TY - JOUR A1 - Zurell, Damaris A1 - Grimm, Volker A1 - Rossmanith, Eva A1 - Zbinden, Niklaus A1 - Zimmermann, Niklaus E. A1 - Schröder-Esselbach, Boris T1 - Uncertainty in predictions of range dynamics black grouse climbing the Swiss Alps JF - Ecography : pattern and diversity in ecology ; research papers forum N2 - Empirical species distribution models (SDMs) constitute often the tool of choice for the assessment of rapid climate change effects on species vulnerability. Conclusions regarding extinction risks might be misleading, however, because SDMs do not explicitly incorporate dispersal or other demographic processes. Here, we supplement SDMs with a dynamic population model 1) to predict climate-induced range dynamics for black grouse in Switzerland, 2) to compare direct and indirect measures of extinction risks, and 3) to quantify uncertainty in predictions as well as the sources of that uncertainty. To this end, we linked models of habitat suitability to a spatially explicit, individual-based model. In an extensive sensitivity analysis, we quantified uncertainty in various model outputs introduced by different SDM algorithms, by different climate scenarios and by demographic model parameters. Potentially suitable habitats were predicted to shift uphill and eastwards. By the end of the 21st century, abrupt habitat losses were predicted in the western Prealps for some climate scenarios. In contrast, population size and occupied area were primarily controlled by currently negative population growth and gradually declined from the beginning of the century across all climate scenarios and SDM algorithms. However, predictions of population dynamic features were highly variable across simulations. Results indicate that inferring extinction probabilities simply from the quantity of suitable habitat may underestimate extinction risks because this may ignore important interactions between life history traits and available habitat. Also, in dynamic range predictions uncertainty in SDM algorithms and climate scenarios can become secondary to uncertainty in dynamic model components. Our study emphasises the need for principal evaluation tools like sensitivity analysis in order to assess uncertainty and robustness in dynamic range predictions. A more direct benefit of such robustness analysis is an improved mechanistic understanding of dynamic species responses to climate change. Y1 - 2012 U6 - https://doi.org/10.1111/j.1600-0587.2011.07200.x SN - 0906-7590 VL - 35 IS - 7 SP - 590 EP - 603 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Zurell, Damaris A1 - Berger, Uta A1 - Cabral, Juliano Sarmento A1 - Jeltsch, Florian A1 - Meynard, Christine N. A1 - Muenkemueller, Tamara A1 - Nehrbass, Nana A1 - Pagel, Jörn A1 - Reineking, Bjoern A1 - Schroeder, Boris A1 - Grimm, Volker T1 - The virtual ecologist approach : simulating data and observers N2 - Ecologists carry a well-stocked toolbox with a great variety of sampling methods, statistical analyses and modelling tools, and new methods are constantly appearing. Evaluation and optimisation of these methods is crucial to guide methodological choices. Simulating error-free data or taking high-quality data to qualify methods is common practice. Here, we emphasise the methodology of the 'virtual ecologist' (VE) approach where simulated data and observer models are used to mimic real species and how they are 'virtually' observed. This virtual data is then subjected to statistical analyses and modelling, and the results are evaluated against the 'true' simulated data. The VE approach is an intuitive and powerful evaluation framework that allows a quality assessment of sampling protocols, analyses and modelling tools. It works under controlled conditions as well as under consideration of confounding factors such as animal movement and biased observer behaviour. In this review, we promote the approach as a rigorous research tool, and demonstrate its capabilities and practical relevance. We explore past uses of VE in different ecological research fields, where it mainly has been used to test and improve sampling regimes as well as for testing and comparing models, for example species distribution models. We discuss its benefits as well as potential limitations, and provide some practical considerations for designing VE studies. Finally, research fields are identified for which the approach could be useful in the future. We conclude that VE could foster the integration of theoretical and empirical work and stimulate work that goes far beyond sampling methods, leading to new questions, theories, and better mechanistic understanding of ecological systems. Y1 - 2010 UR - http://www3.interscience.wiley.com/cgi-bin/issn?DESCRIPTOR=PRINTISSN&VALUE=0030-1299 U6 - https://doi.org/10.1111/j.1600-0706.2009.18284.x SN - 0030-1299 ER - TY - JOUR A1 - Wichmann, Matthias A1 - Groeneveld, Jürgen A1 - Jeltsch, Florian A1 - Grimm, Volker T1 - Mitigation of climate change impacts on raptors by behavioural adaptation : ecological buffering mechanisms N2 - The predicted climate change causes deep concerns on the effects of increasing temperatures and changing precipitation patterns on species viability and, in turn, on biodiversity. Models of Population Viability Analysis (PVA) provide a powerful tool to assess the risk of species extinction. However, most PVA models do not take into account the potential effects of behavioural adaptations. Organisms might adapt to new environmental situations and thereby mitigate negative effects of climate change. To demonstrate such mitigation effects, we use an existing PVA model describing a population of the tawny eagle (Aquila rapax) in the southern Kalahari. This model does not include behavioural adaptations. We develop a new model by assuming that the birds enlarge their average territory size to compensate for lower amounts of precipitation. Here, we found the predicted increase in risk of extinction due to climate change to be much lower than in the original model. However, this "buffering" of climate change by behavioural adaptation is not very effective in coping with increasing interannual variances. We refer to further examples of ecological "buffering mechanisms" from the literature and argue that possible buffering mechanisms should be given due consideration when the effects of climate change on biodiversity are to be predicted. (c) 2004 Elsevier B.V. All rights reserved Y1 - 2005 SN - 0921-8181 ER - TY - JOUR A1 - Wichmann, Matthias A1 - Groeneveld, Jürgen A1 - Jeltsch, Florian A1 - Grimm, Volker T1 - Mitigation of climate change impacts on raptors by behavioural adaption : ecological buffering mechanism Y1 - 2005 ER - TY - GEN A1 - Weise, Hanna A1 - Auge, Harald A1 - Baessler, Cornelia A1 - Bärlund, Ilona A1 - Bennett, Elena M. A1 - Berger, Uta A1 - Bohn, Friedrich A1 - Bonn, Aletta A1 - Borchardt, Dietrich A1 - Brand, Fridolin A1 - Jeltsch, Florian A1 - Joshi, Jasmin Radha A1 - Grimm, Volker T1 - Resilience trinity BT - Safeguarding ecosystem functioning and services across three different time horizons and decision contexts T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Ensuring ecosystem resilience is an intuitive approach to safeguard the functioning of ecosystems and hence the future provisioning of ecosystem services (ES). However, resilience is a multi-faceted concept that is difficult to operationalize. Focusing on resilience mechanisms, such as diversity, network architectures or adaptive capacity, has recently been suggested as means to operationalize resilience. Still, the focus on mechanisms is not specific enough. We suggest a conceptual framework, resilience trinity, to facilitate management based on resilience mechanisms in three distinctive decision contexts and time-horizons: 1) reactive, when there is an imminent threat to ES resilience and a high pressure to act, 2) adjustive, when the threat is known in general but there is still time to adapt management and 3) provident, when time horizons are very long and the nature of the threats is uncertain, leading to a low willingness to act. Resilience has different interpretations and implications at these different time horizons, which also prevail in different disciplines. Social ecology, ecology and engineering are often implicitly focussing on provident, adjustive or reactive resilience, respectively, but these different notions of resilience and their corresponding social, ecological and economic tradeoffs need to be reconciled. Otherwise, we keep risking unintended consequences of reactive actions, or shying away from provident action because of uncertainties that cannot be reduced. The suggested trinity of time horizons and their decision contexts could help ensuring that longer-term management actions are not missed while urgent threats to ES are given priority. