The Conservation Status of the World’s Reptiles

Effective and targeted conservation action requires detailed information about species, their distribution, systematics and ecology as well as the distribution of threat processes which affect them. Knowledge of reptilian diversity remains surprisingly disparate, and innovative means of gaining rapid insight into the status of reptiles are needed in order to highlight urgent conservation cases and inform environmental policy with appropriate biodiversity information in a timely manner. We present the first ever global analysis of extinction risk in reptiles, based on a random representative sample of 1500 species (16% of all currently known species). To our knowledge, our results provide the first analysis of the global conservation status and distribution patterns of reptiles and the threats affecting them, highlighting conservation priorities and knowledge gaps which need to be addressed urgently to ensure the continued survival of the world’s reptiles. Nearly one in five reptilian species are threatened with extinction, with another one in five species classed as Data Deficient. The proportion of threatened reptile species is highest in freshwater environments, tropical regions and on oceanic islands, while data deficiency was highest in tropical areas, such as Central Africa and Southeast Asia, and among fossorial reptiles. Our results emphasise the need for research attention to be focussed on tropical areas which are experiencing the most dramatic rates of habitat loss, on fossorial reptiles for which there is a chronic lack of data, and on certain taxa such as snakes for which extinction risk may currently be underestimated due to lack of population information. Conservation actions specifically need to mitigate the effects of human-induced habitat loss and harvesting, which are the predominant threats to reptiles

