Distribution, encounter rate and conservation status of Aquiloeurycea cafetalera (Caudata: Plethodontidae), a recently described Mexican salamander

The knowledge of the natural history of a species, its population traits and spatial distribution are essential to evaluate its risk of extinction and proposing strategies for its conservation. For poorly studied species inhabiting regions with a high degree of habitat conversion by anthropogenic activities, it is even more urgent to obtain this information. In this study, we carried out fieldwork and database analyses to obtain information on the ecology, natural history and spatial distribution of the plethodontid salamander Aquiloeurycea cafetalera, and we evaluated its conservation status according to the IUCN and the Mexican environmental agency (SEMARNAT). We found 109 individuals in 20 of the 43 localities visited (sampling effort = 1,174 person-hours). The salamander counts ranged from one to 21 individuals per locality and the average encounter rate was 21 salamanders per 100 person-hours of surveying, within a range from 2 to 117 salamanders. The current potential distribution calculated is about 2,000 km2 and fragmented, which means less than half of its original potential distribution. Our results suggest that it is necessary to include this species in biodiversity conservation programs because only a very small portion of its spatial distribution falls within natural protected areas.O conhecimento da história natural de uma espécie, suas características populacionais e sua distribuição espacial são essenciais para avaliar seu risco de extinção e para propor estratégias para sua conservação. Para as espécies mal estudadas e que habitam regiões com um alto grau de conversão de habitat por atividades antropogênicas, é ainda mais urgente obter essas informações. Neste estudo, nós compilamos informação de banco de dados juntamente com trabalho de campo para obter informações sobre a ecologia, história natural e distribuição espacial da salamandra Aquiloeurycea cafetalera, e também avaliamos seu estado de conservação de acordo com a IUCN e a Agência Ambiental Mexicana (SEMARNAT). Encontramos 109 indivíduos em 20 das 43 localidades visitadas (esforço de amostragem = 1174 horas.pessoa). A contagem de salamandras variou de um a 21 indivíduos por localidade, e a taxa média de encontro foi de 21 salamandras por 100 horas.pessoa de levantamento, num intervalo de 2 a 117 salamandras. A atual distribuição potencial calculada é de cerca de 2000 km2 e é fragmentada, o que significa menos da metade da sua distribuição potencial original. Nossos resultados sugerem que é necessário incluir essa espécie em programas de conservação da biodiversidade, visto que somente uma pequena porção de sua distribuição espacial está incluída em áreas naturais protegidas

In Search of Critically Endangered Species: The Current Situation of Two Tiny Salamander Species in the Neotropical Mountains of Mexico

Worldwide, one in every three species of amphibian is endangered, 39 species have gone extinct in the last 500 years and another 130 species are suspected to have gone extinct in recent decades. Of the amphibians, salamanders have the highest portion of their species in one of the risk categories, even higher than the frogs. To date there have been few studies that have used recent field data to examine the status of populations of endangered salamanders. In this study we evaluate the current situation of two tiny salamanders, Parvimolge townsendi and Thorius pennatulus, both of which are distributed at intermediate elevations in the mountains of the northern Neotropics and are considered to be critically endangered; the first has been proposed as possibly extinct. By carrying out exhaustive surveys in both historical and potentially suitable sites for these two species, we evaluated their abundance and the characteristics of their habitats, and we estimated their potential geographic distribution. We visited 22 sites, investing 672 person-hours of sampling effort in the surveys, and found 201 P. townsendi salamanders in 11 sites and only 13 T. pennatulus salamanders in 5 sites. Both species were preferentially found in cloud forest fragments that were well conserved or only moderately transformed, and some of the salamanders were found in shade coffee plantations. The potential distribution area of both species is markedly fragmented and we estimate that it has decreased by more than 48%. The results of this study highlight the importance of carrying out exhaustive, systematic field surveys to obtain accurate information about the current situation of critically endangered species, and help us better understand the crisis that amphibians are facing worldwide

FIGURE 2 in A new species of Isthmura (Caudata: Plethodontidae) from the montane cloud forest of central Veracruz, Mexico

FIGURE 2. Holotype of Isthmura corrugata. A) Lateral and B) Ventral view. C) Coloration and form of costal grooves. D) Left hand (up) and left foot (down). E) Details of the head. F) Dorsal view. (G – H) Holotype (above) and paratype (below) dorsal and ventral coloration in preservation. All photographs by A. Sandoval-Comte

The environmental variables that make the greatest contribution in modeling the potential distribution of both species.

<p>Blue circles are the sites where the presence of <i>Parvimolge townsendi</i> was used for the model, and the orange triangles are those where the presence of <i>Thorius pennatulus</i> was used for the model.</p

Rate of finding <i>Parvimolge townsendi</i> and <i>Thorius pennatulus</i> per site.

<p>Each visit represents a search effort of 16 person hours.</p

Potential distribution of <i>Parvimolge townsendi</i> and <i>Thorius pennatulus</i>.

<p>(A) Potential distribution area for <i>P. townsendi</i>; black square are the sites used in to generate the model, (B) Potential distribution are for <i>P. townsendi</i>, cropped to include only the appropriate vegetation (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0034023#s2" target="_blank">Methods</a>), (C) Potential distribution area for <i>T. pennatulus</i>; black triangles are the sites used in to generate the model and (D) Potential distribution area for <i>T. pennatulus</i>, cropped to include only the appropriate vegetation. The colored area is the predicted distribution area and the black stars indicate large cities.</p

Microhabitat use.

<p>Number of <i>Parvimolge townsendi</i> (A) and <i>Thorius pennatulus</i> (B) salamanders found in different microhabitats and at different times of the day.</p

<i>Parvimolge townsendi</i> and <i>Thorius pennatulus</i>.

<p>A and B) Two <i>P. townsendi</i> males with different patterns of coloration (standard length = 20.7 and 23.8 mm, respectively). C and D) Two adult <i>T. pennatulus</i> salamanders (standard length = 17.8 and 16.8 mm, respectively).</p