Lower Wabi Shebelle

ETHTIPA010
Map of tropical important plant area site of Lower Wabi Shebelle

Country: Ethiopia

Administrative region: Somali (Regional State)

Central co-ordinates: 5.49616 N, 44.34613 E

Area: 4935km²

Qualifying IPA Criteria

A(i)Site contains one or more globally threatened species

IPA assessment rationale

The Lower Wabi Shebelle qualifies as an IPA under criterion A(i) due to the presence of eight globally threatened species. The IPA is a key locality for Boswellia ogadensis (CR), Euphorbia piceoides (CR), Euphorbia suborbicularis (CR), Kleinia isabellae (CR), Senegalia pseudonigrescens (CR), Euphorbia ogadenensis (EN), Orthosiphon grandiflorus (EN) and Blepharis gypsophila (VU). At least seven of these species are only known to occur within the IPA, suggesting high site irreplaceability. The eighth (Senegalia pseudonigrescens) has one potential occurrence record just north of the IPA, although there are no herbarium vouchers to support this human observation. Either way, this site also represents a globally important locality for Senegalia pseudonigrescens. Further research is needed to understand the range of Cordeauxia edulis (EN) and confirm its presence in this IPA. Livestock overgrazing, population growth and agricultural development schemes all pose significant threats to these species and the area's wider vegetation and natural habitats.

Site description

The Lower Wabi Shebelle IPA is situated in the Harerege and Bale floristic regions of Somali Regional State, in the southeast Ethiopian lowlands (Friis et al., 2010). The Wabi Shebelle River originates in the Bale Mountains and is one the country's major rivers. In the eastern part of the IPA, the Ferfer River (the main seasonal tributary) joins the Wabi Shebelle River (BirdLife, 2024). The IPA also encompasses a number of towns and villages, including Kelafo and Mustahil, and borders the town of Gode to the west and the national border with Somalia to the east. The Wabi Shebelle River actually extends into Somalia towards Mogadishu, before turning south and, during seasonally wet periods, joining the Jubba River near its mouth in southern Somalia.

Botanical significance

The Ogaden region, within which the Lower Wabi Shebelle IPA resides, is one of the most floristically underexplored areas in Ethiopia due to accessibility and security issues over recent decades, attributable to drought, famine, violence and other socio-political tensions (Mabberley, 2009; Majid et al., 2022). The IPA and its surrounding areas are thought to have a high potential for the discovery of new endemic species, especially succulent species and those associated with gypsum and limestone outcrops (Sebsebe & Dioli, 2000; Thulin & Vollesen, 2015). In the Ogaden region, the abundance and diversity of endemic floristic species is thought to be relatively high compared to other regions in Ethiopia (Thulin, 2011; cited in Thulin & Vollesen, 2015).

Despite the lack of botanical exploration across the region, the Lower Wabi Shebelle IPA is known to be a key locality for eight globally threatened endemic species, namely the tree species, Boswellia ogadensis (CR), Euphorbia piceoides (CR), Senegalia (Acacia) pseudonigrescens (CR) and Euphorbia ogadenensis (EN), the shrubs, Kleinia isabellae (CR) and Blepharis gypsophila (VU), and the subshrubs, Euphorbia suborbicularis (CR) and Orthosiphon grandiflorus (EN). The IPA is thus an important site for five Critically Endangered species and the only known locality for seven of the eight globally threatened species. Given the lack of botanical exploration in the region, however, further fieldwork campaigns could reveal a more widespread distribution for some of these species (Dioli, 2002; Thulin, 2009; Thulin & Vollesen, 2015).

The globally threatened and socio-economically important endemic evergreen shrub species, Cordeauxia edulis (EN), was also noted in the KBA and IBA assessments of the Lower Wabi Shebelle River and Warder, although it is likely present in Warder rather than along the Lower Wabi Shebelle River (Key Biodiveristy Areas, 2024; BirdLife, 2024). The presence of Cordeauxia edulis thus needs to be confirmed as its natural distribution is not thought to extend as far south as the Wabi Shebelle region (Yusuf et al., 2013), and there are no supporting herbarium vouchers within the IPA. Also of note is the locally abundant endemic tree, Acacia fumosa (LC), which is believed to occur within the IPA (Thulin & Vollesen, 2015).

