Distribution and species richness of amphibians in Awi zone and Wombera District, Northwest Ethiopia

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1 2016; 3(4): ISSN JOZS 2016; 3(4): JOZS 2016 Received: Accepted: Abeje Kassie Teme Wild animals Case team, Animal Biodiversity Directorate, Ethiopian Biodiversity Institute, P.O. Box 30726, Addis Ababa, Ethiopia Distribution and species richness of amphibians in Awi zone and Wombera District, Northwest Ethiopia Author: Abeje Kassie Teme Abstract The study conducted to describe the distribution and species richness of amphibians found in Awi zone and Wombera district.the present study deals with amphibian species distribution and richness at Awi zone and Wombera district during the period February 15 to March 5/ Visual encounter survey method was used in careful visual estimation and amphibians were recorded in all possible habitats of the study area. The total of eleven amphibian species are recorded, belonging to 5 genera in four families under order anura in the Awi zone and Wombera District. Alelitu river and wetland at the Wombera district had the highest species richness which accounts for 7 species and Mengeha (Ambiki) wetland followed by 6 species from Awi zone. This study reveals that the Awi zone and Wombera district are rich in amphibian species and endemism. Further studies are needed on the abundance and population structure across seasonal variation, habitat use by amphibians for better understanding and also impose of several conservation strategies in Awi zone and Wombera district, in particular Alelitu wetland and river near to the town Debrezeit ( town of Wombera district). Keywords: Amphibian, Awi zone, Distribution, Species richness, Wombera 1. Introduction Corresponding Author: Abeje Kassie Teme Wild animals Case team, Animal Biodiversity Directorate, Ethiopian Biodiversity Institute, P.O. Box 30726, Addis Ababa, Ethiopia. All amphibians are members of the tetrapod vertebrate Class Amphibia. There are more than 7,528 currently recognized species of extant amphibians of which Anura 88%, Caudata 9%, and Gymnophiona are 3%, [1] with representatives present in virtually all terrestrial and freshwater habitats, but absent from the coldest and driest regions, and from the most remote oceanic islands [2]. Amphibians are important components of species assemblages of many terrestrial ecosystems, often having a diverse number of species occupying a range of niches. Amphibians are often considered to be good habitat indicators, given their usually relatively narrow environmental tolerance [3, 4], in addition amphibians also contribute a lot to the ecosystem energetic and carbon flow [5]. However, the distribution and richness of amphibians now a day declines due to may anthopogenic factors [6, 7]. Among these factors, habitat change seems to be connected to many amphibian population declines [3]. Ethiopia has diverse wildlife populations which are comparable, species wise to other countries of east Africa. About 73 species of amphibians found in Ethiopia 30 of them are endemics (EBI, 2014, unpublished document). The main reason of this is due to the topography of the country that comprises lowland (120bsl, Dallol) and highlands (4620asl, Ras Dejen mountain).the highlands of Ethiopia are the main repositories of moist forests and wetlands in Ethiopia, which are known to be home for, among others, a diverse and unique amphibian fauna [8]. Page 1

