Relationship Between the EPT Index and Dissolved Oxygen in Aquatic Ecosystems
This project will run a pilot study to test whether the EPT index responds to a gradient of aquatic ecosystem (environmental) condition in south western Australia. The pilot study will sample numerous sites within the Kalgan River catchment. This river is located within a partially salanised, agricultural landscape, and exhibits a variety of ecosystem conditions from ‘good’ to ‘severely’ degraded. Using standardized sampling techniques, macronvertebrates will be collected from numerous study sites, and EPT taxa will be live-picked in the field. Instream and riparian environmental conditions (habitat, water quality etc) will be quantified using a randomized quadrate design at each site. EPT samples from each site will be identified to the lowest possible taxonomic level using keys and photographs of regional EPT taxa. Also available is a historical database of EPT taxa and water quality at sampling sites, and a predictive model output of EPT presence within the catchment.
A variety of specific research questions are possible using both the field data and additional datasets/model predictions. You will develop a specific research question under the broad aim of assessing application of the EPT index in south western Australia.
You need to communicate the findings of our research in the form of a 'Short Report' for the journal "Ecological Management & Restoration". Please consult the instructions to authors for the precise format required by that iournal in terms of word length (we will set this at approximately 1700-2000 words at the most), presentation of figures and tables, referencing and general format. You should also read a few Short Reports in this journal to familiarise yourself with approaches taken to scientific writing in succinct form. You will find examples of Short reports published in this journal in the item below. The major sections in vour report will be: Summarv/Abstract. Introduction. Methods, Results.
Discussion/Management and Policy Implications, Acknowledgements and References. You can use subheadings in the Methods, Results and/or Discussion sections. You may include one table and one figure (although the guidelines for authors for this journal say one table or figure, there are examples in the journal where Short reports have a table and a figure). As you can only include one figure, design your figure carefully - it is likely to be a 'composite' type figure. Some more detail of the format and structure required is contained within the author guidelines for the journal.
Short Report: Relationship Between the EPT Index and Dissolved Oxygen in Aquatic Ecosystems
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Abstract
This research project, conducted during the ENVT 5576 Aquatic Ecology Albany Field Trip 2022, aimed to explore the suitability of the EPT Index as an indicator of aquatic ecosystem conditions in southwestern Australia, specifically within the Kalgan River catchment. The study involved comprehensive field collections, sample processing, and data analysis, incorporating insights from site visits. By addressing specific research questions, this pilot study sought to evaluate the responsiveness of EPT taxa to regionally specific environmental conditions, considering factors such as taxonomic richness, consistency in responses, and the behavior of endemic EPTs in southwestern Australian aquatic ecosystems.
(EPT taxa, aquatic ecosystems, Dissolved Oxygen)
Introduction
Aquatic ecosystems, characterized by their intricate web of life and ecological interdependencies, are fundamental components of our natural environment. They provide habitats for a wide array of flora and fauna, serving as the lifeblood of countless organisms. To understand and preserve these vital ecosystems, scientists and researchers have developed various methods to assess their health and integrity. One such method, the EPT index, stands out as a significant biological indicator, representing a combination of Ephemeroptera, Plecoptera, and Trichoptera taxa. These taxa, commonly known as mayflies, stoneflies, and caddisflies, are particularly sensitive to environmental changes, making them invaluable indicators of aquatic ecosystem health (Lopez et al., 2019).
The level of Dissolved Oxygen (DO) present in water bodies is central to the sustenance of aquatic life. DO is a vital parameter in evaluating the quality of aquatic habitats, profoundly influencing aquatic organisms' survival, behavior, and distribution patterns (Saroglia et al., 2016). Adequate levels of DO are essential for the respiration and metabolism of various aquatic organisms, including fish, invertebrates, and microorganisms. Consequently, deviations in DO concentrations can significantly impact aquatic ecosystems' overall biodiversity and ecological balance (Lopez et al., 2019).
This study focuses on exploring the intricate relationship between the EPT index and DO levels, with a specific emphasis on the Kalgan River catchment in southwestern Australia. This region, encompassing a diverse range of environmental conditions, presents a unique opportunity to investigate this relationship across a spectrum of ecosystem states. The Kalgan River, flowing through a partially salinized agricultural landscape, showcases varying degrees of ecosystem health, from 'good' to 'severely' degraded states. Understanding how the EPT index responds to these diverse conditions is paramount for deciphering the health dynamics of aquatic ecosystems in this region (Poff et al., 2006).
