Development of land for cropping in the Darwin area can occur away from the habitats of threatened species

Insight 1: almost no overlap between land suitable for soybean cropping and the habitats of the two threatened species investigated

Within those areas not currently excluded from agriculture development, protecting those areas of high Yellow Snouted Gecko and Adelaide Rivers Chat suitability would still leave large areas of land suitable for soybean cropping. Of the 233,950 hectares available for soybean, almost all of this (233,900) is outside the area of high habitat suitability for the both the gecko and the chat. This represents about 0.05% of the areas of high suitability for the gecko and 0.04% for the chat.

Insight 2: the habitats of these two threatened species are already excluded from agriculture

Almost all of the areas of high suitability for the Yellow Snouted Gecko and Adelaide Rivers Chat are within the area of land currently excluded from agriculture development. Of the 39,070 hectares of high habitat suitability for the Gecko 38,993 hectares is within the area of land currently excluded from agriculture development. Of the 57,750 hectares of high habitat suitability for the Chat 49,380 hectares is within the area of land currently excluded from agriculture development.

Note: this case study looked at limited species (based on one of many possible variables) and only considered direct overlap of agricultural expansion footprint with species distribution models, i.e. it does not consider indirect or associated /facilitated impacts such as loss of connectivity between areas of species habitat, changes to hydrological regimes (ground and surface water), fertiliser / pesticide use etc. and the introduction of environmental weeds and feral animals. 

Figure 1 shows the areas of the Darwin region that are most suitable for the Yellow-snouted gecko (Figure 1a) and for dry-season sobyean crops (Figure 1b).  While there is significant overlap between the two areas, Figure 1c shows that the majority (more than 99%) of the overlapping area is already excluded from agriculture development.

Figure 1 Areas of high and low habitat suitability for the Yellow-snouted Gecko and dry-season soybean

Figure 2 shows the areas of the Darwin region that are most suitable for the Alligator Rivers yellow chat (Figure 2a) and for dry-season sobyean crops (Figure 2b). The majority of the area suitable for the yellow chat is in areas of low land suitability for soybean crops. 

Figure 2 Areas of high and low habitat suitability for the Alligator Rivers Yellow Chat and dry-season soybean

Figure 3 highlights the habitat and land suitability of areas that are not excluded from agriculture development. The majority of the Darwin region has low suitability for both soybean and the gecko and chat (the light blue areas). The brown areas show that there are significant areas of land that have high suitability for soybean but low habitat suitability for the threatened species. The red areas show where high habitat suitability for the threatened species intersect with high soybean land suitability; these areas are almost non-existent.

Figure 3 Intersection between habitat suitability and land suitability

Insight 3: 

Land use at the regional scale can effectively accommodate both intensified agricultural production and conservation of these two threatened species.

Insight 4: 

Development of land in the study area for cropping is not incompatible with nature conservation of these two threatened species.