Assessing how uncertainty and stochasticity affect the dispersal of fish in river networks
Authored by Johannes Radinger, Franz Hoelker, Christian Wolter
Date Published: 2017
DOI: 10.1016/j.ecolmodel.2017.05.029
Sponsors:
German Federal Ministry of Education and Research (BMBF)
Platforms:
No platforms listed
Model Documentation:
Other Narrative
Model Code URLs:
Model code not found
Abstract
Species dispersal and population dynamics determine the spatio-temporal
patterns of species spread and thus, species invasions and
recolonization following habitat restorations. However, the effects of
stochasticity and spatial habitat heterogeneity on species spread are
poorly understood.
By coupling a fish dispersal model and a population growth model in GIS,
we simulated the spread of a model fish species (Salmo trutta) over five
years in river networks of varying habitat heterogeneity. Replicated
model runs and a sampling-based sensitivity analysis allowed us to
disentangle the uncertainty in the rate of spread related to (i)
specific model input parameters and (ii) stochasticity inherent to the
dispersal process.
Our results revealed the spread of the model species being particularly
sensitive to the choice of parameters determining fish dispersal (e.g.
fish size) and less to demographic parameters (e.g. reproductive rate).
Moreover, the spread of fish is strongly affected by stochasticity
inherent to dispersal and the availability and spatial arrangement of
suitable habitats patches. Stochastic effects cause considerable
variations in the predictability of up to 120\% of the median dispersal
distance whereof 52\% is solely attributed to stochasticity inherent to
dispersal decisions.
Our findings demonstrate that process-based models combining individual
dispersal, population dynamics and spatial habitat heterogeneity as well
as carefully selected model input parameters are crucial for reasonably
simulating the spread of fishes in river networks. Moreover, we suggest
considering stochasticity inherent to dispersal in models of species
spread as this contributes to a considerable variation in the
predictability of movement distances. (C) 2017 Elsevier B.V. All rights
reserved.
Tags
individual-based models
movement
Sensitivity Analysis
ecology
habitat
aleatory uncertainty
epistemic uncertainty
Latin hypercube sampling
Population-dynamics
Spread
Sensitivity-analysis
Biological invasions
Range expansion
Stream fish
River fish dispersal
Spatial habitat
heterogeneity