New habitats for Northern quolls in Far North Queensland
A project used spatial multi-criteria analysis to identify new habitats for the endangered species Northern quolls in Far North Queensland
Introduction
The northern quoll (Dasyurus hallucatus) is generally considered as the most unique Australian quoll which belongs to the family Dasyuridae. The male northern quoll will die after mating, and the survival time of northern quolls in the wild is quite short with only 1 to 3 years.
The northern quoll is distributed from the Pilbara region of Western Australia across the Northern Territory to southeastern Queensland (Figure. 1). Although it has a wide range of distribution, the Australian government classified it as an endangered species (Department of Agriculture, Water and the Environment, 2020). Its distribution has declined sharply, especially in the drier areas of its range.
The threat to this species is predation by wild cats, dingoes, and foxes, followed by habitat destruction caused by human activities such as land clearing, pasture improvement, and mining, as well as being easily hit by cars on roads. This species is most abundant in rocky ranges and open eucalypt forests. Another threat is the proliferation of cane toads for northern quolls in Far North Queensland. Cane toads were originally introduced in Queensland, but now they have occupied the Top End of the Northern Territory (Australian Geographic, 2014). Northern quolls will be poisoned after eating or swallowing cane toads, resulting in a decrease in population.
This project aims to use Fuzzy Logic of spatial multi-criteria analysis with land cover, land use, roads and native vegetation layers to identify new habitats for Northern quolls in Far North Queensland in ArcGIS Pro. According to the Australian government, there are currently no approved conservation advice for this species. This species is in a highly dispersed state in Queensland. There was no previous research about the habitat of northern quoll and choosing a new habitat will greatly help this species's reproduction and survival.
Data and methods
1. The data of Far North Queensland downloaded from Queensland Government- Queensland Spatial Catalogue (https://qldspatial.information.qld.gov.au/catalogue/custom/index.page) with the state roads, Far North Queensland boundary, native vegetation, land use and land cover. The state roads, native vegetation and Far North Queensland boundary data layers were polyline, polygon and polygon. The land use and land cover data layers were raster.
2. The method used in this study was multiple criteria analysis (MCA). This method is a preliminary screening process, prior to the final selection of auxiliary colonization sites for endangered species (Dade et al., 2014). In this study, an alternative MCA which employed the use of fuzzy logic was used. Reclassify, Raster to Polygon, Polygon to Raster, Euclidean distance, Fuzzy membership, Fuzzy overlay, and Locate Regions tools were used in ArcGIS Pro (2.6).
3. The Euclidean distance tool was used in the state roads and native vegetation layers. Further away from state roads and close to native vegetation is more favorable. For land use and land cover layers, the Raster to Polygon tool was used because these two layers were raster, their attribute table could not edit. Then according to the suitability, reclassed the values of two layers from 0 to 1 by creating a new field and selecting the values to assign a new value (Table 1). Next was converting the vector layers of land use and land cover into raster layers because only raster layers could be processes in the Fuzzy membership.
4. Prior to running Fuzzy Overlay, the Fuzzy membership tool was run for each layer. The model parameter was Linear and for state roads layer the minimum distance was 2000 and maximum distance was 50000. The minimum distance of native vegetation was 6000 and maximum distance was 100. The relationship of native vegetation was negative because closing to native vegetation is more favorable. As for land use and land cover layers, the minimum value was 0.2 and maximum value was 1.
5. After all the Fuzzy Membership processing, the Fuzzy Overlay used to combine all layers using the Product method.
6. The final step was using the Locate Regions tool to identify habitats of high suitability for northern quolls. The total area was 500 km2 across 5 sites which each site of 10000 ha had achieved the best minimum size for a site with 200 ha (Dade et al., 2014).
Results
The map of habitat regions (Figure. 2) shows the five sites of 500 km2 which have high suitability above the whole Far North Queensland. The result shows that four of the habitats considered state roads, land use, land cover and native vegetation are located in the east region of Far North Queensland near or in the Jardine River National Park, Heathlands Resources Reserve and Jardine River Resources Reserve and another one is on the Moa island.
Discussion
The results show that the most regions of high suitability are in the east region of Far North Queensland. Some habitats are in the Jardine River National Park, Heathlands Resources Reserve and Jardine River Resources Reserve, while others are nearby. The advantage of establishing in a protected area is that the ecological environment can be guaranteed, and the impact of human activities is relatively small. At the same time, these five suitable habitats are not far from the existing distribution places, and it is very convenient if animals need to migrate. However, it is necessary to ensure that there are not many cane toads in the reserve, or that there are special measures to control cane toads so that northern quolls will not die from swallowing cane toads. And there is a region located on the Moa island with only 448 people which means that the human impact on the species is minimal. In addition, the island is far from the major land of Far North Queensland and there is no evidence that cane toads have spread to the island, which is a good thing for northern quolls. But the Moa island is too far from the land, how to move the habitat is worth studying and planning.
The results of this study may be inaccurate because of insufficient data. For example, the lack of land cover contains all the information, because northern quolls like to live in rocky and eucalyptus forests, but the downloaded land cover layer does not contain this information, so there may be deviations in the choice of habitat. In addition, the parameters entered in the geoprocessing step can be changed to get slightly different results. Also, the total area of the habitat area can be smaller to be more accurate.
The North quoll has a variety of habitats within its range, including rocky areas, eucalyptus forests and woodlands, rainforests, sandy lowlands and beaches, bushes, grasslands and deserts (Threatened Species Scientific Committee, 2005). The choice of habitats are abundant but the preference of northern rats for habitat types is unknown. So the suitability index needs to be further studied, because there is no previous research as a reference, so when setting the index, it is not guaranteed to be accurate.
For future research on the habitat of this species, field visits can be added and more data can be included. For example, including more land cover types or other types of data, these data can better locate the habitat of northern quolls. At the same time, the number of cane toads needs to be controlled to ensure that the number of northern quolls remains stable.
Conclusion
The project studied the problem of northern quolls relocating more suitable habitats in Far North Queensland. The results of the study indicate that the more suitable habitats can be located in the east region of Far North Queensland near Heathlands Regional Park. The size of the habitat area and sufficient data will lead to a more accurate area. The research results provide an overall direction for future research and lay a foundation for future research on the selection of the northern quolls’ habitat and species migration.
Reference
Department of Agriculture, Water and the Environment, Australian Government (2020). http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=331
Australian Geographic (2014), New populations of endangered species found. https://www.australiangeographic.com.au/news/2014/08/new-populations-of-endangered-species-found-in-wa/
Gis data from Queensland Government- Queensland Spatial Catalogue https://qldspatial.information.qld.gov.au/catalogue/custom/index.page
Dade, M., Pauli, N., & Mitchell, N. (2014). Mapping a new future: using spatial multiple criteria analysis to identify novel habitats for assisted colonization of endangered species. Animal Conservation, 17(S1), 4–17.
Threatened Species Scientific Committee (2005). NON-APPROVED Conservation Advice on Northern Quoll (Dasyurus hallucatus). http://www.environment.gov.au/biodiversity/threatened/species/dasyurus-hallucatus.html#conservation .
