Environmental flow assessment in estuaries taking into consideration species dispersal in fragmented potential habitats
Authored by Tao Sun, Wei Yang, Heyue Zhang, SuFeng Xue, Xinan Yin
Date Published: 2017
DOI: 10.1016/j.ecolind.2017.03.042
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Abstract
Here, we propose an approach to environmental flow assessment that pays
attention to species dispersal among fragmented potential habitat
patches affected by river inflow and tidal currents in estuaries. The
approach consists of three steps. In step one, potential suitable
habitats were mapped and the Habitat Aggregation Index (HAI) was
determined to understand the fragmentation of potential suitable
habitats by integrating the requirements for critical environmental
factors that have temporal and spatial variability. In the second step,
an individual-based model was developed to simulate the dispersal of
target species among potential habitat patches. The model provided the
species distributions for altered hydrological processes. In the third
step, environmental flows were defined by comparing the occupancy of
suitable habitat patches by individual organisms and habitat aggregation
for varying freshwater inflows. This approach was tested using a case
study in the Yangtze River Estuary. We stressed the ecological
importance of flood pulse, rather than average discharge, and recommend
a Gaussian-type flood pulse, as provides a win-win point for both the
numbers of individuals that could occupy suitable habitat and the HAI.
We also demonstrated the importance of the peak flow and flood pulse
duration in terms of affecting species distribution. Based on the
results presented here, the proposed approach offers a flexible
assessment of environmental flow for aquatic ecosystems. (C) 2017
Elsevier Ltd. All rights reserved.
Tags
Individual-based model
China
Water
population
Model
Estuary
Fish
Salinity
Requirements
Environmental flow assessment
Species dispersal
Yangtze river estuary
Yangtze-river
Hydrological connectivity
Global perspective