Trees as templates for tropical litter arthropod diversity

Abstract

Increased tree species diversity in the tropics is associated with even greater herbivore diversity, but few tests of tree effects on litter arthropod diversity exist. We studied whether tree species influence patchiness in diversity and abundance of three common soil arthropod taxa (ants, gamasid mites, and oribatid mites) in a Panama forest. The tree specialization hypothesis proposes that tree-driven habitat heterogeneity maintains litter arthropod diversity. We tested whether tree species differed in resource quality and quantity of their leaf litter and whether more heterogeneous litter supports more arthropod species. Alternatively, the abundance-extinction hypothesis states that arthropod diversity increases with arthropod abundance, which in turn tracks resource quantity (e.g., litter depth). We found little support for the hypothesis that tropical trees are templates for litter arthropod diversity. Ten tree species differed in litter depth, chemistry, and structural variability. However, the extent of specialization of invertebrates on particular tree taxa was low and the more heterogeneous litter between trees failed to support higher arthropod diversity. Furthermore, arthropod diversity did not track abundance or litter depth. The lack of association between tree species and litter arthropods suggests that factors other than tree species diversity may better explain the high arthropod diversity in tropical forests.

Effects of Fire Intensity on Litter Arthropod Communities in Ozark Oak Forests, Arkansas, U.S.A

“…Although leaf litter depth is a potentially important determinant of arthropod community structure (e.g., Kaspari and Yanoviak, 2008), the lack of strong relationship between leaf litter depth and arthropod community parameters in this study is not surprising and is consistent with other studies (e.g., Donoso et al, 2010). Litter in Ozark forests is dominated by refractory detritus (tough oak leaves and pine needles) perched on rocky substrates.…”

The Humpbacked Species Richness-Curve: A Contingent Rule for Community Ecology

“…But the relationship between plant and arthropod species richness is weak [121], and patterns evident in field experiments may be masked by noise in real communities. Oddly enough, tree species diversity on Barro Colorado Island, Panama, does not influence the diversity of ants and mites of the leaf litter [125].…”

Using nutritional ecology to predict community structure: a field test in Neotropical ants

“…It is interesting to speculate how a longer-term experiment may have increased the signal of food addition. But the continual shifting litter habitat as trees drop their leaves (Donoso et al 2010) may make habitat based patchiness a dominant theme regardless of food supply.…”