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1444 KW - concepts KW - ecosystems KW - ecosystem services provisioning KW - management KW - resilience Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-515284 SN - 1866-8372 IS - 4 ER - TY - JOUR A1 - Weise, Hanna A1 - Auge, Harald A1 - Baessler, Cornelia A1 - Bärlund, Ilona A1 - Bennett, Elena M. A1 - Berger, Uta A1 - Bohn, Friedrich A1 - Bonn, Aletta A1 - Borchardt, Dietrich A1 - Brand, Fridolin A1 - Jeltsch, Florian A1 - Joshi, Jasmin Radha A1 - Grimm, Volker T1 - Resilience trinity BT - safeguarding ecosystem functioning and services across three different time horizons and decision contexts JF - Oikos N2 - Ensuring ecosystem resilience is an intuitive approach to safeguard the functioning of ecosystems and hence the future provisioning of ecosystem services (ES). However, resilience is a multi-faceted concept that is difficult to operationalize. Focusing on resilience mechanisms, such as diversity, network architectures or adaptive capacity, has recently been suggested as means to operationalize resilience. Still, the focus on mechanisms is not specific enough. We suggest a conceptual framework, resilience trinity, to facilitate management based on resilience mechanisms in three distinctive decision contexts and time-horizons: 1) reactive, when there is an imminent threat to ES resilience and a high pressure to act, 2) adjustive, when the threat is known in general but there is still time to adapt management and 3) provident, when time horizons are very long and the nature of the threats is uncertain, leading to a low willingness to act. Resilience has different interpretations and implications at these different time horizons, which also prevail in different disciplines. Social ecology, ecology and engineering are often implicitly focussing on provident, adjustive or reactive resilience, respectively, but these different notions of resilience and their corresponding social, ecological and economic tradeoffs need to be reconciled. Otherwise, we keep risking unintended consequences of reactive actions, or shying away from provident action because of uncertainties that cannot be reduced. The suggested trinity of time horizons and their decision contexts could help ensuring that longer-term management actions are not missed while urgent threats to ES are given priority. KW - concepts KW - ecosystems KW - ecosystem services provisioning KW - management KW - resilience Y1 - 2020 U6 - https://doi.org/10.1111/oik.07213 SN - 0030-1299 SN - 1600-0706 VL - 129 IS - 4 SP - 445 EP - 456 PB - Wiley-Blackwell CY - Oxford ER - TY - JOUR A1 - Wang, Ming A1 - White, Neil A1 - Grimm, Volker A1 - Hofman, Helen A1 - Doley, David A1 - Thorp, Grant A1 - Cribb, Bronwen A1 - Wherritt, Ella A1 - Han, Liqi A1 - Wilkie, John A1 - Hanan, Jim T1 - Pattern-oriented modelling as a novel way to verify and validate functional-structural plant models BT - a demonstration with the annual growth module of avocado JF - Annals of botany N2 - Background and Aims Functional-structural plant (FSP) models have been widely used to understand the complex interactions between plant architecture and underlying developmental mechanisms. However, to obtain evidence that a model captures these mechanisms correctly, a clear distinction must be made between model outputs used for calibration and thus verification, and outputs used for validation. In pattern-oriented modelling (POM), multiple verification patterns are used as filters for rejecting unrealistic model structures and parameter combinations, while a second, independent set of patterns is used for validation. Key Results After calibration, our model simultaneously reproduced multiple observed architectural patterns. The model then successfully predicted, without further calibration, the validation patterns. The model supports the hypothesis that carbon allocation can be modelled as being dependent on current organ biomass and sink strength of each organ type, and also predicted the observed developmental timing of the leaf sink-source transition stage. KW - Pattern-oriented modelling KW - agent-based model KW - individual-based model KW - functional-structural plant model KW - model analysis KW - model verification KW - model validation KW - ODD (Overview, Design concepts, Details) protocol KW - Persea americana KW - plant architecture KW - carbon allocation KW - L-systems Y1 - 2018 U6 - https://doi.org/10.1093/aob/mcx187 SN - 0305-7364 SN - 1095-8290 VL - 121 IS - 5 SP - 941 EP - 959 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Topping, Christopher J. A1 - Alroe, Hugo Fjelsted A1 - Farrell, Katharine N. A1 - Grimm, Volker T1 - Per Aspera ad Astra: Through Complex Population Modeling to Predictive Theory JF - The American naturalist : a bi-monthly journal devoted to the advancement and correlation of the biological sciences N2 - Population models in ecology are often not good at predictions, even if they are complex and seem to be realistic enough. The reason for this might be that Occam's razor, which is key for minimal models exploring ideas and concepts, has been too uncritically adopted for more realistic models