Identification of some terrestrial isopods at two stations in Algerian East

F.B. Ahmed; A. Boukachabia; I. Houhamdi; M. Houhamdi; M. Boutarfa

doi:10.15421/2023_425

Research - (2023) Volume 13, Issue 2

Identification of some terrestrial isopods at two stations in Algerian East

F.B. Ahmed¹^*, A. Boukachabia¹, I. Houhamdi², M. Houhamdi² and M. Boutarfa³

^*Correspondence: F.B. Ahmed, Department of Biology, Environmental Science and Agroecology Laboratory, University Chadli Bendjedid El Tarf, Algeria, Email:

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Abstract

In Algeria, wetlands are considered as remarkable habitats for their faunal and floristic diversity. Very few studies have been devoted for the identification of terrestrial isopods. In order to contribute to the knowledge of this isopod fauna, a field campaign was carried out at two stations in the Algerian East (Annaba and El Tarf). The preliminary study of the general composition of Oniscoid populations showed that a total of 269 specimens were collected during 6 months of sampling (January 2021 to June 2021). The observation of the morpho-anatomical characters of the oniscids collected in the two sampling stations during the study period, allowed to identify, according to the identification key of Noël and Séchet (2014), 5 species of isopods attached to 04 genera including Armadillidium, Armadillo, Porcellio and Porcellionides and five (05) species Armadillidium vulgare, Armadilloofficinalis, Porcelliolaevis, Porcelliovariabilis and Porcellionidespruinosus. We observe a stability of the richness at the level of the two stations during the winter and spring season, on the other hand, it tends to decrease during the summer when it reaches level 1. The highest value of the Shannon-Wiener diversity index was observed at Annaba station. However, the equitability index tends towards 1 for both sites. These data reflects a balance between the numbers of species in each station.

Keywords

Diversity, Terrestrial isopods, Oniscidae, Biodiversity.

Introduction

Biodiversity plays an important role in the functioning of ecosystems and in the many services they provide. These services include nutrient cycling, water cycling, soil formation, plant pollination, climate regulation, and pest and pollution control. Terrestrial ecosystems are essential components of our environment; They evolve according to their own bioecological dynamics.

Soil fauna constitutes the bulk of the biomass and animal biodiversity present in terrestrial ecosystems (Wall, et al., 1999). These organisms possess unique genetic characteristics and belong to different trophic levels, and each fulfills essential ecological functions (Ghilarov, 1977; Giller, 1996). The richness and abundance of soil fauna are controlled by regional factors such as climatic conditions, altitude, type of vegetation (Toutain, 1987; Bernier, 1996; Grossi and Brun, 1997; Materna, 2004), as well as by local factors such as the type of humus, the pH, the humidity, the chemical constitution of the soil and the degree of anthropisation (Ponge, 1993; Paquin and Coderre, 1997; Feener and Schupp, 1998; Bird, et al., 2000; Loranger, et al., 2001; Kuznetsova, 2002; Magura, et al., 2003; Scheue, et al., 2003; Cassagne, et al., 2003; Ponge, et al., 2004).

Communities of Oniscidea are considered among the most important groups of soil fauna, especially the decomposer community (Herrick, 2002; Wolter, 2001), as they play a crucial role in soil ecology (Quadros and Araujo, 2008). In addition, they are a food source for a variety of animals (Sunderland and Sutton, 1980; Van Sluys, Rocha and Souza, 2001). As macro decomposers, they contribute significantly to detritus processing (grinding, inoculation) and the nutrient release (Zimmer, Kautz and Topp, 2003) and they also occur in extreme habitats, such as salt marshes, arid grasslands and deserts (Hornung, Szlavecz and Dombos, 2015). Therefore, a good knowledge of the isopod fauna is crucial both for the Caruso and Lombardo, 2011; Messina, Pezzino, Montesanto, Caruso, and Lombardo, 2012; Messina et al., 2014). Caruso and Lombardo, 2011; Messina, Pezzino, Montesanto, Caruso, and Lombardo, 2012; Messina, et al., 2014).

The aim of this study was to fill the gaps in the knowledge of Oniscidae in the eastern regions of Algeria by presenting the species of terrestrial isopods collected on its stations, knowing that the diversity and abundance of terrestrial arthropods can provide a rich basis of information to assist in biodiversity conservation efforts, planning and management of nature reserves” (Kremen, et al., 1993, Massa and Ingegnoli, 1999).

Materials and Methods

Sampling

The samples were collected twice a month for 6 months from January 2021 until June 2021, the specimens were collected by hand early in the morning using a randomly placed 50 × 50 cm quadrat were found under leaves and stones, when collected, the isopods are transferred to a labeled glass bottle containing 70° alcohol in order to preserve the collected specimens. The individuals collected are counted and then observed using a binocular magnifying glass. Each bottle is then returned to the laboratory for identification according to the key of (Noël and Sechet, 2014) and then counting of trapped individuals.

Study zone

The study was carried out at two stations in the Algerian East, including the first one is the wilaya of Annaba (6°54′ 15″ N, 7°45′ 07″ E) located at 600 km from the capital Algiers, in the extreme east of the country which it shares with its neighbor El-Tarf, open to the Mediterranean coast for 80 km. It extends over 1412 km². Its relief consists mainly of mountains with a forest vocation (52.16%); hills and piedmonts (25.82%) and plains (18.08%). The region is richly watered, it receives a precipitation of 650 to 1000 mm/year, its average temperature is 18°C and its climate is humid. The second station is El Tarf (36°46′01″N,8°18′49″E) located in the far North-east of the country, it covers an area of 2892 km².

