Related Experiment Video
Updated: Jul 24, 2025
04:35
Development of an Individual-Tree Basal Area Increment Model using a Linear Mixed-Effects Approach
Published on: July 3, 2020
3.4K
Which demographic processes control competitive equilibria? Bayesian calibration of a size-structured forest
Lukas Heiland1,2, Georges Kunstler3, Vladimír Šebeň4
1Bayreuth Center of Ecology and Environmental Research (BayCEER), Ecosystem Analysis and Simulation (EASI) Lab University of Bayreuth Bayreuth Germany.
Ecology and Evolution
|July 6, 2023
Summary
The JAB model predicts that Fagus sylvatica will dominate 94% of future forest communities due to its superior shade tolerance, even though it is not dominant initially. This highlights the importance of early-life stage traits in forest assembly.
Area of Science:
- Forest Ecology
- Population Dynamics
- Community Assembly
Background:
- Light competition is crucial for forest community assembly, with seedling and sapling shade tolerance determining late-successional species composition.
- Current forests often deviate from late-successional equilibria, hindering direct evaluation of species composition.
- Understanding early life-stage demographics is vital for predicting forest community dynamics.
Purpose of the Study:
- To introduce and apply the JAB model, a dynamic model focusing on sapling demography and overstory competition, for extrapolating competitive equilibria from short-term data.
- To investigate the long-term competitive dynamics between the shade-tolerant species Fagus sylvatica and other competing species in temperate European forests.
- To assess the influence of demographic differences, particularly shade tolerance, on competitive outcomes in forest communities.
Main Methods:
- Developed and applied the parsimonious JAB model, incorporating size-structured populations and sapling demography.
- Utilized Bayesian calibration with prior data from Slovakian National Forest Inventory (NFI) to fit the JAB model to German NFI time series.
- Simulated counterfactual equilibria by switching species parameters to evaluate the impact of specific demographic processes.
Main Results:
- Extrapolation using the JAB model indicates Fagus sylvatica will be predominant in 94% of competitive equilibria, contrasting with its 24% initial predominance.
- Simulations confirmed that the higher shade tolerance of Fagus sylvatica saplings is the primary driver of its long-term competitive advantage.
- Demographic differences in early life stages significantly influence tree species assembly and future forest composition.
Conclusions:
- The JAB model provides a valuable tool for extrapolating competitive equilibria in forest communities.
- Fagus sylvatica's shade tolerance is a critical factor for its future dominance in temperate European forests.
- Early-life stage demographic traits are key determinants of long-term forest community structure and assembly.
Related Concept Videos
00:30What are Populations and Communities?
34.0K
Overview
34.0K
01:29Mechanistic Models: Compartment Models in Algorithms for Numerical Problem Solving
81
Mechanistic models play a crucial role in algorithms for numerical problem-solving, particularly in nonlinear mixed effects modeling (NMEM). These models aim to minimize specific objective functions by evaluating various parameter estimates, leading to the development of systematic algorithms. In some cases, linearization techniques approximate the model using linear equations.
In individual population analyses, different algorithms are employed, such as Cauchy's method, which uses a...
In individual population analyses, different algorithms are employed, such as Cauchy's method, which uses a...
81
01:23Mechanistic Models: Compartment Models in Individual and Population Analysis
65
Mechanistic models are utilized in individual analysis using single-source data, but imperfections arise due to data collection errors, preventing perfect prediction of observed data. The mathematical equation involves known values (Xi), observed concentrations (Ci), measurement errors (εi), model parameters (ϕj), and the related function (ƒi) for i number of values. Different least-squares metrics quantify differences between predicted and observed values. The ordinary least...
65
02:04Conservation of Small Populations
13.2K
Small population sizes put a species at extreme risk of extinction due to a lack of variation, and a consequent decrease in adaptability. This weakens the chances of survival under pressures such as climate change, competition from other species, or new diseases. Large populations are more likely to survive pressures such as these, as such populations are more likely to harbor individuals that have genetic variants that are adaptive under new stresses. Small populations are much less...
13.2K
02:07Conservation of Declining Populations
9.7K
Conservation of declining population focuses on ways of detecting, diagnosing, and halting a population decline. The approach uses methods to prevent populations from going extinct.
9.7K
01:26Distributions to Estimate Population Parameter
4.1K
The accurate values of population parameters such as population proportion, population mean, and population standard deviation (or variance) are usually unknown. These are fixed values that can only be estimated from the data collected from the samples. The estimates of each of these parameters are sample proportion, the sample mean, and sample standard deviation (or variance). To obtain the values of these sample statistics, data are required that have particular distribution and central...
4.1K