of systems. This can tic models too closely to certain situations, thereby preventing them from predicting the response to new conditions. We therefore advocate a new kind of parsimony to improve the application of Occam's razor. This new parsimony balances two contrasting strategies for avoiding errors in modeling: avoiding inclusion of nonessential factors (false inclusions) and avoiding exclusion of sometimes-important factors (false exclusions). It involves a synthesis of traditional modeling and analysis, used to describe the essentials of mechanistic relationships, with elements that arc included in a model because they have been reported to be or can arguably be assumed to be important under certain conditions. The resulting models should be able to reflect how the internal organization of populations change and thereby generate representations of the novel behavior necessary for complex predictions, including regime shifts. KW - complexity KW - error avoidance KW - agent-based models KW - model development KW - modest approach Y1 - 2015 U6 - https://doi.org/10.1086/683181 SN - 0003-0147 SN - 1537-5323 VL - 186 IS - 5 SP - 669 EP - 674 PB - Univ. of Chicago Press CY - Chicago ER - TY - JOUR A1 - Thiele, Jan C. A1 - Grimm, Volker T1 - Replicating and breaking models: good for you and good for ecology JF - Oikos N2 - There are two major limitations to the potential of computational models in ecology for producing general insights: their design is path-dependent, reflecting different underlying questions, assumptions, and data, and there is too little robustness analysis exploring where the model mechanisms explaining certain observations break down. We here argue that both limitations could be overcome if modellers in ecology would more often replicate existing models, try to break the models, and explore modifications. Replication comprises the re-implementation of an existing model and the replication of its results. Breaking models means to identify under what conditions the mechanisms represented in a model can no longer explain observed phenomena. The benefits of replication include less effort being spent to enter the iterative stage of model development and having more time for systematic robustness analysis. A culture of replication would lead to increased credibility, coherence and efficiency of computational modelling and thereby facilitate theory development. Y1 - 2015 U6 - https://doi.org/10.1111/oik.02170 SN - 0030-1299 SN - 1600-0706 VL - 124 IS - 6 SP - 691 EP - 696 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Teckentrup, Lisa A1 - Grimm, Volker A1 - Kramer-Schadt, Stephanie A1 - Jeltsch, Florian T1 - Community consequences of foraging under fear JF - Ecological modelling : international journal on ecological modelling and engineering and systems ecolog N2 - Non-consumptive effects of predators within ecosystems can alter the behavior of individual prey species, and have cascading effects on other trophic levels. In this context, an understanding of non-consumptive predator effects on the whole prey community is crucial for predicting community structure and composition, hence biodiversity patterns. We used an individual-based, spatially-explicit modelling approach to investigate the consequences of landscapes of fear on prey community metrics. The model spans multiple hierarchical levels from individual home range formation based on food availability and perceived predation risk to consequences on prey community structure and composition. This mechanistic approach allowed us to explore how important factors such as refuge availability and foraging strategy under fear affect prey community metrics. Fear of predators affected prey space use, such as home range formation. These adaptations had broader consequences for the community leading to changes in community structure and composition. The strength of community responses to perceived predation risk was driven by refuge availability in the landscape and the foraging strategy of prey animals. Low refuge availability in the landscape strongly decreased diversity and total biomass of prey communities. Additionally, body mass distributions in prey communities facing high predation risk were shifted towards small prey animals. With increasing refuge availability the consequences of non-consumptive predator effects were reduced, diversity and total biomass of the prey community increased. Prey foraging strategies affected community composition. Under medium refuge availability, risk-averse prey communities consisted of many small animals while risk-taking prey communities showed a more even body mass distribution. Our findings