Seasonal dynamics of carabid beetles (Coleoptera: Carabidae) in areas with anthropogenic disturbances: The case of Uzungwa scarp nature forest reserve, Tanzania

Abstract

Seasonal variation in diversity and community composition of ground beetles was investigated in the Uzungwa Scarp Nature Forest Reserve (USNFR), Tanzania. Carabid beetles were collected using three methods, namely pitfall traps, active day search and active night searching. Sampling of ground beetles was carried out in three seasons: dry season, wet season, and end of dry season in 2016, 2018 and 2019.Results showed that the diversity of ground beetles was highest during the wet season (Shannon-Wiener H' = 2.19) and lowest at the end of the dry season (H' = 1.83). The difference was statistically signi cant when comparing the end of dry season against the wet season, and between wet and dry season (t = 5.85 and 4.88, respectively, p < 0.05). Species richness was highest during the wet season and the difference was statistically signi cant among the three seasons (χ 2 = 13.46, p < 0.05). Abundance was highest during the wet season, with mean number of carabid beetles 1.256 ± 0.08 per sample, and lowest at the end of dry season (0.48 ± 0.05 individuals per sample). Kruskal-Wallis test revealed that the difference in abundance among the three seasons was statistically signi cant (H = 128.3, p < 0.05). Bray-Curtis similarity index showed low similarity in community composition among all three seasons. We conclude that ground beetles communities in anthropogenically disturbed areas vary with season, therefore to have a comprehensive sampling of ground beetles, sampling should cover at least one-year involving different seasons of the year.