Biology subjects

Bertuzzo, E.

Publications and source records attributed to Bertuzzo, E..

3 recordsLinked to original sources

bioRxiv2025

Reactive persistence of riverine metapopulations

Understanding the conditions that favor the persistence of metapopulations inhabiting riverine landscapes (riverscapes) is critical to guiding conservation and restoration efforts aimed at preserving biodiversity and ecological integrity in freshwater environments. In this study, we present a modeling framework to examine the transient persistence of fluvial metapopulations---the temporary occupation of riverscape patches by a metapopulation expected to become extinct in the long run. Our approach is theoretically grounded in the concept of ecological reactivity, which effectively complements asymptotic stability analysis in the study of the short-term response of ecological systems to impulsive perturbations of otherwise stable steady states. Our results suggest that, under ecohydrological conditions conducive to reactive metapopulation extinction equilibria, a metapopulation asymptotically bound to extinction can still colonize parts of the riverscape for significant periods of time. We also find that, in the presence of repeated positive perturbations of the extinction equilibrium, the temporal scales associated with these transient phenomena may allow for reactive pseudo-persistence. This phenomenon involves an arbitrarily long delay in the eventual extinction of the metapopulation, which may occur well below the deterministic extinction threshold. Identifying the ecohydrological drivers of reactivity-driven metapopulation persistence and the riverscape patches that contribute most to transient metapopulation dynamics over different temporal scales may provide valuable suggestions for the spatial prioritization of conservation and restoration efforts.

ecology↗

bioRxiv2020

Generation and application of river network analogues for use in ecology and evolution

O_LISeveral key processes in freshwater ecology and evolution are governed by the connectivity inherent to dendritic river networks. These networks have extensively been analyzed from a geomorphological and hydrological viewpoint, yet network structures classically used in modelling have only been partially representative of the structure of real river basins, and have often failed to capture well known scaling features of real river networks. Pioneering work has identified optimal channel networks (OCNs) as spanning trees that reproduce all scaling features characteristic of real, natural stream networks worldwide. While these networks have been used to generate landscapes for studies on metapopulations, biodiversity and epidemiology, their generation has not been generally accessible. C_LIO_LIGiven the increasing interest in dendritic riverine networks by ecologists and evolutionary biologists, we here present a method to generate OCNs and, to facilitate its application, we also provide the R-package OCNet. Owing to the random search process that generates OCNs, multiple network replicas spanning the same surface can be built, allowing one to perform computational experiments whose results do not depend on the particular shape of a single river network. The OCN construct also enables the generation of elevational gradients derived from the optimal network configuration, which can constitute three-dimensional landscapes for spatial studies in both terrestrial and freshwater realms. Moreover, the OCNet package provides functions that aggregate the OCN into an arbitrary number of nodes, calculate several metrics and descriptors of river networks, and draw relevant features of the network. C_LIO_LIWe describe the main functionalities of the package and present how it can be integrated into other R-packages commonly used in spatial ecology. Moreover, we exemplify the generation of OCNs and discuss an application to a metapopulation model for an invasive riverine species. C_LIO_LIIn conclusion, OCNet provides a powerful tool to generate and use realistic river network analogues for various applications. It thereby allows the design of spatially realistic studies in increasingly impacted ecosystems, and enhances our knowledge on spatial processes in freshwater ecology in general. C_LI

ecology↗

bioRxiv2018

Micro-hotspots of Risk in Urban Cholera Epidemics

Targeted interventions have been delivered to neighbors of cholera cases in epidemic responses in Haiti and Africa despite little evidence supporting impact. Using data from urban epidemics in Chad and D.R. Congo we estimate the size and extent of spatiotemporal zones of increased cholera risk around cases. In both cities, we found zones of increased risk of at least 200-meters during the 5-days immediately following case presentation to a clinic. Risk was highest for those living closest to cases and diminished in time and space similarly across settings. These results provide a rational basis for targeting interventions, if delivered rapidly.

epidemiology↗