• Ctenosaura acanthura. The IUCN Red List of Threatened Species 2020

      Reynoso, V.H.; Vázquez-Cruz, M.; Rivera-Arroyo, R.C.; Morales-Mávil, J.; Grant, Tandora D. (2020)
      The Veracruz Spiny-tailed Iguana is widely, but unevenly distributed along the Gulf of México versant, from the state of Tamaulipas in the north, to the edge of Tabasco in the south, México, and Huehuetenango, Guatemala. Within their range, 62% of their habitat has been converted for large- and small-scale agricultural, ranching, oil extraction, and urbanization. It is suspected there has been a decrease in the iguana population correlated with this habitat loss. Although habitat degradation is ongoing, the majority of this loss occurred more than three generations ago. This iguana seems to be distributed among isolated subpopulations, with large concentrations in some areas and rare to absent in others. Data are unavailable on the overall population size or trend. These iguanas occur in mildly human-impacted areas, such as the peripheries of crop/ranchlands and suburban areas; however, they are more vulnerable to predation by free-ranging and feral cats and dogs in these areas. Survival may be limited as a result of this predation pressure. Hunting for human food occurs mostly in the south at a moderate level; quantitative data on the extent of this threat is unknown. The occurrence of these iguanas in the international pet trade is an emerging concern. At the western end of their range, these iguanas hybridize with the central Balsas form of the Guerreran Spinytailed Iguana (Ctenosaura pectinata). Currently, they are considered Least Concern due to their extensive range and large roughly-estimated population size; however, further research on the population size, trends, natural history, and threats is needed.
    • Ctenosaura macrolopha. The IUCN Red List of Threatened Species 2020

      Reynoso, V.H.; Vázquez-Cruz, M.; Rivera-Arroyo, R.C.; Morales-Mávil, J.; Zarza-Franco, E.; Grant, Tandora D. (2020)
      The Sonoran Spiny-tailed Iguana is widely, but unevenly distributed in Sonora, Sinaloa, and a small portion of southwestern Chihuahua, México. In this area, 29% of their habitat has been converted to large- and small-scale agricultural, ranching, and urban uses. It is suspected that there has been a rate of loss in the iguana population correlated to this habitat loss; 20% of this loss occurred more than three generations ago. The population seems to be structured in small, isolated subpopulations, with large concentrations in some areas and absent in others. There are no data available on the population size, trend, or density at any locality. They are able to exist in mildly human-impacted areas, such as the peripheries of crop/ranchlands and suburban areas, however, here they are more vulnerable to predation by free-ranging and feral cats and dogs. Survival of juveniles may be limited as a result. In some regions iguanas are persecuted as a pest, while in others they are not intentionally harmed and can be found in city gardens. Hunting for human food occurs mostly for celebrations and is declining according to local interviews. There are no quantitative data on the level of this take. At the southern end of their range, these iguanas are declining in number as they hybridize with the resident Guerreran Spiny-tailed Iguana (Ctenosaura pectinata). Currently, they are considered Least Concern, but further research on the population size, trends, and threats is needed.
    • Ctenosaura pectinata. The IUCN Red List of Threatened Species 2020

      Reynoso, V.H.; Vázquez-Cruz, M.; Rivera-Arroyo, R.C.; Zarza-Franco, E.; Grant, Tandora D. (2020)
      The Guerreran Spiny-tailed Iguana is widely, but unevenly distributed throughout western México to the southern part of the Tehuantepec Isthmus in Oaxaca. In this area, 36% of their habitat has been converted to large- and small-scale agricultural, ranching, and urban uses. It is suspected that there has been a decline in the iguana population correlated with this habitat loss; the majority of this habitat loss occurred more than three generations ago. The population seems to be structured in isolated subpopulations, with very large concentrations in some areas and absent in others. There are no data available on the population trends or fine-scale density and size information. They are hunted extensively for human food, medicinal uses, and handicrafts, from wild and cultivated sources. Density has been observed to be over 100 times greater in areas where they are not hunted. The level of consumption is not fully known but estimated to be in the tens of thousands annually....
    • Efectos del manejo tradicional sobre la palma Brahea aculeata en una selva seca del sur de Sonora, México

      López-Toledo, Leonel; Espinosa-Hidalgo, Carlos; Horn, Christa M.; Endress, Bryan A. (2015)
      En este estudio se evaluaron los efectos del manejo tradicional de Brahea aculeata (Arecaceae), sobre algunos atributos funcionales (hojas totales, producción y tamaño de hojas) y demográficos (mortalidad, crecimiento y reproducción). Las hojas de la especie son utilizadas para techos de casas y artesanías; y debido al pastoreo libre de ganado vacuno en el bosque, la especie puede sufrir herbivoría. Para evaluar los efectos del pastoreo y la cosecha de hojas se estableció un experimento en la Reserva “Sierra de Álamos”, Sonora, México, en el que se simularon las diferentes prácticas del manejo tradicional. Se establecieron seis tratamientos que combinan el pastoreo (con/sin) e intensidades de cosecha (sin cosecha/baja/intensiva). En general, en palmas pequeñas (≤ 200 cm de largo de tallo), se encontraron efectos interactivos del pastoreo y la cosecha de hojas, mientras que en palmas grandes (> 200 cm) únicamente para la cosecha. En palmas pequeñas se encontraron efectos negativos en el número y tamaño de hojas; mientras que la producción de hojas, la mortalidad y el crecimiento, el efecto fue positivo. Para palmas grandes, el efecto fue positivo en todos los casos; excepto en la mortalidad, en los que no se encontraron efectos. Los efectos positivos se podrían explicar como una respuesta sobrecompensatoria en la que la pérdida de área foliar se puede suplir mediante la alteración de procesos relacionados con la fotosíntesis y/o la asignación de recursos. Este estudio contribuye con información útil para el establecimiento de un programa de manejo, basado en el aprovechamiento tradicional de la especie en el área.
    • Genetic population structure of Peninsular bighorn sheep (Ovis canadensis nelsoni) indicates substantial gene flow across US–Mexico border

      Buchalski, Michael R.; Navarro, Asako Y.; Boyce, Walter M.; Winston, Vickers T.; Tobler, Mathias W.; Nordstrom, Lisa A.; García, Jorge Alaníz; Gille, Daphne A.; Penedo, Maria Cecilia T.; Ryder, Oliver A.; et al. (2015)
      …Within the United States (US), Peninsular bighorn sheep (Ovis canadensis nelsoni, PBS) are listed as federally endangered…. Patterns of genetic spatial structure indicate gene flow throughout the ranges is common, and construction of a US–Mexico border fence or wind energy infrastructure would disrupt connectivity of the metapopulation….
    • Seed dynamics of an endemic palm in a Northwestern Mexican tropical dry forest: implications for population spatial structure

      López-Toledo, Leonel; Portillo-Cruz, Y.; Pulido, M.T.; Endress, Bryan A. (2013)
      Seed dynamics are an important part of the life history of plants and may have strong implications on abundance and spatial distribution of populations. In this study, we explored how seed dynamics (removal, predation, germination) interact with micro-environmental conditions to affect the spatial structure of populations of Brahea aculeata (Arecaceae) in a tropical dry forest. B. aculeata is distributed throughout arroyo basins and attains its highest densities near to arroyos/rivers....