The forest cover, estimated at 57% or 167,688 Ha, is essentially composed of Kermes oak, Cork oak, Zeen oak, Maritime pine and Eucalyptus reforestation. The climate of El Tarf is a humid Mediterranean climate, up to 1200 mm of rainfall is recorded with snowfall at altitude. The economic activities practiced: breeding, fishing, tourism and subsistence agriculture. The wilaya has a great biodiversity in animal and plant species with the specificity of a mosaic of ecosystems (marine, dune, lake, forest) giving it biological and ecological importance in the Mediterranean basin. This environment is completely open, it is a meadow characterized by a combination of legumes and grasses (Fig. 1).

Fig 1. Geographical location of the study sites.

Results

Abundance and species richness

Our results shows a relatively high abundance of species in Annaba during the winter season. On the other hand, a fall in species which begin from spring and decreases significantly, especially at the level of the El Tarf station (Table 1 and 2).

Annaba	Abundance	Species richness
Winter	138	5
Spring	29	4
Summer	5	1

Table 1. Abundance and species richness at Annaba station.

El Tarf	Abundance	Species richness
Winter	76	5
Spring	20	4
Summer	1	1

Table 2. Abundance and species richness at the El Tarf station.

The richness is diversified in winter when the maximum number of species is recorded with a decrease until summer and this at the level of the two study stations (Annaba and El Tarf).

The shannon index/equitability

The population equilibrium indexes H´ evolve in the same way, the maximums are observed in winter and the minimums in summer for the two stations (Annaba and ElTarf). However, both stations showed an equitability index that tends towards 1. These data reflects equilibrium between the numbers of species in each station (Fig. 2).

Fig 2. Species collected at the two study sites. a) Armadillidium vulgare; b) Porcelliovariabilis; c) Porcellionidespruinosus; d) Armadilloofficinalis; e) Porcellioleavis.

The diversity is higher in Annaba compared to El Tarf with almost a balanced individual representativeness (Table 3 and 4).

Annaba	Shannon index	Equitability Index
Winter	2.210	0.952
Spring	1.704	0.786
Summer	1	1

Table 3. Shannon and equitability index at Annaba station.

El Tarf	Shannon index	Equitability Index
Winter	2.108	0.908
Spring	1.648	0.824
Summer	1	1

Table 4. Shannon and equitability index at El Tarf station.

Discussion

This preliminary research work aiming to the evaluation of terrestrial isopods in two study areas showed the presence of a total of 269 individuals of isopods collected. These ones are divided into 3 families Porcellionidae, Armadillidiidae and Armadillidae and 4 genera Porcellionides, Porcellio, Armadillidium and Armadillo. The genus Porcellionides is represented by the species Porcellionidespriunos while the genus Porcellio is represented by two species, Porcelliovariabilis and Porcelliolaevis. For the genus Armadillidium, it is represented by the species Armadillidium vulgare and the genus Armadillo by the species Armadilloofficinalis. This is due to the selectivity of the technique used (sight hunting) which does not allow the collection of small-scale terrestrial isopods such as Platyarthrus, Ligia, Tyloset on the other hand of the types of habitats surveyed and of a minimal number of samplings. In addition, in relation to other studies carried out on the diversity of terrestrial Isopods in different regions of the world, this collection remains restricted to two stations in the Algerian East. In fact, 13 species of terrestrial Isopods are identified in south-western Cameroon (Schmalfuss et al., 1982), 14 species in northern Brazil (Lopes et al., 2005), 30 species in the former Yugoslavia (Schmalfuss, 1998) and 13 species in north-eastern Italy (Paoletti, et al., 1999; Warburg, et al., 1984) identified climate as the main factor affecting the distribution and abundance of isopods and their association with habitat types is strongly affected by soil and humus types (Judas and Hauser 1998).

The distribution of Oniscidae was significantly correlated with seasonal variation in plant associations. The same was exposed on the shores of the lagoon of Ghar El-Melh (Khemaissia, et al., 2012b). Achourie, et al., (2008a) showed that the greatest diversity of species was linked to the greatest diversity of flora. Several studies have demonstrated that the variation in the distribution of isopods is strongly influenced mainly by environmental factors (Paris, 1963; McQueen and Carnio, 1974; Kheirallah, 1979; Dangerfield, 1993; ZimmeR, 2004), in particular temperature (Hopkin and Read 1992 Zimmer et at., 2000; Souty Grosset et al., 2005; Hasall, et al., 2006; Fraj, et at., 2010; Khemaissia et at., 2017). Moreover, other studies have shown that their variation is according to the different bioclimatic zones (Khemaissia, et al., 2017). The life cycle of woodlice can be affected by natural fluctuations in the environment (Jones and Hopkin, 1998).

Conclusion

This study allowed us to identify some species of terrestrial isopods present in two sites of the extreme North-East of Algeria. This work could serve as a reference for any research work that will be carried out subsequently to study the evolution of biodiversity in these regions with the use of other methods and other sampling techniques (the barber pot) in different types of habitats. It aims to assess the biological diversity of isopods and test the influence of environmental conditions on their abundance and distribution. The influence of particularly climatic environmental conditions on the richness, abundance and distribution of isopods constitutes a key element of this ecological component. However, the abundance and specific richness values are high during the winter season and tend to fall during the summer in the different stations studied. Similarly for the population equilibrium indexes which evolve in the same way, where the maximums are observed in winter. The equitability index proved an equilibrium between the numbers of species in each station.

References

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Identification of some terrestrial isopods at two stations in Algerian East

Abstract

Keywords

Introduction

Materials and Methods

Results

Discussion

Conclusion

References

Author Info