Boundary of ecosystem services: Differentiating between ecosystem services and geosystem services is needed

Geosystem services (GSs) and ecosystem services (ESs) are interconnected, both representing nature's contributions to people. Whether GSs are a subset of ESs depends on the definition of ESs. The answer would be "not necessarily" (i.e., some GSs are, while other GSs are not), if ESs are the benefits humans derive from ecological functions, processes, or characteristics. The boundary proposed by Chen et al. (2023) to differentiate ESs from other ecosystem-related benefits adopted this definition, and suggested that ESs are renewable and affected by biotic elements to occur. Gray et al. (2024) criticized this boundary for separating out bits of nature and ignoring the contributions of GSs and abiotic elements to ESs and human wellbeing. In fact, highlighting that ESs are affected by biotic elements to occur does not deny that ESs' occurrence is also affected by abiotic elements. However, ESs' dependence on abiotic elements cannot be a criterion to differentiate ESs from other benefits because abiotic elements are integral to geosystems, ecosystems, and many other natural and artificial systems, as well as to these systems' services. Conversely, while geosystems might persist without biotic elements, ecosystems cannot. Chen et al. (2023) only excluded those (not the whole) abiotic benefits, such as wind energy, that may occur independently of biotic elements, while allowing for integrating certain GSs into ESs. For example, geological structures can offer flood protection and water storage as GSs, which can also be classified as ESs when their qualities or quantities are affected by biotic elements. Differentiation between GSs and ESs should not be misinterpreted as splitting their interconnections or undervaluing or dividing nature. Instead, such differentiation and classification of nature's benefits serve to facilitate communication, management, education, research, and policy-making associated with nature's benefits, while also highlighting the richness and diversity of nature's benefits.