Deckenia imitatrix 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Arthropoda Malacostraca Decapoda Potamonautidae

Scientific Name: Deckenia imitatrix
Species Authority: Hilgendorf, 1868
Taxonomic Notes: This genus was formerly assigned to the family Deckeniidae Ortmann, 1897. The genus Deckenia is now assigned to the Potamonautidae: Deckeniinae: Deckenini: Deckenina (Cumberlidge et al. 2007). This species was described by Ng et al. (1995) and Reed and Cumberlidge (2006), and its distribution was updated by Marijnissen et al. (2005).

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2008
Date Assessed: 2008-01-01
Assessor(s): Cumberlidge, N.
Reviewer(s): Cumberlidge, N. & Marijnissen, S. and McIvor, A.
Listed as Near Threatened (close to VU under A2c), because although its extent of occurrence is more than 20,000 km² and it is known from a large number of localities in three different countries, there is evidence that there is an on-going and major decline in the extent and quality of its habitat (marshes, wetlands) which is fragmented and declining, and there are long-term threats to its habitat from disturbance and pollution.
Previously published Red List assessments:

Geographic Range [top]

Range Description:Tanzania, Kenya, Somalia, East Africa. Found in the East African coastal region, from northeast Tanzania to Taru, Kenya, to Giohar and Eil, Somalia and inland in Kenya as far as Nairobi. Somalia: The northernmost point of D. imitatrix’s distribution appears to be the Eyl District in Puntland, Somalia (Marijnissen et al. 2005), an area with marshes, permanent freshwater, and a major well system (M. Thulin, pers. comm.). The other localities in Somalia where specimens of D. imitatrix were found are all associated with two large rivers, the Shebeele (Uebi Scebeli or Wabi Shabelle) and the Jubba (Giuba or Ganane). The Shebeele River runs from the Ethiopian highlands to the Somali coast where it flows parallel to the coastline forming swamps and dry reaches that end close to the Jubba River. The Jubba runs from Ethiopia to the south of Somalia and is the only river in the area with a reliable year-round flow. Kenya: D. imitatrix is found in waterholes and swampy areas in the coastal lowlands, near Kasigau Mountain, and inland along the Galana and Athi Rivers (Marijnissen et al. 2005, and references therein). Tanzania. Tanga. Marijnissen et al. (2005) argued that the type locality is Kadiaro, Kenya (and not Zanzibar), and that the report of D. imitatrix from Zanzibar is most probably the result of a mistake arising from the replacement of a lost label.
Countries occurrence:
Kenya; Somalia; Tanzania, United Republic of
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:There is evidence that the population size is decreasing due to habitat disturbance and loss associated with increasing human populations. Its population levels were estimated to be stable based on indirect measures such as the fact that it has been collected recently from more localities and that it is well represented in museum collections. However, recent field surveys by S. Marijnissen (pers comm.) have revealed that this species may be potentially more vulnerable that previously thought. Although this species has a wide extent of occurrence that is much greater than 20,000 km² (which is above the threshold for vulnerable, VU), it may have an increasingly restricted area of occupancy due to habitat disturbance that would fall into the range for vulnerable (VU). While it is difficult to estimate the population status and trends of this species, its population is estimated to possibly be in decline due to the fact that its habitat is restricted to marshes and wetlands, and these are fragmented and declining in this part of East Africa. The dependence of this species on wetland habitats that are vulnerable to human disturbance and that are associated with a growing human population in the region would argue for the upgrading of the conservation status of D. imitatrix from least concern to vulnerable in the light of the new data.
Current Population Trend:Decreasing
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:This species exhibits a preference for areas with marshes and low-lying swamps with stagnant surface water. The habitats where this species is found include wetlands, streams, and slow-flowing rivers. Deckenia imitatrix inhabits burrows dug into soft, silt-clay types of sediment and appear to avoid course-grained, sandy soils. It is likely that the area of occupancy of both species of Deckenia within their distributional range is limited by their restriction to areas with a high groundwater level.

Threats [top]

Major Threat(s): Habitat disturbance from increasing human population growth. Between 1970 and 1990 the human population in East Africa has more than doubled and it is still growing rapidly (UNEP, 2004). The major threats to freshwater biodiversity in the East African region include the effects of increasing human population growth on the loss of freshwater habitats through deforestation and agricultural encroachment (Darwall et al. 2005). Recent field studies in Tanzania indicate that the quantity and quality of freshwater habitats available to this species have decreased drastically over the past several decades and that habitat disturbance could be a major factor in driving declining population levels of this species.

Conservation Actions [top]

Conservation Actions: No conservation measures are known to be in place for this species and it is not found in a protected area.

Citation: Cumberlidge, N. 2008. Deckenia imitatrix. The IUCN Red List of Threatened Species 2008: e.T44516A10909993. . Downloaded on 28 February 2017.
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