Aim Extreme climatic events and large wildfires are predicted to increase as the world's climate warms. Understanding how they shape species’ distributions will be critical for conserving biodiversity. We used a 7‐year dataset of mammals collected during and after south‐east Australia's Millennium Drought to assess the roles of fire history, climatic extremes and their interactions in shaping mammal distributions. Location Grampians National Park, south‐eastern Australia. Methods We surveyed mammals at 36 sites along a ~50‐year post‐fire chronosequence in each of the 7 years. We modelled ten mammal species in relation to fire history, productivity and recent rainfall. Next, we examined the consistency of species’ fire response curves across each of three climatic phases relating to the Millennium Drought. Finally, we identified the optimal distribution of fire ages for small and medium‐sized mammal conservation in each of the three climatic phases. Results The majority of species were influenced by fire history, and all native species were negatively associated with recently burned vegetation. Seven of ten species responded positively to the end of the Millennium Drought, but six of these declined quickly thereafter. Species’ responses to fire history differed depending on the climatic conditions. However, the optimal distribution of fire‐age classes consistently emphasized the importance of older age classes, regardless of climatic phase. This distribution is in stark contrast to the current distribution of fire ages across the study region. Main conclusions Mammals in the study region face an uncertain future. The negative impact of drought, the short‐lived nature of post‐drought recovery and, now, the possibility of a new drought beginning forewarn of further declines. The stark contrast between the optimal and current fire‐age distributions means that reducing the incidence of further fires is critical to enhance the capacity of native mammal communities to weather an increasingly turbulent climate.

The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACT We use 2.0 Msec of Chandra observations to investigate the cocoon shocks of Cygnus A and some implications for its lobes and jet. Measured shock Mach numbers vary in the range 1.18-1.66 around the cocoon. We estimate a total outburst energy of ≃ 4.7 × 10 60 erg, with an age of ≃ 2 × 10 7 yr. The average postshock pressure is found to be 8.6 ± 0.3 × 10 −10 erg cm −3 , which agrees with the average pressure of the thin rim of compressed gas between the radio lobes and shocks, as determined from X-ray spectra. However, average rim pressures are found to be lower in the western lobe than in the eastern lobe by ≃ 20%. Pressure estimates for hotspots A and D from synchrotron self-Compton models imply that each jet exerts a ram pressure 3 times its static pressure, consistent with the positions of the hotspots moving about on the cocoon shock over time. A steady, one-dimensional flow model is used to estimate jet properties, finding mildly relativistic flow speeds within the allowed parameter range. Models in which the jet carries a negligible flux of rest mass are consistent with with the observed properties of the jets and hotspots. This favors the jets being light, implying that the kinetic power and momentum flux are carried primarily by the internal energy of the jet plasma rather than by its rest mass.

1. Introduced carnivores are often cryptic, making it difficult to quantify their presence in ecosystems, and assess how this varies in relation to management interventions. Survey design should thus seek to improve detectability and maximize statistical power to ensure sound inference regarding carnivore population trends. Roads may facilitate carnivore movements, possibly leading to high detectability. Therefore, targeting roads may improve inferences about carnivore populations. 2. We assessed our ability to monitor feral cats Felis catus and red foxes Vulpes vulpes on-and off-road, with explicit consideration of the location of monitoring sites on our ability to detect population changes. We also assessed whether there was evidence of spatial or temporal interaction between these species that might influence their roaduse. 3. Surveys were conducted in a conservation reserve in southeastern Australia between 2016 and 2018. At each of 30 sites, we deployed two motion-sensor cameras, one on-road, and the other off-road. Using occupancy models, we estimated cat and fox occupancy and detectability, and conducted a power analysis to assess our ability to detect declines in occupancy under three monitoring regimes (efforts targeted equally on-and off-road, efforts targeted entirely off-road and efforts targeted entirely onroad). 4. On average, on-road detectability was seven times higher for cats and three times higher for foxes. Targeting survey effort on-road yielded the greatest power for detecting declines in both species, but our ability to detect smaller declines decreased with decreasing initial occupancy probability. No level of decline was detectable for cats This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

We present a spectral analysis of the lobes and X-ray jets of Cygnus A, using more than 2 Ms of Chandra observations. The X-ray jets are misaligned with the radio jets and significantly wider. We detect non-thermal emission components in both lobes and jets. For the eastern lobe and jet, we find 1 keV flux densities of 71 +10 −10 nJy and 24 +4 −4 nJy, and photon indices of 1.72 +0.03 −0.03 and 1.64 +0.04 −0.04 respectively. For the western lobe and jet, we find flux densities of 50 +12 −13 nJy and 13 +5 −5 nJy, and photon indices of 1.97 +0.23 −0.10 and 1.86 +0.18 −0.12 respectively. Using these results, we modeled the electron energy distributions of the lobes as broken power laws with age breaks. We find that a significant population of non-radiating particles is required to account for the total pressure of the eastern lobe. In the western lobe, no such population is required and the low energy cutoff to the electron distribution there needs to be raised to obtain pressures consistent with observations. This discrepancy is a consequence of the differing X-ray photon indices, which may indicate that the turnover in the inverse-Compton spectrum of the western lobe is at lower energies than in the eastern lobe. We modeled the emission from both jets as inverse-Compton emission. There is a narrow region of parameter space for which the X-ray jet can be a relic of an earlier active phase, although lack of knowledge about the jet's electron distribution and particle content makes the modelling uncertain.

We use new and archival Chandra observations of Cygnus A, totalling ∼1.9 Ms, to investigate the distribution and temperature structure of gas lying within the projected extent of the cocoon shock and exhibiting a rib-like structure. We confirm that the Xrays are dominated by thermal emission with an average temperature of around 4 keV, and have discovered an asymmetry in the temperature gradient, with the southwestern part of the gas cooler than the rest by up to 2 keV. Pressure estimates suggest that the gas is a coherent structure of single origin located inside the cocoon, with a mass of roughly 2 × 10 10 M . We conclude that the gas is debris resulting from disintegration of the cool core of the Cygnus A cluster after the passage of the jet during the early stages of the current epoch of activity. The 4 keV gas now lies on the central inside surface of the hotter cocoon rim. The temperature gradient could result from an offset between the centre of the cluster core and the Cygnus A host galaxy at the switch-on of current radio activity.