The Herpetological Journal

DOI: https://doi.org/10.33256/33.1.115

pp. 1-5

Authors: Michaël A. Eijkelkamp, Mirjam J. Borger, Ruben Kluit & Jan Komdeur

Abstract: Road mortality can have a significant negative impact on amphibian population survival. Amphibian roadkill and how to avoid it are therefore widely studied, mostly on car roads but limitedly on bicycle paths. We investigated whether amphibian mortality on bicycle paths in Bargerveen, a Dutch Natura 2000 site, was affected by the number of passing cyclists and crossing amphibians. We investigated four transects on a daily basis during most of the amphibian spring migration in 2021. We counted and identified (to species level) all killed amphibians; further, we used cyclist counters and toad fences to assess the number of passing bicycles and crossing amphibians, respectively. We found 11 killed smooth newts Lissotriton vulgaris, out of 5,037 that crossed the bicycle paths. Although 11,453 anurans crossed, we found no killed anurans. The occurrence of killed smooth newts was not affected by the number of passing bicycles or crossing newts. The probability of being killed was extremely low for crossing smooth newts (0.22 %) and anurans (0 %), possibly because cyclists successfully avoid cycling over amphibians. Future monitoring should occur from early February to late November to include the complete active period of amphibians including juvenile dispersal, and across multiple successive years because amphibian numbers can vary largely between years. During our study period, however, amphibian mortality on bicycle paths in Bargerveen seems no threat to populations, despite the high numbers of cyclists. 

Keywords: road ecology, animal-cyclist collisions, smooth newts, anurans, conservation

Authors: Michaël A. Eijkelkamp, Mirjam J. Borger, Ruben Kluit & Jan Komdeur

DOI: https://doi.org/10.33256/33.1.613

pp. 6-13

Authors: Oscar Mauricio Cuellar-Valencia, Oscar Enrique Murillo-García, Gustavo Adolfo Rodriguez-Salazar, Wilmar Bolívar-García

Abstract: The use of mercury in mining gold is an illegal but still common practice in developing countries and is the world’s largest source of mercury pollution. The mercury released into the environment bioaccumulates in organism tissues due to its chemical properties and can adversely alter wildlife's neurological and reproductive systems. Frogs are susceptible to mercury contamination from gold mining because of their high skin permeability and association with aquatic environments. However, the effect of mercury pollution on direct-developing frogs is poorly known, particularly in tropical highlands. To understand the impact of mercury due to gold mining contamination on biodiversity of Tropical Andes, we assessed the bioaccumulation of mercury on direct-developing frogs of genus Pristimantis in a montane forest. We assessed bioaccumulation by comparing muscle tissue samples of frogs and sediments of streams in an area previously affected by illegal gold mining inside the Farallones de Cali National Park. Even though gold mining has not been conducted in the area for several years, we found mercury in muscle samples of direct-developing species of genus Pristimantis and alarming mercury concentrations in the sediment samples that exceed risk thresholds according international guidelines of the WHO (1.0749 μg.g-1) and countries such as Canada, USA and Brazil (0.35 μg.g-1). Our results suggest that the use of heavy metals in the gold mining can affect non-aquatic species causing bioaccumulation of heavy metals, which can be an important threat to wildlife populations, the stability of the ecosystem, and public health.

Keywords: Andean forests, mercury pollution, muscle tissue, streams pollution, sediments, total mercury

DOI: https://doi.org/10.33256/33.1.1424

Authors: Walter E. Meshaka, Jr., Eugene Wingert, Daren Riedle, Scott Boback & Daniel F. Hughes

Abstract: The demography of a painted turtle Chrysemys picta picta X C. p. marginata population from a eutrophic habitat was examined at a wetland site in south-central Pennsylvania (USA) during 2011–2019. Males reached sexual maturity at 90 mm carapace length (CL) in half the time taken, but at the same size, as painted turtles studied elsewhere in the north-eastern portion of the United States. Females matured at 130 mm CL at our site, which was larger and began at an earlier age than conspecifics. Our data corroborate findings of faster growth in C. picta juveniles resulting in earlier maturity at body sizes equal to or larger than slower growing juveniles. Our results also conform to previous findings linking wetlands altered by added nutrient input to increased growth patterns of their resident painted turtle population. Rapid growth rates for aquatic turtles are likely to become more common globally as urbanisation continues to expand and alter wetland habitats.

Keywords: Growth, population size, population structure, survivorship, urban