Revista mexicana de biodiversidad ISSN: 1870-3453 ISSN: 2007-8706 Instituto de Biología Delgado-Trejo, Carlos; Herrera-Robledo, Rubén; Martínez-Hernández, Nabil; Bedolla-Ochoa, Cutzi; Hart, Catherine E.; Alvarado-Díaz, Javier; Suazo- Ortuño, Ireri; Nava-Bravo, Héctor; Lopez-Toledo, Leonel; Mendoza, Eduardo Vehicular impact as a source of wildlife mortality in the Western Pacific Coast of Mexico Revista mexicana de biodiversidad, vol. 89, no. 4, 2018, pp. 1234-1244 Instituto de Biología DOI: 10.22201/ib.20078706e.2018.4.2084 Available in: http://www.redalyc.org/articulo.oa?id=42559319023 How to cite Complete issue Scientific Information System Redalyc More information about this article Network of Scientific Journals from Latin America and the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Project academic non-profit, developed under the open access initiative Revista Mexicana de Biodiversidad Revista Mexicana de Biodiversidad 89 (2018): 1234 - 1244 Conservation Vehicular impact as a source of wildlife mortality in the Western Pacific Coast of Mexico Impacto vehicular como fuente de mortalidad de fauna silvestre en la costa occidental del Pacífico de México Carlos Delgado-Trejo a, Rubén Herrera-Robledo a, Nabil Martínez-Hernández a, Cutzi Bedolla-Ochoa a, Catherine E. Hart b, Javier Alvarado-Díaz a, Ireri Suazo-Ortuño a, Héctor Nava-Bravo a, Leonel Lopez-Toledo a, Eduardo Mendoza a, * a Instituto de Investigaciones sobre los Recursos Naturales, Universidad Michoacana de San Nicolás de Hidalgo, Ave. San Juanito Itzícuaro s/n, Col. Nueva Esperanza, 58330 Morelia, Michoacán, Mexico b Centro Universitario de la Costa, Universidad de Guadalajara, Av. Universidad de Guadalajara 203, Delegación Ixtapa, 48280 Puerto Vallarta, Jalisco, Mexico *Corresponding author: [email protected] (E. Mendoza) Received: 17 January 2016; accepted: 3 May 2018 Abstract Road construction produce abrupt changes in landscape topography, microclimate, vegetation cover and levels of traffic noise. Moreover, road networks negatively affect vertebrate abundance, population gene flow, animal behavior and individual survival. Between July 2010 and January 2011, we conducted 10 surveys of animals killed on a road in Michoacán, Mexico. We recorded a total of 314 animals killed which included: 15 species of reptiles, 13 of mammals, 9 of birds, and 1 amphibian. Mammals were the most impacted accounting for 65% of the road kills followed by reptiles (25%). Mortality concentrated on road sections combining low sinuosity with high forest cover. Of the 15 reptile species recorded, 6 were endemic and 10 were listed as globally threatened or subject to special protection in Mexico. Road killed mammals also included species of conservation concern, 3 of which were endemic to Mexico. Our findings confirm that roads are a major mortality source for wild fauna. Strategies are greatly needed, at the global and local level, to mitigate the impact of roads on biodiversity. Keywords: Human impacts; Michoacán; Road kill; Vertebrates Resumen La construcción de caminos produce cambios drásticos en la topografía, microclima, cobertura vegetal y los niveles de contaminación por ruido. Asimismo, afecta negativamente la abundancia de la fauna silvestre, el flujo génetico entre sus poblaciones, su conducta y en última instancia su supervivencia. En 10 muestreos realizados entre julio del 2010 y enero del 2011, recopilamos información sobre la mortalidad de vertebrados en una carretera de la ISSN versión electrónica: 2007-8706; Universidad Nacional Autónoma de México, Instituto de Biología. Open Access bajo la licencia CC BY-NC-ND (4.0) https://doi.org/10.22201/ib.20078706e.2018.4.2084 C. Delgado-Trejo et al. / Revista Mexicana de Biodiversidad 89 (2018): 1234 - 1244 1235 https://doi.org/10.22201/ib.20078706e.2018.4.2084 costa de Michoacán. Registramos un total de 314 animales atropellados que incluyeron: 15 especies de reptiles, 13 de mamíferos, 9 de aves y 1 de anfibio. Los mamíferos tuvieron más individuos atropellados (65% del total) seguidos por los reptiles (25%). La mortalidad se concentró en las rectas de la carretera que tuvieron una mayor cobertura de bosque a su alrededor. De las 15 especies de reptiles registradas, 6 fueron endémicas y 10 globalmente amenazadas o sujetas a protección especial en México. Asimismo, 3 especies de mamíferos fueron endémicas de México y de preocupación para su conservación. Nuestros resultados confirman la evidencia de que las carreteras son un factor causante de una alta mortalidad entre la fauna silvestre. Se requiere urgentemente de estrategias a nivel local y global que permitan mitigar este impacto. Palabras clave: Impactos humanos; Michoacán; Atropellamientos; Vertebrados Introduction on reviewing the ecological