ALT Conceptual diagram showing our funded research plan, from ecosystem ecology to population and organismal ecology, focused on understanding the influence of climate change and deforestation on reach/microhabitat biogeochemistry, hellbender population density and age structure, and individual hellbender fitness and behavior (parental self-care vs. self-maintenance, cannibalism). Images show reach-scale river microhabitats that support fish, mussels, and hellbenders with dissolved oxygen sensors deployed at the stream bottom and within the water column; different ages of hellbenders in a population; different life stages of hellbenders; and predictive plots for how dissolved oxygen will vary over space and time due to respiration, declines in population density and increasing % of old adults with cannibalism, the trade-off between self-maintenance and parental care with changes in dissolved oxygen due to predicted increases in cannibalism with decreasing oxygen levels.