An integrated approach for spatio-temporal variability analysis of wetlands: a case study of Abaya and Chamo lakes, Ethiopia

Kassawmar, N. Tibebu; Rao, K. Ram Mohan; Abraha, Gebregiorgis

doi:10.1007/s10661-010-1790-z

Cited by 16 publications

(11 citation statements)

References 12 publications

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“…However, it has been threatened in recent years due to rapid population growth and resettlement, as well as expansion of agricultural and irrigation activities in the landscape [26][27][28]. For the last few decades, an increasing demand for fuelwood and wood for construction, land clearing for agricultural expansion and irrigation activities, and bush burning for pasture have greatly modified the landscape and affected the water quality of lakes found in the basin [29][30][31]. High rates of LULC changes have been reported for the southern part of the basin [27,32,33].…”

Section: Introductionmentioning

confidence: 99%

Land Use and Land Cover Changes and Their Effects on the Landscape of Abaya-Chamo Basin, Southern Ethiopia

Woldeyohannes

Cotter

Kelboro

et al. 2018

Land

103

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This study uses a combination of remote sensing data, field interviews and observations, and landscape indices to examine the dynamics of land use and land cover (LULC), identify their driving forces, and analyze their effects on the landscape of Abaya-Chamo Basin (ACB) between 1985, 1995, and 2010. The results reveal that the landscape of ACB has changed considerably during the past 25 years between 1985 and 2010. The main changes observed imply a rapid reduction in shrubland (28.82%) and natural grassland (33.13%), and an increase in arable land (59.15%). The basin has become more fragmented and formed less connected patches in 2010 compared to 1985. Rapid population growth, internal migration, policy shifts, and regime change were identified as the key driving forces of LULC changes in ACB. The LULC changes and related trend of increasing landscape fragmentation in the basin increased soil erosion, the volume of surface runoff, and sediment transport in the landscape and, consequently, affected the levels and water quality of the lakes found in the rift floor. Furthermore, the destruction and fragmentation of shrubland and natural grassland led to the decline of wild plants and animals previously prominent in the basin. Therefore, protective measures that take into consideration the economic, social, and ecological dynamics of the basin are urgently needed to save the aquatic and terrestrial ecosystems of the basin from further damage.

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Section: Introductionmentioning

confidence: 99%

Land Use and Land Cover Changes and Their Effects on the Landscape of Abaya-Chamo Basin, Southern Ethiopia

Woldeyohannes

Cotter

Kelboro

et al. 2018

Land

103

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“…). Both lakes are key determinants of the ecology of the region and have high socio‐economic importance, including fisheries, water supply and tourism (Awulachew , b; Golubtsov & Habteselassie ; Kassawmar, Rao & Abraha ; Alemayehu & Raju ). Unfortunately, these lakes suffer from severe ecological degradation caused by sediment accumulation, nutrient pollution and overfishing (Schutt & Thiemann ; Golubtsov & Habteselassie ).…”

Section: Introductionmentioning

confidence: 99%

Intra‐ and interspecific niche variation as reconstructed from stable isotopes in two ecologically different Ethiopian Rift Valley lakes

et al. 2017

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Summary The concept of species niches has enhanced our understanding of community assembly and food web structure in a variety of ecosystem types. Niche‐based species sorting profoundly determines community composition along strong environmental gradients, while interspecific interactions tend to be more important within habitats at local spatial scales. The role of intraspecific niche variation in community assembly and ecosystem functioning has only recently been highlighted. The present study undertakes a quantitative comparison of the trophic structure of fish communities in two iconic Ethiopian Rift Valley lakes, Lake Abaya and Lake Chamo, which are biodiversity hotspots with high societal importance. The lakes differ strongly in ecology: whereas Lake Abaya is turbid due to a very high sediment loading, Lake Chamo is a clear‐water lake, which in recent years is, however, rapidly becoming more turbid. Using stable isotopes, we compare the structure of the food web in both lakes, and investigate the degree to which differences in trophic structure between the two lakes are mediated by changes in species composition with fixed within‐species niches or rather by flexibility in food acquisition within species. Different food web compartments, including fish and the main basal sources, were sampled in both lakes. We used Bayesian stable isotope mixing models and Bayesian community‐wide metrics for a quantitative comparison of the food web structure between the two lakes. We demonstrate that the isotopic niche of the fish community in Lake Abaya is larger and more diversified compared to that in Lake Chamo. Sediment organic material seems to be a major energy source for fish in Abaya, while zooplankton is a dominant source for fish in Chamo. This is consistent with the different ecology of the two lakes, where high turbidity impedes primary and secondary production in Abaya. Differences in trophic structure between the two lakes resulted from intraspecific isotopic niche variation rather than from compositional variation between fish communities. Our results point to the importance of intraspecific variation in feeding ecology of fish communities inhabiting two large Ethiopian Rift Valley lakes with distinct environmental conditions. We anticipate that the approach we used has strong potential to explore large‐scale patterns in food web organization in relation to niche variation across different types of ecosystems. http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.12852/suppinfo is available for this article.

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“…Certainly, Lake Langano and Lake Shala experienced only small amount of changes over the last three decades ( Table 1). The extent of Abaya and Chamo (the other rift valley lakes) were reduced, significantly, between 1986 and 2000 (Tibebu Kassawmar et al, 2011).…”

Section: Awei = 4 *(Green-mir) − (025×nir + 275 ×Swir)mentioning

confidence: 99%

“…Therefore, a continues inventory and monitoring of their extent using remote sensing is highly needed (Ozesmi and Bauer, 2002). Incidentally, various reports were provided on the extent of lakes in the earlier works (Ariti et al, 2015;Tibebu Kassawmar et al, 2011;Sisay, 2016). These works, however, give information earlier than 2015.…”

Section: Introductionmentioning

confidence: 99%

Water surface Changes of Lakes in the Central Rift Valley of Ethiopia

Kedirkan

2019

International Journal of Environment and Geoinformatics

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Lakes are one of the most important biologically diverse ecosystems. However, extensive human and natural factors contributed to the loss of this ecosystem. Until recently, knowledge on the recent status of rift valley lakes was lacking. The aim of this study was, therefore, to estimate the current extent of selected lakes in the central Rift Valley of Ethiopia using Landsat image. Satellite images of Landsat OLI_TIRS for the year 2018 were used for this study. Selected bands (green, near infrared, shortwave infrared and middle infrared) were selected in calculating automated water extraction index to distinguish water surface from non-water. The result revealed that the extent of water surface was reduced between 2015 and 2018 with an amount of 47.6, 2.4 and 0.9 % for lake Abjata, Shala and Langano, respectively. Such rapid conversions of aquatic ecosystem need urgent management and policy intervention. Furthermore, applied researches are needed to reduce the magnitude of change.

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An integrated approach for spatio-temporal variability analysis of wetlands: a case study of Abaya and Chamo lakes, Ethiopia

Cited by 16 publications

References 12 publications

Land Use and Land Cover Changes and Their Effects on the Landscape of Abaya-Chamo Basin, Southern Ethiopia

Land Use and Land Cover Changes and Their Effects on the Landscape of Abaya-Chamo Basin, Southern Ethiopia

Intra‐ and interspecific niche variation as reconstructed from stable isotopes in two ecologically different Ethiopian Rift Valley lakes

Water surface Changes of Lakes in the Central Rift Valley of Ethiopia

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