The conservation status of the herpetofauna of Honduras

The conservation status of the members of the Honduran herpetofauna is discussed. Based on current and projected future human population growth, it is posited that the entire herpetofauna is endangered. The known herpetofauna of Honduras currently consists of 334 species, including 117 amphibians and 217 reptiles (including six marine reptiles, which are not discussed in this paper). The greatest number of species occur at low and moderate elevations in lowland and/or mesic forest formations, in the Northern and Southern Cordilleras of the Serranía, and the ecophysiographic areas of the Caribbean coastal plain and foothills. Slightly more than one-third of the herpetofauna consists of endemic species or those otherwise restricted to Nuclear Middle America. Honduras is an area severely affected by amphibian population decline, with close to one-half of the amphibian fauna threatened, endangered, or extinct. The principal threats to the survival of members of the herpetofauna are uncontrolled human population growth and its corollaries, habitat alteration and destruction, pollution, pest and predator control, overhunting, and overexploitation. No Honduran amphibians or reptiles are entirely free of human impact. A gauge is used to estimate environmental vulnerability of amphibian species, using measures of extent of geographic range, extent of ecological distribution, and degree of specialization of reproductive mode. A similar gauge is developed for reptiles, using the first two measures for amphibian vulnerability, and a third scale for the degree of human persecution. Based on these gauges, amphibians and reptiles show an actual range of Environmental Vulnerability Scores (EVS) almost as broad as the theoretical range. Based on the actual EVS, both amphibian and reptilian species are divided into three categories of low, medium, and high vulnerability. There are 24 low vulnerability amphibians and 47 reptiles, 43 medium vulnerability amphibians and 111 reptiles, and 50 high vulnerability amphibians and 53 reptiles. Theoretical EVS values are assessed against available information on current population status of endemic and Nuclear Middle American taxa. Almost half (48.8%) of the endemic species of Honduran amphibians are already extinct or have populations that are in decline. Populations of 40.0% of the Nuclear Middle American amphibian species are extirpated or in decline. A little less than a third (27.0%) of the endemic reptiles are thought to have declining populations. Almost six of every ten (54.5%) of the Nuclear Middle American reptilian species are thought to have declining populations. EVS values provide a useful indicator of potential for endangerment, illustrating that the species whose populations are currently in decline or are extinct or extirpated have relatively high EVS. All high EVS species need to be monitored closely for changes in population status. A set of recommendations are offered, assuming that biotic reserves in Honduras can be safeguarded, that it is hoped will lead to a system of robust, healthy, and economically self-sustaining protected areas for the country’s herpetofauna. These recommendations will have to be enacted swiftly, however, due to unremitting pressure from human population growth and the resulting deforestation.Se discute el estatus de conservación de los miembros de la herpetofauna de Honduras. Basados en el crecimiento presente y proyectado de la población del ser humano, se propone que toda la fauna herpetológica de Honduras está en peligro de extinción. Lo que se conoce de la fauna herpetológica hondureña en el presente consiste de 334 especies, incluyendo 117 anfibios y 217 reptiles (incluyendo seis reptiles marinos, que no se discuten en este artículo). La mayoria de las especies se presentan en bajas y moderadas elevaciones en formaciones forestales de tierras bajas y/o húmedas, en las Cordilleras Septentrional y Meridional de la Serranía, y las áreas ecofisiográficas de la costa y las faldas de la montaña del Caribe. Un poco mas de un tercero de la fauna herpetológica consiste de especies endémicas o sino de esas especies restringidas al Mesoamérica Nuclear. Honduras es una área severemente afectada por la disminución de las poblaciones de anfibios, con cerca de la mitad de la fauna anfibia amenazada, en peligro, o extinta. Las principales amenazas a la sobreviviencia de los miembros de la fauna herpetológica son el crecimiento sin control de la población humana y sus vástagos, la alteración y destructión de habitación, polución, el control de pestes y predadores, el exceso de caza y explotación. Ningun anfibio o reptil hondureño está totalmente libre de el impacto humano. Se ha desarrollado una regla de medir para estimar la vulnerabilidad ambiental de las especies de anfibios, usando medidas de extensión del rango geografíco, amplitud de distribución ecológica, y estado de especialización del modo de reproducción. Se ha desarrollado una medida similar para los reptiles, usando las dos primeras medidas de vulnerabilidad usados con los anfibios, y una tercera medida para el grado de persecusión humana. Basados en estas medidas, los anfibios y reptiles muestran un rango actual de una marca de vulnerabilidad medioambiental (EVS) casi tan amplia como el rango teorético. Basados en la EVS, ambas especies de anfibios y reptiles están divididas en tres categorías, de baja, media, y alta vulnerabilidad. Hay 24 especies de anfibios y 47 de reptiles de baja vulnerabilidad, 43 especies de anfibios y 111 de reptiles de media vulnerabilidad, y 50 especies de anfibios y 53 de reptiles de alta vulnerabilidad. Teoréticamente, los valores de EVS son determinados de acuerdo de información disponible del estado presente de las taxas endémicas de Mesoamérica Nuclear. Casi la mitad (48.8%) de las especies endémicas de anfibios hondureños están ya extintos o tienen poblaciones en disminución. Poblaciones de 40.0% de las especies de anfibios de Mesoamérica Nuclear están extintas o en disminución. Un poco menos de un tercio (27.0%) de los reptiles endémicos se piensa que tienen poblaciones en disminución. Casi seis de cada diez (54.5%) de las especies de reptiles de Mesoamérica Nuclear se piensa que tienen poblaciones en disminución. Los valores de EVS proporcionan un indicador utíl del riesgo potencial, el cual muestra que las especies cuyas poblaciones actuales están disminuyendo, o son extintos o extirpados tienen EVS relativamente altos. Todas las especies con un EVS alto necesitan ser observadas de cerca para anotar los cambios en el estado de las poblaciones. Ofrecemos un grupo de recomendaciones, asumiendo que las reservas bióticas de Honduras pueden ser preservadas, se espera que esto resulte en un sistema de áreas protegidas que es robusta, saludable, y sostenible economicamente para la fauna herpetológica del país. Estas recomendaciones tienen que ser observados rapidamente, debido a la presión continua causada por el crecimiento de la población humana y la resultante destrucción de los bosques

