Pilliga GISERA fragmentation project

This entry contains remote sensing data and threatened species survey data collected as part of the Pilliga GISERA fragmentation project, aimed at better understanding the risks of forest fragmentation due to the Narrabri Gas Project. \nLineage: \nThreatened species surveys \n\nFieldwork was undertaken from October 2023 to October 2024, a period of moderate rainfall that included the occurrence of a large wildfire in December 2023 that burnt 129,000 ha of the study area. Such wildfires occur periodically in the Pilliga Forest. Four threatened species of vertebrates (Eastern pygmy-possum, squirrel glider, black-striped wallaby, pale-headed snake,) were surveyed across a range of sites including a set of 30 sites that were repeat sampled (3-4 times each) during nocturnal walk transects. Two of the four target species (Eastern pygmy-possum, black-striped wallaby) were located. Only the Eastern pygmy-possum was present on the network of 30 repeat sampled sites. \n\nFive threatened species of plants (Bertya opponens, Lepidium aschersonii, Lepidium monoplocoides, Androcalva procumbens, Vincetoxicum linearis) were surveyed using a range of methods. Some of the survey sites overlapped with those used for vertebrate surveys but most were standalone. Each of the five species was detected during field surveys. Soil and root samples were taken from individuals of each species for laboratory analysis of mycorrhizal symbiont diversity. \n\nRemote sensing \n\nA light-detection-and-ranging (LiDAR) remote sensing approach was adopted to quantify the structural attributes of a subset (15) of vertebrate and plant survey sites. This was done with an Acecore Noa hexacopter fitted with a RIEGL survey-grade VUX-120 laser scanner (UAV-LiDAR). Each UAV flight covered an area of 15 ha, flown at an altitude of 80 meters above ground level (AGL) using a cross-hatched east-west/north-south pattern at a speed of 5.3 m s-1 and with a line spacing of 60 m. \n\nFragmentation and connectivity were quantified using metrics that have been developed to harness the potential of earth observation science to measure these processes at large spatial scales. Fragmentation was measured with the Foreground Area Density (FAD) approach that describes the density of a foreground class of interest. It is designed to provide a pixel-level measure of fragmentation. Connectivity was measured with Morphological Spatial Pattern Analysis (MSPA). This approach uses mathematical morphometry techniques to classify binary patterns into discrete classes including cores, edges, and bridges, that can be used to assist in identifying important habitat patches and components of the landscape that connect core habitats to one another. \n\nFungal communities \n\nThe mycorrhizal status of four of the threatened plants (A. procumbens, B. opponens, L. monoplocoides, V. forsteri) was assessed to determine if the fungal partners of each (should they exist) were widespread in the region. Roots from individuals of each species were collected along with loose rhizosphere soil (as an indication of fungal communities immediately adjacent to the plant). The samples were examined in pairs (root:soil) by species using a DNA-based approach (next generation sequencing of the internal transcribed spacer region). A total of 5,669 fungal OTUs (operational taxonomic units ≈ species) was observed across the 54 samples examined.