Conserving the unique to save the diverse — Identifying key environmental determinants for the persistence of the viviparous Nimba toad in a West African World Heritage Site

Sandberger-Loua, Laura; Doumbia, Joseph; Rödel, Mark‐Oliver

doi:10.1016/j.biocon.2016.03.033

Cited by 7 publications

(15 citation statements)

References 31 publications

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“…These ponds are very shallow (< 5 cm). Due to the rarity of open water, the harsh climatic conditions and the isolation of the mountain a high percentage of the species in the high altitude grasslands is endemic (Lamotte and Roy 1961a), such as the Nimba toad, which occurs exclusively in the high altitude grasslands above 1,200 m asl (Lamotte 1959, Hillers et al 2008, Sandberger-Loua et al 2016a). …”

Section: A Short History Of the Taxonomy Of Nimbaphrynoides Occidentalismentioning

confidence: 99%

“…The very pronounced differences between the rainy and the dry season has strong effects on the toad's activity patterns (Lamotte 1959, Sandberger-Loua et al 2016a) and their reproductive cycle (Xavier 1971, Gavaud 1977. Nimba toads are only active during the rainy season (Lamotte 1959, Sandberger-Loua et al 2016a.…”

Section: Annual Seasonality and Activity Patternsmentioning

confidence: 99%

“…Nimba toads are only active during the rainy season (Lamotte 1959, Sandberger-Loua et al 2016a. With the first rains gestating females emerge from the aestivation sites, later joined by virgin females and males (Lamotte 1959, Xavier 1971, Lamotte and Sanchez-Lamotte 1999.…”

Section: Annual Seasonality and Activity Patternsmentioning

confidence: 99%

“…Across a total range of 4 km² the total toad population was estimated to comprise 16 million individuals in August in the 1950s (Lamotte 1959) and 14 million in 1966 (Xavier 1971). A calculation based on an assumed equal range size, our annual monitoring data (2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016); 1,160 exa mined plots of 5 × 5 m², of those 178 in August, and 88 in high density areas in August compare Sandberger-Loua et al 2016a), would result in 2.8 million toads in August (population size oscillates throughout season). This translates into an 82% decrease in toad numbers since 1959, which quite likely underestimates the decrease as our distribution estimate is smaller than 4 km², and we only included numbers from areas with high toad abundances to calculate the average number of toads per 1 m².…”

Section: Conservationmentioning

confidence: 99%

“…This unique matrotrophic (and pueriparous) anuran is a small (snout vent length (SVL) 15-27 mm, Lamotte 1959, Xavier 1971) West African bufonid, endemic to a few square kilometres (4 km², Lamotte 1959) of the high altitude grasslands of the Nimba mountains (Lamotte 1959, Lamotte and Sanchez-Lamotte 1999, Hillers et al 2008, Sandberger-Loua et al 2016a), a small mountain chain in the tri-border area of Guinea, Ivory Coast and Liberia (Figure 1). Shortly after its description as Nectophrynoides occidentalis Angel, 1943, its unique viviparous reproductive mode was recognised (Angel andLamotte 1944a, 1944b) and led to numerous, partly very detailed studies.…”

Section: Introductionmentioning

confidence: 99%

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A review of the reproductive biology of the only known matrotrophic viviparous anuran, the West African Nimba toad, Nimbaphrynoides occidentalis

Sandberger-Loua¹,

Müller²,

Rödel³

2017

ZSE

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Amphibians, and anurans in particular, show the highest diversity of reproductive modes among tetrapods. Nevertheless, viviparity is scarce in anurans and its occurrence is even more often assumed rather than confirmed. Probably the best studied viviparous amphibian is the Nimba toad, Nimbaphrynoides occidentalis. During more than 40 years of research, the Nimba toad's reproductive morphology, endocrine activity of the ovary as well as the pituitary gland, and to some extent the ecological impact (seasonality, humidity, food availability) on reproduction was examined. Due to the Nimba toad's unique reproductive mode, summaries are usually included in reviews discussing amphibian reproduction and articles on reproductive biology often discuss the exceptional reproductive system of Nimba toads. However, to our knowledge a detailed synthesis, summarising all the different original studies on the toad's reproduction, is so far missing. In this paper we review and summarise all available initial publications, which often have been published in French and/or are difficult to access. A short overview is given of the climatic and environmental conditions experienced by Nimba toads and the key findings supporting a "true" viviparous reproduction with matrotrophy (maternal provision of nutrition during the gestation) and pueriparity (birth of juveniles). Then foetal development (morphological, gonad and pituitary development), and the female (ovary, oviduct, pituitary and their endocrine interactions) and the male reproductive system (testes and pituitary) are reviewed. Finally, the reproductive cycle and its link to the Nimba mountains' seasonality and ecological/ conservation implications are discussed. Key WordsAmphibia development evolution ovary oviduct pueriparity seasonality testes uterus

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Section: A Short History Of the Taxonomy Of Nimbaphrynoides Occidentalismentioning

confidence: 99%