Abundance, population trends, and negative associations with lake water levels for six colonial waterbird species over five decades in southern Manitoba

The continuing decline in lake water levels is both a concern and daunting challenge to scientists and policymakers in this era, demanding a rethinking of technological and policy interventions in the context of broader political and socio-economic realities. It is self-evident that diverse factors interact in space and time in complex dynamics to cause these water-level changes. However, the major question demanding sound answers is how these factors interact and by what magnitude they affect lake water balance with time. This chapter uses Lake Victoria’s hydrological system to shed light on the extensive and flexible modelling and simulation capabilities availed by modern computer models to understand the bigger picture of water balance dynamics. The study used the 1950-2000 hydrological data and riparian population growth to develop a dynamic simulation model for the lake’s water level. The intuitive structure of the model provided clear insights into the combined influence of the main drivers of the lake’s water balance. The falling lake water levels appeared to be mainly due to dam outflows at the outlet and reduced rainfall over the lake. The ensuing conclusions stressed the need for checks against over-release of lake water for hydropower production and measures for sustainable land and water management in the entire basin.

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Lake water level response to drought in a lake-rich region explained by lake and landscape characteristics

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2019-0270 ◽

2020 ◽

Vol 77 (11) ◽

pp. 1836-1845

Author(s):

K. Martin Perales ◽

Catherine L. Hein ◽

Noah R. Lottig ◽

M. Jake Vander Zanden

Keyword(s):

Climate Change ◽

Water Level ◽

Lake Water ◽

Water Levels ◽

Water Level Fluctuations ◽

Lake Area ◽

Lake Water Level ◽

Landscape Characteristics ◽

Lake Ecology ◽

Coarse Woody Habitat

Climate change is altering hydrologic regimes, with implications for lake water levels. While lakes within lake districts experience the same climate, lakes may exhibit differential climate vulnerability regarding water level response to drought. We took advantage of a recent drought (∼2005–2010) and estimated changes in lake area, water level, and shoreline position on 47 lakes in northern Wisconsin using high-resolution orthoimagery and hypsographic curves. We developed a model predicting water level response to drought to identify characteristics of the most vulnerable lakes in the region, which indicated that low-conductivity seepage lakes found high in the landscape, with little surrounding wetland and highly permeable soils, showed the greatest water level declines. To explore potential changes in the littoral zone, we estimated coarse woody habitat (CWH) loss during the drought and found that drainage lakes lost 0.8% CWH while seepage lakes were disproportionately impacted, with a mean loss of 40% CWH. Characterizing how lakes and lake districts respond to drought will further our understanding of how climate change may alter lake ecology via water level fluctuations.

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Zooplankton species richness and abiotic conditions in Thirlmere Lakes, New South Wales, Australia, with reference to water-level fluctuations

Australian Zoologist ◽

10.7882/az.2020.020 ◽

2020 ◽

Vol 41 (1) ◽

pp. 107-123

Author(s):

Tsuyoshi Kobayashi ◽

Martin Krogh ◽

Hiroyuki ◽

Russell J. Shiel ◽

Hendrik Segers ◽

...

Keyword(s):

Species Richness ◽

Water Level ◽

Lake Water ◽

New South ◽

Water Levels ◽

Water Level Fluctuations ◽

Zooplankton Species ◽

Abiotic Conditions ◽

Lake Water Level ◽

South Wales

Water-level fluctuations can have significant effects on lake biological communities. Thirlmere Lakes are a group of five interconnected lakes located near Sydney. Water levels in Thirlmere Lakes have fluctuated over time, but there has been a recent decline that is of significant concern. In this study, we examined over one year the species composition and richness of zooplankton (Rotifera, Cladocera and Copepoda) and abiotic conditions in Lakes Nerrigorang and Werri Berri, two of the five Thirlmere lakes, with reference to lake water level. We recorded a total of 66 taxa of zooplankton, with the first report of the rotifer Notommata saccigera from Australia, and the first report of the rotifers Keratella javana, Lecane rhytida and Rousseletia corniculata from New South Wales. There was a marked difference in abiotic conditions between the two lakes, with more variable conditions in Lake Nerrigorang. There was a significant positive correlation between zooplankton species richness and lake water level but only for Lake Nerrigorang. Although the two lakes are closely situated and thought to be potentially connected at high water levels, they show distinct ecological characters and the effect of water-level fluctuations on zooplankton species richness seems to differ between the lakes.

