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.