Kouamé_etal_Roedel_etal_Rediscovery_hyperolius_nimbae_heRPeTozoA.qxd 08.08.2016 10:08 Seite 1 heRPeTozoA 29 (1/2): 3 - 13 3 Wien, 30. Juli 2016 Rediscovery of the Mount Nimba Reedfrog, Hyperolius nimbae LAuReNT , 1958, in western Ivory Coast (Anura: hyperoliidae) Wiederentdeckung des Mount Nimba Riedfrosches, Hyperolius nimbae LAuReNT , 1958 im Westen der elfenbeinküste (Anura: hyperoliidae) N’G oRAN GeRMAIN KouAMé & N’G ueSSAN eMMANueL ASSeMIAN & b LAydA Tohé & P ATRICK JoëL AdebA & G eRMAIN GouRèNe & M ARK -o LIveR RödeL KuRzFASSuNG die vorliegende Arbeit berichtet über die Wiederentdeckung von Hyperolius nimbae LAuReNT , 1958, einer Riedfroschart, die nur vom Fuß der östlichen Flanke des Mount Nimba im Westen der elfenbeinküste bekannt ist. die Art wurde 1958 beschrieben und 1963 zum letzten Mal beobachtet. Siebenundvierzig Jahre später wurden innerhalb des bekannten verbreitungsgebietes, kleine Populationen dieses Riedfrosches in der Nähe der dörfer dagbonpleu, danipleu, Kouan-houlé und zéalé wiederentdeckt. Allerdings konnten nur insgesamt sieben exemplare registriert werden. die Lebensräume zeigten unterschiedliche Grade der degradierung von Sumpf - wäldern bis zu Reisfeldern in degradiertem Wald oder Sekundärwuchs. der starke menschliche einfluß im Gebiet, besonders seine landwirtschaftliche Nutzung, könnte das langfristige Überleben der Art gefährden. die Autoren empfehlen eine intensive weitere Suche nach bestehenden Populationen und deren Monitoring, um die Gefährdung für das Überleben von H. nimbae abzuschätzen. AbSTRACT The authors report the rediscovery of Hyperolius nimbae LAuReNT , 1958, a reedfrog species known only from the lowlands of the eastern flanks of Mount Nimba, western Ivory Coast. The species was described in 1958 and last seen in 1963. Forty-seven years after that date small populations were rediscovered near four villages, dagbonpleu, danipleu, Kouan-houlé and zéalé, within the formerly known range. however, only a total of seven individuals were recorded. The habitats showed various degrees of degradation, ranging from swampy forest to rice fields within degraded forest and secondary growth. The strong anthropogenic impact, in particular agricul - tural activities, may be an imminent risk compromising the species’ long-term survival. The authors recommend further intensive search for persisting populations and their monitoring to evaluate the factors threatening the sur - vival of H. nimbae . Key WoRdS Amphibia: Anura: hyperoliidae; Hyperolius nimbae , reedfrog, biodiversity hotspot, conservation status, Mount Nimba endemic, Côte d’Ivoire, Ivory Coast, upper Guinea INTRoduCTIoN The Mount Nimba massif is located in summaries were published by GuIbé & L A- the border region collectively shared by the MoTTe (1958, 1963) and LAuReNT (1958). West African countries Liberia, Guinea and The flagship species of the massif is the en - Ivory Coast ( LAMoTTe 1983, 1998). These demic Nimba Toad, Nimbaphrynoides occi - mountains harbor a rich endemic fauna and dentalis (ANGeL , 1943), the only truly vivip - flora ( LAMoTTe & R oy 2003), including arous anuran species worldwide ( LAMoTTe reptiles ( INeICh 2003) and amphibians 1959; XAvIeR 1986; LAMoTTe & S ANChez - (RödeL et al. 2004). The amphibian fauna LAMoTTe 1999; hILLeRS et al. 2008; SANd- is dealt with in numerous publications. First beRGeR et al. 2010). Recently two frog spe - Kouamé_etal_Roedel_etal_Rediscovery_hyperolius_nimbae_heRPeTozoA.qxd 08.08.2016 10:08 Seite 2 4 N’G. G. K ouAMé & N’G. e. A SSeMIAN & b. T ohé & P. J. A debA & G. G ouRèNe & M.-o. R ödeL cies were described from the Liberian part tions started recently about the possibility of of the Nimba Massif ( Rö deL et al. 2009, the extinction of this reedfrog. Some 2010a). attempts to locate the species at other sites one species believed to be endemic to of close proximity to the known area, e.g., the Ivorian foothills of the Nimba Moun - the Mont Sangbé National Park ( RödeL tains was described in 1958 by LAuReNT 2003) and Guinean parts of the Nimba from “yanlé”, Ivory Coast, under the name mountains ( J. d ouMbIA , L. S ANdbeRGeR - Hyperolius viridiflavus nimbae . In July LouA & M.-o. R ödeL , unpublished data), 1963, the danish herpetologist ARNe revealed no records. SChIøTz collected a larger series (28 males, Ivory Coast is quoted among the coun - 5 females) of the species between the tries where rainforests are the most threat - Ivorian settlements danané and zéalé, ened in the world ( hANSeN et al. 2013). As approximately 40 km south-east of the a result of large scale deforestation, almost Mount Nimba chain ( SChIøTz 1967). 