Beetle assemblages from an Australian tropical rainforest show that the canopy and the ground strata contribute equally to biodiversity

Abstract

There remains great uncertainty about how much tropical forest canopies contribute to global species richness estimates and the relative specialization of insect species to vertical zones. To investigate these issues, we conducted a four-year sampling program in lowland tropical rainforest in North Queensland, Australia. Beetles were sampled using a trap that combines Malaise and flight interception trap (FIT) functions. Pairs of this trap, one on the ground and a second suspended 15-20 m above in the canopy were located at five sites, spaced 50 m or more apart. These traps produced 29 986 beetles of 1473 species and 77 families. There were similar numbers of individuals (canopy 14 473; ground 15 513) and species (canopy 1158; ground 895) in each stratum, but significantly more rare species in the canopy (canopy 509; ground 283). Seventy two percent of the species (excluding rare species) were found in both strata. Using IndVal, we found 24 and 27% of the abundant species (nR20 individuals) to be specialized to the canopy and the ground strata, respectively, and equivalent analyses at the family level showed figures of 30 and 22%, respectively. These results show that the canopy and the ground strata both provide important contributions to rainforest biodiversity.

Alpha and beta diversity of plants and animals along a tropical land‐use gradient

“…While in some taxa species richness is more pronounced in one vegetation layer, others contribute equally to lower strata as well as the upper canopy (e.g., DeVries et al 1997, Schulze et al 2001, Stork and Grimbacher 2006. Natural and anthropogenic forest disturbance can cause a breakdown of vertical stratification as documented for butterflies in selectively logged forest (Dumbrell andHill 2005, Fermon et al 2005), at tree-fall gaps (Hill et al 2001), and forest edges (DeVries et al 1997).…”

Vertical stratification and effect of petiole and dry leaf size on arthropod feeding guilds in Cecropia pachystachya(Urticaceae)

“…Our results are similar to those of Grimbacher and Stork (2007), who failed to find vertical stratification among most ground and canopy beetle feeding guilds. However, Stork and Grimbacher (2006), using the same dataset, checked the effect of vertical stratification on the composition of the beetle community. The contrasting results of vertical stratification at the species and feeding guild levels suggest an uniformity in resources between the studied strata, but also suggest that resource partitioning occurs at a finer scale (Grimbacher and Stork, 2007).…”

“…Arthropod diversity usually shows a clear stratification and decreases from the canopy to lower strata (Longino and Nadkarni, 1990;Basset et al, 1992Basset et al, , 2001Basset et al, , 2003Stork and Grimbacher, 2006;Schroeder et al, 2009;Davis et al, 2011).…”

“…The stratification of organisms is determined by resource quantity and quality, microclimate conditions, and the pressure of interactions such as predation (DeVries et al, 1999;Basset et al, 2001Basset et al, , 2003Stork and Grimbacher, 2006;Brehm, 2007). However, few studies have investigated whether patterns at the species level are reflected in the vertical stratification of feeding guilds, which may be more informative regarding the functional role of arthropods in tropical forests (Grimbacher and Stork, 2007).…”

Insect Functional Guilds in the Flowering Canopy of Myristica Fatua in a Lowland Swamp, Central Western Ghats, India

“…Erwin's canopy fogging studies in Panama [2] sent the global arthropod species richness on a tumultuous rise from 3-5 million to 30-100 million, and more recent studies suggest an estimate of 6.1 million arthropod species in the tropics alone (3,4). A number of studies throughout the tropical world have given us detailed information on canopy invertebrates [5][6][7], yet much of the diverse canopy fauna [8,9] remains largely undiscovered or unquantified [10], especially outside of the intensively studied field sites. In the Indian subcontinent, in spite of the conservation value of such research, canopy biodiversity studies are rare [9].…”