Hauke Reuter

Selforganization of fish schools: An object-oriented model

Abstract Simulation models help to understand how individual interactions can lead to selforganization of large, moving polarized schools of fish. To some extend the underlying mechanisms in these models are still hypothetical. This paper investigates and confirms previously published results and suggests an alternative model. Previous models of fish schools used the assumption that individuals modify their swimming direction and speed as a reaction to a small fixed number of other individuals swimming closest to their own swimming direction (front priority). They also used discrete transitions between different reaction types to their neighbours (see Huth and Wissel, this volume). These models are able to simulate school movement in a homogeneous environment but fail under certain heterogeneous conditions (e.g. when schools meet obstacles) and do not adequately simulate the formation process of schools. We present an alternative model, in which a fishs new speed and swimming direction is influenced by all visible neighbours. Each neighbour contributes a vector component weighted according to its distance. These components are aggregated to determine to what extent the different behavioural modes of searching, attraction, parallel orientation and repulsion contribute to a modification of an individuals movement in a particular situation. The resulting model reproduces schooling behaviour, organization of schools and has fewer artificial requirements concerning a biological interpretation of the underlying mechanisms. It shows how a comparison of different modelling approaches, empirical observation of inter-organismic interaction, and physiological research can stimulate each other in order to understand a complex, dynamic phenomenon.

Information system for monitoring environmental impacts of genetically modified organisms

Background, aim and scopeEuropean legislation stipulates that genetically modified organisms (GMO) have to be monitored to identify potential adverse environmental effects. A wealth of different types of monitoring data from various sources including existing environmental monitoring programmes is expected to accumulate. This requires an information system to efficiently structure, process and evaluate the monitoring data.MethodsA structure for an Information System for Monitoring GMO (ISMO) was developed by a multidisciplinary research team. It is based on the requirement to organise all relevant information in a logical, readily accessible and functional manner.ResultsFor the ISMO, we present a combination of three interrelated components: Firstly, an ISMO should comprise a knowledge database structured according to information related to the different scale levels of biological organisation relevant to GMO monitoring and scientific hypotheses on cause–effects which should be validated by monitoring data. Secondly, a monitoring database should be part of an ISMO containing GMO-specific monitoring data and meta-data. This monitoring database should be linked with monitoring data from other monitoring programmes which are relevant for GMO-related questions. Thirdly, an ISMO should encompass a database covering administrative and procedural data. Neither national nor international approaches to an ISMO exist yet.ConclusionsAn ISMO as designed in this paper could support competent authorities in both the GMO notification process and in post-market monitoring. This includes evaluating the environmental risks of experimentally releasing GMO and placing them on the market, assessing monitoring plans and evaluating monitoring results. The ISMO should be implemented on both the national and international level, preferably combining different administrative scales. Harmonisation approaches towards GMO monitoring data are at an initial stage, but they are a precondition to coordinated GMO monitoring and to successfully implementing an ISMO. It is recommended to set up a legal basis and to agree on common strategies for the data coordination and harmonisation.

The ecological effect of phenotypic plasticity — Analyzing complex interaction networks (COIN) with agent-based models

Abstract Analyzing complex dynamics of ecological systems is complicated by two important facts: First, phenotypic plasticity allows individual organisms to adapt their reaction norms in terms of morphology, anatomy, physiology and behavior to changing local environmental conditions and trophic relationships. Secondly, individual reactions and ecological dynamics are often determined by indirect interactions through reaction chains and networks involving feedback processes. We present an agent-based modeling framework which allows to represent and analyze ecological systems that include phenotypic changes in individual performances and indirect interactions within heterogeneous and temporal changing environments. We denote this structure of interacting components as COmplex Interaction Network (COIN). Three examples illustrate the potential of the system to analyze complex ecological processes that incorporate changing phenotypes on the individual level: • A model on fish population dynamics of roach ( Rutilus rutilus ) leads to a differentiation in fish length resulting in a conspicuous distribution that influences reproduction capability and thus indirectly the fitness. • Modeling the reproduction phase of the passerine bird Erithacus rubecula (European Robin) illustrates variation in the behavior of higher organisms in dependence of environmental factors. Changes in reproduction success and in the proportion of different activities are the results. • The morphological reaction of plants to changes in fundamental environmental parameters is illustrated by the black alder ( Alnus glutinosa ) model. Specification of physiological processes and the interaction structure on the level of modules allow to represent the reaction to changes in irradiance and temperature accurately. Applying the COIN-approach, individual plasticity emerges as a structural and functional implication in a self-organized manner. The examples illustrate the potential to integrate existing approaches to represent detailed and complex traits for higher order organisms and to combine ecological and evolutionary aspects.