reveal that non-consumptive predator effects can have important implications for prey community diversity and should therefore be considered in the context of conservation and nature management. KW - Predator-prey interactions KW - Individual-based model KW - Landscape of fear KW - Home range KW - Biodiversity KW - Foraging Y1 - 2018 U6 - https://doi.org/10.1016/j.ecolmodel.2018.05.015 SN - 0304-3800 SN - 1872-7026 VL - 383 SP - 80 EP - 90 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Sundelof, Andreas A1 - Grimm, Volker A1 - Ulmestrand, Mats A1 - Fiksen, Oyvind T1 - Modelling harvesting strategies for the lobster fishery in northern Europe: the importance of protecting egg-bearing females JF - Population ecology KW - European lobster KW - Female moratorium KW - Individual-based model KW - Management KW - Minimum landing size KW - Yield per recruit (YPR) Y1 - 2015 U6 - https://doi.org/10.1007/s10144-014-0460-3 SN - 1438-3896 SN - 1438-390X VL - 57 IS - 1 SP - 237 EP - 251 PB - Springer CY - Tokyo ER - TY - JOUR A1 - Stillman, Richard A. A1 - Railsback, Steven Floyd A1 - Giske, Jarl A1 - Berger, Uta A1 - Grimm, Volker T1 - Making Predictions in a Changing World: The Benefits of Individual-Based Ecology JF - Bioscience N2 - Ecologists urgently need a better ability to predict how environmental change affects biodiversity. We examine individual-based ecology (IBE), a research paradigm that promises better a predictive ability by using individual-based models (IBMs) to represent ecological dynamics as arising from how individuals interact with their environment and with each other. A key advantage of IBMs is that the basis for predictions-fitness maximization by individual organisms-is more general and reliable than the empirical relationships that other models depend on. Case studies illustrate the usefulness and predictive success of long-term IBE programs. The pioneering programs had three phases: conceptualization, implementation, and diversification. Continued validation of models runs throughout these phases. The breakthroughs that make IBE more productive include standards for describing and validating IBMs, improved and standardized theory for individual traits and behavior, software tools, and generalized instead of system-specific IBMs. We provide guidelines for pursuing IBE and a vision for future IBE research. KW - ecology KW - fitness-maximization KW - individual-based KW - modeling KW - prediction Y1 - 2015 U6 - https://doi.org/10.1093/biosci/biu192 SN - 0006-3568 SN - 1525-3244 VL - 65 IS - 2 SP - 140 EP - 150 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Sibly, Richard M. A1 - Grimm, Volker A1 - Martin, Benjamin T. A1 - Johnston, Alice S. A. A1 - Kulakowska, Katarzyna A1 - Topping, Christopher J. A1 - Calow, Peter A1 - Nabe-Nielsen, Jacob A1 - Thorbek, Pernille A1 - DeAngelis, Donald L. T1 - Representing the acquisition and use of energy by individuals in agent-based models of animal populations JF - Methods in ecology and evolution : an official journal of the British Ecological Society N2 - 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. KW - bioenergetics KW - energy budget KW - individual-based models KW - population dynamics Y1 - 2013 U6 - https://doi.org/10.1111/2041-210x.12002 SN - 2041-210X VL - 4 IS - 2 SP - 151 EP - 161 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Scherer, Cedric A1 - Jeltsch, Florian A1 - Grimm, Volker A1 - Blaum, Niels T1 - Merging trait-based and individual-based modelling: An animal functional type approach to explore the responses of birds to climatic and land use changes in semi-arid African savannas JF - Ecological modelling : international journal on ecological modelling and engineering and systems ecolog N2 - Climate change and land use management practices are major drivers of biodiversity in terrestrial ecosystems. To understand and predict resulting changes in community structures, individual-based and spatially explicit population models are a useful tool but require detailed data sets for each species. More generic approaches are thus needed. Here we present a trait-based functional type approach to model savanna birds. The aim of our model is to explore the response of different bird functional types to modifications in habitat structure. The functional types are characterized by different traits, in particular body mass, which is related to life-history traits (reproduction and mortality) and spatial scales (home range area and dispersal ability), as well as the use of vegetation structures for foraging and nesting, which is related to habitat quality and suitability. We tested the performance of the functional types