On the biological concept of stress.

One of the most important questions in ecology is to identify how species respond to multiple factors and predict their differential vulnerability to environmental changes [ 1. Sutherland W.J. et al. Identification of 100 fundamental ecological questions. J. Ecol. 2013; 101: 58-67 Crossref Scopus (552) Google Scholar ]. This requires a solid understanding of the stress concept, which was recently questioned by Schradin et al. [ 2. Schradin C. et al. Harshness is not stress. Trends Ecol. Evol. 2023; 38: 224-227 Abstract Full Text Full Text PDF PubMed Scopus (0) Google Scholar ]. The authors brought an insightful discussion, arguing that there is no consensus on the definition of stress and suggested distinguishing stressful from harsh environments, since they would trigger differential responses (stress versus harsh responses), affecting animals’ resilience to global change. Despite their focus on mammals, they suggest that it must also be defined for other groups, such as plants. With the intention of contributing to this debate, we provide a counterpoint arguing that consensus does exist about the definition [ 3. Levitt J. Responses of Plants to Environmental Stresses. Academic Press, 1980 Google Scholar , 4. Galviz Y. et al. The biological concept of stress revisited: relations of stress and memory of plants as a matter of space – time. Theor. Exp. Plant Physiol. 2022; 34: 239-264 Crossref Scopus (5) Google Scholar , 5. Blum A. Stress, strain, signaling, and adaptation-not just a matter of definition. J. Exp. Bot. 2016; 67: 562-565 Crossref PubMed Scopus (43) Google Scholar ]. We bring the solid theoretical basis of stress built over past decades in plant ecophysiology [ 3. Levitt J. Responses of Plants to Environmental Stresses. Academic Press, 1980 Google Scholar , 4. Galviz Y. et al. The biological concept of stress revisited: relations of stress and memory of plants as a matter of space – time. Theor. Exp. Plant Physiol. 2022; 34: 239-264 Crossref Scopus (5) Google Scholar , 6. Larcher W. Stress bei pflanzen. Naturwissenschaften. 1987; 74: 158-167 Crossref Scopus (82) Google Scholar ], which may have important guidelines for studies on animal ecology.