Treesearch

As persistent wetlands in arid regions, ciénegas represent important resources for the maintenance and preservation of regional biodiversity. The history of ciénegas in the American Southwest over the last 8,000 years provides information on the dynamics of growth, longevity, and stability of these habitats under previous climate conditions. Proxy data such as sedimentology, pollen, charcoal, and isotopes preserved in ciénega sediments provide information on the formation, disturbance, resilience and state changes within these systems. This long-term perspective is compared to the recent...

Conservation biologists, NGOs, and the USFWS have established a goal of returning a viable population of jaguars into the United States. The source population for this recovery will come from Sonora, Mexico, the closest sub-population of the species. To maintain a viable population there must be females and an active corridor that allows passage of jaguars between Sonora, Arizona, and New Mexico. While considerable attention has been paid to the corridor, little attention has been paid to the potential rate of expansion of the existing population and the importance of female jaguars to...

The Northern Jaguar Reserve is in the western foothills of the Sierra Madre Occidental and in a broad transition zone between Nearctic and Neotropical faunal realms. We have assessed the distribution and abundance of birds across all four seasons in foothills thornscrub, oak woodland, and adjacent riparian areas, and discuss issues relevant to conservation and management. Since 2007, we have observed 205 species of birds including 131 that are Neotropical migrants, 104 that likely breed on the reserve, and 35 species of binational conservation concern. Observations suggest this 20,140 -ha...

The Northern Jaguar Reserve is 50,000 acres and one of the largest privately owned wildlife preserves in Sonora. Buying land in remote parts of Sonora takes special knowledge as ownership rules may not be clear and boundaries may not be defined in the records. There are complex legal procedures to guarantee ownership in which letters of intent play a crucial role, and there are special complexities for ejido lands. In addition, only a presidential decree as a natural protected area can prevent mining in the long term. The lessons learned at the Northern Jaguar Reserve for conservation land...

To compare and contrast herpetofaunas at Ranchos Los Fresnos and El Aribabi in north-central Sonora, México, we conducted herpetological surveys during 2006-2011, contacted others working in these two areas, and queried 27 museums and collections for specimens collected at or near these ranches. Based on this work, nine and seven amphibian, and 27 and 24 reptile species are known to occur at Ranchos El Aribabi and Los Fresnos, respectively. Significant findings at Los Fresnos include presence of presumed Sonora tiger salamanders (Ambystoma mavortium stebbinsi), of which there are only...

Contemporary climate change is driving transitions in many Madrean ecosystems, but the time scale of these changes is accelerated greatly by severe landscape disturbances such as wildfires and insect outbreaks. Landscape-scale disturbance events such as wildfires interact with prior disturbance patterns and landscape structure to catalyze abrupt transitions to novel ecosystem configurations. These reorganized landscapes are characterized by new disturbance regimes and potentially dramatic departures in species diversity and distributions, community composition, carbon storage, landscape...

The Madrean Archipelago and its associated valleys have the highest diversity of lizards in the United States. This is due to a convergence of ecoregions in an area that provides excellent environmental conditions for life history needs of terrestrial ectotherms. The study area, near Safford, Arizona, is known to have about 20 species of sympatric lizards, although only about one-half are common. The lizard community is represented by species of the Sonoran and Chihuahuan deserts, semi-desert grasslands, and lower Madrean and boreal woodlands. It has recently been suggested that lizard...

Climate change is a serious immediate and long-term threat to wildlife species. State and federal agencies are working with universities and non-government organizations to predict, plan for, and mitigate such uncertainties in the future. Endemic species may be particularly at-risk as climate-induced changes impact their limited geographic ranges. The Madrean Archipelago is characterized by high levels of endemism, natural fragmentation, and increasingly poor connectivity among the mesic montane islands within an arid matrix of low elevation deserts and grasslands. The region already has...

During the first week of May 2012, the Third Conference on Biodiversity and Management of the Madrean Archipelago brought together more than 300 people with an interest in this region. It included scientists, land managers, activists, and land owners from both sides of the international border. After three and a half days of presentations, the participants gathered for a moderated discussion of major issues for biodiversity and management. They were also asked to suggest ways in which people could build stronger collaborations. The following is a summary of those discussions, with minor...

Many conservation strategies have been developed by the U.S. Fish and Wildlife Service in cooperation with others to protect habitat and enhance the recovery of fish and wildlife populations in the San Bernardino Valley, which straddles Arizona, United States, and Sonora, Mexico. Habitats along this international border have been impacted by illegal activities, frustrating recovery of rare species. In addition, potential threats to national security have prompted the United States to aggressively control the country’s boundaries, thus creating additional challenges for land managers...