Population Status, Distribution Patterns and Conservation Needs of Endangered &amp;lt;i&amp;gt;Croton alienus&amp;lt;/i&amp;gt; Pax in Kenya

Mary Nyawira Muchane

doi:10.11648/j.ijnrem.20190405.13

Abstract

Kenya has a very rich plant biodiversity, many which are economically important. However this rich botanical resource continue to decline at an alarming rate as a result of over-exploitation through unsustainable human activities and unpredictable effect of changing climate. Endemic species with restricted geographic ranges and specific habitats are most vulnerable to extinction under the changing environmental and climatical conditions. To aid in their conservation, sound knowledge on their population status, distribution and conservation is urgently needed. The population status, distribution pattern, economic uses and conservation needs of Croton alienus Pax 1909, an endemic and endangered plant species in Kenya are reviewed. This was achieved through screening of herbarium specimen at East Africa Herbarium and detailed review of published and un-published research articles. The result indicates, Croton alienus has restricted area of occupancy occurring mainly in high altitude region between 1500-1800 m above sea level. Due to its narrow altitude range, Croton alienus is restricted to forests in central Kenya (Aberdare forest, Mt Kenya forest), Nairobi region (Karura forest, Ngong forest, Arboretum) and Western Kenya (Kakamega forest). Very low population density of 1 species per hectare in Karura forest suggests urgent conservations needs. Earlier conservations efforts included seed propagation activities to produce seedling, but their sustainability may have been halted by its limited usage. The species is medicinal with antibiotic properties against Croton alienus and Leishmania donovanii micro-organisms which can be tapped to aid its domestication and conservation. This review highlights need for urgent conservation measures for endemic species with restricted geographic ranges and specific habitat needs like Croton alienus in awake of climate change.

Highlights

Kenya is global biodiversity hotspot rich in botanical resources, many which are economically important
Results of this study indicate that Croton alienus is among the least known endangered species in Kenya, with restricted area of occupancy and narrow altitude range restricting it to forests in central Kenya (Aberdare forest, Mt Kenya forest), Nairobi region (Karura forest, Ngong forest, Arboretum) and Western Kenya (Kakamega forest)
Croton alienus has been classified as endemic to Kenya, result of this study suggest it may be found in other parts of Africa following its documentation in Madagascar and Equatorial Guinea

Summary

Introduction

Kenya is global biodiversity hotspot rich in botanical resources, many which are economically important. Over 8000 vascular plants are estimated to occur in Kenya, out of which 8-10% is considered endemic [1]. Over 80% of endemic species are mainly found in Coastal Forests of Eastern Africa Hotspot (Kenyan Coast) and in isolated Eastern Afromontane Hotspot afro-montane forests (Kenya Mountainous ecosystems). Botanic resources continue to be threatened by human disturbances as a result of unsustainable human activities such illegal logging and excision of forested ecosystems to give way to other land uses systems such as agriculture, economic development [2]. About 258 plant species are threatened with extinctions in Kenya and about 6 extinctions have been reported [4]

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