The distribution and local density of the critically endangered frog Conraua derooi Hulselmans, 1972 in Togo, West Africa

Abstract

Conraua derooi is a Critically Endangered frog, endemic to the hilly forest region between Ghana and Togo, West Africa. Field surveys were conducted in the Togolese areas, considered to be potentially suitable for C. derooi in November 2015 and November 2016. The species was not encountered in several potentially suitable sites. However, C. derooi was recorded in two areas, Missahohe and Danyi Yikpa, including two new sites, one rediscovered site, and three confirmed sites within these areas. In total we recorded 522 adult individuals. The number of observed frogs ranged from 14 and 150 individuals × km-1. Due to heavy habitat alteration the known populations are isolated. Some conservation considerations are presented.

Full text

INTRODUCTION
Togo slippery frog, Conraua derooi (Fig. 1) was described
from the forest around Missahohe in south-western Togo
(Hulselmans, 1972). In 1980, a further small population
of the species was discovered north of the type locality in
the Danyi Yikpa area (Bourgat et al., 1996). Records of
C. derooi from Togo and Ghana, identied as Conraua alleni
(a species-complex which occurs from western Ghana to
Sierra Leone and Guinea; Mark-Oliver Rödel et al., unpubl.
data), prior to the description of C. derooi, were published
by Schiøtz (1964) and Lamotte & Perret (1968). Surveys
conducted from 2000 to 2005 on the Ghanaian part of the
Ghana-Togo highlands failed to detect the species (Rödel &
Agyei, 2003; Leaché et al., 2006). Segniagbeto et al. (2007)
summarised the known sites from Togo but they did not nd
any new sites. Finally Kouamé et al. (2007) presented new
records from the Atewa Range in Ghana; Hillers et al. (2009)
conrmed the persistence of C. derooi at several known
sites along the Togo-Ghana border. Preliminary results
indicate, however, that the Atewa records may represent
an undescribed species (Rödel, unpubl. data). In summary,
C. derooi has a very restricted distribution, with all known
Togolese populations found along the Camalo torrent in the
forests of Missahohe and Yikpa (Segniagbeto et al., 2007,
2013).
Typical habitats of the species are torrents in hilly forested
landscapes. Previous studies (Rödel & Agyei, 2003; Hillers
et al., 2009 and Segniagbeto et al., 2013) have shown that
available habitat for this species is highly fragmented and
degraded, as natural forest ecosystems being transformed
into coffee and cocoa plantations. As a result and because
of its Extent of Occurrence, C. derooi has been assessed as
Critically Endangered, Criteria B2ab(iii), by IUCN (Rödel &
Schiøtz, 2004). In addition, the species should be considered
a priority for conservation on the basis of its evolutionary
distinctiveness and global endangerment (Isaac et al., 2012).
In order to obtain up-to-date scientic data on the distribution
and conservation status of the C. derooi populations in
Togo, we conducted eld surveys in November 2015 and
November 2016 in areas considered, based on habitat, as
potentially suitable for the species. In this paper, we present
data on the number of observed individuals and some
hitherto unknown sites.
The distribution and local density of the critically endangered frog
Conraua derooi Hulselmans, 1972 in Togo, West Africa
GABRIEL HOINSOUDÉ SÉGNIAGBETO1*, DELAGNON ASSOU1, DANIELE DENDI2,5,
MARK-OLIVER RÖDEL3, ANNEMARIE OHLER4, ALAIN DUBOIS4 & LUCA LUISELLI2,5
1Département de Zoologie et Biologie animale, Faculté des Sciences, Université de Lomé, BP 1515,
Lomé, Togo
2IDECC – Institute for Development, Ecology, Conservation and Cooperation, via G. Tomasi di
Lampedusa 33, I-00144 Rome, Italy
3Museum für Naturkunde, Berlin, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstr.
43, 10115 Berlin, Germany
4Institut de Systématique, Évolution, Biodiversité, ISYEB – UMR 7205 – CNRS, MNHN, UPMC, EPHE,
Muséum national d’Histoire naturelle, Sorbonne Universités, 57 rue Cuvier, CP 30, F-75005, Paris, France
5Department of Applied & Environmental Biology, Rivers State University of Science & Technology,
P.M.B 5080, Port Harcourt, Rivers State, Nigeria
Corresponding author Email: h_segniagbeto@yahoo.fr
RESEARCH ARTICLE The Herpetological Bulletin 141, 2017: 23-27
Figure 1. Adult C. derooi from Camalo I, south-western Togo.
Herpetological Bulletin 141 (2017) 23
ABSTRACT - Conraua derooi is a Critically Endangered frog, endemic to the hilly forest region between Ghana and
Togo, West Africa. Field surveys were conducted in the Togolese areas, considered to be potentially suitable for C. derooi
in November 2015 and November 2016. The species was not encountered in several potentially suitable sites. However,
C. derooi was recorded in two areas, Missahohe and Danyi Yikpa, including two new sites, one rediscovered site, and
three conrmed sites within these areas. In total we recorded 522 adult individuals. The number of observed frogs ranged
from 14 to 150 individuals × km-1. Due to heavy habitat alteration the known populations are isolated. Some conservation
considerations are presented.

