The contribution to annual mortality of migrating monarch butterflies (Danaus plexippus) due to collisions with vehicles is poorly understood but likely significant. Recent estimates based on a study in Texas suggests that mortality during autumn migration may be of the order of 2 million per year or about 3% of the population. However, MaxEnt models used in that study are not well suited to quantifying mortality at hotspots where monarchs are concentrated by topography such as canyons when crossing highways. Potentially catastrophic mortality could occur at such sites if timing of migration and weather conditions conspire to force a large proportion of the migrating population across highways at low altitude. We investigated monarch mortality 15 October to 11 November, 2018 at two highway crossings in northeastern Mexico known for their frequent and extensive collisions (La Muralla and Santa Catarina). During a 15-19 day period of migration, we collected dead and injured monarchs along a series of 500 m roadside transects. We estimated a minimum total mortality during fall migration at just these sites of about 196,560 individuals. Monarchs exhibited a diurnal pattern of passage at Santa Catarina of peaks in late morning and late afternoon. Average vehicle speeds exceeded posted 60 km/h limits designed to protect monarchs, ranging from 75.1 to 99.6 km/h at La Muralla and 86.6 to 106.8 km/h at Santa Catarina. We recommend finer-scale documentation of migration pathways and an inventory of significant highway crossing hotspots for monarchs during fall migration in northeast Mexico. Mitigative measures could include better enforced vehicle speeds at least during the short period of migration, deflection structures to raise the height of crossing monarchs, and/or manipulation of habitat to lower the potential for monarchs descending to roost near key crossing points.

Monarch butterflies (Danaus plexippus) fuel their migration and overwinter energy needs through accumulated fat stores derived from plant nectars. Determining origins of these fuels is crucial to effective conservation programs. We used stable-hydrogen (δ 2 H) and carbon (δ 13 C) isotope measurements in stored lipids of monarchs raised under laboratory conditions as a proof of principle for the isotopic spatial sourcing of stored lipids. We then applied this approach to wild specimens collected from 2015 to 2018 to infer spatial information on nectaring by fall migrants through northeast Mexico and at the Mexican overwinter sites. Migrating monarchs derived from wide geographic natal origins but lipid δ 2 H values from migratory cohorts were not related to natal origin. Instead, migrants exploited isotopically similar nectar sources. Distributions of lipid δ 2 H values in overwintering monarchs were broader and more negative by ∼40 suggesting more transport of lipids from higher latitudes or additional nectaring while migrating at higher elevations though northeastern to central Mexico. Our work establishes a new isotopic technique for tracking origins of stored lipids in monarchs and other migratory animals and emphasizes the importance of nectar availability in the southern portion of the range, and especially the nectar corridor through central Mexico.

No abstract

Recibido el 11 de marzo de 2015; aceptado el 30 de septiembre de 2015 Disponible en Internet el 26 de febrero de 2016 ResumenPresentamos los primeros registros de jaguar Panthera onca (Carnivora: Felidae) para el Parque Nacional Cumbres de Monterrey, Nuevo León, México. Entre los años 2013 a 2015 se colocaron cámaras trampa en los bosques templados del parque. Se obtuvieron 15 fotografías y 7 vídeos de varios individuos de la especie, que evidencian la presencia de una población dentro del parque nacional y que representa la población residente de jaguares más al norte de su área de distribución, por la vertiente del golfo de México. Por esta razón resulta necesario fortalecer acciones de protección ambiental para asegurar la conservación de esta población como: promover el pago de servicios ambientales, implementar el pago del seguro ganadero, capacitar a comités de vigilancia comunitarios y atender las denuncias sobre conflictos por depredación de ganado doméstico en esta área. Derechos Reservados © 2015 Universidad Nacional Autónoma de México, Instituto de Biología. Este es un artículo de acceso abierto distribuido bajo los términos de la Licencia Creative Commons CC BY-NC-ND 4.0. AbstractWe present the first records of jaguar (Panthera onca) in Cumbres de Monterrey National Park, Nuevo León, Mexico. We placed remote cameras between 2013 and 2015 in oak forest habitats of the Park and obtained 15 pictures and 7 videos of 4 different individuals of the species. Our results constitute the first evidence of a resident population of jaguars in this protected area and the northernmost population of the species along the Gulf of Mexico. Strenthenging of conservation measures such as environmental services compensation, livestock compensation programs, conflict management and law enforcement are

No abstract