Afroalpine Wetlands of the Bale Mountains, Ethiopia: Distribution, Dynamics, and Conceptual Flow Model

Chignell, Stephen M.; Laituri, Melinda; Young, Nicholas E.; Evangelista, Paul

doi:10.1080/24694452.2018.1500439

Cited by 14 publications

(13 citation statements)

References 74 publications

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“…Several studies have examined the hydrologic function of wetlands and meadows in high mountain catchments (Chignell, Laituri, Young, & Evangelista, 2019; Chimner et al, 2019; Cooper et al, 2010, 2019; Lowry, Loheide, Moore, & Lundquist, 2011; Millar, Cooper, & Ronayne, 2018; Mosquera, Lazo, Célleri, Wilcox, & Crespo, 2015; Mosquera et al, 2016; Polk et al, 2017; Streich & Westbrook, 2019). Due to their excess of water and decreasing permeability with drying, wetlands can self‐regulate to keep the water table near the land surface (Rezanezhad et al, 2016).…”

Section: Mountain Aquifers and Flow Pathwaysmentioning

confidence: 99%

A review of groundwater in high mountain environments

2020

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Mountain water resources are of particular importance for downstream populations but are threatened by decreasing water storage in snowpack and glaciers. Groundwater contribution to mountain streamflow, once assumed to be relatively small, is now understood to represent an important water source to streams. This review presents an overview of research on groundwater in high mountain environments (As classified by Meybeck et al. (2001) as very high, high, and mid-altitude mountains). Coarse geomorphic units, like talus, alluvium, and moraines, are important stores and conduits for high mountain groundwater. Bedrock aquifers contribute to catchment streamflow through shallow, weathered bedrock but also to higher order streams and central valley aquifers through deep fracture flow and mountain-block recharge. Tracer and water balance studies have shown that groundwater contributes substantially to streamflow in many high mountain catchments, particularly during lowflow periods. The percentage of streamflow attributable to groundwater varies greatly through time and between watersheds depending on the geology, topography, climate, and spatial scale. Recharge to high mountain aquifers is spatially variable and comes from a combination of infiltration from rain, snowmelt, and glacier melt, as well as concentrated recharge beneath losing streams, or through fractures and swallow holes. Recent advances suggest that high mountain groundwater may provide some resilience-at least temporarily-to climate-driven glacier and snowpack recession. A paucity of field data and the heterogeneity of alpine landscapes remain important challenges, but new data sources, tracers, and modeling methods continue to expand our understanding of high mountain groundwater flow.

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Section: Mountain Aquifers and Flow Pathwaysmentioning

confidence: 99%

A review of groundwater in high mountain environments

2020

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“…They also constitute important fresh water sources, for both mountain and lowland ecosystems and communities, as they generate a continuous base flow in rivers through the release of water that is temporarily stored in wetlands and soils and in some areas also in snowfields and glaciers (e.g. Buytaert et al, 2006;Kaser et al, 2010;Mosquera et al, 2015;Chignell et al, 2019). All this emphasises that tropical mountains are crucial ecosystems that are locally, regionally, and globally of relevance to sustain biodiversity, water availability, and groundwater recharge.…”

Section: Introductionmentioning

confidence: 99%

An hourly ground temperature dataset for 16 high-elevation sites (3493–4377 m a.s.l.) in the Bale Mountains, Ethiopia (2017–2020)