Spatio-Temporal Patterns in Coral Reef Communities of the Spermonde Archipelago, 2012–2014, I: Comprehensive Reef Monitoring of Water and Benthic Indicators Reflect Changes in Reef Health

Pollution, fishing, and outbreaks of predators can heavily impact coastal coral reef ecosystems, leading to decreased water quality and benthic community shifts. To determine the main environmental drivers of coral reef status in the Spermonde Archipelago, Indonesia, we monitored environmental variables and coral reef benthic community structure along an on-to-offshore gradient annually from 2012-2014. Findings revealed that concentrations of phosphate, chlorophyll a-like fluorescence, suspended particulate matter, and light attenuation significantly decreased from on-to-offshore, while concentrations of dissolved O2 and values of water pH significantly increased on-to-offshore. Nitrogen stable isotope signatures of sediment and an exemplary common brown alga were significantly enriched nearshore, identifying wastewater input as a primary N source from the city of Makassar. In contrast to the high temporal variability in water quality, coral reef benthic community cover did not show strong temporal, but rather, spatial patterns. Turf algae was the dominant group next to live coral, and was negatively correlated to live coral, crustose coralline algae (CCA), rubble and hard substrate. Variation in benthic cover along the gradient was explained by water quality variables linked to trophic status and physico-chemical variables. As an integrated measure of reef status and structural complexity, the benthic index, based on the ratio of relative cover of live coral and CCA to other coral reef organisms, and reef rugosity were determined. The benthic index was consistently low nearshore and increased offshore, with high variability in the midshelf sites across years. Reef rugosity was also lowest nearshore and increased further offshore. Both indices dropped in 2013, increasing again in 2014, indicating a period of acute disturbance and recovery within the study and suggesting that the mid-shelf reefs are more resilient to disturbance than nearshore reefs. We thus recommend using these two indices with a selected number of environmental variables as an integral part of future reef monitoring.

Breaking resilience for a sustainable future: Thoughts for the anthropocene

Strong resilience of a system usually enables the protection of a status quo. Most resilience studies assume that resilience-building is the central objective of sustainability work. Even though transformation has become a central theme in the development and social-ecological debates, questions surrounding the weakening resilience of undesired system states are rarely analyzed. We suggest that resilience studies not only serve to protect systems and feedbacks we want to maintain, but may also help to understand and overcome chronic, undesirable, - and thus wicked - resilience. This contribution focuses on reef fisheries in the Spermonde Island Archipelago in Indonesia, based on social and ecological studies between 2004 and 2016. We identify a number of interlocking wickedly resilient vicious cycles as predominant drivers of the poverty and exploitation of fishing households and the overexploited, polluted and degraded state of the coral reefs that fishers’ livelihoods depend on. We argue that, more often than not in the Anthropocene, breaking resilience has a central role in the pursuit of sustainable human-nature relations. Therefore, the link between the resilience and the transformation debates needs to be much more explicitly made. Breaking interlocking, wicked resilience at multiple levels is needed to move towards sustainable human-nature relations from the local to the global level. There are lacunae in debate, literature, and research practice as to when, where and how wicked resilience might need to be weakened. A more complete resilience lens is particularly needed under Anthropocene conditions to support the unmaking of chronically resilient, anthropogenic systems.

Information System for the Monitoring of Genetically Modified Organisms (GMO) – ISMO –

Abstract.Regarding the increasing number of GMO, a large amount of different types of data from various sources will be accumulated. Expected amount and quality of data emphasises the need for a respective information system to efficiently process and evaluate monitoring data. A concept for such an Information System for the MOnitoring of GMOs (ISMO) has been developed for the German Agency for Nature Conservation (BfN). The aim of the system is to support the competent authorities, especially the BfN, with their tasks in the notification process and the post market analysis of environmental effects.This paper will focus on the conceptual background as well as on components and structure of the information system to be developed.