in artificial landscapes varying in shrub:grass ratio and clumping intensity of shrub patches. We found that an increase in shrub encroachment and a decrease in habitat quality caused by land use mismanagement and climate change endangered all simulated bird functional types. The strength of this effect was related to the preferred habitat. Furthermore, larger-bodied insectivores and omnivores were more prone to extinction due to shrub encroachment compared to small-bodied species. Insectivorous and omnivorous birds were more sensitive to clumping intensity of shrubs whereas herbivorous and carnivorous birds were most affected by a decreasing amount of grass cover. From an applied point of view, our findings emphasize that policies such as woody plant removal and a reduction in livestock stocking rates to prevent shrub encroachment should prioritize the enlargement of existing grassland patches. Overall, our results show that the combination of an individual-based modelling approach with carefully defined functional types can provide a powerful tool for exploring biodiversity responses to environmental changes. Furthermore, the increasing accumulation of worldwide data sets on species’ core and soft traits (surrogates to determine core traits indirectly) on one side and the refinement of conceptual frameworks for animal functional types on the other side will further improve functional type approaches which consider the sensitivities of multiple species to climate change, habitat loss, and fragmentation. KW - IBM KW - Functional types KW - Trait-based approach KW - Shrub encroachment KW - Birds Y1 - 2016 U6 - https://doi.org/10.1016/j.ecolmodel.2015.07.005 SN - 0304-3800 SN - 1872-7026 VL - 326 SP - 75 EP - 89 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Rossmanith, Eva A1 - Grimm, Volker A1 - Blaum, Niels A1 - Jeltsch, Florian T1 - Behavioural flexibility in the mating system buffers population extinction: lessons from the Lesser Spotted Woodpecker (Picoides minor) N2 - In most stochastic models addressing the persistence of small populations, environmental noise is included by imposing a synchronized effect of the environment on all individuals. However, buffer mechanisms are likely to exist that may counteract this synchronization to some degree. We have studied whether the flexibility in the mating system, which has been observed in some bird species, is a potential mechanism counteracting the synchronization of environmental fluctuations. Our study organism is the lesser spotted woodpecker Picoides minor (Linnaeus), a generally monogamous species. However, facultative polyandry, where one female mates with two males with separate nests, was observed in years with male-biased sex ratio. We constructed an individual-based model from data and observations of a population in Taunus, Germany. We tested the impact of three behavioural scenarios on population persistence: (1) strict monogamy; (2) polyandry without costs; and (3) polyandry assuming costs in terms of lower survival and reproductive success for secondary males. We assumed that polyandry occurs only in years with male-biased sex ratio and only for females with favourable breeding conditions. Even low rates of polyandry had a strong positive effect on population persistence. The increase of persistence with carrying capacity was slower in the monogamous scenario, indicating strong environmental noise. In the polyandrous scenarios, the increase of persistence was stronger, indicating a buffer mechanism. In the polyandrous scenarios, populations had a higher mean population size, a lower variation in number of individuals, and recovered faster after a population breakdown. Presuming a realistic polyandry rate and costs for polyandry, there was still a strong effect of polyandry on persistence. The results show that polyandry and in general flexibility in mating systems is a buffer mechanism that can significantly reduce the impact of environmental and demographic noise in small populations. Consequently, we suggest that even behaviour that seems to be exceptional should be considered explicitly when predicting the persistence of populations Y1 - 2006 U6 - https://doi.org/10.1111/j.1365-2656.2006.01074.x ER - TY - JOUR A1 - Radchuk, Viktoriia A1 - Oppel, Steffen A1 - Groeneveld, Juergen A1 - Grimm, Volker A1 - Schtickzelle, Nicolas T1 - Simple or complex: Relative impact of data availability and model purpose on the choice of model types for population viability analyses JF - Ecological modelling : international journal on ecological modelling and engineering and systems ecolog N2 - Population viability analysis (PVA) models are used to