Incubation mound building by the Australian megapode (malleefowl, Leipoa ocellata) creates novel, resource-rich patches in a semi-arid woodland

Desert ecosystems are characterised by a patchy distribution of resources. Nutrient sinks associated with landscape modulators (trees) differ markedly from the resource-poor interpatch matrix. Fauna can also act as landscape modulators, modifying patch dynamics by redistributing resources via 'ecosystem engineering'. In semi-arid woodlands, malleefowl (Leipoa ocellata: Megapodiidae) reconfigure surface characteristics by scavenging leaf litter to construct large incubation mounds. The extent to which this movement of resources creates a novel patch and alters extant patches is largely unknown. Ecosystem engineering effects by megapodes have been little studied, but are potentially great, particularly in drylands, where mammalian engineers are known to enhance ecosystem function and drive restoration. We measured vegetation, ground cover and soil chemistry at malleefowl mounds and four extant microsites (trees and open areas close to, and far from, mounds) and predicted that: (1) malleefowl mounds would represent enriched, yet novel, microsites; (2) the characteristics of tree and open patches close to the mounds would differ from those away from the mounds, because of the diminishing intensity of disturbance; and (3) effects at tree and open patches close to the mound would be shorter term, compared to the more substantial high-resource patch formation occurring at the mound, but we expected all effects would diminish with time since malleefowl activity. We found that: (1) malleefowl mounds were novel microsites with soil chemistry more similar to tree-modulated patches, and groundcover and vegetation variables more similar to the open, interpatch matrix; (2) effects extended to tree and open patches near the mound, but most effects were short lived; and (3) some novel mound attributes (e.g. soil pH, phosphorus, nitrogen, carbon) were greater at mounds, irrespective of their age, while less plant cover and richness on young mounds dissipated with age. Synthesis. Mound-building megapodes can modulate the distribution of locally derived resources and create a novel microsite. Engineering effects can enhance spatial heterogeneity and ecosystem function over broad spatial and temporal scales, and may assist with ecological restoration, particularly in depauperate, arid systems.

Automated summary

Mound-building megapodes, such as malleefowl, can modify the distribution of resources in desert ecosystems through their engineering activities. This can enhance spatial heterogeneity and ecosystem function, making them important for ecological restoration in arid systems.