Gabriel Ségniagbeto et al.
24 Herpetological Bulletin 141 (2017)
STUDY AREA
The study area was within the forest zone in south-western
Togo (Figure 2; ecological zone IV according to Ern, 1979).
In this area, different sites were surveyed, these included
the forest of Assoukoko, the forest of “les Deux Béna”, the
forest of Assimé, Yikpa, Missahohe and Mount Agou (Table
1). Overall, this comprises hilly area with altitudes of up
to 972 m asl. Localities in these areas usually have very
steep slopes (Addra et al., 1994). The climate is transitional
subequatorial (Papadakis, 1966; Trochain, 1980), being
characterised by a prolonged rainy season from March to
October, with decreasing amounts of rainfall in August or
September. The survey periods were selected on the basis of
logistical opportunities, in order to avoid periods of heavy
rains that would have caused difculties in exploration of
some sites in remote areas of the forest. It is the wettest
area in Togo, with an average annual rainfall amounting to
1,300–1,500 mm. This area is characterised by the presence
of several rivers spread over three water-sheds, with the basin
River Volta source being the most important in terms of size.
The main water-courses are: Assoukoko and its tributaries
Yégué and Koo; Wawa and its tributaries Kpon (also called
Gbanhou), Obéka, Ové and Gonobe; Danyi and its tributaries
Tonon, Iwé, Sassa and Agoumatsa. The vegetation varied
between the sites investigated (see Table 1 for site names).
Geographic coordinates of the various presence sites are not
provided for conservation reasons (Lindenmayer & Scheele,
2017), but are available on request from the authors.
Djiguégué consists of a mosaic of semi-deciduous, more
or less degraded, dense forests, a few small gallery forests,
savannas, fallow land and crops (see Figure 2 for its location
within Togo).
Assoukoko is similar to Djiguégué in that the site is a
mosaic of semi-deciduous forests, dry dense forests, wooded
savannas, fallow land and crops. In accessible parts of the
semi-deciduous forests, coffee and cocoa is cultivated. The
forests in this area gradually shift from semi-deciduous
on valley oors, to dense dry forests on upper slopes, and
nally transition into wooded savannas at the top.
The area of Akloa (Badou) includes patches of heavily
degraded forest, dominated by cash crops (mainly coffee
and cocoa), growing under forest canopy. Fruit such as
Persea americana, Citrus spp., Musa sapitum and Musa
paradisiaca is also cultivated in these agroforestry systems.
Atigba (Danyi) comprises agroforestry systems (mainly
coffee), some narrow gallery forests and wooded savanna.
The vegetation in Dany Yikpa resembles that in
the Assoukoko area, i.e. comprising a mosaic of semi-
deciduous forests, dense dry forests and wooded savannas;
the undergrowth of accessible semi-deciduous forests is
cultivated with coffee and cocoa.
The Missahohé forest comprises a mosaic of mesophilic
or semi-deciduous forests (Akpagana, 1989) and savannas.
It is heavily impacted because of human settlements and the
cultivation of both, cash crops and food crops.
Figure 2. Map of Togo, showing the two study areas with presences of C. derooi. The new localities discovered during the present
surveys are presented in red colour. Locality 1 was rediscovered after it was rstly discovered in 1980.