Spatio-Temporal Patterns in the Coral Reef Communities of the Spermonde Archipelago, 2012–2014, II: Fish Assemblages Display Structured Variation Related to Benthic Condition

The Spermonde Archipelago is a complex of ~70 mostly populated islands off Southwest Sulawesi, Indonesia, in the center of the Coral Triangle. The reefs in this area are exposed to a high level of anthropogenic disturbances. Previous studies have shown that variation in the benthos is strongly linked to water quality and distance from the mainland. However, little is known about the fish assemblages of the region and if their community structure also follows a relationship with benthic structure and distance from shore. In this study, we used eight islands of the archipelago, varying in distance from 1-55 km relative to the mainland, and three years of surveys, to describe benthic and fish assemblages and to examine the spatial and temporal influence of benthic composition on the structure of the fish assemblages. Cluster analysis indicated that distinct groups of fish were associated with distance, while few species were present across the entire range of sites. Relating fish communities to benthic composition using a multivariate generalized linear model confirmed that fish groups relate to structural complexity (rugosity) or differing benthic groups; either algae, reef builders (coral and crustose coralline algae) or invertebrates and rubble. From these relationships we can identify sets of fish species that may be lost given continued degradation of the Spermonde reefs. Lastly, the incorporation of water quality, benthic and fish indices indicates that local coral reefs responded positively after an acute disturbance in 2013 with increases in reef builders and fish diversity over relatively short (one year) time frames. This study contributes an important, missing component (fish community structure) to the growing literature on the Spermonde Archipelago, a system that features environmental pressures common in the greater Southeast Asian region.

What Are the General Conditions Under Which Ecological Models Can be Applied

The purpose of this chapter is to discuss the conditions under which models can be applied. Modelling can help to solve specific problems, but not all questions in ecology require or benefit from the application of a model. It is therefore necessary to have an idea about the criteria under which the development of a model can provide useful information or help to solve questions in ecological analysis and which conceptual and technical approaches are the most appropriate ones. Technical knowledge about the particular modelling techniques is presented in the subsequent chapter of this book. Here, we intend to give an overview of the basic criteria of model application.

Entwicklung eines Modells zur Abschätzung der regionalen Pollenverbreitung von gentechnisch verändertem Mais (MaMo)

Wir haben im Rahmen der Wirkungspfadanalyse ( Kap. 3) festgestellt, dass die Untersuchung von Wirkungen und Risiken von GVO skalenspezifisch unterschiedlich intensiv erfolgten. Fur grose Skalen liegen zunehmend weniger wissenschaftlich abgesicherte Kenntnisse uber potenzielle Auswirkungen vor. Hier ergab sich die Moglichkeit, die Methodik der okologischen Modellierung in einem neuen Zusammenhang anzuwenden und in diesem Anwendungsfeld innovativ zu erproben. Wir beschreiben hier zunachst die Modellkonzeption und die Parametrisierung und sodann die ersten Anwendungsergebnisse fur verschiedene Raumausschnitte ( Kap. 5).

Historical Background of Ecological Modelling and Its Importance for Modern Ecology

The chapter outlines major routes of development leading to the current spectrum of concepts and applications in ecological modelling. The field is closely linked to achievements in other sciences, in particular physics, numerics, computer science, and cross-disciplinary adoption of ideas. Ecological modelling emerged initially as a relatively homogeneous field and mainly employed differential equations which originated in classical mechanics. Quantitative ecological dynamics were initially described in a formal analogy to physical processes. In the last few decades, the methodological repertoire in ecological modelling was successively expanded. Nowadays, the whole range of quantitative methods available in numerical mathematics can be seen as a foundation for future model development in ecology. Some pioneers in the field are briefly introduced and their contributions linked to some of the mainstreams and sidelines of the state-of-the-art in ecological sciences. The overview provided here will not be able to provide historical completeness but attempts to facilitate an understanding of the origin of the major approaches presented in this book and how they obtained their role in current ecological modelling.