impacts of roads, included no studies from tropical latitudes (Trombulak & Frissell, Roads are an increasingly ubiquitous sign of landscape 2000; Van der Ree et al., 2011). A deeper understanding anthropization across the globe even in regions supporting of the characteristics and magnitude of road impact on very fragile ecosystems. There is no question that roads tropical wildlife is particularly urgent due to the high are an important element within territory integration, but vertebrate biodiversity and anthropogenic threat occurring plenty of evidence exists showing that their construction therein (Laurance et al., 2009). and operation bring about a myriad of impacts over natural The general goals of this study were threefold. Firstly, ecosystems and biodiversity (Laurence et al., 2014; Van to contribute with a more geographically balanced view der Ree et al., 2015). Road construction can produce of the magnitude and characteristics of wildlife mortality abrupt changes in landscape topography, vegetation cover, caused by roads. Secondly, to evaluate to what extent road microclimate, pollution inflow, hydrological dynamics, mortality contrasts among different vertebrate groups. And soil erosion, sediment deposition and traffic noise (Coffin, finally, to evaluate how different landscape and road traits 2007; Forman & Alexander, 1998; Spellerberg, 1998). affect wildlife mortality. Moreover, road networks reduce vertebrate abundance (Fahrig & Rytwinski, 2009) alter population gene flow Materials and methods (Epps et al., 2005), affect animal´s behavior (Parris & Schneider, 2009; Parris et al., 2009), increase individual´s This study was conducted on the road running along mortality (Hels & Buchwald, 2001; Taylor & Goldingay, the Pacific coastal plain in the state of Michoacán, western 2004) and favor the spread of alien species. Mexico (Fig. 1). This two-lane road crosses the municipalities Roedenbeck et al. (2007) put forward a research agenda of Lázaro Cárdenas, Aquila and Coahuayana, which are aimed at furthering our understanding about the negative located within the physiographic province of the Sierra impacts that roads have on wildlife. This agenda focused on Madre del Sur (Correa, 1974). The specific section of the the following 5 questions: 1) Under what circumstances do road we studied was the 210 km located between the towns roads affect population persistence? 2) What is the relative of Acalpican and Coahuayana (Fig. 1). This section of the importance of road effects vs. other impacts on population road is surrounded by a modified landscape consisting of persistence? 3) Under what circumstances can road effects mostly small human settlements (50-200 inhabitants) with be mitigated? 4) What is the relative importance of the the exception of La Placita de Morelos (1,500 inhabitants), different mechanisms by which roads affect population tracts of well-conserved forest, secondary vegetation and persistence? and 5) Under what circumstances do road lands destined to cattle pasture and to a variety of crops. networks affect population persistence at the landscape Monthly average temperature in this region is 26 °C and level? Over the last years several efforts have been made annual precipitation ranges from 600 to 800 mm. Main to try to answer these questions, however, we are still vegetation types found in the coastal region of Michoacán in need to obtain a more geographically balanced view include: a) tropical dry forest, b) tropical sub-deciduous of the magnitude and characteristics of the impact of forest, c) riparian forest, d) savanna, and e) wetlands. road networks on wildlife. Most of the studies currently We conducted 10 surveys to search for animals killed available have been conducted in the USA, Europe and (amphibians, reptiles, birds and mammals). All surveys Oceania, whereas studies from tropical regions are still were conducted between July 2010 and January 2011 scant. This lack of balance is exemplified by the fact that 2 early in the morning to avoid repetitive damage of animals special issues, published in 2000 and 2010, which focused by passing vehicles. The road was travelled in a vehicle 1236 C. Delgado-Trejo et al. / Revista Mexicana de Biodiversidad 89 (2018): 1234 - 1244 https://doi.org/10.22201/ib.20078706e.2018.4.2084 To analyze the relative contribution by different species of killed individuals within each vertebrate group, we constructed rank-abundance graphs (Mueller-Dombois & Ellenberg, 1974). We applied analysis of covariance to compare slopes of fitted logarithmic regression models, among species, as a way to contrast species evenness (Izsák, 2006). Moreover, we assessed the completeness of the inventory of each vertebrate group by calculating the percentage that the