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Modeling the distribution of riverine vegetation in regulated rivers - from dynamic to static equilibrium
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Autores
Orientador(es)
Resumo(s)
While methodological advances in ecosystem modeling reflect the growing recognition in the
importance of accounting for dynamic change in river ecosystems, it is also recognized that
various forms of regulation measures have completely disrupted its natural dynamics. In this
context the underlying research question of this PhD is how river regulation affects the spatial
distribution of riverine vegetation (aquatic and riparian) and whether rather simple static
models that assume equilibrium between vegetation and environmental factors are adequate
tools for its prediction.
In a first step, we presented a systematic, quantitative literature review on models to predict
the distribution of riverine vegetation on reach scale and identified research gaps to guide the
further development of the thesis. Then, we developed and tested a habitat suitability model
for aquatic vegetation based on hydrological variables. We concluded that during artificially
stabilized (static) low flows the vegetation is in equilibrium with the physical instream
condition and showed how the model can be used to define a flow threshold that reduces the
risk of species invasion and proliferation. Further, we reconstructed the historic succession
dynamics of a large river floodplain using a dynamic vegetation model and showed that typical
regulation measures led to a steady progression of the vegetation communities toward
mature phases without regression to younger stages. Finally, we applied different static and
dynamic modeling approaches for the distribution of floodplain vegetation to the same study
area and concluded from the comparison of their results that due to regulation measures the
relevance of succession dynamics and disturbance stochasticity for the prediction of
vegetation patterns is much reduced.
Consequently, from a river manager ́s perspective, static models seem to be an adequate
option for the modeling of the distribution of riverine vegetation in artificially stabilized
environments since they show high accuracy, need relatively few resources (data, time, expert
knowledge) when compared to dynamic models and are reproducible
Descrição
Doutoramento FLUVIO - River Restoration and Management / Instituto Superior de Agronomia / Faculdade de Arquitetura / Instituto Superior Técnico. Universidade de Lisboa
Palavras-chave
riparian vegetation aquatic vegetation modeling spatial distribution river restoration
Contexto Educativo
Citação
Ochs, K. - Modeling the distribution of riverine vegetation in regulated rivers - from dynamic to static equilibrium. Lisboa: ISA, 2021, 213 p.