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Abnormal high water levels of Lake Malawi? ? An attempt to assess the future behaviour of the lake water levels

GeoJournal ◽

10.1007/bf00171596 ◽

1984 ◽

Vol 9 (4) ◽

Cited By ~ 1

Author(s):

H. Neuland

Keyword(s):

Lake Water ◽

High Water ◽

Lake Malawi ◽

Water Levels ◽

The Future

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Ecological Correlates of 20-Year Population Trends of Wintering Waterbirds in Deep Bay, South China

Frontiers in Ecology and Evolution ◽

10.3389/fevo.2021.658084 ◽

2021 ◽

Vol 9 ◽

Author(s):

Yik-Hei Sung ◽

Chun-chiu Pang ◽

Tom Chung-hoi Li ◽

Paulina Pui Yun Wong ◽

Yat-tung Yu

Keyword(s):

South China ◽

Population Trends ◽

The Yellow Sea ◽

Bay Area ◽

Waterbird Species ◽

Wide Range ◽

Conservation Actions ◽

Deep Bay

Along the East Asian-Australasian flyway (EAAF), waterbirds are threatened by a wide range of human activities. Studies have shown that wintering populations of many species have declined in Australia and Japan; however, long term data along China’s coast are limited. In this study, we analyzed data collected from monthly bird surveys to quantify population trends of wintering waterbirds from 1998 to 2017 in the Deep Bay area, South China. Of the 42 species studied, 12 declined, while nine increased significantly. Phylogenetic comparative analysis revealed that population trends were negatively correlated to reliance on the Yellow Sea and body size. Further, waterbird species breeding in Southern Siberia declined more than those breeding in East Asia. These findings, coupled with a relatively high number of increasing species, support the continual preservation of wetlands in the Deep Bay area. This study provides another case study showing that data collected from wintering sites provide insights on the threats along migratory pathway and inform conservation actions. As such, we encourage population surveys in the EAAF to continue, particularly along the coast of China.

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Drying Lakes: A Review on The Health Conditions and Restoration Strategies

10.5194/egusphere-egu2020-1207 ◽

2020 ◽

Author(s):

Anchita Anchita ◽

Kamshat Tussupova ◽

Peder Hjorth

Keyword(s):

Water Level ◽

Lake Water ◽

Saline Lakes ◽

Saline Lake ◽

Dust Storms ◽

Water Levels ◽

Aral Sea ◽

Water Withdrawal ◽

Local Context ◽

Lake Urmia

Abstract: Decrease of saline lakes, which comprises of 44% of all the available lake water, is a major concern. It additionally brings to desertification process to the region. Thus, various countries have taken different actions in protecting their lake&#8217;s water level. The aim of this paper is to assess different strategies directed to tackle the decreasing saline lake water levels. Lake Urmia and the Aral Sea which split into North Aral and South Aral were among the world's largest saline lakes and now have reduced to 10% of their original size. A thorough review of academic reports, official documents and databases were considered. Although the dry-up of the lake is a natural process, it has been sped up by human interventions in the hydrology cycle. Dust storms (strong winds) in the case of the Aral Sea, transmit the pollutants from dry lake surface which initially accumulated in the lakebed causing severe health issue. Various strategies were implemented to manage the socio-economic conditions caused due to the drying of lakes. The strategy implemented for the North Aral Sea was to restore the lake by reducing the water withdrawal from tributary rivers which leads to increased water level in the sea. The strategy implemented for Lake Urmia was to restore the lake by water transfer activities from neighbouring water sources which until now show no increase in water level. The strategy implemented for the South Aral Sea was to use a dry lakebed to diversify the economy by oil and mineral extraction which shows the adaptation to the environmental conditions with no restoration strategy. As a conclusion, it is found that there is no common best solution for this kind of problem. The best fit depends on the local context and it is strongly path dependent.&#160;Keywords: Drying saline lake; Dust storms; Aral sea; Health impacts; Lake Urmia; Restoration of saline lake; Strategies.

