Bioclimatic Drivers of Terrestrial Isopod Diversity Across A North–South Gradient in Algeria

Abstract

This study examines the diversity of terrestrial isopods across Algeria's bioclimatic gradient, from the humid north to the arid south, over 2 years (2015–2017). Monthly sampling using pitfall traps, hand searching and microhabitat exploration yielded 712 individuals (217 males, 343 females, 152 juveniles) from four families, five genera and 12 species. Porcellionidae was the most abundant family (76.25%), with Porcellionides pruinosus (Brandt, 1833), Porcellio laevis Latreille, 1804 and Armadillidium vulgare (Latreille, 1804) as dominant species. The highest abundance was recorded in Hamda (Laghouat) (342 individuals), followed by the olive grove (62) and degraded oasis (46) stations in El Menea. A latitudinal gradient was observed, with increasing species richness toward the south. Canonical correspondence analysis showed a negative correlation with temperature and a positive correlation with precipitation. Humid bioclimatic stations supported P. laevis Latreille, 1804, Porcellio sp.1, Porcellio sp.2 and Ligidium hypnorum (Cuvier, 1792), whereas Saharan stations, characterised by low precipitation, were associated with Porcellio variabilis Lucas, 1849, Porcellio sp.3 and Porcellio sp.4.