The importance of forest floor connectivity on saproxylic arthropod succession in a lowland tropical rainforest.

Sharpe, Izzy and Sayer, Emma and Barlow, Jos (2024) The importance of forest floor connectivity on saproxylic arthropod succession in a lowland tropical rainforest. Masters thesis, Lancaster University.

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Abstract

Tropical saproxylic arthropods form a high proportion of diversity on earth yet are significantly understudied compared to their temperate counterparts. Litter provides habitat space, a stable microclimate and nutrients for arthropods. However, the influence of the forest floor on saproxylic arthropods remains relatively unknown. This study investigates the effects of longterm litter removal and its interactions with tree-size (diameter at breast height (DBH), wood density and deadwood age on saproxylic arthropods in a neotropical forest. Complementary sampling methods, namely emergence traps and wood samples were used to collect arthropods from deadwood. In wood samples, arthropod abundance and richness increased with deadwood age in control plots and declined in litter removal plots. Furthermore, community composition showed a clear trajectory in the control plots that was disrupted by litter removal. This suggests that forest floor connectivity is important for saproxylic succession with isolated deadwood fragments acting as refuges between the hostile bare soil. Wood density and DBH did not influence arthropod succession. Non-significant findings for emergence traps are attributed to the collection of flying taxa, which are less susceptible to the challenges posed by the bare soil in the litter removal plots. Comparison with the results of a previous studies on soil and litter fauna in the same litter manipulation experiment found distinct communities between habitats: a high proportion of fauna were forest floor generalists, some were specialists of a particular habitat, and others appeared to migrate between. I conclude that forest floor connectivity plays a vital role in the succession of arthropods in deadwood.