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The present paper seeks to study the diversity and ant community composition of some Algerian islands. This study is considered as the first exhaustive survey of ant species of Algerian islands since 1957. The survey was carried out in the spring and summer seasons between April and July of two years 2014 and 2015. Vegetation richness, island area, mainland distance, and elevation variables were measured for each island. Relative abundance (RA), frequency of occurrence (FO), as well as species richness (S), Shannon’s diversity index (H), and equitability (E) for each island were used to compare the diversity pattern among islands. Patterns of species composition and community structure were compared among the sampling islands through ordination analysis (nonmetric multidimensional scaling [NMDS]). SIMPER analysis using a Bray–Curtis similarity index matrix was performed to determine the contribution of each ant species to the dissimilarities among islands. Canonical correspondence analysis (CCA) was performed to highlight the impact of environmental variables on the ant community. All analyses were computed by using PAST software. Two sampling methods (pitfall trap and hand collecting) were used, which led to the identification of 1039 individuals belonging to 16 species. Diversity indexes were different among islands. Ant community was significantly different between islands of the two regions Bejaia and Jijel. Three species contributed to 50.74% of the differences between islands of the two regions. Part of the ant community composition was influenced directly or indirectly by three environmental variables: vegetation richness, island area, and mainland distance. It is important to point out the absence of two invasive ants, Linepithema humile and Paratrechina longicornis, in our islands.

This study investigated the association of environmental factors with insect richness and nested patterns in the distribution of species of insects on small islands (northeastern Algeria). Insect species on eleven (11) islands were sampled using pitfall traps, sweep netting and a Japanese umbrella. To explain patterns in insect diversity on small islands, a generalized linear model (GLM) was used to determine the association of the overall richness and that of the dominant orders of insects with environmental variables (altitude, surface area, isolation, plant richness and number of habitats). To determine the nestedness pattern on these islands, the online interface NeD was used to measure total matrix nestedness. Of the variables measured, only plant richness was associated with variations in the overall species richness and that of the five dominant orders. The overall number of insects and that of the five dominant insect orders were significantly nested in all null models except the very restrictive FF model. Plant richness accounted for the nested structure of the overall number of insects and that of the five dominant orders (Coleoptera, Hymenoptera, Hemiptera, Diptera and Lepidoptera). Surface area was also important in the nested structure of overall number of insects and that of the order Lepidoptera. The nestedness of the overall number of insects and that of the five dominant orders of insects, however, did not result from passive sampling and selective colonization. The most effective way of conserving overall number of insects and that of the five dominant orders of insects on the Algerian islands studied is to protect their plant richness and to maximize the overall number of species and that of Lepidoptera on these islands, conservation should concentrate on the largest islands. [ABSTRACT FROM AUTHOR]

The relationship between the abundance of breeding birds on the studied islands and the topographic variables (surface and distance from the continent) was tested via data on the breeding birds of 11 islands in Algeria. A nestedness calculator program was used to study the nestedness of breeding birds. Islands' surface conditions and their isolation explain clearly the richness of breeding birds. The distribution of island breeding birds showed a strong nested structure that differs significantly from the distribution of the random model. [ABSTRACT FROM AUTHOR]

During spring and summer (April to July) of 2009, insects of three islets in the North-East of Algeria were sampled by pitfall traps, sweep net and Japanese umbrella. Analysis of insect diversity shows the existence of 144 species in the three islets. Petit Cavallo island is the most rich with 140 species, followed by Grand Cavallo island and Grand Cavallo islet with 92 and 25 species, respectively. Diversified orders were Coleopters on the two main islet (Petit Cavallo island: 42 species, Grand Cavallo Island: 33 species) and Hymenopters on Grand Cavallo islet (10 species). For abundance, Hymenoptera was the most dominant on the three islands (Petit Cavallo: 428 individuals, Grand Cavallo island: 229 individuals, and Grand Cavallo islet: 118 individuals). The main three richer families in Petit Cavallo island were Formicidae (9 species), Pentatomidae (8 species) and Miridae (7 species). In Grand Cavallo island, two families were prosperous: Formicidae (8 species) and Chrysomelidae (6 species). However, Formicidae seemed to be richer in Grand Cavallo islet with 5 species. In terms of abundance, Formicidae was the most dominate in three islands (Grand Cavallo islet: 69.87%, Petit Cavallo island: 34.95%, Grand Cavallo isalnd: 25.88%). From the point of view of the similarity, the composition of insect fauna seemed to be close between Petit Cavallo island and Grand Cavallo island (77.58%). [ABSTRACT FROM AUTHOR]