AMPHIBIAN AND REPTILE COLONIZATION OF RECLAIMED COAL SPOIL GRASSLANDS

While habitat loss is a major driver of amphibian and reptile declines globally, a subset of post-industrial landscapes, reclaimed and restored, are creating habitat for these animals. In a previous work, we showed that amphibians and reptiles use reclaimed and restored grasslands. In the present work we quantify captures at drift-fence/pitfall trap arrays over two consecutive years and show that several species of amphibians are not only successfully reproducing but that juveniles are being recruited into the population. In particular, 15,844 amphibians and 334 reptiles representing 25 species (14 amphibians, 11 reptiles) were captured at drift fences in 2009 and 2010. Nine additional reptile species were found opportunistically while conducting other research activities at the study site. Out of a total of 8,064 metamorphosing juveniles we detected 126 malformations, a 1.6% rate. The major malformation types were limbs missing (amelia) or foreshortened (ectromely), eye discolorations, and digits foreshortened (ectrodactyly) or small (brachydactyly). Our data show that reclaimed, restored, and properly managed landscapes can support reproducing populations of amphibians and reptiles with low malformation rates, including species in decline across other portions of their range

Loathsome Beasts: Images of Reptiles and Amphibians in Art and Science

The mythology and symbolism historically associated with reptiles and amphibians is unequaled by that of any other taxonomic group of animals. Even today, these creatures serve as icons - often indicating magic or evil - in a variety of media. Reptiles and amphibians also differ from other vertebrates (i.e. fish, mammals and birds) in that most have never been valued in Europe as food or for sport. Aside from some limited medicinal uses and the medical concerns related to venomous species, there was little utilitarian value in studying the natural history of reptiles and amphibians. Because of this history and other characteristics of these animals, the images of reptiles and amphibians played a unique role in the study of natural history from the Medieval through the Early Modern periods. The images I will discuss come from books that have been analyzed by other scholars, but in most cases there has been little or no scrutiny of the portrayal of the herpetofauna. Because much of my research as a biologist has focused on reptiles and amphibians, I will consider their differences from mammals and birds. In doing so, I will address image content from a somewhat different point of view than that of an art or science historian. My contention is that understanding the evolving portrayal of these “loathsome beasts” is particularly useful in tracing the development of the study of natural history. I also will address how changes in these images over time reflect a transformation in how nature was viewed and valued in western European culture. [excerpt

Reptile scale paradigm: Evo-Devo, pattern formation and regeneration

The purpose of this perspective is to highlight the merit of the reptile integument as an experimental model. Reptiles represent the first amniotes. From stem reptiles, extant reptiles, birds and mammals have evolved. Mammal hairs and feathers evolved from Therapsid and Sauropsid reptiles, respectively. The early reptilian integument had to adapt to the challenges of terrestrial life, developing a multi-layered stratum corneum capable of barrier function and ultraviolet protection. For better mechanical protection, diverse reptilian scale types have evolved. The evolution of endothermy has driven the convergent evolution of hair and feather follicles: both form multiple localized growth units with stem cells and transient amplifying cells protected in the proximal follicle. This topological arrangement allows them to elongate, molt and regenerate without structural constraints. Another unique feature of reptile skin is the exquisite arrangement of scales and pigment patterns, making them testable models for mechanisms of pattern formation. Since they face the constant threat of damage on land, different strategies were developed to accommodate skin homeostasis and regeneration. Temporally, they can be under continuous renewal or sloughing cycles. Spatially, they can be diffuse or form discrete localized growth units (follicles). To understand how gene regulatory networks evolved to produce increasingly complex ectodermal organs, we have to study how prototypic scale-forming pathways in reptiles are modulated to produce appendage novelties. Despite the fact that there are numerous studies of reptile scales, molecular analyses have lagged behind. Here, we underscore how further development of this novel experimental model will be valuable in filling the gaps of our understanding of the Evo-Devo of amniote integuments