A simple coupled biogeochemical model to examine recovery of terrestrial ecosystems from disturbances that remove vegetation, e.g. voles. The model is complex enough to represent the interactions between C and N and between vegetation and soil-microbial processes that are important to the questions we address, but still simple enough to be broadly illustrative of terrestrial ecosystems and easily implemented and analyzed. The model is based on five mass balance equations representing changes in C and N in vegetation biomass (BC and BN), C and N in soil organic matter and associated microbes and fauna (DC and DN), and inorganic N (N). The model is driven by atmospheric CO2 concentration, air temperature, vole density and inorganic nitrogen inputs .The model incorporates the temperature sensitivity of six metabolic processes (photosynthesis, autotrophic and heterotrophic respiration, plant and microbial N uptake, and N mineralization) and the effects of voles on the transfer of C and N from vegetation to soil organic matter and the transfer of N in urine from vegetation to inorganic N (although not all N in urine is inorganic, it is labile, and we treat it as inorganic).
The full VOLE model is desribed in the file, Model descriptionVole V4.txt.
Rastetter, E. B., K.L. Griffin, R.J. Rowe, L. Gough, J.R. McLaren, N.T. Boelman. In press 2021. Model Responses to CO2 and Warming Are Underestimated without Explicit Representation of Arctic Small-Mammal Grazing. Ecological Applications. Uses VOLE V4.0: http://doi.org/10.5281/zenodo.5083290. Data available from EDI: https://doi.org/10.6073/pasta/67108cef344d93cfdd060e7e0f0911f5 and https://doi.org/10.6073/pasta/42e6660b2d1f2b59985ed0940e53f0d4
The vole model is written for modelshell, a model develepment package, which is written in Lazarus/Free Pascal. Modelshell allows the user to create a model by making creating a plain text file description of the model. Modelshell provides a GUI interface, an integrator, file IO, and a simple graph. All output files created by modelshell are comma delimited text files.
Detailed instructions for compiling and running the model are in "Install and Run VOLE.docx"
This work was supported in part by the National Science Foundation under NSF grants 1651722, 1637459, 1603560, 1556772, 1841608, 1603777, 1603654, 1603760, 1603677. Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect those of the National Science Foundation.