What is it about?
Previous wetland condition indexes that were developed separately by considering a single wetland component could not provide sufficient information about the wetland condition. Recently, efforts have been made to combine and alter a few indices to develop an integrative expression that considers different environmental components. The Integrated Wetland Condition Index (IWCI) is like Magnetic Resonance Imaging (MRI) tests in medicine that produce detailed images of almost every internal structure in the human body. The lacustrine wetland condition index was developed based on four key characteristics (hydrology, water quality, sediment quality, and wetland biota) that define wetlands. Hydrology, water, and soil parameters within three wetland impact level categories were compared using Friedman post-hoc and Fisher’s LSD pairwise comparison in R version 4.1.3. The Friedman test was performed using the R package “agricolae,” and when significant, we used Fisher’s least significant difference (LSD) test. Macrophyte, diatom, and zooplankton indicator species tests (IndVal% and p (raw)) were calculated using PAST 4.14 (PAleontological STatistics). The results of IWCI of the low water level period indicated that moderately impacted conditions (44.44%); similarly, eight wetland-sampling sites were found within a good or mildly impacted condition, and 11.11% were found in an excellent or reference condition. Our findings could contribute to informing decision-makers on lacustrine wetland conservation and restoration priorities. Indicators at the landscape level, wetland biota of fish, and wetland birds as indicator species were not included in this research work. Thus, further research needs to be done by including landscape, fish, birds, and long-term water level variability indicators in the future research work.
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Why is it important?
Few studies have focused on integrated wetland condition indices. In order to manage and conserve wetlands, there is a need for integrated methods of assessment [13]. Recently, efforts have been made to combine and alter a few indices to develop an integrative expression that considers different environmental components. Thus, this lacustrine wetland condition index was developed based on four key characteristics (hydrology, water quality, sediment quality, and wetland biota) that define wetlands. The four wetland components (hydrology, water chemistry, sediment, and biota) were weighted according to their contribution to overall wetland condition. Weights were assigned using the Decision Support System Software of DEFINITE.
Perspectives
Although this IWCI developed and tested in this study could be a tool to inform decision-makers on lacustrine wetland conservation and restoration priorities throughout the Lake Tana Ecosystem, there are some limitations of the methods used in the study as well as the proposed index and future prospects of the study that needed to be strengthened. Factors that limit the development and test of IWCI for lacustrine fringe wetlands in Lake Tana were (a) limitations in spatial scale (only six selected wetlands were not sufficiently representative of the entire lacustrine wetland in Lake Tana). (b) limitation in temporal scale (the study was conducted only during two seasons: the pre-rainy (drawdown phase) of May 2021 and the post-rainy (flooding phase) of October 2021, i.e., the rest of the dry season of water level declining (recession phase) and the rainy season of water level rising (refill phase) were not covered). (c) IWCI does not sufficiently discriminate reference from impaired sites (CCP value of below 70%). Low CCP value could be associated with the limitation of the prior knowledge classification approach. The precise reference sites could not be identified since the selection of sites was based on a prior understanding of the effect pressures caused by human disturbances. This could influence the overall index value. Therefore, reference and impacted sites need to be chosen using a post-classification approach rather than prior knowledge of the impact pressures caused by human disturbances for future research projects on the development of the wetland state index. (d) Indicators at the landscape level, wetland biota of fish, and wetland birds as indicator species were not included in this research work. Thus, further research needs to be done by including landscape, fish, birds, and long-term water level variability indicators in the future.
Dr. Yirga Kebede Wondim
Bahir Dar University
Read the Original
This page is a summary of: Development and use of integrated wetland condition index for lacustrine fringe wetlands of Lake Tana, Northwest Ethiopia, PLOS One, June 2025, PLOS,
DOI: 10.1371/journal.pone.0314673.
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