Robin D. Moore

The Challenge of Conserving Amphibian Megadiversity in Madagascar

Highly diverse and so far apparently untouched by emergent diseases, Malagasy frogs nevertheless are threatened by ongoing habitat destruction, making pro-active conservation actions especially important for preserving this unique, pre-decline, amphibian fauna.

Low gene flow but high genetic diversity in the threatened Mallorcan midwife toad Alytes muletensis

We investigated fine‐scale genetic structuring in the rare and vulnerable Mallorcan midwife toad Alytes muletensis using eight polymorphic microsatellite markers. The current range of this amphibian is restricted to some 19 sites of which six are derived from reintroductions, all located in the mountain ranges of Mallorca. We sampled tadpoles from 14 pools covering 10 natural sites and two reintroduction sites for microsatellite DNA analyses. Relatively high levels of genetic variation were found in most pools (HE = 0.38–0.71, allelic richness = 2.6–6.2). Only at one pool has the population recently gone through a bottleneck. Dispersal between pools in different torrents does not occur whereas downstream dispersal between pools within the same torrent does happen at low frequencies. This occasional exchange of individuals does not lead to neighbouring pools in the same torrent being panmictic. This can be concluded because all FST values (0.12–0.53) differ significantly from zero and structure analyses identified neighbouring pools as separate populations. Furthermore, assignment and migration tests showed little exchange between neighbouring pools. If upstream locations or complete torrents go extinct, they are unlikely to be recolonized naturally. For conservation purposes, reintroductions of tadpoles to sites where local extinctions have occurred may therefore be advisable.

Induced defences in an endangered amphibian in response to an introduced snake predator

Introduced species have contributed significantly to the extinction of endemic species on islands. They also create new selection pressures on their prey that may result in modified life history strategies. Introduced viperine snakes (Natrix maura) have been implicated in the decline of the endemic midwife toad of Mallorca (Alytes muletensis). A comparison of A. muletensis tadpoles in natural pools with and without snakes showed that those populations subject to snake predation possessed longer tails with narrower tail fins but deeper tail muscles. Field and laboratory experiments showed that these changes in tail morphology could be induced by chemical and tactile cues from snakes. Populations of tadpoles that were subject to snake predation also displayed clear bimodal size-frequency distributions, with intermediate-sized tadpoles missing from the pools completely. Tadpoles in pools frequented by snakes developed faster in relation to their body size than those in pools without snakes. Variation in morphology between toad populations may therefore be caused by a combination of size-selective predation and tadpole plasticity. The results of this study indicate that the introduction of alien species can result in selection for induced defences, which may facilitate coexistence between predator and prey under certain conditions.

Is the international frog legs trade a potential vector for deadly amphibian pathogens

There have been surprisingly few analyses of how the international trade in amphibians for food affects the conservation status of this group. We analyzed information from the UN Commodity Trade Statistics Database and found that, by volume, Indonesia supplied nearly half of the animals entering the worlds US

Introduced Alien or Persecuted Native? Resolving the Origin of the Viperine Snake (Natrix Maura) on Mallorca

40 million per year international frog legs trade, and that – collectively – France, Belgium, and the US imported more than 75% of all frog legs traded internationally. Nonetheless, a close examination of available information from 1996 through 2006 revealed that most countries throughout the world participated in the frog legs trade at some level. These extensive international amphibian trade networks could facilitate the spread of pathogens, including Batrachochytrium dendrobatidis, which has been identified as a threat connected with the disappearance and possible extinction of over 90 amphibian species around the world. Given the size and extent of the international trade in frog legs, we advoca...

Distribution of the Mallorcan midwife toad (Alytes muletensis) in relation to landscape topography and introduced predators

The viperine snake (Natrix maura) is an important agent of decline of the threatened midwife toad (Alytes muletensis) of Mallorca. However, there is a paucity of biological data to support the notion that the viperine snake is an introduced species to the island. Here we compare mitochondrial cytochrome b gene sequences and genomic ISSR-PCR fingerprints from Mallorcan and mainland European viperine snakes. Identical or nearly identical haplotypes and very similar ISSR-PCR profiles provide strong evidence that N. maura arrived only recently to Mallorca. There is no indication of a recent natural colonization of the island by transmarine dispersal. The data therefore support historical information that N. maura was introduced to Mallorca by human agency comparatively recently, and that management measures to reduce the impact of the snake on toad populations are justified.

A review of the international trade in amphibians:the types, levels and dynamics of trade in CITES-listed species

The endemic midwife toad of Mallorca (Alytes muletensis) is restricted to a small number of breeding populations in the mountainous northwest of the island. The decline of the species has been attributed to the impacts of introduced species such as the viperine snake (Natrix maura) and green frog (Rana perezi), and toads may be surviving only in areas that are suboptimal for these predators. The influence of landscape features (elevation, aspect and maximum slope) on the distribution of toads and associated predators was therefore investigated using GIS. The presence of toads was positively associated with steep slopes. At sites where they occurred with toads, the distribution of predators was negatively associated with elevation. Reproductive success within toad populations was strongly associated with the number of pools at each site, while reproductive success within individual pools was positively associated with elevation. These findings may be used to optimise the design and location of future reintroduction sites.

Pinpointing and preventing imminent extinctions

Globally, amphibians face many potential threats, including international trade. However, there is a lack of knowledge regarding the types, levels and dynamics of the amphibian trade at the global scale. This study reviewed the trade in CITES-listed species between 1976 and 2007. Four main trade groups (eggs, skins, meat and individuals) were identified. Trade in amphibian leather focused on Hoplobatrachus tigerinus (5,572 individuals), whereas trade in eggs focused on Ambystoma mexicanum (6,027 eggs). However, for the entire study period (1976–2007), trade in skins and eggs was small compared with trade in meat and live animals. The meat trade was estimated to be worth >xa0USD 111 million, whereas the trade in live animals was estimated to be worth >xa0USD 11.5 million in only three of the genera involved. Trade dynamics have changed as a result of changes in legislation, such as a ban on H. tigerinus exports from Bangladesh for meat. Within the live trade 22 species categorized as either Critically Endangered or Endangered were traded during the study period, and these require greater attention. International trade and potential conservation benefits are affected by countries supplying captive-bred individuals to their domestic markets as this trade goes unrecorded. However, this study only investigated trade in species listed by CITES, and other species may comprise a significant additional component of international trade. The trade in amphibians is dynamic, and changes in both the types of trade and the species concerned were identified over the study period. Conservation concerns have multiplied from issues concerning population depletions to include indirect impacts associated with disease, predation and competition, which requires a reappraisal of data capture and reporting.