Several studies have underscored the significance of EPT taxa as reliable indicators of water quality and habitat conditions. For instance, research by Tampo et al. (2020) demonstrated the effectiveness of EPT taxa in indicating the impacts of urbanization on stream ecosystems. Additionally, Paul and Meyer (2001) highlighted the sensitivity of EPT taxa to pollution, emphasizing their utility in assessing the ecological integrity of aquatic environments. Moreover, the study by Thai et al. (2018) emphasized the importance of understanding the correlation between DO levels and aquatic macroinvertebrate communities. These studies provide a theoretical foundation for our research, guiding the exploration of the interplay between DO concentrations and the EPT index in the specific context of the Kalgan River catchment. In this case, this study contributes significantly to understanding aquatic ecosystem dynamics and aids in formulating informed conservation and management strategies tailored to the unique conditions of the Kalgan River catchment.
Methods
The fieldwork commenced with standardized 10m x 1m transects of representative habitats at multiple sites within the Kalgan River catchment, ranging from 'good' to 'severely' degraded conditions. Macroinvertebrates, particularly EPT taxa, were meticulously sampled and live-picked in the field, preserving the integrity of specimens for subsequent identification. Concurrently, quantitative field sampling procedures and water quality analyses were employed to quantify environmental conditions at each site. The samples were then transported to the UWA-Albany laboratory for taxonomic identification using regional keys and photographs of EPT taxa.
Results
Descriptive Statistics
Descriptive statistics were calculated for the collected water quality parameters across different sites and waterways, providing insights into these parameters' central tendencies and variations. The mean temperature was approximately 19.34°C, with a moderate standard deviation of 2.76°C. The temperature ranged from 12.5°C to 23.05°C, indicating notable variation among the sampled sites, potentially influenced by geographical and climatic factors. The mean conductivity was 21.84 ms/cm, with a 15.02 ms/cm standard deviation. Conductivity levels ranged from 1.6 ms/cm to 29 ms/cm, showcasing substantial variability in the conductive properties of the water samples. Variations in conductivity could be attributed to dissolved minerals, pollutants, and organic matter. Salinity levels exhibited stability across sites, with a mean salinity of 1.13 ppt and a standard deviation of 0.65 ppt. Salinity ranged from 0.8 to 1.9 ppt, indicating a moderate salinity range in the sampled waterways. Stable salinity levels suggest a balance between freshwater input and evaporation rates.
Table SEQ Table \* ARABIC 1: Descriptive Statistics of Water Quality Parameters
Parameter
Mean
Standard Deviation
Range
Temperature (°C)
19.34
2.76
12.5°C - 23.05°C
Conductivity (ms/cm)
21.84
15.02
1.6 ms/cm - 29 ms/cm
Salinity (ppt)
1.13
0.65
0.8 ppt - 1.9 ppt
Dissolved Oxygen (mg/l)
6.05
1.16
0.8 mg/l - 11.3 mg/l
pH
7.12
0.51
6.26 - 7.95
Turbidity (NTU)
17.43
24.66
0 NTU - 100 NTU
As shown in Table 1, the mean dissolved oxygen level was 6.05 mg/l, with a standard deviation of 1.16 mg/l. DO levels varied widely between 0.8 mg/l and 11.3 mg/l, indicating diverse oxygen availability in the water samples. Aquatic plant activity, temperature, and pollution can influence DO levels (Zheng et al., 2017). The mean pH was 7.12, with a standard deviation of 0.51. pH levels ranged from 6.26 to 7.95, indicating the water samples' slightly acidic to slightly alkaline nature. pH values are vital indicators of water quality, reflecting the water's acidity or basicity, often influenced by geological formations and anthropogenic activities (Zainab et al., 2022). Turbidity levels showed significant variation, with a mean of 17.43 NTU and a standard deviation of 24.66 NTU. Turbidity ranged from 0 NTU to 100 NTU, indicating diverse levels of suspended particles and water clarity. High turbidity, as observed in specific sites, suggests the presence of pollutants or sediment runoff, impacting aquatic habitats.
Figure SEQ Figure \* ARABIC 1: Dissolved oxygen variations across sites
Temporal Analysis
A subtle increase in water temperature was observed from historical data (2006/07) to 2022, suggesting...