Beetles’ distribution and diversity along an altitudinal gradient across seasons in northeastern Algerian woodlands (case study: the Belezma National Park)

Abstract

The study investigates how elevation gradients in mountainous forests affect biodiversity, particularly focusing on Coleopteran species in Belezma National Park, northeastern Algeria. Sampling was conducted across three woodland patterns with varying elevations (from 1085 m to 1472 m), slopes, and northern exposure, using three methods (sight hunting, barber pots, and yellow pan traps) over a year (from May 2017 to April 2018). Soil and abiotic factors were assessed at each site, noting significant variations with altitude. Ninety-five beetle species were identified, with Carabidae exhibiting the highest representation (35 taxa; 1312 individuals). The altitudinal gradient influenced beetle diversity and abundance, with the Cedar2 site showing the highest diversity. Both Hierarchical clustering analysis and nonmetric multidimensional scaling revealed three distinct cluster groups serving as altitude indicators. Detrended correspondence analysis highlighted the influence of precipitation, altitude, and soil characteristics on beetles’ distribution. In the Venn diagram, seasonal variations were observed, with summer exhibiting the highest diversity and winter the lowest. These findings provide valuable insights into beetle diversity along elevation gradients and across seasons, serving as a reference for future research in similar ecosystems.