Bothriechis bicolor (Bocourt, 1868)

Clause, Adam G., Luna-Reyes, Roberto, Lang, Noé Jiménez, Oca, Adrián Nieto-Montes de & Hernández, Luis Alberto Martínez, 2020, Problems with imperfect locality data: distribution and conservation status of an enigmatic pitviper, Amphibian & Reptile Conservation (e 246) 14 (2), pp. 185-197 : 192

IUCN Status of B. bicolor

Our recommendation to re-categorize B. bicolor from Least Concern to Vulnerable on the IUCN Red List of Threatened Species reflects advances in our understanding of its distribution, and the threats facing the species. We estimate the current extent of occurrence (EOO) and area of occupancy (AOO) for B. bicolor at 6,400 km 2 and 108 km 2, respectively. These estimates are well within the minimum thresholds for Vulnerable categorization, which are not exceeded even if all seven problematic localities for B. bicolor are added. Importantly, this estimated AOO value actually lies within the minimum threshold for Endangered categorization (AOO <500 km 2). However, we consider our estimated AOO to be artificially low due to the severe lack of survey effort across intact, remote habitat within our estimated EOO. To ensure that our recommendation remains robust to future discoveries, we consider it premature to advocate for Endangered categorization. Regarding population size, we infer a reduction exceeding 30% within three generations, coupled with severe fragmentation of the range of this species and declines in habitat quality. We coarsely estimate generation length as 10 years for B. bicolor , based on available data for Crotalus o. oreganus and other Bothriechis spp. ( Campbell and Lamar 2004; Maida et al. 2018). Widespread, historical deforestation is continuing across the range of B. bicolor ( Campbell and Lamar 2004; Campbell and Muñoz-Alonso 2014; Cortina-Villar et al. 2019; Godínez-Gómez and Mendoza 2019; Elsen et al. 2020). This continuing forest loss even affects protected areas inhabited by the species, either because some land conversion remains legal within park boundaries or because socioeconomic issues prevent enforcement of forest protections ( Figueroa and Sánchez-Cordero 2008; Acevedo et al. 2010; García-Amado et al. 2013). Additionally, recent climate change models for the Mexican portion of the Sierra Madre de Chiapas forecast over 90% loss of montane cloud forest by 2080 ( Ponce-Reyes et al. 2012; Rojas-Soto et al. 2012). Across the entire mountain range, similar range reductions for hypothetical species are predicted due to climate change ( Elsen et al. 2020). Climate change also exacerbates human-caused wildfires that likely impact western B. bicolor populations ( Johnson et al. 2010; Myers 2011). The adaptability of B. bicolor probably modulates these pressures, given that it can persist in coffee fincas and often occupies montane moist forests below the cloud forest belt ( Campbell and Lamar 2004; Acevedo et al. 2010; Johnson et al. 2010). However, fearbased killing of B. bicolor in coffee fincas, plus possible illegal collecting for the pet trade, negatively effects some populations to an unquantified degree. Although substantial uncertainty exists, we infer that observed and predicted habitat degradation coupled with targeted removal of individual snakes across the small range of this species justifies its threatened status.