Disturbance theory for ecosystem ecologists: A primer

Abstract

Understanding what regulates ecosystem functional responses to disturbance is essential in this era of global change. However, many pioneering and still influential disturbance-related theorie proposed by ecosystem ecologists were developed prior to rapid global change, and before tools and metrics were available to test them. In light of new knowledge and conceptual advances across biological disciplines, we present four disturbance ecology concepts that are particularly relevant to ecosystem ecologists new to the field: (a) the directionality of ecosystem functional response to disturbance; (b) functional thresholds; (c) disturbance-succession interactions; and (d) diversity-functional stability relationships. We discuss how knowledge, theory, and terminology developed by several biological disciplines, when integrated, can enhance how ecosystem ecologists analyze and interpret functional responses to disturbance. For example, when interpreting thresholds and disturbance-succession interactions, ecosystem ecologists should consider concurrent biotic regime change, non-linearity, and multiple response pathways, typically the theoretical and analytical domain of population and community ecologists. Similarly, the interpretation of ecosystem functional responses to disturbance requires analytical approaches that recognize disturbance can promote, inhibit, or fundamentally change ecosystem functions. We suggest that truly integrative approaches and knowledge are essential to advancing ecosystem functional responses to disturbance.

Keywords: disturbance ecology; ecological theory; ecosystem ecology; ecosystem functioning; net primary production; resilience; resistance; stability; succession; system dynamics.

FIGURE 1

Disturbance is often assumed to have disruptive effects on ecosystem processes, but observed responses may be positive, negative, or neutral and change over time, influencing how disturbance effects are perceived and reported. Such dynamic responses may also explain why conflicting disturbance responses are reported in the literature and underscore the need for long‐term repeated measurements.

FIGURE 2

Drawing from theoretical frameworks developed by community ecologists and recent observations of ecosystem processes, functional thresholds can be conceptualized as abrupt non‐linear transitions from one functional regime to another resulting from press or pulse disturbance (a) and using a basin attractor analogy (b). Press disturbances, such as sustained drought or gradually rising temperatures, may push a function closer to its threshold as limiting resources decline, priming the system for greater sensitivity to subsequent pulse disturbance.

FIGURE 3

Early community ecology‐driven successional theory posited and often observed partial to full resetting of plant community development in response to disturbance (a). Observations of plant community and ecosystem functioning dynamics suggest that disturbance can alternatively advance or change axes of succession altogether, and site degradation can lead to retrogression. Disturbance may increase some elements of ecosystem functioning, while reducing others, resulting in potentially neutral “net effects” in which opposing fluxes offset one another. For example, within the same north temperate forested landscape, different neighborhood‐scale disturbance–succession interactions caused variable initial responses in net primary production (NPP), net ecosystem production (NEP), soil respiration (Rs), gross primary production (GPP), and ecosystem respiration (ER). ‐, =, and + indicate negative, neutral, and positive responses; ¹Gough et al. 2007; ²Gough et al. 2021; ³Scheuermann et al. 2018; ⁴Clay et al. 2022; ⁵Stuart‐Haentjens et al., 2023; ⁶Gough et al. 2021.