The construction of small-scale, quasi-mechanistic spatial models of insect energetics in habitat restoration: a case study of beetles in Western Australia

Aim: The management and restoration of ecological processes mediated by biotic interactions is now broadly advocated and may be achieved by targeting restoration towards key agents. Although theoretically examined, a practical approach to incorporating the physiology and energetics of insects into restoration planning is poorly articulated. I aimed to provide a case study using the thermal biology and energetics of beetles to identify the distribution of habitat suitability in a large restoration landscape. Location: South-west Western Australia. Methods: I modelled the thermal performance of metabolic rates of thirteen Phyllococerus purpurascens, and twenty Colpochila “species 2,” measured repeatedly at seven temperatures between five and 40°C using flow-through respirometry. Thermal constraints were used to inform a species distribution model of each species at extremely high spatiotemporal resolution, projecting the physiological state of each species for every hour at 5″ resolution across a 152-km² restoration landscape in south-western Australia to estimate the habitat suitability for beetles. Results: Both species’ metabolic rates increased exponentially to a critical point, followed by rapid decline, but the thermal tolerance thresholds were different for each species. Both had strikingly high-thermal tolerance relative to their nocturnal habits and local climatic conditions. The models of beetle prevalence estimated both species to be active and able to access the entire project area for all of the austral spring, summer and autumn. Main conclusions: The results reported here suggest ubiquitous habitat suitability for flower beetles in disturbed landscapes. Incorporation of similar mechanistic models for other species at high resolution offers potential insight into habitat suitability for a broad range of ectotherms.Sean Tomlinso