Designing a large-scale track-based monitoring program to detect changes in species distributions in arid Australia.

Monitoring trends in animal populations in arid regions is challenging due to remoteness and low population densities. However, detecting species' tracks or signs is an effective survey technique for monitoring population trends across large spatial and temporal scales. In this study, we developed a simulation framework to evaluate the performance of alternative track-based monitoring designs at detecting change in species distributions in arid Australia. We collated presence-absence records from 550 2-ha track-based plots for 11 vertebrates over 13 years and fitted ensemble species distribution models to predict occupancy in 2018. We simulated plausible changes in species' distributions over the next 15 years and, with estimates of detectability, simulated monitoring to evaluate the statistical power of three alternative monitoring scenarios: (1) where surveys were restricted to existing 2-ha plots, (2) where surveys were optimized to target all species equally, and (3) where surveys were optimized to target two species of conservation concern. Across all monitoring designs and scenarios, we found that power was higher when detecting increasing occupancy trends compared to decreasing trends owing to the relatively low levels of initial occupancy. Our results suggest that surveying 200 of the existing plots annually (with a small subset resurveyed twice within a year) will have at least an 80% chance of detecting 30% declines in occupancy for four of the five invasive species modeled and one of the six native species. This increased to 10 of the 11 species assuming larger (50%) declines. When plots were positioned to target all species equally, power improved slightly for most compared to the existing survey network. When plots were positioned to target two species of conservation concern (crest-tailed mulgara and dusky hopping mouse), power to detect 30% declines increased by 29% and 31% for these species, respectively, at the cost of reduced power for the remaining species. The effect of varying survey frequency depended on its trade-off with the number of sites sampled and requires further consideration. Nonetheless, our research suggests that track-based surveying is an effective and logistically feasible approach to monitoring broad-scale occupancy trends in desert species with both widespread and restricted distributions.

Including indigenous knowledge in species distribution modeling for increased ecological insights.

Indigenous knowledge systems hold detailed information on current and past environments that can inform ecological understanding as well as contemporary environmental management. Despite its applicability, there are limited examples of indigenous knowledge being incorporated in species distribution models, which are widely used in the ecological sciences. In a collaborative manner, we designed a structured elicitation process and statistical framework to combine indigenous knowledge with survey data to model the distribution of a threatened and culturally significant species (greater bilby or mankarr [Macrotis lagotis]). We used Martu (Aboriginal people of the Australian western deserts) occurrence knowledge and presence data from track-based surveys to create predictive species distribution models with the Maxent program. Predictions of species distribution based on Martu knowledge were broader than those created with survey data. Together the Martu and survey models showed potential local declines, which were supported by Martu observation. Both data types were influenced by sampling bias that appeared to affect model predictions and performance. Martu provided additional information on habitat associations and locations of decline and descriptions of the ecosystem dynamics and disturbance regimes that influence occupancy. We concluded that intercultural approaches that draw on multiple sources of knowledge and information types may improve species distribution modeling and inform management of threatened or culturally significant species.

Inclusión del Conocimiento Indígena en el Modelado de la Distribución de Especies para Incrementar el Conocimiento Ecológico Resumen Los sistemas de conocimiento indígena albergan información detallada sobre ambientes actuales y pasados que pueden informar al entendimiento ecológico así como al manejo ambiental contemporáneo. A pesar de su utilidad, los ejemplos de incorporación del conocimiento indígena dentro de los modelos de distribución de especies, usados ampliamente en las ciencias ecológicas, son limitados. Diseñamos de manera colaborativa un proceso estructurado de elicitación y un marco de trabajo estadístico para combinar el conocimiento indígena con información de censos para modelar la distribución de una especie amenazada y culturalmente significativa (el bilbi mayor o mankarr [Macrotis lagotis]). Usamos el conocimiento de los Martu (pueblo aborigen de los desiertos occidentales de Australia) sobre la incidencia de la especie junto con los datos de presencia de la misma obtenidos de censos basados en rastros para crear modelos predictivos de la distribución de la especie mediante el programa Maxent. Las predicciones de la distribución de la especie basados en el conocimiento de los Martu fueron más amplias que aquéllas creadas con los datos de los censos. En conjunto, ambos modelos, el de los Martu y el de los censos, mostraron declinaciones locales potenciales, las cuales estuvieron respaldadas con las observaciones de los Martu. Ambos tipos de datos estuvieron influenciados por el sesgo de muestreo que pareció afectar al desempeño y a las predicciones del modelo. Los Martu proporcionaron información adicional sobre las asociaciones de hábitat y las ubicaciones de las declinaciones, además de descripciones de las dinámicas del ecosistema y los regímenes de perturbación que influyen sobre la ocupación de la especie. Concluimos que las estrategias interculturales que parten de varias fuentes de conocimiento y tipos de información pueden mejorar el modelado de la distribución de especies y generar información para el manejo de especies amenazadas o culturalmente significativas.

Conservation of the patchily distributed and declining purple-crowned fairy-wren (Malurus coronatus coronatus) across a vast landscape: the need for a collaborative landscape-scale approach.

Conservation of species that are patchily distributed must consider processes that influence both the occurrence of individuals within patches, and the persistence of populations across multiple habitat patches within the landscape. Here we present a rare regional assessment of the population size and distribution of a patchily distributed, threatened species, the purple-crowned fairy-wren (Malurus coronatus coronatus), across a vast landscape. We used data from aerial vegetation mapping of waterways, with on-ground bird surveys to predict the occurrence of suitable habitat for M. c. coronatus across 14 catchments in the Kimberley region of Western Australia. Suitable habitat was extremely limited (305 km of riparian vegetation) and fragmented (342 patches) along the 2700 km of waterway surveyed within catchments where the species occurs. Populations were predicted to be large on the Fitzroy, Durack and Drysdale catchments, and small on the Isdell and northern Pentecost catchments, and a total population of 2834 to 4878 individuals could be supported. The sub-populations spanned numerous patches of habitat across multiple properties of varying tenure. Therefore, a landscape-scale approach to conservation management, across multiple tenures, is critical to safe-guard connectivity within populations. The greatest benefit may be achieved by a combination of broad-scale actions to reduce the impact of ubiquitous threatening processes, and fine-scale targeted effort in areas where populations are most vulnerable. Controlling access of stock to waterways and management of fire are most important to conserve suitable habitat. Such a landscape-scale approach to conservation may be of benefit to other patchily distributed species.