Grant is an aquatic ecologist and ecotoxicologist. His research examines the response of groundwater ecosystems, invertebrate and microbial communities to environmental change, and develops tools for assessing change in ecosystem health and condition. Hose and his team undertake field surveys and laboratory manipulative experiments, to identify correlative and causal links to community change. His team has expertise in groundwater invertebrate taxonomy and using environmental DNA (eDNA) to characterise the composition and function of groundwater ecosystems, and through this work has established an international reputation in groundwater ecology research. His current research focuses on the ecology of groundwater ecosystems and assessment of ecosystem health, ecological risk assessments and ecotoxicology for groundwater biota and the roles of stygofauna in providing ecosystem services.