estimate population extinction risk under different scenarios. Both simple and complex PVA models are developed and have their specific pros and cons; the question therefore arises whether we always use the most appropriate model type. Generally, the specific purpose of a model and the availability of data are listed as determining the choice of model type, but this has not been formally tested yet. We quantified the relative importance of model purpose and nine metrics of data availability and resolution for the choice of a PVA model type, while controlling for effects of the different life histories of the modelled species. We evaluated 37 model pairs: each consisting of a generally simpler, population-based model (PBM) and a more complex, individual-based model (IBM) developed for the same species. The choice of model type was primarily affected by the availability and resolution of demographic, dispersal and spatial data. Low-resolution data resulted in the development of less complex models. Model purpose did not affect the choice of the model type. We confirm the general assumption that poor data availability is the main reason for the wide use of simpler models, which may have limited predictive power for population responses to changing environmental conditions. Conservation biology is a crisis discipline where researchers learned to work with the data at hand. However, for threatened and poorly-known species, there is no short-cut when developing either a PBM or an IBM: investments to collect appropriately detailed data are required to ensure PVA models can assess extinction risk under complex environmental conditions. (C) 2015 Elsevier B.V. All rights reserved. KW - Model complexity KW - Individual-based model KW - Population-based model KW - Matrix model KW - Structured population model KW - Stage-based model Y1 - 2016 U6 - https://doi.org/10.1016/j.ecolmodel.2015.11.022 SN - 0304-3800 SN - 1872-7026 VL - 323 SP - 87 EP - 95 PB - Elsevier CY - Amsterdam ER - TY - GEN A1 - Radchuk, Viktoriia A1 - Kramer-Schadt, Stephanie A1 - Grimm, Volker T1 - Transferability of mechanistic ecological models is about emergence T2 - Trends in ecology and evolution Y1 - 2019 U6 - https://doi.org/10.1016/j.tree.2019.01.010 SN - 0169-5347 SN - 1872-8383 VL - 34 IS - 6 SP - 487 EP - 488 PB - Elsevier CY - London ER - TY - JOUR A1 - Radchuk, Viktoriia A1 - Johst, Karin A1 - Gröneveld, Juergen A1 - Grimm, Volker A1 - Schtickzelle, Nicolas T1 - Behind the scenes of population viability modeling predicting butterfly metapopulation dynamics under climate change JF - Ecological modelling : international journal on ecological modelling and engineering and systems ecolog N2 - Studies explaining the choice of model structure for population viability analysis (PVA) are rare and no such study exists for butterfly species, a focal group for conservation. Here, we describe in detail the development of a model to predict population viability of a glacial relict butterfly species, Boloria eunomia, under climate change. We compared four alternative formulations of an individual-based model, differing in the environmental factors acting on the survival of immature life stages: temperature (only temperature impact), weather (temperature, precipitation, and sunshine), temperature and parasitism, and weather and parasitism. Following pattern-oriented modeling, four observed patterns were used to contrast these models: one qualitative (response of population size to habitat parameters) and three quantitative ones describing population dynamics during eight years (mean and variability of population size, and magnitude of the temporal autocorrelation in yearly population growth rates). The four model formulations were not equally able to depict population dynamics under current environmental conditions; the model including only temperature was selected as the most parsimonious model sufficiently well reproducing the empirical patterns. We used all four model formulations to test a range of climate change scenarios that were characterized by changes in both mean and variability of the weather variables. All models predicted adverse effects of climate change and resulted in the same ranking of mean climate change scenarios. However, models differed in their absolute values of population viability measures, underlining the need to explicitly choose the most appropriate model formulation and avoid arbitrary usage of environmental drivers in a model. We conclude that further applications of pattern-oriented modeling to butterfly and other species are likely to help in identifying the key factors impacting the viability of certain