Context Gopher tortoises, Gopherus polyphemus, are a keystone species of south-eastern North America due to their historically high density, grazing habits, and the burrows that they maintain across upland landscapes. Many gopher tortoise populations are demographically non-viable due to low population density and/or population size. Management for this species frequently utilize measures such as translocation and head-starting. Aims Between 2020 and 2024, we used short-distance translocation to consolidate a low-density resident population of gopher tortoises and monitored spatial biology and apparent survival in the translocated animals immediately following translocation. We also conducted head-starting of tortoises collected as eggs from the same site and manipulated head-start release conditions to test whether soft- versus hard-release affected apparent survival. Methods We tracked both wild and head-started tortoises via radiotelemetry for 1 year during and 1 year after penning; we determined apparent survival by direct observation of individuals remaining alive and within the site approximately 1.5 years after all enclosure pens had been removed. Key results Home ranges of free-ranging tortoises were approximately the same in the enclosure pen as they were after the enclosure pen was removed, but apparent survival of free-ranging tortoises at the study site was only 56% after the enclosure was removed. Male adult tortoises had higher apparent survival in the site than did females, and translocation distance was a negative predictor of apparent survival. Release condition did not affect head-started tortoise apparent survival, and overall apparent survival of head-started tortoises was 70% 2 years after release. Conclusions Head-starting and direct hard release of juveniles are likely to be successful tools for gopher tortoise conservation, whereas population consolidation may cause poor adult survival and/or site fidelity. Implications Short-distance translocations of wildlife populations should be further studied before this tool is more broadly applied in conservation projects.
Context Small mammals of northern Australian tropical savanna continue to face severe declines. The brush-tailed rabbit-rat (Conilurus penicillatus) is among the most threatened mammals, having undergone a dramatic range contraction to mesic coastal areas and islands. The Cobourg Peninsula supports what is likely to be the last rabbit-rat population on the Northern Territory mainland. Concerningly, there has been limited targeted and systematic monitoring of the Cobourg Peninsula population in the past decade, despite the high forecasted extinction risk and steep declines having also been recently detected in a neighbouring refuge population. Aims This study broadly aimed to investigate the spatial distribution of brush-tailed rabbit-rats on the Cobourg Peninsula and assess whether variation in the species’ abundance was associated with habitat features and fire metrics. Methods A baited camera survey across 70 sites in Garig Gunak Barlu National Park on the Cobourg Peninsula was conducted in the late dry season of 2025. Royle–Nichols occupancy modelling was used to estimate the species’ current distribution and investigate correlates of relative abundance derived from both remotely-sensed datasets and field-based habitat assessments. Key results Rabbit-rats had a naïve occupancy of 93%, which is currently the highest reported for any population monitored using remote cameras. However, rabbit-rat relative abundance was patchy across the peninsula, influenced by woody plant species composition and increased with time since fire. Conclusions The Cobourg Peninsula continues to remain one of the last strongholds for the brush-tailed rabbit-rat. Implications Despite no apparent decline in occupancy within the study area, management should not become complacent given that declines can occur without any appreciable change in the threat landscape. Ideally, a species-wide monitoring program is established to ascertain trends in occupancy, particularly given that populations in similar environments appear to be declining at varying rates. This will further assist in assessing the effectiveness of certain management responses.
Context In recent years, the rapid increase in wild boar (Sus scrofa) numbers has sparked broad concern about this species’ impacts on ecosystems and biodiversity. Aims This study aimed to investigate interspecific relationships between wild boar and major sympatric species in terms of space-use overlap, occupancy probability, diel activity rhythms and short-term dynamic responses, and to determine whether wild boar activity was associated with spatial avoidance, temporal partitioning or short-term behavioural responses. Methods We deployed 91 infrared camera traps and monitored the study area continuously for 12 months. We quantified relative abundance, spatial overlap, occupancy and detection processes, diel activity rhythms and short-term post-detection responses for adult wild boar records, other wild boar records, all wild boar records and major sympatric species. Key results We obtained 25,306 effective camera-days and 9607 independent valid records, and recorded 37 wild vertebrate species. Reeves’s muntjac (Muntiacus reevesi), silver pheasant (Lophura nycthemera) and wild boar were the dominant species. Wild boar showed high space-use overlap with Reeves’s muntjac (92.06%), silver pheasant (83.04%), rhesus macaque (Macaca mulatta, 66.80%), other pheasants and masked palm civet (Paguma larvata). Single-species occupancy models showed no general negative effect of wild boar activity intensity on sympatric species; only all wild boar was marginally positively associated with rhesus macaque, and reverse models showed a marginally positive association only between rhesus macaque and other wild boar. Detection models indicated positive codetection associations between wild boar and several sympatric species within the same 10-day survey occasion, while NDVI0422 was the most important variable explaining the occupancy probability of other wild boar. Adult wild boar differed significantly in diel activity rhythms from several sympatric species. Piecewise exponential additive mixed model results showed increased short-term visitation risk of Reeves’s muntjac, silver pheasant and crab-eating mongoose (Herpestes urva) after wild boar occurrence, but decreased short-term visitation risk of rhesus macaque. Conclusions The relationship between wild boar and sympatric species did not reflect a single pattern of spatial exclusion. Instead, it involved a complex combination of high space-use overlap, species-specific occupancy responses, short-term positive codetection associations, diel activity partitioning and short-term dynamic responses. Implications Management of wild boar in subtropical forest ecosystems should be guided by long-term monitoring of activity intensity, population density, habitat conditions, road disturbance and community dynamics, rather than by assuming a uniformly negative effect on sympatric species.
