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Abstract Few studies have investigated how mature trees recover physiologically from wildfire damage, and none have comprehensively linked tree hydraulics with belowground function. Uncovering mechanistic links between rates of above‐ and belowground recovery is necessary for improving predictions of forest resilience and carbon dynamics following wildfire. We coupled continuous measurements of tree water flow and soil CO₂efflux with detailed physiological measurements of above‐ and belowground function following a mixed‐severity wildfire. We found that maturePinus ponderosatrees with up to 85% canopy and stem damage resumed physiological functioning by the second growing season post‐fire. However, these trees also exhibited delayed peak water uptake (relative to less‐burned trees) that coincided with summer heat and drought. Our results suggest fire damage may prevent the critical timing in which peak physiological function overlaps with optimal growing conditions (e.g., moisture and nutrient availability). As a result, we suggest the degree of root and microbial damage should be assessed along with observed aboveground damage to more effectively predict tree recovery potential. While significantly damaged trees resumed typical hydraulic function within two years, observed delays in peak water uptake could require higher water and nutrient use efficiency to maintain carbon sequestration rates. 

Apex consumers are declining worldwide. While the effects of apex predator declines on ecosystems are widely documented, the cascading effects of apex scavenger declines are poorly understood. We evaluated whether disease‐induced declines of an apex scavenger, the Tasmanian devil (Sarcophilus harrisii), increased carrion use by invertebrate scavengers. We manipulated devil access to 36 carcasses across a gradient of devil density from east to west Tasmania and measured carcass use by invertebrates. We found the amount of carcass removed within 5 days was 3.58 times lower at sites with the lowest devil densities. Adult carrion beetle (Ptomaphila lacrymosa) and blow fly (Calliphoridae) larvae abundances were two times higher at open‐access carcasses at low‐density sites than at intermediate‐ and high‐density sites. Adult beetles persisted for 10 days at the low‐density site but declined after 5 days when devils had access to carcasses in intermediate‐ and high‐density sites. Blow fly larvae abundance was not affected by devils in the low‐density site but decreased with devil access in intermediate‐ and high‐density sites. Our results suggest that apex scavenger declines may increase invertebrate scavenger abundance and their contribution to carrion decomposition, with potential cascading effects on nutrient cycling and ecosystems. 

In an increasingly flammable world, wildfire is altering the terrestrial carbon balance. However, the degree to which novel wildfire regimes disrupt biological function remains unclear. Here, we synthesize the current understanding of above- and belowground processes that govern carbon loss and recovery across diverse ecosystems. We find that intensifying wildfire regimes are increasingly exceeding biological thresholds of resilience, causing ecosystems to convert to a lower carbon-carrying capacity. Growing evidence suggests that plants compensate for fire damage by allocating carbon belowground to access nutrients released by fire, while wildfire selects for microbial communities with rapid growth rates and the ability to metabolize pyrolysed carbon. Determining controls on carbon dynamics following wildfire requires integration of experimental and modelling frameworks across scales and ecosystems. 

Global apex scavenger declines strongly alter food web dynamics, but studies rarely test whether trophic downgrading impacts ecosystem functions. Here, we leverage a unique, disease‐induced gradient in Tasmanian devil (Sarcophilus harrisi) population densities to assess feedbacks between carcass persistence, subordinate scavenger guilds, and biogeochemical cycling. We further explored interkingdom and seasonal interactions by manipulating carcass access and replicating experiments in warmer, drier summer versus cooler, wetter winter periods. We show Tasmanian devil declines significantly extend carcass persistence and increase the flux of carcass‐derived nutrients belowground (e.g., by 18–134‐fold for ammonium). Greater nutrient availability reduces soil microbiome diversity by up to 26%, increasing the relative abundance of putative zoonotic pathogens. Nutrient subsidies also shift microbial communities toward faster‐growing taxa that invest less energy in resource acquisition, with implications for soil carbon sequestration. Rates of carcass decomposition were reduced in the winter, dampening soil biogeochemical responses and interkingdom competition. Notably, while less efficient scavenger guilds clearly facilitate carcass consumption, they were not able to fill the functional role of apex scavengers. Our study illustrates how trophic downgrading effects can ripple across all levels of ecological organization.