80 % of the forests in the western part of the SChIøTz (1967) raised LAuReNT ’s (1958) country were destroyed up to the end of the taxon to species level, compared it to other last millennium ( PARReN & de GRAAF 1995; treefrog species, provided first biological ChATeLAIN et al. 1996). The only sites from data and, in particular, wondered why the where H. nimbae was known face severe range of this species was so restricted as its anthropogenic impact. The former rainfor - habitat preferences seemed to be by no way est area is now largely dominated by an particular. Later, LAuReNT (1983) and agricultural landscape ( N. G. K ouAMé , pers. SChIøTz (1971) considered this frog a sub - obs.). species of Hyperolius tuberculatus (MoC- In 2010, Conservation International quARd , 1897), a species otherwise known initiated the campaign “Search For the Lost from western Central Africa ( AMIeT 2012; Frogs”, focusing on the search for 100 FRéTey et al. 2012). In a subsequent publi - amphibian species that have not been seen cation, SChIøTz (1999) again recognized H. for decades, but scientists believe may have tuberculatus and H. nimbae as distinct survived (compare e.g., oNAdeKo et al. species. SChIøTz ’s observations from July 2014 for a similar African example) . 28, 1963 seem to be the latest encounters Among these species, H. nimbae, not seen with the species in the wild. at that date for 47 years, was listed. This is Following the global awareness of a why the authors decided to reinvestigate the tremendous worldwide amphibian decline known range of H. nimbae and its surround - (e.g., bLAuSTeIN & K IeSeCKeR 2002; ings. The aim of the study was to rediscov - FeRRAz et al. 2003; STuART et al. 2004, er the Nimba Reedfrog and find further per - 2008; MooRe & ChuRCh 2008), specula - sisting populations. MATeRIALS ANd MeThodS Study area forest and smaller mountains. The regions of Man and danané are characterized by Surveys took place in the danané region swampy valleys between granite outcrops, of western Ivory Coast, south-east of the so-called inselbergs ( MouToN 1959). The Nimba Mountains. Mean annual tempera - surveyed sites comprised high grass areas, ture in danané (342 m a.s.l.) is 25.1 °C; farmland and degraded forests. Large parts mean annual precipitation 1,967 mm. The of this forest zone are subject to logging rainy season lasts between seven and nine activities. Field work was done at the months, with maximum precipitation in beginning of the core rainy season from 26 September; January is the driest month August to 1 September 2010. A hand-held (CLIMATe -d ATA .oRG 2015). The south- and GPS de vice (Garmin 12XL) was used to central-western part of Ivory Coast is natu - record the geographical positions of the rally covered by a mosaic of lowland rain - study sites (Table 1). Kouamé_etal_Roedel_etal_Rediscovery_hyperolius_nimbae_heRPeTozoA.qxd 08.08.2016 10:08 Seite 3 Rediscovery of Hyperolius nimbae LAuReNT , 1958 5 r f e o Field work and vouchers d ) r s , l e m b r h y b m , t n u , a a 1 p s r s a - m e z 5 s o e e h m Searching techniques included acous - . t 7 u n n r n e m . s 4 ) n n r 8 o a u 0 e A t b . a f y , c tic and visual encounter surveys by day and 1 l h g , 1 p n b g d , . p d e n f p . e ) n n s p e a d o a i night. All available habitats were examined e c i g h r a p i d i e d e t g r a w h a r s i F n m t t a r e w ( i by three people (N.G.K. and two field assis - o b h e h d u g d a h c t 0 i ) u t b r q e c r e d 5 h m n o a tants) who searched for frogs on seven days w r d i a h m h 1 g ) u b t , , s i f 4 g w . N a ) o 0 p - , h s o n (26 August to 1 September), eight hours , p m 1 c e e r 5 s i 3 / p t p g M 1 n . ( s e e d 2 m 0 i m a a ( a n g . n d m . (07:00-11:00 and 18:00-22:00 GMT) per s a 1 v i r m o u a 5 g o 3 e i p t l d b a p . i g i F t - i b 3 f r e t e p ( w i p F e r day, i.e., 168 person hours. After capture, frogs t 2 m m . y a p s t ( e d ( i a p y z a i a p r b , r , r n a % b e u s d N s p h n t e h were measured and sexed. Morphometric c w a l g i d i b a c h s s 0 d a e e a t e s m s u u e i s e e l 6 g r r t h s r h g t f l e t l measurements were taken by one person e t d t e i a t a d u a s h n b a s f g t y d v f t u s d e n s o e n r l a l i r n a d o y o a (N.G.K.) with a dial calliper (accuracy ± 0.5 , e u l t t ( o o g e r o i d i b y c b t a l m f b n g a b a e a ( b d m i m o e d mm).