|1||Title: A probabilistic framework for windows of opportunity: the role of temporal variability in critical transitions |
Speaker: Dr. Jim van Belzen, NIOZ Royal Netherlands Institute for Sea Research
The establishment of young organisms in harsh environments often requires a window of opportunity (WoO). That is, a short time window in which environmental conditions drop long enough below the hostile average level, giving the organism time to develop tolerance and transition into stable existence. It has been suggested that this kind of establishment dynamics is a noise-induced transition between two alternate states. Understanding how temporal variability (i.e. noise) in environmental conditions affects establishment of organisms is therefore key, yet not well understood or included explicitly in the WoO framework. In this paper, we develop a coherent theoretical framework for understanding when the WoO open or close based on simple dichotomous environmental variation. We reveal that understanding of the intrinsic timescales of both the developing organism and the environment is fundamental to predict if organisms can or cannot establish. These insights have allowed us to develop statistical laws for predicting establishment probabilities based on the period and variance of the fluctuations in naturally variable environments. Based on this framework, we now get a clear understanding of how changes in the timing and magnitude of climate variability or management can mediate establishment chances.
|2||Title: A thermodynamic approach to coastal dynamics: feedback relationships between bioturbation, energy use, information processing and sediment dynamics|
Speaker: Dr. Francesco Cozzoli, Italian National Research Council CNR, Research Institute on Terrestrial Ecosystems IRET
Bioturbation is an ecosystem engineering process defined as the physical movement of soil by fauna or plant roots. It has a huge effect on the stability, structure and chemical composition of sediments. By regulating the flows of energy, matter and information between sediments, water and air, bioturbation constitutes a hinge point between the biosphere, lithosphere, hydrosphere and atmosphere. Bioturbators are often involved in feedback relationships (i.e., cybernetic loops) with their habitat as they tend to modify environmental conditions relevant to their own fitness. For example, the structure and functioning of coastal sedimentary habitats are partially determined by the constant destabilization and oxygenation of sediments carried out by endobenthic and epibenthic organisms. In turn, these habitat conditions influence the species identity, life history, abundance, activity of benthic organisms and, therefore, their ecosystem engineering effects. The effect of the accumulation of bioturbator-induced habitat changes in combination with physical processes increases to become a major driver of landscape evolution and global climate. Deepening the mechanistic knowledge of the bioturbation process and the cybernetics of the ecosystems in which it is involved is therefore fundamental to understanding the ecological dynamics and predicting the future functioning and stability of the Earth system.
The sediment reworking rate by the ectotherms endobenthic fauna is strictly dependent on the metabolic needs of oxygen and food of individuals. It follows that sediment reworking rates should scale predictably based on the same general factors as individual metabolic rates, namely individual body mass and temperature. This inference allows us to frame anecdotal observations on the effects of bioturbation and coastal feedback dynamics in the broader context of ecological energy, that is, the set of ecological theories that interpret the thermodynamic rules underlying individuals' energy use and its effect at multiple levels of ecological organization. Supporting this hypothesis, we observed empirically that the per capita effect of benthic bioturbators on sediment erodibility scales with individual body mass aligns with theoretical expectations for metabolic rate scaling of individual and population metabolic rates. Our goal now is to extend this energy-based approach from the individual and population level to the community and ecosystem level, leveraging ecological information theory and ecosystem cybernetics. Such a framework would account for the effect of climate change on the cybernetics of coastal ecosystems through the temperature dependence of the metabolic rates of ectothermic bioturbators, therefore allowing mechanistic predictions on future ecosystem dynamics.
|3||Title: Hindcasting Ecosystem Functioning Change in an Anthropogenized Estuary: Implications for an Era of Global Change|
Speaker: Dr. Xiaoyu Fang, State Key Laboratory of Estuarine and Coastal Research,
East China Normal University
Understanding how altered hydrodynamics related to climate change and anthropogenic modifications affect ecosystem integrity of shallow coastal soft-sediment environments requires a sound integration of how species populations influence ecosystem functioning across heterogeneous spatial scales. Here, we hindcasted how intertidal habitat loss and altered hydrodynamic regimes between 1955 and 2010 associated with geomorphological change to accommodate expansion in anthropogenic activities in the Western Scheldt altered spatial patterns and basin-wide estimates of ecosystem functioning. To this end we combined an empirically derived metabolic model for the effect of the common ragworm Hediste diversicolor on sediment biogeochemistry (measured as sediment oxygen uptake) with a hydrodynamic and population biomass distribution model. Our integrative modeling approach predicted an overall decrease by 304 tons in ragworm biomass between 1955 and 2010, accounting for a reduction by 28% in stimulated sediment oxygen uptake at the landscape scale. Local gains or losses in habitat suitability and ecosystem functioning were primarily driven by changes in maximal current velocities and inundation regimes resulting from deepening, dredging and disposal practices. By looking into the past, we have demonstrated how hydro- and morphodynamic changes affect soft-sediment ecology and highlight the applicability of the integrative framework to upscale anticipated population effects on ecosystem functioning.
For additional information, please refer to the following link: https://www.frontiersin.org/articles/10.3389/fmars.2021.747833/full
|4||Title: Marine Ecosystem Engineers Long-term Evolution Modeling in Response to Climate Change and Sediment Transport in Seine Estuary|
Speaker: Ms. Amélie Lehuen, Université de Caen Normandie, Biologie des Mollusques Marins et des Ecosystèmes Associés (BioMEA)
The etymology of ecology is "the study of habitat", and in biology translates into the study of the relationships between living organisms and their physical environment. An estuary is a particularly complex ecosystem, where physical conditions have a major influence on the habitats found there. Sedimentary and hydrological parameters have a direct impact on the spatial distribution and activity of benthic macrofauna, with sediments acting as food sources, refuges, and breeding grounds.