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Worldwide lake level trends and responses to background climate variation

Hydrology and Earth System Sciences ◽

10.5194/hess-24-2593-2020 ◽

2020 ◽

Vol 24 (5) ◽

pp. 2593-2608 ◽

Cited By ~ 1

Author(s):

Benjamin M. Kraemer ◽

Anton Seimon ◽

Rita Adrian ◽

Peter B. McIntyre

Keyword(s):

Water Level ◽

Lake Water ◽

Environmental Changes ◽

Southern Oscillation ◽

Climate Variation ◽

Water Levels ◽

P Value ◽

Long Term Trends ◽

Background Climate

Abstract. Lakes provide many important benefits to society, including drinking water, flood attenuation, nutrition, and recreation. Anthropogenic environmental changes may affect these benefits by altering lake water levels. However, background climate oscillations such as the El Niño–Southern Oscillation and the North Atlantic Oscillation can obscure long-term trends in water levels, creating uncertainty over the strength and ubiquity of anthropogenic effects on lakes. Here we account for the effects of background climate variation and test for long-term (1992–2019) trends in water levels in 200 globally distributed large lakes using satellite altimetry data. The median percentage of water level variation associated with background climate variation was 58 %, with an additional 10 % explained by seasonal variation and 25 % by the long-term trend. The relative influence of specific axes of background climate variation on water levels varied substantially across and within regions. After removing the effects of background climate variation on water levels, long-term water level trend estimates were lower (median: +0.8 cm yr−1) than calculated from raw water level data (median: +1.2 cm yr−1). However, the trends became more statistically significant in 86 % of lakes after removing the effects of background climate variation (the median p value of trends changed from 0.16 to 0.02). Thus, robust tests for long-term trends in lake water levels which may or may not be anthropogenic will require prior isolation and removal of the effects of background climate variation. Our findings suggest that background climate variation often masks long-term trends in environmental variables but can be accounted for through more comprehensive statistical analyses.

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Comparison of random forests and other statistical methods for the prediction of lake water level: a case study of the Poyang Lake in China

Hydrology Research ◽

10.2166/nh.2016.264 ◽

2016 ◽

Vol 47 (S1) ◽

pp. 69-83 ◽

Cited By ~ 42

Author(s):

Bing Li ◽

Guishan Yang ◽

Rongrong Wan ◽

Xue Dai ◽

Yanhui Zhang

Keyword(s):

Water Level ◽

Random Forests ◽

Lake Water ◽

Poyang Lake ◽

Time Lag ◽

Water Levels ◽

Support Vector ◽

Lake Water Level ◽

Water Level Variations

Modeling of hydrological time series is essential for sustainable development and management of lake water resources. This study aims to develop an efficient model for forecasting lake water level variations, exemplified by the Poyang Lake (China) case study. A random forests (RF) model was first applied and compared with artificial neural networks, support vector regression, and a linear model. Three scenarios were adopted to investigate the effect of time lag and previous water levels as model inputs for real-time forecasting. Variable importance was then analyzed to evaluate the influence of each predictor for water level variations. Results indicated that the RF model exhibits the best performance for daily forecasting in terms of root mean square error (RMSE) and coefficient of determination (R2). Moreover, the highest accuracy was achieved using discharge series at 4-day-ahead and the average water level over the previous week as model inputs, with an average RMSE of 0.25 m for five stations within the lake. In addition, the previous water level was the most efficient predictor for water level forecasting, followed by discharge from the Yangtze River. Based on the performance of the soft computing methods, RF can be calibrated to provide information or simulation scenarios for water management and decision-making.

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