2 However, now a day Ethiopia has faced a number of threats which gradually reduced the diversity of wildlife. The major threats are highly associated with current anthropogenic activities. The major threats include habitat destruction for different purposes like agriculture expansion, investments and deforestation. Further, the current status of wildlife of the country, especially herpetofauna are not assessed and well documented. Herpetology has been one of the zoological disciplines to which little attention was given in Ethiopia until recently. Even though diverse amphibian fauna with varied ecosystems intended to be present, little is known about the updated taxonomy, evolution, population biology and conservation status of the different species. Therefore, accurate information on species conservation and distribution is an essential first step to facilitate the delivery of conservation updates, recognize biodiversity hotspots and encourage habitat protection and restoration [9]. Awi zone has different qualities and habitat-types that will be assessed. Each habitat has characteristics that contribute to the overall richness of the natural biodiversity in Agaw Medir. All sites are not well studied concerning to herpetofauna therefore, we identified amphibians to study. 2. Materials and methods 2.1. Study Area The study was conducted at Awi zone of Amhara regional state and Wombera district at Benishangul regional state, North - West Ethiopia (Figure 1), during the period February 15 to March 5/ Awi Zone: is an autonomous administrative unit within Amhara Regional state and is governed by its local people, the Agaw, who speak Awgni. The Zone is on the western side of the central plateau in Ankasha and Banja Weredas of what used to be called Agaw Medir near. It is located at the coordinates N E and altitude between 1,800m - 3,100m (on the nearby hills and mountains) with total area of 131,844ha. The area is crossed by about nine permanent rivers that drain into the Abbay (Blue Nile) and has two crater lakes, Zengena and Tirba. Use of communal resources, particularly water and forests, is carefully controlled by the local communities. These practices have enabled the Agaw to sustain the fertility of the soil and minimize erosion so that this area is recognized as one of the most productive in the Amhara Region. Wombera wereda: is found in the Metekel zone of Benishangul Gumuz regional state. It is characterized by three agroecological zone such as dega, woinadega, and kola. The major tribes living in the wereda are Gumuz, Oromo, Shinasha and Amhara. The district is reach in natural forest and coffee. Fig 1: Map of the study areas 2.2 Sampling techniques Systematic random sampling was used to assess the abundance and distribution of amphibians and Visual Encounter Surveys was observed the presence and absence of amphibians. Visual Encounter Survey is a favourable core method for surveying amphibians [10, 11]. Even though amphibian visual encounter survey can have a low probability of detection for many species, depending on the ecosystem and search effort; in the field investigation we used Visual Encounter Survey for frogs and toads by searching under stones and logs for sedentary forms, digging for fossorial forms, and active searching in vegetation for larger species of amphibians. In addition to this, auditory survey was important to investigate the presence of amphibians. Amphibians assessment and recordings was carried out by direct observations. Data was collected by walking on foot. Amphibian species was identified by using field guide [12] and the study area coordinates was recorded using GPS. 2.3 Data analysis Amphibian species richness was expressed in terms of numbers of species observed. Descriptive statistics was used to show the distribution and species richness of amphibians in different sampling sites. 3. Result and discussion In this study, eleven amphibian species are recognized, belonging to 5 genera in four families under order anura (Table 1). They account over 15% of the total Page 2

3 species of amphibians in Ethiopia. Amoung families, Hyperoliidae, Hemisotidae, and Ptychadenidae possesses the endemics species. Paracassina obscura, Hemisus microscaphus, Ptychadena erlangeri and Ptychadena wadei are the endemic amphibian species that have been recorded. Endemicity accounting over 36% of the recorded amphibians species in the study area and about 13% from all endemic amphibians of Ethiopia. Table 1: Distribution of amphibians species recorded in the localities of Awi Zone and Wombera district Study areas Family Species IUCN Red List Status Zoogeographic category Ptychadena mascareniensis Least Concern Warki (Kessa) Ptychadenidae Ptychadena tellini Least Concern Ekuste river Ptychadenidae Ptychadena erlangeri Near threatened Endemic Arbatuensesa Ptychadenidae Ptychadena wadei Data Deficient Endemic Hyperoliidae Hyperoliidae Afrixalus spp. Paracassina obscura Least Concern Endemic Mengeha (Ambiki) Alelitu river and wetland Faro river Hemisus microscaphus Least Concern Endemic Hemisotidae Hemisus marmoratus Least Concern Ptychadenidae Ptychadena wadei Data Deficient Endemic Ptychadena mascareniensis Least Concern Bufonidae Bufo regularis Least Concern Hyperoliidae Paracassina obscura Least Concern Endemic Hemisotidae Hemisus microscaphus Least Concern Endemic Ptychadena mascareniensis Least Concern Ptychadenidae Ptychadena wadei Data Deficient Endemic Ptychadena anchietae Least Concern Ptychadena tellini Least Concern Bufonidae Bufo regularis Least Concern Ptychadenidae Unidentified Ptychadena spp. Two species from Warki (Kessa), one species from Ekuste river, two species from Arbatuensesa, six species from Mengeha (Ambiki), seven species from Alelitu river and wetland, one unidentified frog species from Faro river have been recorded (Figure 2 and Table 1). According to the IUCN Red List category [13], most of the amphibian species recorded in the study area are catagorized as List Concern (LC) (Table 1). Ptychadena erlangeri and Ptychadena wadei are the endemic amphibian species of Ethiopia and they categorized as Near Threatened and Data Deficient (DD) respectively. Alelitu wetland and river had highest species richness (seven species), followed by Mengeha wetland accounts for six species and the Ekuste and Faro rivers are the least (each accounts for one species) (Figure 2). Page 3

