Spatial modelling of vegetation change in dynamic landscapes: a review of methods and applications

2006 ◽  
Vol 30 (1) ◽  
pp. 47-72 ◽  
Author(s):  
George L.W. Perry ◽  
Neal J. Enright
Keyword(s):  
Vegetation Change ◽  
Simulation Models ◽  
Spatial Modelling ◽  
Coarse Grained ◽  
Ecological Change ◽  
Forest Gap ◽  
Landscape Models ◽  
Dynamic Landscapes ◽  
Gap Models ◽  
Landscape Level

Because of the spatiotemporal scales involved and the logistical constraints in collecting landscape-level data, spatially explicit simulation models have become important tools in ecological and biogeographical studies conducted over broad extents. Here we review the methods used and some of the applications of landscape-level models of succession and disturbance dynamics. Mechanistic and stochastic models are compared and contrasted and the development, over the last 15 years, of spatial landscape models of ecological change is discussed. Coarse-grained spatial landscape models are compared with finer-grained individual-based approaches (eg, forest gap models). Management and monitoring applications of landscape models are considered alongside a discussion of the appropriate use of models in this context. A key area where spatial landscape models of the type described here need to develop is improved integration with the social sciences - both in terms of the parameters and the processes that the models incorporate. Finally issues related to scale and scaling are outlined and, in particular, the utility of methods for linking ecological models operating at disparate scales (eg, forest gap models versus landscape models) is examined.

scholarly journals Mathematical Models Arising in the Fractal Forest Gap via Local Fractional Calculus

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Chun-Ying Long ◽  
Yang Zhao ◽  
Hossein Jafari
Keyword(s):  
Fractional Calculus ◽  
Fractional Derivative ◽  
Mathematical Models ◽  
Cantor Sets ◽  
Forest Gap ◽  
Local Fractional Derivative ◽  
Local Fractional Calculus ◽  
Growth Equations ◽  
Gap Models ◽  
Individual Trees

The forest new gap models via local fractional calculus are investigated. The JABOWA and FORSKA models are extended to deal with the growth of individual trees defined on Cantor sets. The local fractional growth equations with local fractional derivative and difference are discussed. Our results are first attempted to show the key roles for the nondifferentiable growth of individual trees.

scholarly journals Integrating Knowledge for Simulating Vegetation Change at Landscape Scales

2004 ◽  
Vol 19 (2) ◽  
pp. 102-108 ◽  
Author(s):  
Jimmie D. Chew ◽  
Christine Stalling ◽  
Kirk Moeller
Keyword(s):  
Vegetation Change ◽  
Time Frame ◽  
Management Scenarios ◽  
Planning Decisions ◽  
Conflicting Objectives ◽  
Disturbance Processes ◽  
Dynamic Landscapes ◽  
Desired Future Conditions ◽  
Landscape Scales ◽  
Resource Specialists

Abstract Managers of public lands are increasingly faced with making planning decisions for dynamic landscapes with conflicting objectives. A modeling system has been designed to serve as a decision support system to help managers and resource specialists integrate the available knowledge of vegetation change and disturbance processes, and quantify concepts that are often difficult to interpret for specific landscapes. The system is named SIMPPLLE, an acronym taken from “<bi>SIM</bi>ulating vegetation <bi>P</bi>atterns and <bi>P</bi>rocesses at Landscape scaLEs.” SIMPPLLE can be used to help define and evaluate future conditions at landscape scales, to identify areas that are more prone to disturbances over a given time frame, to identify the options for influencing these disturbance processes, and to help design and evaluate different strategies for achieving desired future conditions. The emphasis in this article is to give an overview of the design of the system, the types of knowledge integrated, and the type of output produced. The initial validation work discussed indicates that the approach used for capturing and integrating process knowledge in SIMPPLLE does predict realistic results at landscape scales. SIMPPLLE provides managers a tool to integrate and interpret concepts of desired future conditions, range of variability, and the interaction between vegetation patterns and disturbance processes. SIMPPLLE provides a way to help evaluate proposed management scenarios within a future that includes stochastic processes. West. J. Appl. For. 19(2):102–108.

scholarly journals Using forest gap models and experimental data to explore long-term effects of tree diversity on the productivity of mixed planted forests

2020 ◽  
Vol 77 (2) ◽  
Author(s):  
Xavier Morin ◽  
Thomas Damestoy ◽  
Maude Toigo ◽  
Bastien Castagneyrol ◽  
Hervé Jactel ◽  
...  
Keyword(s):  
Rotation Period ◽  
Tree Diversity ◽  
Forest Growth ◽  
Forest Gap ◽  
Gap Model ◽  
Mixing Effect ◽  
Full Rotation ◽  
New Forest ◽  
Gap Models