Context Reptile species are declining globally, but low detection success is a challenge for reptile monitoring. The Victorian grassland earless dragon (Tympanocryptis pinguicolla; VGED) is the most imperilled reptile in Australia and faces immediate threats from habitat destruction. Detecting VGED is challenging; however, detection dog teams present a promising method. Aims We aimed to (1) determine whether detection dog-handler teams would be a feasible survey method for VGED scat, and (2) measure VGED scat persistence within the environment. Methods Two experienced detection dogs were trained on VGED scat (originally captive sourced, then wild sourced) and assessed on their sensitivity and precision in odour line ups. One dog was then assessed across 21 single-blind area searches for novel captive VGED scat. Concurrently, a scat persistence study occurred using 44 captive scats in the following two treatments: (1) exposed scats and (2) contained scats. These samples were placed within VGED habitat for 50 days and monitored for persistence. Key results Both dogs achieved 100% sensitivity and precision detecting defrosted and fresh captive-VGED scat. However, both dogs failed to spontaneously generalise to wild-sourced scats, requiring a second or third presentation. During search assessments, the detection dog had a sensitivity of 72.9% for captive scats and confirmed species presence in 81.3% of sites. Average time to first detection was 3 min and 30 s; however, this varied amongn search locations (P = 0.01). In the scat persistence study, 36% of the exposed scats persisted less than 24 h and only two remained to Day 50. Conclusions Detection dogs can be highly specific and sensitive to both fresh and degraded VGED scat. However, considering the high rate at which wild scats are degraded and the search intensity required to detect them with dogs, we suggest that VGED scat detection dogs are also trained to detect live dragons, to maximise data collection and chance of detecting VGED presence. Implications Our research supports future involvement of detection dog teams in reptile surveys, while highlighting important considerations when employing dog teams, including access to training samples and survey design.
Context Dryland ecosystems are highly vulnerable to biological invasions because of strong climatic constraints and limited resource availability. In the Chihuahuan Desert, the introduced ungulate Ammotragus lervia represents an increasing conservation concern owing to its potential to alter native communities through ecological interactions and pathogen transmission. Anticipating its response to climate change is essential for assessing future impacts and informing management strategies. Aims This study aimed to (i) estimate the current and future climatically suitable habitats of A. lervia in the Chihuahuan Desert, (ii) quantify spatial and environmental niche overlap with three native ungulates, and (iii) assess potential expansion and risks within protected areas under multiple climate scenarios. Methods Occurrence records were compiled from multiple biodiversity databases and subjected to rigorous cleaning and spatial filtering. Ecological niche models were developed in MaxEnt by using the kuenm workflow with CHELSA climatic variables and CMIP6 climate projections under three Shared Socio-economic Pathways (SSPs) spanning constransting levels of future climate forcing: SSP126 (low forcing), SSP370 (high forcing), and SSP585 (very high forcing). Candidate models were selected using partial ROC (Receiver Operating Characteristic), omission rates (≤5%), and Akaike information criterion for small sample sizes (AICc), whereas area under the curve (AUC) and TSS (True Skill Statistic) were used only as complementary measures. Niche overlap was quantified using Schoener’s D, and changes in suitable habitat and protected-area overlap were evaluated from binary suitability maps. Key results Models showed high predictive performance (mean AUC = 0.875 ± 0.022). Current climatically suitable area for A. lervia covered 233,571 km2 and remained extensive under future climate scenarios, with non-monotonic net changes ranging from −5.0 to +8.5%. In contrast, native ungulates showed stronger and more scenario-dependent responses, particularly O. hemionus, for which suitable area declined by 21.7–50.2%, and O. canadensis mexicana, which shifted from projected expansion under SSP126 and SSP370 to a 55.6% contraction under SSP585. Climatic niche overlap with A. lervia was moderate (D = 0.16–0.22), although spatial overlap remained extensive and persisted in mountainous regions under all scenarios. Conclusions Ammotragus lervia is likely to sustain a stable and potentially expanding distribution under climate change, contrasting with the more limited responses of native ungulates. Persistent climatic suitability and geographic overlap identify protected areas where ecological interactions may become more likely under future projections. These areas should therefore be considered priorities for monitoring, early detection, and adaptive management. Implications Results support spatially explicit management focused on high-risk areas, particularly mountainous refugia and protected areas, integrating climatic projections with long-term ecological monitoring to improve invasion prevention and conservation planning.