Groos

Niederhauser

Lemma

et al. 2022

Earth Syst. Sci. Data

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Abstract. Tropical mountains and highlands in Africa are under pressure because of anthropogenic climate and land-use change. To determine the impacts on the afro-alpine environment and to assess the potential socio-economic consequences, the monitoring of essential climate and environmental variables at high elevation is fundamental. However, long-term temperature observations on the African continent above 3000 m are very rare. Here we present a consistent multiannual dataset of hourly ground temperatures for the Bale Mountains in the southern Ethiopian Highlands, which comprise Africa's largest tropical alpine area. The dataset covers the period from January 2017 to January 2020. To characterise and continuously monitor the mountain climate and ecosystem of the Bale Mountains along an elevation gradient from 3493 to 4377 m, ground temperature data loggers have been installed at seven sites at 2 cm depth; at four sites at 10 cm depth; and at five sites at 2, 10, and 50 cm depth. The statistical analysis of the generated time series reveals that ground temperatures in the Bale Mountains are subject to large daily fluctuations of up to 40 ∘C and minor seasonal variations on the order of 5 to 10 ∘C. Besides incoming short-wave radiation, ground moisture, and clouds at night, slope orientation and the type of vegetation coverage seem to be the main factors controlling daily and seasonal ground temperature variations. On the central Sanetti Plateau above 3800–4000 m, the mean annual ground temperature ranges from 9 to 11 ∘C. However, nocturnal ground frost down to a depth of 5 cm occurs frequently during the dry season from November to February. At the five sites where ground temperature is measured at three depths, the monitoring will be continued to trace long-term changes. To promote the further use of the ground temperature dataset by the wider research community dealing with the climate and geo-ecology of tropical mountains in eastern Africa, it is made freely available via the open-access repository Zenodo: https://doi.org/10.5281/zenodo.6047457 (Groos et al., 2022).

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“…Judging from the internal hydrological connectivity changes of different hotspots, most hotspots in the study area presented a declining trend to varying extents in terms of both structural and functional connectivity. Further analysis indicated that the decline in hydrological connectivity was mainly attributable to climate change and human activities such as hydraulic engineering and land use [9,39,40].…”

Section: Discussionmentioning

confidence: 99%

The Relationship between Hydrological Connectivity Changes Inside and Outside Biodiversity Hotspots and Its Implication for Sustainable Environmental Management

et al. 2022

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The conservation management of biodiversity hotspots is of vital significance for biological conservation. For wetlands, which are a special type of ecosystems that are based on water as their main medium, a decline in external hydrological connectivity often leads to wetland degradation inside biodiversity hotspots. In this context, the relationship between hydrological connectivity changes inside and outside hotspots is worth exploring. Based on the wetland biodiversity hotspots identified using systematic conservation planning, this study selected eight representative biodiversity hotspots with concentrated area. Integral index of connectivity, probability of connectivity (representing structural connectivity), and morphological spatial pattern analysis (representing functional connectivity) were used to analyze the hydrological connectivity changes inside various hotspots for 1995–2015. By taking the catchment area involved as the minimum basin perimeter, this study calculated the external hydrological connectivity changes of various hotspots during this period and analyzed the relationship between hydrological connectivity changes inside and outside of hotspots. The internal and external hydrological connectivity of wetland biodiversity hotspots were found to be significantly correlated. Moreover, the internal hydrological connectivity of hotspots not only declined with declining external structural connectivity, but also changed with the proportion of core wetlands, the proportion of edge wetlands, and the proportion of branch corridors. In addition, hotspots located at intersections of high-grade rivers were more significantly affected by climate change than by human activities and their hydrological connectivity increased with increasing rainfall. The internal hydrological connectivity of hotspots near low-grade rivers presented a declining trend, mainly because of human activities. This study clarified the relationship between internal and external hydrological connectivity of wetland biodiversity hotspots. Targeted internal and external control strategies are proposed, with the aim to offer references for the conservation of wetland biodiversity.

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Afroalpine Wetlands of the Bale Mountains, Ethiopia: Distribution, Dynamics, and Conceptual Flow Model

Cited by 14 publications

References 74 publications

A review of groundwater in high mountain environments

A review of groundwater in high mountain environments

An hourly ground temperature dataset for 16 high-elevation sites (3493–4377 m a.s.l.) in the Bale Mountains, Ethiopia (2017–2020)

The Relationship between Hydrological Connectivity Changes Inside and Outside Biodiversity Hotspots and Its Implication for Sustainable Environmental Management

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