Abstract Key message In this exploratory study, we show how combining the strength of tree diversity experiment with the long-term perspective offered by forest gap models allows testing the mixture yielding behavior across a full rotation period. Our results on a SW France example illustrate how mixing maritime pine with birch may produce an overyielding (i.e., a positive net biodiversity effect). Context Understanding the link between tree diversity and stand productivity is a key issue at a time when new forest management methods are investigated to improve carbon sequestration and climate change mitigation. Well-controlled tree diversity experiments have been set up over the last decades, but they are still too young to yield relevant results from a long-term perspective. Alternatively, forest gap models appear as appropriate tools to study the link between diversity and productivity as they can simulate mixed forest growth over an entire forestry cycle. Aims We aimed at testing whether a forest gap model could first reproduce the results from a tree diversity experiment, using its plantation design as input, and then predict the species mixing effect on productivity and biomass in the long term. Methods Here, we used data from different forest experimental networks to calibrate the gap model ForCEEPS for young pine (Pinus pinaster) and birch (Betula pendula) stands. Then, we used the refined model to compare the productivity of pure and mixed pine and birch stands over a 50-year cycle. The mixing effect was tested for two plantation designs, i.e., species substitution and species addition, and at two tree densities. Results Regarding the comparison with the experiment ORPHEE (thus on the short term), the model well reproduced the species interactions observed in the mixed stands. Simulations showed an overyielding (i.e., a positive net biodiversity effect) in pine-birch mixtures in all cases and during the full rotation period. A transgressive overyielding was detected in mixtures resulting from birch addition to pine stands at low density. These results were mainly due to a positive mixing effect on pine growth being larger than the negative effect on birch growth. Conclusion Although this study remains explorative, calibrating gap models with data from monospecific stands and validating with data from the manipulative tree diversity experiment (ORPHEE) offers a powerful tool for further investigation of the productivity of forest mixtures. Improving our understanding of how abiotic and biotic factors, including diversity, influence the functioning of forest ecosystems should help to reconsider new forest managements optimizing ecosystem services.

Modelling Landscape-level Effects of Reduced Herbicide Use in Two Forests in Northern Ontario

2011 ◽  
Vol 87 (02) ◽  
pp. 290-309 ◽  
Author(s):  
Jennifer Dacosta ◽  
Kandyd Szuba ◽  
F. Wayne Bell ◽  
Tom Moore ◽  
Ken Lennon ◽  
...  
Keyword(s):  
Forest Management ◽  
Scale Up ◽  
Transportation Cost ◽  
Spatial Modelling ◽  
Wildlife Habitat ◽  
Forest Composition ◽  
Wood Supply ◽  
Forest Management Planning ◽  
Herbicide Use ◽  
Landscape Level

In Ontario, forest management planning requires that legal obligations to sustain forest composition and pattern, wildlife habitat, and other values are met, while at the same time addressing, for example, wood supply needs, costs, forest access, and stakeholder concerns. One of the latter is pressure to reduce herbicide use. Stand-level effects of vegetation management alternatives have been documented, but how these effects scale up to the landscape-level and affect the achievement of social, ecological, and economic objectives embedded in forest management plans (FMPs) remains uncertain. We applied nine modelling scenarios in the context of approved FMPs to explore the potential landscape-level effects of replacing herbicide use with an alternative (brush saw) for two large forests in northeastern Ontario. Results of non-spatial and spatial modelling over 60 years suggested that although herbicides are applied to only 25% to 34% of the harvested area in these forests, reductions in use would affect: (i) overall wood supply, with 14% to 44% less conifer and 6% to 17% less hardwood available; (ii) habitat supply, with less habitat for species preferring recent disturbances and more habitat for species preferring mature and older forest; (iii) costs, with wood transportation cost increasing by 16% to 20% and increased spending on silviculture; (iv) size and distribution of cutblocks and disturbance patches, with more small patches; and (v) the extent of the active road network, which would increase.

Model convergence and state variable update in forest gap models

1996 ◽  
Vol 89 (1-3) ◽  
pp. 197-208 ◽  
Author(s):  
Harald Bugmann ◽  
Andreas Fischlin ◽  
Felix Kienast
Keyword(s):  
Forest Gap ◽  
State Variable ◽  
Gap Models

scholarly journals Molecular stripping in theNF-κB/IκB/DNAgenetic regulatory network

2015 ◽  
Vol 113 (1) ◽  
pp. 110-115 ◽  
Author(s):  
Davit A. Potoyan ◽  
Weihua Zheng ◽  
Elizabeth A. Komives ◽  
Peter G. Wolynes
Keyword(s):  
Free Energy ◽  
Transcription Factor ◽  
Free Energy Calculations ◽  
Coarse Grained ◽  
Genetic Switch ◽  
Binary And Ternary Complexes ◽  
Landscape Models ◽  
Gene Switches ◽  
Dna Release ◽  
Dynamics Simulations

Genetic switches based on theNF-κB/IκB/DNAsystem are master regulators of an array of cellular responses. Recent kinetic experiments have shown thatIκBcan actively removeNF-κBbound to its genetic sites via a process called “molecular stripping.” This allows theNF-κB/IκB/DNAswitch to function under kinetic control rather than the thermodynamic control contemplated in the traditional models of gene switches. Using molecular dynamics simulations of coarse-grained predictive energy landscape models for the constituent proteins by themselves and interacting with the DNA we explore the functional motions of the transcription factorNF-κBand its various binary and ternary complexes with DNA and the inhibitorIκB. These studies show that the function of theNF-κB/IκB/DNAgenetic switch is realized via an allosteric mechanism. Molecular stripping occurs through the activation of a domain twist mode by the binding ofIκBthat occurs through conformational selection. Free energy calculations for DNA binding show that the binding ofIκBnot only results in a significant decrease of the affinity of the transcription factor for the DNA but also kinetically speeds DNA release. Projections of the free energy onto various reaction coordinates reveal the structural details of the stripping pathways.

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