Herpetological Bulletin 141 (2017) 25
MATERIALS AND METHODS
Two eld surveys, on 1–11 November 2015 and 8–13
November 2016, were carried out in the localities mentioned
above. Each study site was visited twice. Prior to eld
work we conducted interviews in the nearby villages (n
= 21 villages). In each village, 4 to 12 local persons were
interviewed. All interviewers were males, and the same
was for interviewees, as only men collect frogs in Togo.
Interviewees were asked about the presence of the species
by presenting them photos of the frogs and by imitating
their advertisement call (high-pitched whistles). With the
support of two local guides, and based on the results of the
interviews, potential sites of the species were identied.
Small waterfalls in forested areas, streams with a width of
about two to three meters and streambeds with rocks or
pebbles (mainly quartzites) were targeted as survey sites,
as these habitat features were already seen to be associated
with C. derooi populations in the past (e.g., Segniagbeto
et al., 2013). All identied sites were surveyed between 7
and 10 pm. Air temperature was not recorded because it is
very constant at the study areas, and because all surveys
were made in the same period of the year (November, i.e.
end of the wet season). The name-places and the distance
walked in each site are presented in Table 2. The eld team
consisted of 3 people (GHS and two students). Surveys were
undertaken with the team proceeding slowly upstream, until
walking became impossible because the terrain became
too difcult to traverse. Flashlight and head torches were
used for exploring the sites. The length of the stream which
could be investigated varied between sites from 200 m to
1.8 km (Table 2). At each site, all the observed frogs were
counted. Adults and subadults were pooled in our counts.
All members of the team walked slowly and parallel to
each other, thus ascertaining that no specimen was counted
twice. Tadpoles and newly metamorphosed individuals were
observed but not counted. However, their presence was
always recorded.
Density of C. derooi, at each site, was determined
as the number of adult individuals that were observed
per km of transect. Four times per year, interviews with,
and examination of collected animals by, reptile farms
in Lomé were carried out in order to monitor the current
trade of species. During these surveys, the dealers were
interviewed about the collected animals, and any details of
interest (apparent abundance, locality of capture, destination
country, etc.) were recorded.
RESULTS AND DISCUSSION
In total, 23 independent sites were visited and in 21 of
them a total of 138 local people were interviewed (Table
1). Overall, in six distinct localities (including four localities
were also interviews were made) we recorded 522 C. derooi
individuals, 349 in 2015 and 173 in 2016 (Table 2). A greater
number of C. derooi were observed in the southern part of
Togo’s ecological zone IV compared to the northern part
(Fig. 1). Our surveys did not reveal the presence of the
species in Diguengue, Assoukoko, Akloa, Danyi Atigba and
Mount Agou, despite all sites being surveyed twice (once
in each year of study). Based on its habitat features, the
mountain side at Agou looked particularly suitable for the
species. However, the species was not detected. Based on
our interview data and subsequent eld surveys, the local
communities appeared to often confuse C. derooi with the
widespread, abundant, and similarly aquatic Hoplobatrachus
occipitalis. It should be noted that, in Djiguégué and Akloa,
the hilly areas were extremely difcult to access and the
area had many small waterfalls within a forest environment.
Interviews with people from some villages in this area
indicated the potential presence of the species. The respective
areas thus should be re-surveyed and this will entail the use
of specialist climbing equipment.
The presence of the species was conrmed in just two
forest regions which are known to have supported the species
in the past: Missahohe and Danyi Yikpa (Hulselmans, 1972;
Bourgat, 1979; Kulo, 1980; Hillers et al., 2009; Segniagbeto
et al., 2013). More in detail, the species was recorded at six
distinct sites within these two main areas, two out of which
were newly discovered during the present investigations
and one was rediscovered after 1980 (Fig. 2). In other three
sites, the presence of the study species was conrmed (Fig.
2). The greatest number of C. derooi (30.65% of the total
number of encountered adult individuals per km of transect;
see table 2), were observed at the Zoto site, in the Missahohe
forest, followed by Douane, also situated in Missahohe
forest (Table 2). All sites where the species was present
were surrounded by unsuitable habitat (forestry operations
and coffee and cocoa cultivation in the former forest). Our
Area
investigated
Localities State of record Number
of people
interviewed
Adele area
Yégué No record 8
Assoukoko No record 9
Dikpéléou No record 6
Diguengue No record 12
Akloa area
Akloa No record 10
Wobè No record 6
Tomégbé No record 4
Danyi area
Danyi Atigba No record 7
Yikpa Dzigbé Presence
ascertained
4
Yikpa Anyigbé Presence
ascertained
11
Kloto area
Kouma Tokpli No record 6
Agomé
Tomégbé
No record 6
Kamétonou No record 5
Agomé Yoh No record 8
Kouma Konda Presence
ascertained
7
Anédi Presence
ascertained
5
Kouma Adamé No record 4
Kouma Tsamé No record 6
Agou mountain
area
Kébo Dzigbé No record 6
Kébo Dogbadzi No record 4
Kébo Kpéta No record 4
Table 1. Summary of areas and localities investigated for C.
derooi in the forest area of Togo, where also interviews with local
people were conducted.
The distribution of the critically endangered frog Conraua derooi Hulselmans, 1972 in Togo, West Africa

