A technological advancement in artificial refuges for an endangered marsupial predator

Abstract

Findings from previous research of artificial refuges constructed for northern quolls, as well as collaboration with species experts, engineers, designers, and industry, have led to an advanced design for northern quoll habitat creation. With ongoing habitat destruction, conservationists and land managers are increasingly looking to human-made alternatives to provide shelter to wildlife (Cowan et al., 2021, Watchorn et al., 2022). In the Pilbara region of Western Australia, mining companies are required to offset habitat destruction that affects species of conservation significance. These offsets are often in the form of compensation approaches—including the creation of artificial habitat—so it is critical that compensation measures are effective. One such species of conservation significance is the northern quoll (Dasyurus hallucatus), which is impacted by the destruction of rugged and rocky denning habitat during mining (Moore et al., 2022). In many cases, mining companies have looked to artificial refuges as a potential offset tool to provide denning habitat for quolls—historically created as large piles of rocky material with internal crevices formed by the variation in material used. Cowan et al. (2020) investigated the ability of these artificial refuge designs to imitate natural northern quoll dens and published their findings in Conservation Science and Practice. Artificial refuges had internal microclimates reflective of those inside natural dens but were much shallower and had less complex surrounding habitat. Artificial refuges also had higher visitations of feral cats (Felis catus), a predator of northern quolls. Northern quoll visitation was extremely low at artificial refuges, while feral cats were observed raising young within one artificial refuge, highlighting the potentially negative impacts of these structures if not designed appropriately. These findings had important conservation implications and sparked much activity in this space. Collaboration among industry, government, engineers, designers, consultants, and species experts has led to at least one project aimed at advancing the development of artificial refuges for northern quolls. Habitat Innovation and Management—experts in artificial habitat design and manufacture—in collaboration with industry partner Fortescue Metals Group and northern quoll experts, developed a reproducible artificial refuge for northern quolls (Figure 1). The artificial refuge considers the internal denning requirements of northern quolls (e.g., depth), as described by Cowan et al. (2020), as well as environmental threats such as extreme temperatures, fire, and heavy rain that are common in the Pilbara. The artificial refuge is constructed using linear low-density polyethylene (LLDPE) to which a flame-retardant additive is applied to increase fire resistance. Manufacture of the refuge is achieved using rotational molding which involves rotating a heated mold filled with LLDPE, where the softened material spreads around the walls of the mold, forming the required shape. The artificial refuge incorporates features critical to the ecological needs of northern quolls, including an air-circulating vent, an escape shelf, and an entrance which can be configured with natural or artificial materials to exclude larger predators such as feral cats. The refuge is designed to be easily deployed in the field and covered with layers of soil and rocks to assist in thermal buffering, fire protection, and habitat complexity (Figure 2). Future research will include field testing of the refuges alongside management techniques such as invasive predator control and vegetation restoration. This will help to determine if these artificial refuges can support breeding populations of northern quolls long term. All authors conceived the idea for the manuscript and contributed to writing, editing, and approved final submission. Writing was led by Mitchell A. Cowan. The concept and design of the artificial refuge was led by Michael N. Callan and Carl Tippler at Habitat Innovation and Management with input from Mitchell A. Cowan and Dale G. Nimmo. We thank the editor and reviewers for their thoughtful reviews on this manuscript. Michael N. Callan and Carl Tippler are Directors of Habitat Innovation and Management. No data were used in this manuscript.