Timo Conradi
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timoconradi.bsky.social
Timo Conradi
@timoconradi.bsky.social
Vegetation scientist at the University of Bayreuth, Germany
the two vignettes are hidden in the tar.gz that you can download from CRAN. Then go to TTR.PGM/inst/doc 3/3
September 25, 2025 at 9:39 AM
if you are interested in using the process model for attribution or species distribution modelling, check out our R package: besjournals.onlinelibrary.wiley.com/doi/10.1111/... 2/3
TTR.PGM: An R package for modelling the distributions and dynamics of plants using the Thornley transport resistance plant growth model
An ability to predict the ranges and dynamics of species is central to ecological and evolutionary research. Despite species range modelling being an active area of research for the past three to ...
besjournals.onlinelibrary.wiley.com
September 25, 2025 at 9:39 AM
Congratulations Jens! Truly deserved!
April 3, 2025 at 1:09 PM
another very useful finding of this study imo is that process models parametrized inversely from species distribution data performed better than forward-parametrized process models, at least in this set of species with reasonable distribution data.
February 26, 2025 at 7:04 AM
Okay ;) but if there IS a ‚correct‘ state and we fail to recognize it, as has been the case in the forest-savanna-bistability assertion, then we make badly informed management decisions.
December 19, 2024 at 2:52 PM
References (first 4 forest-savanna, last one lakes):
Higgins 2023: www.science.org/doi/10.1126/...
Mattos 2023: www.pnas.org/doi/abs/10.1...
Williamson 2024: iopscience.iop.org/article/10.1...
Zwaan 2024: iopscience.iop.org/article/10.1...
Davidson 2023 Lakes: www.nature.com/articles/s41...
Limited climatic space for alternative ecosystem states in Africa
Field observations show that the distribution of African forest and savanna are highly predictable based on climate.
www.science.org
December 19, 2024 at 12:46 PM
whereas shorter time series suggest alternative biomass states are possible. I agree that the definition of desired ecosystem states is often debatable, but the use of alternative stable states theory to justify goals is problematic when alternative states are only apparent but not true. 7/7
December 19, 2024 at 12:46 PM
A similar problem occurs when the observation time span in experiments is too short to allow deterministic end points to be reached. For example, when the monitoring time series of phytoplankton biomass is extended, it turns out that phytoplankton is linearly related to nutrient concentrations 6/7
December 19, 2024 at 12:46 PM
A string of recent works shows that when these factors are considered and better data is used, the remaining overlap between forest and savannas is minimal, refuting the hypothesis of widespread bistability and pointing to a predictable endpoint in this system. I include some references below. 5/7
December 19, 2024 at 12:45 PM
such as growing season length and intensity or topography-driven variation in soil hydrology. 4/7
December 19, 2024 at 12:45 PM
The graph from the Pausas and Bond paper you posted is an example: It shows overlap along one variable (annual rainfall), but most people would agree that the distribution of forest and savannas is also influenced by other environmental factors 3/7
December 19, 2024 at 12:45 PM
The problem is that we often misinterpret prediction uncertainty in ecological models as evidence for overlapping environmental conditions between two or more ecosystem states, when in fact this uncertainty can be greatly reduced by better models and data. 2/7
December 19, 2024 at 12:44 PM
I would partly disagree. The evidence for multiple stable states is often not robust enough to use this framework for prescribing management actions. 1/7
December 19, 2024 at 12:44 PM
Thank you!
December 2, 2024 at 8:05 PM