faunal diversity was attributed to the high air and water temperature and the hydrological regime instability. A between station and a between month coinertia analysis was carried out, to analyse the response to spatial and seasonal factors. The first coinertia axis was correlated with altitude and substrate composition, while the second axis was correlated with air and water temperature.The present research emphasizes the urgency for preserving the less disturbed wadis in arid zones, because, despite their species poorness, their uniqueness in faunal composition requires special attention. The presence of few endemic species with very restricted distribution highlights the topicality and the value in investigating these areas, allowing the increase of our knowledge on biodiversity, ecology and biogeography about the benthic macroinvertebrates living in these extreme habitats. IntroductionRelationships between benthic macroinvertebrates and environmental variables were often matter of investigation (Depiereux et al., 1983; Wright et al., 1984;Ormerod, 1987; Ormerod & Edwards, 1987;Boulton & Lake 1992a, 1992bBoumaïza 1994; Gower et al., 1994;Tate & Heiny, 1995), inducing to consider macroinvertebrates communities as good indicators of water quality conditions (De Shon, 1995; Resh, 1995). Furthermore, studies of temporal variation in the community structure of streams (Fisher et al., 1982;Scrimgeour & Winterbourn, 1989) indicated that physical disturbances (e.g., water temperature, substrate composition and the hydrological regime) are important determinants in lotic systems (Sousa, 1984; Resh et al., 1988).Within the framework of the study of relationships between environmental factors and community composition freshwater ecosystems in extreme arid zones require special attention .The chain of Hajar mountain extending from northern Oman and the eastern United Arab Emirates is a part of the Arabian Highlands. The World Wildlife Fund for Nature identified this area as part of the Global 200 Ecoregions, i.e. it a priority area for biodivers...

Response of Chironomids (Diptera, Chironomidae) to Environmental Factors at Different Spatial Scales

“…Kick sample was generally used in kryal, krenal and rhithral, drift samples were collected in potamal, a ponar dredge was used in AL03, AL04,AL05, AL06 and ME lakes, an Ekman dredge was used in Alpine lakes (ALalp). The data are from samples collected in Italy [2,8], Austria and Germany [17], Switzerland [18,19], Montenegro [20], Greece [21], Algeria [22,23], France (Garonna River, unpublished data).…”

Response of Chironomids (Diptera, Chironomidae) to Environmental Factors at Different Spatial Scales

“…Species abundances were standardized to 1 m 2 bottom surface to allow comparison between samples collected in different habitat. Samples were collected mostly in Italy [2,8], and secondarily in other countries: Austria, Germany [17], Switzerland [18,19], Montenegro [20], Greece [21], Algeria [22,23] and France (Garonna River). The maps with sampling sites were prepared using QGIS version 3.34.1 Prizren (2009) (https://www.qgis.org/it/site/, accessed on 1 February 2024) [24].…”

<B>The Odonata (Insecta) of northern and central Oman</B>

“…The distribution of Orthetrum abbotti requires further investigation. Boulaaba et al (2014) recorded nine species of odonates, from larvae, in the Western Hajar including the presumably misidentified Boyeria irene (Fonscolombe, 1838) and Macromia splendens (Pictet, 1834 [sic]). We ignored their records.…”