taxa, which, ultimately, will aid and speed up informed management decisions for endangered species under climate change. KW - Individual-based model KW - Population viability analysis KW - Glacial relict species KW - Life cycle KW - Boloria eunomia KW - Pattern-oriented modeling KW - Model structure Y1 - 2013 U6 - https://doi.org/10.1016/j.ecolmodel.2013.03.014 SN - 0304-3800 VL - 259 IS - 2 SP - 62 EP - 73 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Radchuk, Viktoriia A1 - Johst, Karin A1 - Groeneveld, Jürgen A1 - Turlure, Camille A1 - Grimm, Volker A1 - Schtickzelle, Nicolas T1 - Appropriate resolution in time and model structure for population viability analysis: Insights from a butterfly metapopulation JF - : an international journal N2 - The importance of a careful choice of the appropriate scale for studying ecological phenomena has been stressed repeatedly. However, issues of spatial scale in metapopulation dynamics received much more attention compared to temporal scale. Moreover, multiple calls were made to carefully choose the appropriate model structure for Population Viability Analysis (PVA). We assessed the effect of using coarser resolution in time and model structure on population dynamics. For this purpose, we compared outcomes of two PVA models differing in their time step: daily individual-based model (dIBM) and yearly stage-based model (ySBM), loaded with empirical data on a well-known metapopulation of the butterfly Boloria eunomia. Both models included the same environmental drivers of population dynamics that were previously identified as being the most important for this species. Under temperature change scenarios, both models yielded the same qualitative scenario ranking, but they quite substantially differed quantitatively with dIBM being more pessimistic in absolute viability measures. We showed that these differences stemmed from inter-individual heterogeneity in dIBM allowing for phenological shifts of individual appearance. We conclude that a finer temporal resolution and an individual-based model structure allow capturing the essential mechanisms necessary to go beyond mere PVA scenario ranking. We encourage researchers to carefully chose the temporal resolution and structure of their model aiming at (1) depicting the processes important for (meta)population dynamics of the species and (2) implementing the environmental change scenarios expected for their study system in the future, using the temporal resolution at which such changes are predicted to operate. KW - Temporal grain KW - Model complexity KW - Model comparison KW - Population dynamics KW - Individual-based model KW - Stage-based model Y1 - 2014 U6 - https://doi.org/10.1016/j.biocon.2013.12.004 SN - 0006-3207 SN - 1873-2917 VL - 169 SP - 345 EP - 354 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Radchuk, Viktoriia A1 - De Laender, Frederik A1 - Cabral, Juliano Sarmento A1 - Boulangeat, Isabelle A1 - Crawford, Michael Scott A1 - Bohn, Friedrich A1 - De Raedt, Jonathan A1 - Scherer, Cedric A1 - Svenning, Jens-Christian A1 - Thonicke, Kirsten A1 - Schurr, Frank M. A1 - Grimm, Volker A1 - Kramer-Schadt, Stephanie T1 - The dimensionality of stability depends on disturbance type JF - Ecology letters N2 - Ecosystems respond in various ways to disturbances. Quantifying ecological stability therefore requires inspecting multiple stability properties, such as resistance, recovery, persistence and invariability. Correlations among these properties can reduce the dimensionality of stability, simplifying the study of environmental effects on ecosystems. A key question is how the kind of disturbance affects these correlations. We here investigated the effect of three disturbance types (random, species-specific, local) applied at four intensity levels, on the dimensionality of stability at the population and community level. We used previously parameterized models that represent five natural communities, varying in species richness and the number of trophic levels. We found that disturbance type but not intensity affected the dimensionality of stability and only at the population level. The dimensionality of stability also varied greatly among species and communities. Therefore, studying stability cannot be simplified to using a single metric and multi-dimensional assessments are still to be recommended. KW - Community model KW - disturbance intensity KW - disturbance type KW - extinction KW - individual-based model KW - invariability KW - persistence KW - recovery KW - resistance Y1 - 2019 U6 - https://doi.org/10.1111/ele.13226 SN - 1461-023X SN - 1461-0248 VL - 22 IS - 4 SP - 674 EP - 684 PB - Wiley CY - Hoboken ER -