ABSTRACT
Resumen Entre los impactos negativos sobre la biodiversidad que causan las obras viales, como las carreteras, se tiene la mortandad de fauna por atropello. En el presente estudio se determina la mortandad de anfibios, reptiles, aves y mamíferos por atropello, en tres carreteras que confluyen en el distrito de Tambogrande (Piura en el norte de Perú) y establecer los sitios de mayor incidencia. Los datos se colectaron entre enero y junio de 2018 en 24 recorridos una vez por semana entre las 7:00 y 14:00 horas. Los recorridos se realizaron sobre una moto lineal a 25 km/h, los datos registrados fueron coordenadas geográficas del punto de atropello principalmente. La mortandad de vertebrados en los transectos se analizó usando el Índice Kilométrico de Abundancia. Los sitios de alta incidencia de atropellos se determinaron con un análisis de densidad de Kernel. Se hallaron 437 animales atropellados pertenecientes a 29 especies. Los animales atropellados más abundantes fueron los mamíferos seguidos de aves, reptiles y anfibios. El IKA promedio fue de 0.2 (IC 95% 0.1 - 0.3) N° de atropellos/Km. Se presentaron 24 puntos de alta incidencia en el área de estudio cercanos entre sí. Utilizando la información de este trabajo se sugiere construir ocho pasos de fauna para vertebrados según estándares internacionales y complementados con señalética adecuada.
Abstract Among the negative impacts on biodiversity caused by road works, such as road and highways, are the killed caused by collisions with vehicles. In this study, the mortality of amphibians, reptiles, birds and mammals by collision with vehicles is determined, on three roads that converge in the Tambogrande district (Piura in northern Peru), and the places with the highest incidence are established. Observations were between January and June of 2018 with a frequency of 24 trips once a week between the hours of 7.00 and 14.00. The trips were taken on a motorcycle at 25 km/h. Geographical coordinates of the point of collisions were recorded. The vertebrates mortality in transects lines was analyzed using the Kilometric Abundance Index (KAI). High incidence places were determined with a Kernel Density Analysis. 437 animals were found dead corresponding to 29 species. The animal group most affected was mammals followed by birds, reptiles and amphibians in that order. The mean KAI was 0.2 (95% CI 0.1 - 0.3) N° of incidences/km. We determinate 24 points of high incidence, they were close to each other. Based in our results, we propose to build eight animal crossing structures for vertebrates complemented with appropriate transit signals.
ABSTRACT
In 2018, the Mexican Caribbean coast received a massive influx of pelagic Sargassum spp. that accumulated and decayed on beaches producing organic decomposition products that made the water turbid and brown. Between May and September of the same year there were several reports of mass mortality of marine biota in this area. From these reports we estimate that organisms belonging to 78 faunal species died as result of this event, with demersal neritic fish and Crustacea being the most affected groups. The cause of mortality appears to be the combined effect of high ammonium and hydrogen sulfide concentrations, together with hypoxic conditions. If massive arrival of pelagic Sargassum spp. continues and algae is left to decay on the beach in large volumes then deterioration in water quality could affect coral reefs close to shore. Furthermore, barriers placed in lagoons to intercept the Sargassum spp. before it reaches the beach could impact reef fauna if the algae is left to die and sink on site.