Habitat and geology

The IPA is characterised by arid lowlands, as well as floodplains and seasonal tributaries associated with the Wabi Shebelle river (BirdLife, 2024). Friis et al. (2010) categorised the Wabi Shebelle Valley as desert and semi-desert scrubland with intermittent wetlands and salt-lake shore vegetation, dominated by drought-tolerant species (Asefa et al., 2020). Land cover within the IPA consists of Acacia-Commiphora deciduous bushland and thickets, grassland, rocky limestone and gypsum outcrops, succulent scrub, wetlands, irrigated agricultural fields and urban areas (Thulin, 2009; Thulin & Vollesen, 2015; Friis et al., 2016). Periodic flooding occurs between Kelafo and Ferfer about twice a year, forming a large flood zone (Segalen, 1973; De Sole et al., 1978; BirdLife, 2024).

Frequently encountered flora include the tree and shrub species, Acacia fumosa, Cadaba divaricata, Gossypium bricchettii, Jatropha rivae, Pleuropterantha revoilii and several species of Commiphora, the succulent subshrub, Euphorbia polyantha, and the perennial herb, Indigofera gypsacea (Segalen, 1973; Thulin, 2009; Thulin & Vollesen, 2015). Additionally, the Ferfer and Mustahil woredas (districts), located in the eastern part of the IPA, contain a halophytic community of Bolboschoenus maritimus, Cenchrus biflorus, Cucumis kelleri and Urochondra setulosa (Segalen, 1973; BirdLife, 2024). Grass species dominate the floodplains (BirdLife, 2024).

The lithology of the area is characterised by sedimentary rock dating back to the Early Cretaceous, mainly Korahe gypsum and Mustahil limestone (Persits et al., 2002; JICA, 2013). The gypsum outcrops form flat to undulating land, intersected by a network of rivers and streams, while alluvial deposits are found throughout the IPA (Segalen, 1973; JICA, 2013; BirdLife, 2024). Soils are predominantly calcaric fluvisols, haplic calcisols and haplic gypsisols, although leptisols and vertisols also occur (Jones et al., 2013). The Wabi Shebelle River reportedly has a high saline content (Mohamed, 2013), and salt tends to accumulate in the drier areas of the IPA, between Kelafo and Ferfer (Segalen, 1973).

The climate of the Lower Wabi Shebelle region is arid. The mean annual temperature for Gode is 28 C, with an average humidity of 55% (Segalen, 1973; De Sole et al., 1978). Rainfall is bimodal with two rainy seasons in March-May and October-November (De Sole et al., 1978). Mean annual rainfall varies across the IPA, ranging from 170-210 mm at Kelafo to 335 mm at Gode (Bauduin, 1973; Segalen, 1973).

Conservation issues

There is currently no site protection or management plan in place within the IPA. The IPA overlaps with the eastern section of the Lower Wabi Shebelle and Warder Important Bird Area (IBA) and Key Biodiversity Area (KBA). The IBA was identified under criteria A1, A2 and A3, due to the occurrence of 47 bird species, all now categorised as Least Concern on the IUCN Red List, with the exception of Heterotetrax humilis (little brown bustard, NT), Streptopelia reichenowi (white-winged collared dove, NT) and Sylvietta philippae (Philippa's crombec, DD) (BirdLife, 2024). Its KBA status was determined based on the IBA assessment and is a priority for reassessment under the current Global KBA Standard, since it has not been evaluated since its original assessment in 1996 (Key Biodiversity Areas, 2024).

