Angeler, D. | Search bioRxiv

bioRxiv2022

Parallels of quantum superposition in ecological models: from counterintuitive patterns to eco-evolutionary interpretations of cryptic species

Superposition, i.e. the ability of a particle (electron, photon) to occur in different states or positions simultaneously, is a hallmark in the subatomic world of quantum mechanics but non-sensical from the perspective of macro-systems such as ecosystems and other complex systems of people and nature. Using time series and spatial analysis of bird, phytoplankton and benthic invertebrate communities, this paper shows that superposition can occur analogously in redundancy analysis (RDA), a form of canonical ordination frequently used by ecologists. Specifically, we used correlation analysis to show that species can be associated simultaneously with different orthogonal axes in RDA models, a pattern reminiscent of superposition. We discuss this counterintuitive result in relation to the statistical and mathematical features of RDA and the recognized limitations with current traditional species concepts based on vegetative morphology. We suggest that such "quantum weirdness" is reconcilable with classical ecosystems logic when the focus of research shifts from morphological species to cryptic species that consist of genetically and ecologically differentiated subpopulations. We support our argument with theoretical discussions of eco-evolutionary interpretations that should become testable once suitable data are available.

ecology↗

bioRxiv2020

Low contribution of rare species to resilience and adaptive capacity in novel spatial regimes arising from biome shifts caused by global change

Human activity causes biome shifts that alter biodiversity and spatial resilience patterns, ultimately challenging conservation. Rare species, often considered vulnerable to change and endangered, can be a critical element of resilience by providing adaptive capacity in response to disturbances. However, little is known about changes in rarity and dominance patterns of communities once a biome transitions into a novel spatial regime, and how this affects conservation. We used time series modeling to identify species rarity and dominance patterns in an expanding terrestrial (southern) spatial regime in the North American Great Plains and another (northern) regime that will become encroached by the southern regime in the near future. In this approach, presumably rare and abundant species show stochastic and deterministic dynamics, respectively. We specifically assessed how stochastic species of the northern spatial regime influence the resilience and adaptive capacity of a novel spatial regime once it has been encroached by the southern regime by either becoming deterministic or staying stochastic. Using 47 years (1968 - 2014) of breeding bird survey data and a space-for-time substitution, we found half of the stochastic species from the northern regime to be either deterministic or stochastic in the southern regime. However, the overall contribution of these species to the community of the southern regime was low, manifested in marginal contributions to resilience and adaptive capacity of this regime. Also, none of these species were of conservation concern, suggesting limited need for revised species conservation action in the novel spatial regime. From a systemic perspective our result suggest that while stochastic species can potentially compensate for the loss of dominant species after disturbances and maintain the system in its current regime, they may only marginally contribute to resilience and adaptive capacity in a new spatial regime after fundamental ecological changes have occurred.

ecology↗