MS05 - ECOP-1
Griffin West Ballroom (#2133) in The Ohio Union

Population-level impacts of ecological interactions across scales

Wednesday, July 19 at 10:30am

SMB2023 SMB2023 Follow Wednesday during the "MS05" time block.
Room assignment: Griffin West Ballroom (#2133) in The Ohio Union.
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Amanda Laubmeier


Ecological processes occur over a multitude of scales. These scales may be spatial (centimeters versus kilometers), temporal (days versus years), or ecological (individuals versus ecosystems). When important interactions occur across these scales, outcomes at one level may be drastically impacted by outcomes at another level. Because of this, explaining population-level outcomes often requires that we disentangle the effects of interactions across one or more of these scales. Isolating the effects of these interactions may be difficult or even impossible in practice. However, mathematical models which provide detailed descriptions of interactions across scales can improve our understanding of ecosystems. In this mini-symposium, we highlight work studying four different systems, in which ecological interactions at multiple scales impact a population of interest. The speakers use models across different scales to describe these interactions and provide valuable insight into a range of application-level questions. At the same time, their methodologies highlight the challenges associated with modelling interactions across scales. Such interactions are necessarily complex, leading to challenges in analysis, parameterization, and simulation of the resulting models. This minisymposium will provide a timely opportunity for researchers to compare the practical uses and limitations of ecological models across multiple scales.

Rebecca Everett

Haverford College (Department of Mathematics and Statistics)
"Nutrient driven dynamics of ecosystem diseases"
Autotrophs such as algae play an essential role in the cycling of carbon and nutrients, yet disease-ecosystem relationships are often overlooked in these dynamics. The availability of elemental nutrients like nitrogen and phosphorus impacts infectious disease in autotrophs, and disease can induce reciprocal effects on ecosystem nutrient dynamics. We use a mathematical model to illustrate the impact of disease-ecosystem feedback loops on both disease and ecosystem nutrient dynamics.
Additional authors: Lale Asik, University of the Incarnate Word; Elizabeth Borer, University of Minnesota; Thijs Frenken, Netherlands Institute of Ecology; Angélica González, Rutgers University; Angela Peace, Texas Tech University; Eric Seabloom, University of Minnesota; Alexander Strauss, University of Georgia; Dedmer Van de Waal, Netherlands Institute of Ecology

Mohammad Mihrab Uddin Chowdhury

Texas Tech University (Department of Mathematics and Statistics)
"Understanding Bsal Transmission Dynamics to Safeguard North American Salamander Populations"
Batrachochytrium Salamandrivorans (Bsal), a deadly fungal pathogen, is a significant threat to the survival of salamander populations in North America. It has led to the extinction of some salamander species in Europe and endangered others. Bsal's ability to spread through multiple routes with approximately zero recovery and high mortality underscores the crucial need for effective control measures. We developed a system of ordinary differential equations that incorporates direct and environmental transmission pathways across two spatial scales: aquatic and terrestrial environments. Alongside different routes of transmissibility, our study takes into account the environmental zoospore load, skin spore levels, population density, and temperature fluctuations. By simulating different scenarios and analyzing the results, the study aims to offer insights into effective control measures for reducing transmission and preventing epidemic outbreaks.
Additional authors: Matthew J. Gray, Department of Forestry, Wildlife and Fisheries, University of Tennessee Institute of Agriculture (UTIA) , Knoxville, Tennessee, USA ; Angela Peace, Department of Mathematics and Statistics, Texas Tech University, Lubbock, Texas, USA

Joshua C. Macdonald

Tel Aviv University (Faculty of Life Sciences)
"Forward hysteresis and Hopf bifurcation in a NPZD model with application to harmful algal blooms"
Nutrient-Phytoplankton-Zooplankton-Detritus (NPZD) models, describing the interactions between phytoplankton, zooplankton systems and their ecosystem, are used to predict their ecological and evolutionary population dynamics. These organisms form the base two trophic levels of aquatic ecosystems. Hence understanding their population dynamics and how disturbances can affect these systems is crucial. Here, starting from a base NPZ modeling framework, we incorporate the harmful affects of phytoplankton overpopulation on zooplankton - representing a crucial next step in harmful algal bloom (HAB) modeling - and split the nutrient compartment to formulate a NPZD model. We then mathematically analyze the NPZ system upon which this new model is based, including local and global stability of equilibria, Hopf bifurcation condition and forward hysteresis, where the bi-stability occurs with multiple attractors. Finally, we extend the threshold analysis to the NPZD model, which displays forward hysteresis with bi-stability, and examine ecological implications after incorporating seasonality and ecological disturbances. Ultimately, we quantify ecosystem health in terms of the relative values of the robust persistence thresholds for phytoplankton and zooplankton and find (i) ecosystems sufficiently favoring phytoplankton, as quantified by the relative values of the plankton persistence numbers, are vulnerable to both HABs and (local) zooplankton extinction (ii) even healthy ecosystems are extremely sensitive to nutrient depletion over relatively short time scales.
Additional authors: Hayriye Gulbudak, University of Louisiana, Department of Mathematics

Omar Saucedo

Virginia Tech (Mathematics)
"The impact of host movement on mosquito-borne disease dynamics"
Mosquitos are known for being a source of infectious diseases and are cause of great concern within the public health community. Throughout the world, there are a variety of mosquito species that are associated with different mosquito-borne pathogens. Diseases such as malaria have surfaced in areas where they previously have not been detected, and the incidence of these diseases have been steadily increasing. A better understanding of mosquito-borne pathogens is needed as this poses a severe threat to many communities. In this talk, we will explore how epidemiological and ecological features influence mosquito-borne disease dynamics via a multi-patch compartmental model.

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Annual Meeting for the Society for Mathematical Biology, 2023.