Biodiversity of ground beetles (Coleoptera: Carabidae) along a gradient of land use in Zambia

Changes in climate and land use are the most serious pressures on biodiversity across the world. This study aims to determine consequences of land use on species richness and composition of ground beetles in Zambia. Using pitfall trapping between 2013 and 2014, 23,982 ground beetles consisting of 47 species were sampled in a 14,000 km² landscape consisting of four dominant land use types (agricultural fields, mixed natural forests, eucalypt plantations and pine plantations). Species richness correlated with total abundance landscape (r = 0.94; p < 0.001; n = 50). Average richness decreased from 9.2 in agricultural fields to 3.6 in pine plantations. Plant diversity was not correlated to species richness or density (r = 0.32; p = 0.18; n = 50). However, increasing levels in litter and ground cover (proportion of land not exposed) supported more species of ground beetles (r = 0.89; p < 0.01; n = 50). Compositional dissimilarities were greater between than within land use types (anosim R = 0.20; p < 0.001). Mixed natural forests and eucalypt plantations were rather similar in species composition of ground beetles. Again, litter and ground cover explained a large fraction of variation in species composition. Thus, richness and composition of ground beetles in tropical landscapes is controlled by land use type with litter and ground cover as key modulating factors.