The decline and likely loss of a population of the Northern Long-nosed Potoroo Potorous tridactylus tridactylus in Tyagarah Nature Reserve on the New South Wales Far North Coast

ABSTRACT A population of the Northern Long-nosed Potoroo Potorous tridactylus tridactylus in Tyagarah Nature Reserve on the far north coast of New South Wales was first recorded in 1985. In 1992, a cage-trapping study captured 15 individuals in the central section of the reserve and the population was estimated at 80–90 individuals at that time. A subsequent cage-trapping study in 2004 captured four individuals in the southern section of the reserve, but further cage- and camera-trapping surveys in 2009 and 2012 failed to detect any individuals. Additional camera-trapping surveys between 2012 and 2015 and more intensive surveys between 2015 and 2016 also failed to detect any individuals. The lack of detections from targeted surveys over seven years between 2009 and 2016 suggests that the Tyagarah population of the subspecies has been lost. Reasons for this loss are unclear but may be due to a combination of factors including isolation of the reserve by urban development and highway upgrades, a lack of fire for 40 years, competition for food with the local population of the Australian Brush-turkey Alectura lathami, prolonged drought and possibly, predation by the Red Fox Vulpes vulpes and non-target effects of predator control programs.

Quantitative interpretation of images of long-nosed potoroos at baited camera-traps: defining a 'visit'

We devised a way to distinguish separate visits by animals to a camera station. The probability that an image of a long-nosed potoroo (Potorous tridactylus) would occur declined with time since the last potoroo image, reaching an asymptote after 5min at a level that may represent the probability of initiation of new visits.

Oils ain’t oils: can truffle-infused food additives improve detection of rare and cryptic mycophagous mammals?

We tested whether an artificial food additive, truffle oil, improved detection of mycophagous mammals when added to a standard bait type of peanut butter and rolled oats used with camera traps. Sixteen mammalian taxa were subsequently recorded, the most common being antechinus, bush rat (Rattus fuscipes), swamp wallaby (Wallabia bicolor) and long-nosed bandicoot (Perameles nasuta) as well as the long-nosed potoroo (Potorous tridactylus) and southern brown bandicoot (Isoodon obesulus). The only species for which detection rate was improved by the addition of truffle oil to standard bait was the ringtail possum (Pseudocheirus peregrinus), a species that has never been recorded eating fungi. In contrast, the total number of detections of all species at any given site was significantly higher, on average, using standard bait without truffle oil, as was the average number of detections of the partially mycophagous bush rat. Time to first detection of bush rats and swamp wallabies was significantly shorter using the standard bait type, compared with one with truffle oil added. Overall, the use of the truffle oil additive did not improve the chance or rate of detecting mycophagous mammals. To maximise the number of detections of mammals at camera traps the use of a standard bait type of peanut butter and rolled oats is recommended.

Population characteristics and management of the long-nosed potoroo (Potorous tridactylus) in high-quality habitat in the Southern Highlands of New South Wales

Since European settlement in Australia the long-nosed potoroo (Potorous tridactylus) has suffered greatly from fox predation and habitat loss, fragmentation and degradation. To better understand the threats it faces we examined the population dynamics of the potoroo at two study sites in the Southern Highlands of New South Wales over five years, using live-trapping. As neither site had experienced inappropriate habitat change for over 25 years, fox predation was considered the major threat to this population. An assessment of fox activity and diet was undertaken at both sites for comparison with potoroo abundance. Potoroos increased at both sites over time, although at one site this increase was only in density and not range. The density increase would not have been detected using camera surveys, a monitoring technique recommended for this species. The relative abundance of foxes fluctuated over the study despite fox control in one of the two sites. Analysis of fox scats at the same sites indicated high levels of predation on potoroos. Future management should aim to provide effective fox control (particularly following any fire due to the associated loss of ground cover) and improved fox monitoring to ensure an accurate understanding of what is happening to the fox population.