Bridging Disciplinary Gaps in Studies of Human-Environment Relations: A Modelling Framework

Modern human-environment relations are problematic and difficult to analyse in terms of nature and culture. Many authors suggest to abandon and overcome the nature-culture dichotomy in order to reorganise the academic division of labour, not only on environmental questions. Anthropologist Philippe Descola, for example, surveyed the empirical evidence of patterns in humanenvironmental relations, suggesting four abstract cosmologies. Here, we propose a translation into a modelling terminology, which is compatible with the formalisation of programmes in computer science. The generalised framework contains four ideal types of modelling paradigms. It can be tested on various other classification schemes in a number of disciplines. In each application, the categories of classification can be translated and then the patterns of the four logic types can be compared with the phenomenology of each case. Implications for interdisciplinary cooperation between science and the humanities are sketched for some environmental issues. This work demonstrates how tools from computer science can help, metaphorically, conceptually and technically, to organise interdisciplinary exchanges between science and the humanities. The categorical approach of applying the “divide and conquer” technique to different disciplinary models serves as a yardstick for comparing the implicit logic and modelling assumptions across examples whose phenomenological contents appear as unrelated. It gives useful hints how a dilemma of choosing between rigorous or relevant models can be resolved (e.g., in environmental science) and how the nature-culture dichotomy might be replaced by a general and flexible framework of a few model types

Insight into hydrochemistry: a multi-catchment comparison using Horizontal Visibility Graphs

Long time series of environmental variables are reflecting the dynamics and functioning of ecosystems. Here, we investigate data from a long-term monitoring site in Germany, the Bramke valley in the Harz mountains, where time series of ion concentrations in stream water are obtained since the 1970ies at four measurement locations from three small adjacent forested catchments. Since for (only) one of the catchments daily runoff rates are also available, we invent a method to generate time series of nutrient output from the catchments. Both concentrations and outputs show a number of remarkable long-term changes, including ones not obviously related to changes in atmospheric deposition, management or properties of the forest stands. For the analysis of the Bramke data, we investigate Horizontal Visibility Graphs (HVGs), a recently developed method to construct networks based on time series. Values (the nodes of the network) of the time series are linked to each other if there is no value higher between them. The network properties, such as the degree and distance distributions, reflect the nonlinear dynamics of the time series. For certain classes of stochastic processes and for periodic time series, analytic results can be obtained for some network properties. HVGs have the potential to discern between deterministic-chaotic and correlated-stochastic time series. We classify the Bramke series according to their stochastic nature, with a focus on inter-catchment comparison on one hand, on different nutrients for one catchment on the other, and conclude on possible reasons for the observed changes and their ecological interpretation

Das Anthropozän - Realität oder akademische Konstruktion?

Der Begriff des Anthropozäns fordert auf zu einer neuen Zusammenarbeit zwischen Natur-, Technik-, Sozial- und Kulturwissenschaften.Das Anthropozän - Realität oder akademische Konstruktion?publishedVersio

Emergence of Observational Hierarchies in Natural Evolution

The starting point for our work are (models for) forest ecosystems. We seek to integrate two sources of knowledge about such ecosystems: the scientific approach from the viewpoint of an exo-observer (one that is detached from the system and has theoretically unlimited observational capacity) and the management approach for utilization (one that has a common history with the managed system and includes the possibility of an endo-observer). Within the scientific approach, these ecosystems are often regarded as being among the most "complex" systems that can be abstracted as objects, whereas their practical management for human utilization (including interferences of an occasionally entangled endo-observer) sometimes has allowed economically reliable predictions over time scales from years up to a century. Each approach alone seems to be insufficient to solve the theoretical and applied problems of contemporary ecology. Practical experiences on one hand cannot be extrapolated and become i..

A CRITIQUE OF AGENT-BASED SIMULATION IN ECOLOGY

ABSTRACT Models link empirical observations with formal reasoning. If the computer plays an essential role in their functioning, it seems only fair to consider theoretical computer science as well as the discipline of application. We review some perennial philosophical problems about the nature of state and behaviour in models from that perspective. A mathematical framework for their explication and the unbiased choice of solutions is proposed. Agent-based models play an increasing role in ecological modelling. They are taken here as an example for demonstrating critical assumptions and dilemmas in integrating criteria of methodological rigour with practical relevance of models. Some possible solutions and their practical implications are outlined based on this new theoretical perspective

Water Flowpaths and Residence Times in a Small Headwater Catchment at Gardsjon (Sweden) during Steady State Stormflow Conditions

Since April 1991 the small forested headwater catchment G1 at Gardsjon (Sweden) has been covered by a roof underneath which natural throughfall is replaced by artificial irrigation with a controlled chemical composition. Here, this unique experimental setup was used for a tracer experiment with LiBr. The tracer pulse was applied to a subcatchment of approx. 1000 m 2 that was maintained at steady state flow conditions throughout the experiment. Except these steady state flow conditions, the irrigation rates corresponded to a typical stormflow episode. Infiltration of event water was confined to the steep slope of a subcatchment of G1, no water was applied at the boggy valley bottom or close to the weir. An array of groundwater wells, suction lysimeters, and surface water sampling plots was used to document the soil passage of this pulse. Breakthrough in runoff (i.e., streamflow from the weir) occurred in a single peak within about 17 hours when less than 15% of the estimated total soi..