As aforementioned, the IPA and wider Ogaden region have been underexplored floristically due to relative inaccessibility, caused by poor infrastructure and security issues (Sebsebe & Dioli, 2000; Mabberley, 2009). Severe droughts, floods, periodic famine, territorial wars and a tense political climate have all contributed to socio-political instability in the region (Hogg, 1991; Mohamed & Iman, 2010; Mohamed, 2013; OCHA, 2020), unsurprisingly inhibiting conservation efforts. Pastoralism is the primary livelihood and income-generating activity in the area, resulting in overgrazing by livestock and natural habitat degradation across the IPA (Thulin & Vollesen, 2015). The main livestock are cattle, sheep, goats, and camels (De Sole et al., 1978). The threatened endemics of the IPA are vulnerable to this intense grazing pressure (Alemu et al., 2018a, 2018b, 2018c; Nemomissa et al., 2018).

Other potential threats to the Lower Wabi Shebelle IPA and its flora include agricultural development schemes and increasing populations (Key Biodiversity Areas, 2024; BirdLife, 2024). Irrigation along the Wabi Shebelle River began in the 1960s, coinciding with the creation of a research centre aiming to assess the ‘suitability for large-scale irrigated crop farming’ (Livestock, Crop and Rural Development Bureau, 2013). Irrigation in the 1960s and 1970s was mainly limited to the Kelafo region, downstream from Gode (Bauduin, 1973), but increased under the Derg regime (Livestock, Crop and Rural Development Bureau, 2013). Now, irrigated agricultural fields can be observed all along the Wabi Shebelle River, aided by diesel pumps (Livestock, Crop and Rural Development Bureau, 2013). A large scale, government run, gravity irrigation scheme in West Gode was established in the early 2000s. Construction began during the mid 1990s, with 1000 ha developed by 2001 and a further 2000 ha by 2006 (Livestock, Crop and Rural Development Bureau, 2013). Crop diversification was introduced in 2008, however by 2010 production had declined due to high levels of siltation and canal damage, resulting in the scheme being suspended. In 2013, the Somali Regional State government made plans to revive the West Gode gravity irrigation project, although the current status of the project is unclear.

In 2001, a dam was constructed near Gode as part of irrigation development (Mohamed & Iman, 2010). According to Mohamed (2014), future major development plans for the Wabi Shebelle River include 141 irrigation schemes and six large dams as part of the Wabi Shebelle River Basin Master Plan (2005-2035). The irrigation potential of the Wabi Shebelle River has been estimated to be 204,000 ha (Mohamed, 2013).

Ecosystem services

The ecosystem services provided by this site are not well documented. The area is mainly used as a source of water for crop irrigation along the river, the main crops being sorghum, maize, onion, and sesame (De Sole et al., 1978; Livestock, Crop and Rural Development Bureau, 2013; Mohamed, 2013). The Wabi Shebelle River has many important downstream uses in Somalia as a water source for local communities, agricultural developments, and recharging groundwater aquifers (Mohamed, 2013). In years with exceptionally heavy rain the Wabi Shebelle reaches the Indian Ocean, although the river usually dries up in the southern Somalia desert (Mohamed, 2013). There is no known tourism within the IPA and this is unlikely to change until the region is politically stable and readily accessible. However, Teshale (2020) highlights the site's tourism potential, not least given its diversity of uncommon and range restricted bird species. The Ogaden region is also reported to contain natural resources such as minerals and natural gas (Mohamed, 2013).

Site assessor(s)

Joe Langley, Royal Botanic Gardens, Kew

Eden House, Royal Botanic Gardens, Kew

Iain Darbyshire, Royal Botanic Gardens, Kew

Sebsebe Demissew, Addis Ababa University

Sileshi Nemomissa, Addis Ababa University

Ermias Lulekal, Addis Ababa University

IPA criterion A species

Species Qualifying sub-criterion ≥ 1% of global population ≥ 5% of national population 1 of 5 best sites nationally Entire global population Socio-economically important Abundance at site
Boswellia ogadensis Vollesen A(i) True True True True False Unknown
Acacia pseudonigrescens Brenan & J.H.Ross A(i) True True True False False Unknown
Euphorbia ogadenensis P.R.O.Bally & S.Carter A(i) True True True True False Unknown
Euphorbia piceoides Thulin A(i) True True True True False Unknown
Kleinia isabellae Dioli & Mesfin A(i) True True True True False Unknown
Euphorbia suborbicularis Thulin A(i) True True True True False Unknown
Orthosiphon grandiflorus A.Terracc. A(i) True True True True False Unknown
Blepharis gypsophila Thulin & Vollesen A(i) True True True True False Unknown

