Moisture structures litter faunal communities through productivity and trait filtering effects
- 1Deakin University
Abstract
Litter invertebrates mediate a substantial proportion of decomposition and nutrient cycling in terrestrial ecosystems, yet how moisture availability structures their communities remains poorly understood. We propose that moisture availability could shape litter faunal communities through two alternate pathways: (1) a productivity effect: greater productivity and detrital inputs in wetter forests should increase litter-faunal abundance, (2) a trait effect: phylogenetic differences in water balance should filter communities according to taxon-specific moisture tolerances. We tested these expectations across 100 forest sites spanning a moisture gradient in south-eastern Australia, from dry sclerophyll forest to cool temperate rainforest. Measuring 11 focal invertebrate taxa, total litter-faunal abundance increased threefold across the moisture gradient, from 400,000 individuals per hectare of dry forest to 1.2 million individuals per hectare of rainforest - consistent with greater resource availability in wetter and more productive habitats. However, this overall abundance trend masked pronounced variation in community composition across habitat types. While moisture-sensitive crustaceans and myriapods (particularly Isopoda and Chilopoda) were concentrated in rainforest litter, two groups of hexapods (Blattodea and Embioptera) were most abundant in dry forest litter and declined sharply toward rainforest habitat. These contrasting responses indicate that dry forests do not simply represent depauperate versions of wet-forest communities but harbour their own distinct and abundant litter invertebrate assemblages. Thus, moisture structures litter faunal communities via both proposed mechanisms: (1) a productivity effect and (2) a trait filtering effect. Given that moisture fundamentally structures litter faunal communities, shifts in forest moisture regimes under climate change may substantially alter detritivore communities, with consequences for decomposition processes and nutrient cycling globally.
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BibTeX
@misc{butterworth2026moisture,
title = {{Moisture structures litter faunal communities through productivity and trait filtering effects}},
author = {N. J. Butterworth and N. Porch and A. D. Barnes and A. Carlesso and M. A. McGeoch and N. P. Murphy and M. Dawson and H. Gibb},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.18.752524},
url = {https://www.biorxiv.org/content/10.64898/2026.09.18.752524v1},
note = {CC BY-NC},
}
RIS
TY - UNPB
TI - Moisture structures litter faunal communities through productivity and trait filtering effects
AU - N. J. Butterworth
AU - N. Porch
AU - A. D. Barnes
AU - A. Carlesso
AU - M. A. McGeoch
AU - N. P. Murphy
AU - M. Dawson
AU - H. Gibb
PY - 2026
DA - 2026/09/18
PB - bioRxiv
DO - 10.64898/2026.09.18.752524
UR - https://www.biorxiv.org/content/10.64898/2026.09.18.752524v1
AB - Litter invertebrates mediate a substantial proportion of decomposition and nutrient cycling in terrestrial ecosystems, yet how moisture availability structures their communities remains poorly understood. We propose that moisture availability could shape litter faunal communities through two alternate pathways: (1) a productivity effect: greater productivity and detrital inputs in wetter forests should increase litter-faunal abundance, (2) a trait effect: phylogenetic differences in water balance should filter communities according to taxon-specific moisture tolerances. We tested these expectations across 100 forest sites spanning a moisture gradient in south-eastern Australia, from dry sclerophyll forest to cool temperate rainforest. Measuring 11 focal invertebrate taxa, total litter-faunal abundance increased threefold across the moisture gradient, from 400,000 individuals per hectare of dry forest to 1.2 million individuals per hectare of rainforest - consistent with greater resource availability in wetter and more productive habitats. However, this overall abundance trend masked pronounced variation in community composition across habitat types. While moisture-sensitive crustaceans and myriapods (particularly Isopoda and Chilopoda) were concentrated in rainforest litter, two groups of hexapods (Blattodea and Embioptera) were most abundant in dry forest litter and declined sharply toward rainforest habitat. These contrasting responses indicate that dry forests do not simply represent depauperate versions of wet-forest communities but harbour their own distinct and abundant litter invertebrate assemblages. Thus, moisture structures litter faunal communities via both proposed mechanisms: (1) a productivity effect and (2) a trait filtering effect. Given that moisture fundamentally structures litter faunal communities, shifts in forest moisture regimes under climate change may substantially alter detritivore communities, with consequences for decomposition processes and nutrient cycling globally.
ER -