Testing the intermediate disturbance hypothesis in species‐poor systems: A simulation experiment for mangrove forests

Abstract

Questions: What factors influence tree species diversity of mangrove forests, an example of species-poor systems? What are the respective importance and interactions of these factors? Is the intermediate disturbance hypothesis applicable to such systems? Methods: We used the spatially explicit individual-based model KiWi to investigate the effects on species diversity of perturbation frequency and intensity, different abiotic conditions, and interspecific competition simulated at the individual level. The simulation system considered the three dominant Caribbean mangrove species: Rhizophora mangle, Avicennia germinans and Laguncularia racemosa, applying species-specific growth and mortality characteristics. Firstly, effects on species dominance of the abiotic conditions nutrient availability and porewater salinity were tested with two competition scenarios. Secondly, the effect of perturbation frequency and intensity were investigated with selected abiotic conditions. Results: Abiotic conditions influenced species dominance and, in extreme cases, excluded one or two species. Abiotic and competition settings controlled the successional dynamics and the response of species dominance to perturbation regimes. A response consistent with the intermediate disturbance hypothesis was observed only with a configuration of plant interaction in which one species behaved as a pioneer so that succession occurred by competitive exclusion. Conclusions: We suggest that successional dynamics interact with the intensity and timing of perturbations and determine whether or not mangrove tree diversity conforms to predictions of the intermediate disturbance hypothesis. For mangroves, these successional dynamics are site-specific depending on abiotic conditions and species configurations.Keywords: Individual-based modeling; Interspecific competition; KiWi model; Perturbation regime; Species dominance; Succession.Abbreviations: FON = Field of Neighbourhood; IDH = Intermediate disturbance hypothesis; I SDH = Index of species dominance heterogeneity; psu = Practical salinity units; RNA = Relative nutrient availability.

Multiple Stable States and Catastrophic Shifts in Coastal Wetlands: Progress, Challenges, and Opportunities in Validating Theory Using Remote Sensing and Other Methods

“…Such research is particularly important given the disagreement in the literature as to whether mangrove systems truly exhibit catastrophic shifts within an alternative stable state framework enabled by ecogeomorphological ecosystem engineering (e.g., perhaps as in [201,241]), or rather just continuous phase shifts within the framework of succession (e.g., [233,242]). …”

“…It is possible that species-specific mangrove-sediment interactions might have similar trade-offs. Disturbance can trigger internal rearrangement of the density and patterns of different mangrove species within a mangrove habitat [201][202][203], which is potentially consistent with self-organized ecosystem patterning.…”

Using expert knowledge and modeling to define mangrove composition, functioning, and threats and estimate time frame for recovery

“…), and for testing the validity of the intermediate disturbance hypothesis in the context of species‐poor mangrove systems (Piou et al. ).…”

“…It has also been used to assess the potential of small scale canopy disturbances in driving Vietnamese mangrove plantations towards more natural conditions (Vogt et al 2013) and to investigate desynchronizing effects of lightning strikes on cyclic forest dynamics in mangrove plantations (Kautz et al 2011). KiWi has also been used to understand the zonation patterns that have emerged in mangrove forests recovering from hurricane Hattie 1961 on Calabash island in Belize (Piou et al 2006), and for testing the validity of the intermediate disturbance hypothesis in the context of species-poor mangrove systems (Piou et al 2008).…”

Individual-based modeling of mangrove forest growth: MesoFON – Recent calibration and future direction

“…Tasks 2,4,5,6 are all related to effects of disturbance regime on community dynamics. Natural disturbance events, such as hurricane and lightning impacts, represent local threats at the stand level (compare Piou et al, 2008;Vogt et al, 2014;Grueters et al, 2014). Yet, the main focus on the natural threat of disturbance does not appear adequate given the plethora of anthropogenic threats that have led to the massive global mangrove loss (Valiela et al, 2001;Duke et al, 2007).…”