Boswellia ogadensis Vollesen

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
True
≥ 5% of national population:
True
1 of 5 best sites nationally:
True
Entire global population:
True
Socio-economically important:
False
Abundance at site:
Unknown

Acacia pseudonigrescens Brenan & J.H.Ross

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
True
≥ 5% of national population:
True
1 of 5 best sites nationally:
True
Entire global population:
False
Socio-economically important:
False
Abundance at site:
Unknown

Euphorbia ogadenensis P.R.O.Bally & S.Carter

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
True
≥ 5% of national population:
True
1 of 5 best sites nationally:
True
Entire global population:
True
Socio-economically important:
False
Abundance at site:
Unknown

Euphorbia piceoides Thulin

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
True
≥ 5% of national population:
True
1 of 5 best sites nationally:
True
Entire global population:
True
Socio-economically important:
False
Abundance at site:
Unknown

Kleinia isabellae Dioli & Mesfin

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
True
≥ 5% of national population:
True
1 of 5 best sites nationally:
True
Entire global population:
True
Socio-economically important:
False
Abundance at site:
Unknown

Euphorbia suborbicularis Thulin

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
True
≥ 5% of national population:
True
1 of 5 best sites nationally:
True
Entire global population:
True
Socio-economically important:
False
Abundance at site:
Unknown

Orthosiphon grandiflorus A.Terracc.

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
True
≥ 5% of national population:
True
1 of 5 best sites nationally:
True
Entire global population:
True
Socio-economically important:
False
Abundance at site:
Unknown

Blepharis gypsophila Thulin & Vollesen

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
True
≥ 5% of national population:
True
1 of 5 best sites nationally:
True
Entire global population:
True
Socio-economically important:
False
Abundance at site:
Unknown

General site habitats

General site habitat Percent coverage Importance
Wetlands (inland) - Permanent Rivers, Streams, Creeks [includes waterfalls] No value Major
Shrubland - Subtropical/Tropical Dry Shrubland No value Major
Grassland - Subtropical/Tropical Dry Lowland Grassland No value Major
Artificial - Terrestrial - Urban Areas No value Minor
Artificial - Terrestrial - Arable Land No value Major
Artificial - Terrestrial - Pastureland No value Major
Rocky Areas No value Major
Desert - Hot Desert No value Major
Grassland - Subtropical/Tropical Seasonally Wet/Flooded Lowland Grassland No value Major

Wetlands (inland) - Permanent Rivers, Streams, Creeks [includes waterfalls]

Percent coverage:
No value
Importance:
Major

Shrubland - Subtropical/Tropical Dry Shrubland

Percent coverage:
No value
Importance:
Major

Grassland - Subtropical/Tropical Dry Lowland Grassland

Percent coverage:
No value
Importance:
Major

Artificial - Terrestrial - Urban Areas

Percent coverage:
No value
Importance:
Minor

Artificial - Terrestrial - Arable Land

Percent coverage:
No value
Importance:
Major

Artificial - Terrestrial - Pastureland

Percent coverage:
No value
Importance:
Major

Rocky Areas

Percent coverage:
No value
Importance:
Major

Desert - Hot Desert

Percent coverage:
No value
Importance:
Major

Grassland - Subtropical/Tropical Seasonally Wet/Flooded Lowland Grassland

Percent coverage:
No value
Importance:
Major

Land use types

Land use type Percent coverage Importance
Agriculture (arable) No value Major
Agriculture (pastoral) No value Major
Residential / urban development No value Minor

Agriculture (arable)

Percent coverage:
No value
Importance:
Major

Agriculture (pastoral)