The question of defining the spatial and temporal distribution of a species led to the notion of ecological niche, and the construction of Species Distribution Models (SDM). Among the many possible methods for obtaining an SDM, this work proposes an Optimal Ecological Niche SDM (SDM-NEO), which is a correlative model based on quantile regression using a bifactorial Gaussian distribution. The quantile approach makes it possible to estimate the impact of an abiotic factor on the biological response without considering limiting factors. The original addition of this model is to use a bifactorial Gaussian basis to integrate the classical biological response type and to consider the extreme values of the predictors which can alter the biological response. Four pairs of abiotic predictors are proposed, as well as a habitability index for management purposes. As part of a feedback loop, macrozoobenthic species are often ecosystem engineers, physically modulating the environment around them, and more specifically through a set of sediment reworking processes known as bioturbation. A monospecific bioturbation model is constructed from six erodimetry datasets, assessing the amount of sediment reworked as a function of the metabolic rate of the fauna present in the sample and the sediment type. It is used to model the erosion of this biogenic layer under the various experimental conditions collected. In addition, experimental work has been carried out to quantify the effect of multi-species bioturbation as a function of metabolic rate and temperature.
This work was carried out as part of the MELTING POTES project, whose aim is to determine how the effects of community bioturbation can contribute to the long-term evolution of the estuarine sedimentary bed, and thus impact on the optimal ecological niches in the Seine estuary, both in observed periods and for projections based on climate change scenarios.
|5||Title: Holism in Marine Management: an Integrated Systems Analysis Approach to Marine Social-Ecological Systems|
Speaker: Ms. Gemma Smith, International Estuarine and Coastal Specialists Ltd, University of Hull
This presentation offers insight into the operationalised Integrated Systems Analysis (ISA) approach by Elliott, Borja, and Cormier (2020), a decision-making tool specially designed for managing marine Social-Ecological Systems (SES). These are places where social and ecological aspects interact in complex ways, a prime example being the marine environment. Using principles from cybernetics and the science of systems and controls, the ISA approach provides a structured yet flexible framework for understanding these complex interactions. The ISA model blends several essential elements together. It starts with the DAPSI(W)R(M) framework (pronounced dap-see-worm), which stands for Drivers-Activities-Pressures-State Changes-Impacts-Responses. This framework helps to map out the different aspects of the marine environment, from the driving needs warranting activities which affect the environment to the pressures it faces and the subsequent state changes, all the way to the impacts on human welfare for designing Response Measures. To make sense of these, we also employ systems tools such as Behaviour Over Time graphs and Causal Loop Diagrams, which help to visualise how different parts of the system behave and affect one another. A key feature of the ISA approach is the concept of feedback loops within the system, with particular use of the Kumu software. The ISA model uses an anti-clockwise cycle that starts with studying the impacts on human welfare and leads to potential management responses. This is known as the inner problem-structuring cycle. It constantly feeds information back into the system, helping us learn and adapt our approaches for better outcomes. This inner cycle is overseen by an outer learning action cycle, encompassed within an outer management system that considers aspects such as administration, governance, stakeholder engagement, and data management, ensuring that the approach is holistically managed. To demonstrate the ISA approach in action, this presentation will give insight into the overall approach and detail the application in the Marine SABRES project, which aims to reduce the complexity of these marine systems for easier management. Overall, the ISA approach offers a detailed yet adaptable method that uses cybernetics and recursion to understand better and manage the intricate relationships within marine SESs.
Further information about the project can be found at: https://www.marinesabres.eu/
For further information on the Integrated Systems Analysis, see: Elliott, M., Borja, Á. & Cormier, R. (2020) Managing marine resources sustainably: A proposed Integrated Systems Analysis approach. Ocean & Coastal Management, 197. https://doi.org/10.1016/j.ocecoaman.2020.105315.
|6||Title: Entropy determines the intrinsic value of ecosystems: does it connect to decision making|
Speaker: Dr. Fabio Bozzeda, Department of Biological and Environmental Sciences and Technologies, University of Salento, DiSTeBA
The larger view of ecosystem definition issue we confront is described as a linked system. At the broadest level, an ecosystem may be understood as a (possibly multi-layered) network of connected nodes and links. The links are connected by probability laws, including the degenerate probability 1.00, depending on the mechanistic aspects of the linkages. In general, the connections will not be random (equal probability of occurring). Indeed, for our purposes, the probability laws can include power laws, distribution with infinite first and second moments and so on depending on the nature of the physical system that is studied (e.g., an exponential network such as a road system, or a scale free network, such as an airline system). Because any ecosystem can only be observed at specific intervals of time, regardess of what is being monitored or otherwise observed, inherently we are dealing with probabilistic aspects of observations and process definition. Hence, probability laws are the output of the linkage answering the question: given a linkage, what is the output? To simplify, suppose A and B are connected, what is the distribution function that connects them – the distribution of the possible connections? How can ecosystems and their respective subsystems be described? In this study, I will elucidate the methodology for calculating an intrinsic value for various ecosystem levels employing and merging three entropy definitions: thermodynamic entropy (Boltzmann), Shannon entropy, and informational entropy.
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