The species is in decline (e.g., Adams-Hosking, Grantham, Rhodes, McAlpine, & Moss, 2011) and is listed as an endangered species. The koala ( Phascolarctos cinereus) is an iconic arboreal marsupial occurring in eucalypt forests and woodlands across eastern Australia (Martin, Handasyde, & Krockenburger, 2008). This approach is limited by available knowledge on the importance of different browse species and how this varies across a species range or in association with co-occurring browse species, soil type, moisture, disturbance, etc. As an alternative to occupancy, given that not all habitats of rare species are likely to be occupied, habitat quality can be assessed independently based on the known habitat or dietary preferences of the focal species (e.g., browse species). Both the fit and relationship of predicted occupancy values against a model's output allow field validation based on ground-truth data. One impediment with field validation is confident identification of varying habitat quality and establishing whether it is occupied, and particularly, to avoid false absences by accounting for imperfect detection when estimating occupancy (MacKenzie et al., 2002 Wintle, Kavanagh, McCarthy, & Burgman, 2005). Field validation can assess the accuracy of modelled predictions and their potential benefit to conservation planning management, although frequently this step is not undertaken or possible (Araújo, Pearson, Thuiller, & Erhard, 2005). Such limitations reinforce the need for independent field validation of models as a key step when implementing species distribution models for management purposes (Hirzel, Le Lay, Helfer, Randin, & Guisan, 2006 Latif, Saab, Mellen-Mclean, & Dudley, 2015 Loehle, Irwin, Manly, & Merrill, 2015). However, models relying on “presence only” records are influenced by detection issues and sampling bias, and there is a need to ensure they are fit for purpose (e.g., predicting relative site suitability Guillera-Arroita et al., 2015). Predictive models of species distributions have become increasingly important conservation tools for guiding and informing on-ground management, especially for threatened species that are difficult to reliably survey (Dickson et al., 2014 Liu, White, Newell, & Griffioen, 2013). Field-validated models of similar resolution would assist in guiding management of conservation-dependent species.ĭistribution modeling provides effective tools for spatially-explicit mapping of relationships between species occurrences and biophysical variables over broad extents (e.g., Yost, Petersen, Gregg, & Miller, 2008). The positive relationship of the model with both site occupancy and habitat quality indicates that the model is fit for application at relevant management scales. The Ma圎nt model provided a better fit to estimated koala occupancy than the site-based habitat quality index, probably because many variables were considered simultaneously by the model rather than just browse species. Similarly, a site habitat quality index at ground-truth sites was correlated positively with modeled habitat suitability. Field validation demonstrated a linear increase in koala occupancy with higher modeled habitat suitability at ground-truth sites. Koala bellows ( n = 276) were analyzed in an occupancy modeling framework, while site habitat quality was indexed based on browse trees. We validated the Ma圎nt model at 65 ground-truth sites using independent data on koala occupancy (acoustic sampling) and habitat quality (browse tree availability). The model was effective in discriminating different habitat suitability classes when compared with koala records not used in modeling. Frequency of wildfire, soil type, floristics and elevation had the highest relative contribution to the model, while a number of other variables made minor contributions. A bias file was prepared that accounted for variable survey effort. We reduced substantial spatial clustering of records in coastal urban areas using a 2-km spatial filter and by modeling separately two subregions separated by the 500-m elevational contour. To ensure the model was fit for purpose, we placed emphasis on validating the model using independently-collected field data. We used Ma圎nt to develop a regional-scale model for the koala Phascolarctos cinereus at a resolution (250 m) that could be used to guide management. Species distribution models have great potential to efficiently guide management for threatened species, especially for those that are rare or cryptic.

Koala call sheets update