4 Fig 2: Species richness across the study areas Afrixalus spp. Hemisus marmoratus Paracassina obscura Ptychadena wadei Ptychadena mascareniensis Ptychadena erlangeri Fig 3: Some of the frog species recorded in the study areas Knowledge of the Ethiopian amphibian fauna is limited and remains understudied [14]. Despite this, previous work has revealed a comparatively high diversity for Africa, particularly located in the mountain regions of Ethiopia [3]. South-west of Ethiopia, where most of the country s remaining natural forest is situated, is known to harbour populations of Afrixalus clarkei (Largen), an endemic banana frog, worldwide [14]. Inline with this, the current study showed that amphibian species diversity as well as distribution had not studied in the Page 4

5 area, however, high number of frog species recorded now. In the present study, it is found that the study area is quite rich in amphibian species. The Alelitu river and wetland showed higher species richness compared to other study areas (7 species). This unique ecosystem has been surveyed for its amphibian faunal richness and the frogs recorded belongs to forest as well as aquatic ecosystems. In the present study, 11 amphibian species have been recorded from Warki wetland (near to small town called Kessa), Ekutse river, Arbatuensesa which comprises different water bodies, Mengeha wetland, and Alelitu wetland (the wetland that has been cut by Alelitu river near the town of Wombera district), of which 4 species are endemic to Ethiopia. Different litratures shows that Hemisus marmoratus, Ptychadena anchietae and Ptychadena masacariensis prefer open woodland, grassland and savannah habitats and they can occur in very dry conditions [15]. These species admittedly occupied riverine forest during drier period to avoid desiccation [16]. In line with above studies, Hemisus marmoratus and Ptychadena masacariensis are found in Mengeha (Ambiki) locality, which is grassland with reminant forest. According to [8, 17], the geographic distribution of Hemisus in Ethiopia is restricted to the western and south western plateau. Unlike to this, the current study showed that Hemisus is distributed in the north western part of Ethiopia. The IUCN Red list category has revealed that almost all species are under Least concern category except Ptychadena wadei which is under Data Deficient category and Ptychadena erlangeri which is Near treatened. The present species record from the study area (Mengeha and Alelitu) shows that the area abounds a suitable breeding ground of diverse groups of frogs. 3. Conclusion In the present study, it can be concluded that the study area is an extremely attractive region for biodiversity inventorisation and is quite rich in diverse frog species. The present amphibian species recorded enhances the rich diversity of Awi zone and wombera district. It is essential to protect these ecological indicator species because they play important role in our ecosystem. In this paper author presented, study areas are well potential habitats to determine of amphibian diversity, nevertheless, furthermore molecular and seasonal based studies needed to identify and document amphibian species from different locations of Awi zone to better understanding of their distributional ranges. 4. Acknowledgements I am sincerely thankful to EBI for providing financial support. Special gratitude goes to local communities inhabited in the area of Awi zone and Wombera district forest and environment experts who bring us enough information about the study area during the field work. 5. References 1. Information on Amphibian Biology and Conservation. Amphibian. Web Berkeley, CA. (Accessed on Feb 15, 2016). 2. Stuart SN, Hoffmann M, Chanson JS, Cox NA, Berridge RJ, Ramani P, Young BE. (eds.). Threatened Amphibians of the World. Lynx Edicions, Barcelona, Spain; IUCN, Gland, Switzerland; and Conservation International, Arlington, Virginia, USA Loader S, Mengistu A, Schwaller S, Gower D, Nagel P et.al. Are Ethiopian highlands changing? Amphibians as ecosystem indicators. Mountain Forum Bulletin Volume IX (2), July ISSN Ferguson A, Pilgrim M. Implementation of the North American monitoring program in the upstream region of South Carolina. Journal of Undergraduate Research. 2009; (2): Pearman N, P.B. Correlates of amphibian diversity in an altered landscape of Amazonian Ecuador. Conservation Biology 1997; 11: Stuart SN, Chanson JS, Cox NA, Young BE, Rodrigues ASL, Fischman DL et.al. Status and trends of amphibian declines and extinctions worldwide. Science. 2004; 306: Collins JP, Halliday T. Forecasting changes in amphibian biodiversity: Aiming at a moving target. Philosophical Transactions of the Royal Society Biological Sciences. 2005; 360: Mengistu AA, Nagel P, Getahun A, Samy AS, Loader S. Updated Review of Amphibian Diversity, Distribution and Conservation in Ethiopia. Ethiop. J. Biol. Sci., 2013; 12(1): Rovero F, Menegon M, Fjeldså J, Collett L, Doggart N, Leonard C, et.al. Targeted vertebrate surveys enhance the faunal importance and improve explanatory models within the Eastern Arc Mountains of Kenya Page 5

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