Percent coverage:
No value
Importance:
Major

Residential / urban development

Percent coverage:
No value
Importance:
Minor

Threats

Threat Severity Timing
Human intrusions & disturbance - War, civil unrest & military exercises Unknown Past, not likely to return
Agriculture & aquaculture - Annual & perennial non-timber crops Unknown Ongoing - increasing
Agriculture & aquaculture - Livestock farming & ranching - Nomadic grazing High Ongoing - trend unknown
Agriculture & aquaculture - Livestock farming & ranching - Small-holder grazing, ranching or farming High Ongoing - trend unknown
Climate change & severe weather - Droughts Unknown Ongoing - trend unknown
Natural system modifications - Dams & water management/use Medium Ongoing - trend unknown

Human intrusions & disturbance - War, civil unrest & military exercises

Severity:
Unknown
Timing:
Past, not likely to return

Agriculture & aquaculture - Annual & perennial non-timber crops

Severity:
Unknown
Timing:
Ongoing - increasing

Agriculture & aquaculture - Livestock farming & ranching - Nomadic grazing

Severity:
High
Timing:
Ongoing - trend unknown

Agriculture & aquaculture - Livestock farming & ranching - Small-holder grazing, ranching or farming

Severity:
High
Timing:
Ongoing - trend unknown

Climate change & severe weather - Droughts

Severity:
Unknown
Timing:
Ongoing - trend unknown

Natural system modifications - Dams & water management/use

Severity:
Medium
Timing:
Ongoing - trend unknown

Conservation designation

Designation name Protected area Relationship with IPA Areal overlap
Lower Wabi Shebelle River and Warder IBA Important Bird Area protected/conservation area overlaps with IPA 4398
Lower Wabi Shebelle River and Warder KBA Key Biodiversity Area protected/conservation area overlaps with IPA 4398

Lower Wabi Shebelle River and Warder IBA

Protected area:
Important Bird Area
Relationship with IPA:
protected/conservation area overlaps with IPA
Areal overlap:
4398

Lower Wabi Shebelle River and Warder KBA

Protected area:
Key Biodiversity Area
Relationship with IPA:
protected/conservation area overlaps with IPA
Areal overlap:
4398

Management type

Management type Description Year started Year finished
No management plan in place No value No value

No management plan in place

Year started:
No value
Year finished:
No value

Bibliography

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Atlas of the Potential Vegetation of Ethiopia.

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Available online

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Available online

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Available online

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Ethiopian vegetation types, climate and topography

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Bauduin, K., 1973

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BirdLife, 2024

Important Bird Areas factsheet: Lower Wabi Shebelle river and Warder

Available online

Dioli, M., 2002

Two new species of Pseudolithos P. R. O. Bally (Apocynaceae-Asclepiadoideae) from the Horn of Africa

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Two distinctive new species of Commicrapus (Nyctaginaceae) from gypsum outcrops in eastern Ethiopia

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Hogg, R., 1991

Famine in the Ogaden

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JICA, 2013

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Key Biodiversity Areas factsheet: Lower Wabi Shebelle river and Warder

Available online

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The Lower Shebelle Irrigation Scheme in Ethiopia: An assessment of productive options

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Exploring Terra Incognita

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De Sole, G., Lemma, A., & Mazengia, B., 1978

Schistosoma haematobium in the Wabi Shebelle Valley of Ethiopia

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Tourism Potentials and Challenges of the Somali Region, Ethiopia

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New species of Euphorbia (Euphorbiaceae) from eastern Ethiopia

Kew Bulletin, Vol 64, page(s) 469

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Blepharis gypsophila (Acanthaceae), a new species from Ethiopia

Kew Bulletin, Vol 70, page(s) 26

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Available online

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Recommended citation

Joe Langley, Eden House, Iain Darbyshire, Sebsebe Demissew, Sileshi Nemomissa, Ermias Lulekal (2024) Tropical Important Plant Areas Explorer: Lower Wabi Shebelle (Ethiopia). https://tipas.kew.org/site/lower-wabi-shebelle/ (Accessed on 21/05/2024)