Arthropods as the Engine of Nutrient Cycling in Arid Ecosystems

Abstract

Nutrient dynamics in most terrestrial ecosystems are regulated by moisture-dependent processes. In drylands, nutrient dynamics are often weakly associated with annual precipitation, suggesting that other factors are involved. In recent years, the majority of research on this topic focused on abiotic factors. We provide an arthropod-centric framework that aims to refocus research attention back on the fundamental role that macro-arthropods may play in regulating dryland nutrient dynamics. Macro-arthropods are prevalent in drylands and include many detritivores and burrowing taxa that remain active during long dry periods. Macro-arthropods consume and process large quantities of plant detritus and transport these nutrients to the decomposer haven within their climatically buffered and nutritionally enriched burrows. Consequently, arthropods may accelerate mineralization rates and generate a vertical nutrient recycling loop (VRL) that may assist in explaining the dryland decomposition conundrum, and how desert plants receive their nutrients when the shallow soil is dry. The burrowing activity of arthropods and the transportation of subterranean soil to the surface may alter the desert microtopography and promote desalinization, reducing resource leakage and enhancing productivity and species diversity. We conclude that these fundamental roles and the arthropods’ contribution to nutrient transportation and nitrogen fixation makes them key regulators of nutrient dynamics in drylands.

Climate dependence of the macrofaunal effect on litter decomposition—A global meta‐regression analysis

“…Our metaregression analyses suggest that macro-decomposition in hot drylands may compensate for the limited moisture-dependent decomposition by smaller organisms, leading to much higher overall decomposition rates than those expected based on current theory. These global findings correspond with evidence from local experiments showing that macro-detritivores dominate plant litter decomposition, especially during hot and dry periods (Sagi et al, 2019(Sagi et al, , 2021Torsekar et al, 2023). Consequently, our work provides a plausible resolution to the longstanding DDC, diverting the focus from abiotic factors to macro-arthropods.…”

“…Macrofauna often use climate refuge or even self‐engineer such environments to evade harsh surface conditions. Their large size and adaptation to superficial movement allow them to shuttle between the climatically buffered refuges and the exposed detrital pools and remain active even under unfavourable surface conditions (Sagi & Hawlena, 2021). For example, desert isopods use self‐excavated burrows, allowing them to remain active during the 6‐month‐long dry season.…”

“…These studies, however, either ignored macrofauna (Wall et al., 2008) or did not distinguish between animals of different sizes (García‐Palacios et al., 2013a; Xu et al., 2020). This is despite the well‐established understanding that larger bodied animals can remain active under harsh climatic conditions when smaller organisms cannot (Cloudsley‐Thompson, 1975; de Jonge et al., 2022; Sagi & Hawlena, 2021). Therefore, our mechanistic understanding of how animals and climate regulate decomposition rates may be confounded by animal size.…”

Effects of leaf litter traits on terrestrial isopod and millipede consumption, assimilation and growth

“…Isopods (Isopoda: Oniscidea) and millipedes (Myriapoda: Diplopoda) are important macrodetritivores in many terrestrial environments across the globe (David & Handa, 2010), where they are known to play critical roles in nutrient cycling (Fujimaki et al., 2010; Morgan et al., 1989; Sagi & Hawlena, 2021). Despite their taxonomic separation, isopods and millipedes are highly convergent in their morphology and ecological function.…”

Next generation insect taxonomic classification by comparing different deep learning algorithms

“…They contribute significantly to our environment and are essential to ecological functions such as nutrient recycling, plant propagation, maintenance of the plant community, maintenance of the animal community, and food for insectivorous animals. For instance, the dipterous families Calliphoridae, Rhiniidae, and Sarcophagidae, which are ecologically important and involved intensively in nutrient recycling of organic matter [1], serve as pollinators [2] and are vectors for diseases such as cholera [3]. However, the data on changes in species diversity and abundance are insufficient.…”