26 Herpetological Bulletin 141 (2017)
surveys indicate that the Togolese population of C. derooi is
highly fragmented.
Our observations conrm the known habitat preferences
of this species (Fig. 3), which is associated with torrents.
At Camalo II, some individuals were also found, under
the water, in rock crevices or by being dug from the mud.
Adults, especially calling males, were observed sitting on
rocky substrates outside of the water. Some individuals
were observed 10 m above torrents within the spray zone of
waterfalls.
The habitats of all C. derooi populations are seriously
threatened by logging and agricultural encroachment. The
few remaining forests throughout the hilly forest area along
the border between Togo and Ghana are being converted into
plantations (mostly coffee and cocoa) at increasing rates.
According to the FAO (2011), 43.6% of forest ecosystems
in Togo have been destroyed since 1990. The increasing
production of charcoal by the local populations, following
the recent fall in the global prices for coffee and cocoa, is
accelerating the ongoing process of forest fragmentation and
degradation. What is left of these forests today is practically
conned to forest islands in hard-to-reach areas and along
watercourses. Because of the rapid population growth, these
forest relics are increasingly damaged as well. Even in the
Missahohe Forest, which is a protected area, the habitats of
C. derooi are heavily degraded (Segniagbeto et al., 2013).
Indeed, although legally protected at the country scale, this
forest is heavily subjected to illegal timbering, hunting and
other resource exploitation activities.
Another threat to the populations of C. derooi is the
exploitation of adults for domestic consumption and the
international food trade. To date, the level of exploitation
has not been quantied and requires further study. In
neighboring Bénin, a dramatically increasing exploitation of
frog populations for regional and international food market
has been documented (Mohneke et al., 2010). In addition,
other Conraua species are exploited for meat in West and
Central Africa (e,g, Conraua goliath, see Herrmann et al.,
2005). There is also indication that the C. derooi population
at Yikpa is exploited for local consumption. The interviewed
population of this small village (10 people, all men), situated
between Togo and Ghana, indicates that the species is well
known and interviewees reported that frogs are sold for
100 CFA per frog (= 0.17 $ or 0.15 €) to local households.
This population and those of the Missahohe Forest are
furthermore exploited, especially to supply the demand for
frog meat from the Chinese workforce in Togo. In addition,
interviewed collectors at the various sites also acknowledged
that they collect C. derooi for Togolese reptile farms which
export frogs for the international pet trade. This exploitation
was conrmed by two of the nine reptile farms that were
surveyed (Mare and Toganim). Indeed, about 50 (range:
15-100) C. derooi individuals per year were exported
from Togo to the European Union between 2010 and 2015
(Segniagbeto, unpublished data). Nonetheless, this export
has now been stopped due to the recommendation of the
senior author to the ‘Direction des Ressources Forestrières’
of the Togolese Republic (year 2015) and to the collectors as
well.
However, given that habitat alteration is presumably
the main threat for C. derooi in Togo, we advise that urgent
measures should be taken to protect and (where necessary)
restore the remaining habitats of this species in Togo.
Because of the very few known sites, the high
fragmentation of the range, and the rampant habitat loss, we
consider that this species should be still considered as CR by
IUCN. In this regard, it should be mentioned that C. derooi
has been subjected to conservation initiatives in Ghana,
coordinated by Caleb Ofori-Boateng and internationally
supported by various donors (e.g. see http://www.
saveourspecies.org/projects/amphibians/conservation-
critically-endangered-togo-slippery-frog-conraua-derooi;
lastly accessed: 20 August 2017). Thus, it would be very
important that similar international attention should be
attributed to the Togolese populations as well.
Gabriel Ségniagbeto et al.
Figure 3. Small waterfall, habitat of C. derooi in Danyi Yikpa,
south-western Togo.
Localities
First survey (2015) Second Survey (2016) Transect length
(km)
no. frogs x km-1
(year 2015)
no. frogs x km-1
(year 2016)
Date No. of
C. derooi
Date No. of
C. derooi
Yikpa 2 Nov 30 9 Nov 25 1.8 16.66 13.88
Camalo I, Missahohe 4 Nov 70 12 Nov 45 1.3 53.85 34.61
Zoto, Missahohe 8 Nov 120 10 Nov 40 0.8 150 50
Douane, Missahohe 8 Nov 50 10 Nov 20 0.5 100 40
Camalo, II Missahohe 9 Nov 14 12 Nov 8 0.2 70 40
Anedi, Missahohe 10 Nov 65 11 Nov 35 0.45 144.4 77.77
Table 2. Summary of Togolese localities where C. derooi was recorded, including survey dates and number of observed (No.)
individuals. Abundance is dened as number of individuals × km-1. Tadpoles were observed at all sites.

The distribution of the critically endangered frog Conraua derooi Hulselmans, 1972 in Togo, West Africa
Accepted: 11 September 2017
Herpetological Bulletin 141 (2017) 27
ACKNOWLEDGEMENTS
The two eld surveys were within the framework of the
project “Conservation of the Togo slippery frog (Conraua
derooi) in Missahohe and Assime forests areas (Togo, West
Africa)” funded by Stiftung Artenschutz’s “Amphibian
Funds” in cooperation with the “Verband der Zoologischen
Gärten e.V.” (VdZ). We are very grateful for their support.
We further thank Jan Kamstra and Jaime García Moreno
from the Netherland’s Committee of the IUCN by their
facilitation contact with the Stiftung Artenschutz. We are
very thankful to Agbo-Zegue Ngo who provided logistics
for the eld surveys, and to two anonymous referees for
helpful comments on the submitted draft.
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