Mind, the gap in landscape‐evolution modelling

Abstract

Despite an increasing recognition that human activity is currently the dominant force modifying landscapes, and that this activity has been increasing through the Holocene, there has been little integrative work to evaluate human interactions with geomorphic processes. We argue that agent-based models (ABMs) are a useful tool for overcoming the limitations of existing, highly empirical approaches. In particular, they allow the integration of decision-making into process-based models and provide a heuristic way of evaluating the compatibility of knowledge gained from a wide range of sources, both within and outwith the discipline of geomorphology. The application of ABMs to geomorphology is demonstrated from two different perspectives. The SPASIMv1 (Special Protection Area SIMulator version 1) model is used to evaluate the potential impacts of land-use changeparticularly in relation to wildfi re and subsequent soil conditions, runoff and erosion -over a decadal timescale from the present day to the mid-twenty-fi rst century. It focuses on the representation of farmers with traditional versus commercial perspectives in central Spain, and highlights the importance of land-tenure structure and historical contingencies of individuals' decision-making. CYBEROSION, however, considers changes in erosion and deposition over the scale of at least centuries. It represents both wild and domesticated animals and humans as model agents, and investigates the interactions of them in the context of early agriculturalists in southern France in a prehistoric context. We evaluate the advantages and disadvantages of the ABM approach, and consider some of the major challenges. These challenges include potential process-scale mismatches, differences in perspective between investigators from different disciplines, and issues regarding model evaluation, analysis and interpretation. If the challenges can be overcome, this fully integrated approach will provide geomorphology a means to conceptualize soundly the study of humanlandscape interactions by bridging the gap between social and physical approaches.

The Anthropocene: is there a geomorphological case?

“…Recognition of diachrony does not fatally diminish the argument for recognition of an Anthropocene time interval, as all geological boundaries derived from changes in the stratigraphic record, except the Pleistocene/Holocene boundary (Walker et al ., ), have diachronies in the order of, or much greater than, 5–10 ka. However, process‐based studies and complexity‐theory approaches suggest that diachrony in human impacts on the landscape is likely to be the rule rather than the exception (Wainwright and Millington, ) and is an integral component of the Holocene and what marks it apart from the Pleistocene Epoch. Diachrony does, however, have implications both for how we demarcate the Anthropocene and potentially for its formal chronological status (e.g.…”

Integrating Modelling Approaches for Understanding Telecoupling: Global Food Trade and Local Land Use

“…For example, representation of decision-making can be driven by cultural preferences, e.g., [28] or differentiated between different types of agent (e.g., conventional vs. diversifier farmers [29]). As a result of its flexibility, agent-based modelling has been used widely to investigate human-environment interactions and for understanding land use and landscape change, e.g., [22,30,31]. In the context of land use and global food trade, ABMs have been used to examine smallholder adaptation to climate change by examining agent forecasting and communication [32], decision-making about adoption of organic farming practices [33], and the importance of social networks for farmer decision-making [34].…”

21st century climate change: where has all the geomorphology gone?

“…This is why studies of the relationship between climate change and soil erosion are needed, not just because of potential impacts of climate change upon soil erosion, but because of what these impacts might mean in terms of carbon flux (Dymond et al, 2010;Doetterl et al, 2012). A notable exception is Wainwright and Millington (2010) who show that it is possible to use agent-based models to understand the coupled interaction and co-evolution of physical and social systems and the impacts of this interaction on sediment flux. First, classic studies on the controls of soil erodibility need to be extended to the question of soil carbon release.…”

“…It is a particular challenge because it is probable that soil management will evolve in response to climate forcing, implying that understanding the future net impact of climate change upon the carbon cycle will require us to predict the coupled evolution of social-human geomorphic and hydrological systems, something that is rarely seen in geomorphic enquiry. A notable exception is Wainwright and Millington (2010) who show that it is possible to use agent-based models to understand the coupled interaction and co-evolution of physical and social systems and the impacts of this interaction on sediment flux.…”