@misc{SiblyGrimmMartinetal.2013,
  author    = {Sibly, Richard M. and Grimm, Volker and Martin, Benjamin T. and Johnston, Alice S. A. and Kulakowska, Katarzyna and Topping, Christopher J. and Calow, Peter and Nabe-Nielsen, Jacob and Thorbek, Pernille and DeAngelis, Donald L.},
  title     = {Representing the acquisition and use of energy by individuals in agent-based models of animal populations},
  series = {Methods in ecology and evolution : an official journal of the British Ecological Society},
  volume    = {4},
  journal   = {Methods in ecology and evolution : an official journal of the British Ecological Society},
  number    = {2},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {2041-210X},
  doi       = {10.1111/2041-210x.12002},
  pages     = {151 -- 161},
  year      = {2013},
  abstract  = {Agent-based models (ABMs) are widely used to predict how populations respond to changing environments. As the availability of food varies in space and time, individuals should have their own energy budgets, but there is no consensus as to how these should be modelled. Here, we use knowledge of physiological ecology to identify major issues confronting the modeller and to make recommendations about how energy budgets for use in ABMs should be constructed. Our proposal is that modelled animals forage as necessary to supply their energy needs for maintenance, growth and reproduction. If there is sufficient energy intake, an animal allocates the energy obtained in the order: maintenance, growth, reproduction, energy storage, until its energy stores reach an optimal level. If there is a shortfall, the priorities for maintenance and growth/reproduction remain the same until reserves fall to a critical threshold below which all are allocated to maintenance. Rates of ingestion and allocation depend on body mass and temperature. We make suggestions for how each of these processes should be modelled mathematically. Mortality rates vary with body mass and temperature according to known relationships, and these can be used to obtain estimates of background mortality rate. If parameter values cannot be obtained directly, then values may provisionally be obtained by parameter borrowing, pattern-oriented modelling, artificial evolution or from allometric equations. The development of ABMs incorporating individual energy budgets is essential for realistic modelling of populations affected by food availability. Such ABMs are already being used to guide conservation planning of nature reserves and shell fisheries, to assess environmental impacts of building proposals including wind farms and highways and to assess the effects on nontarget organisms of chemicals for the control of agricultural pests.},
  language  = {en}
}
@misc{BecherOsborneThorbeketal.2013,
  author    = {Becher, Matthias A. and Osborne, Juliet L. and Thorbek, Pernille and Kennedy, Peter J. and Grimm, Volker},
  title     = {Towards a systems approach for understanding honeybee decline - a stocktaking and synthesis of existing models},
  series = {Journal of applied ecology : an official journal of the British Ecological Society},
  volume    = {50},
  journal   = {Journal of applied ecology : an official journal of the British Ecological Society},
  number    = {4},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0021-8901},
  doi       = {10.1111/1365-2664.12112},
  pages     = {868 -- 880},
  year      = {2013},
  abstract  = {1. The health of managed and wild honeybee colonies appears to have declined substantially in Europe and the United States over the last decade. Sustainability of honeybee colonies is important not only for honey production, but also for pollination of crops and wild plants alongside other insect pollinators. A combination of causal factors, including parasites, pathogens, land use changes and pesticide usage, are cited as responsible for the increased colony mortality. 2. However, despite detailed knowledge of the behaviour of honeybees and their colonies, there are no suitable tools to explore the resilience mechanisms of this complex system under stress. Empirically testing all combinations of stressors in a systematic fashion is not feasible. We therefore suggest a cross-level systems approach, based on mechanistic modelling, to investigate the impacts of (and interactions between) colony and land management. 3. We review existing honeybee models that are relevant to examining the effects of different stressors on colony growth and survival. Most of these models describe honeybee colony dynamics, foraging behaviour or honeybee - varroa mite - virus interactions. 4. We found that many, but not all, processes within honeybee colonies, epidemiology and foraging are well understood and described in the models, but there is no model that couples in-hive dynamics and pathology with foraging dynamics in realistic landscapes. 5. Synthesis and applications. We describe how a new integrated model could be built to simulate multifactorial impacts on the honeybee colony system, using building blocks from the reviewed models. The development of such a tool would not only highlight empirical research priorities but also provide an important forecasting tool for policy makers and beekeepers, and we list examples of relevant applications to bee disease and landscape management decisions.},
  language  = {en}
}