Herpetofauna of the Mesa Tres Ríos Area in the Northern Sierra Madre Occidental of Sonora, Mexico

The Sierra Madre Occidental (SMO) extends from northeastern Sonora and northwestern Chihuahua south through western Mexico to the Transverse Volcanic Axis in the state of Guanajuato, which forms a montane bridge to the Sierra Madre del Sur to the south and the Sierra Madre Oriental to the east. All of these mountain ranges are volcanic in origin and are part of the American Cordillera that shapes the western backbone of North, Central, and South America, and Antarctica (Dickinson 2004).

The Tropical Madrean Flora of Yecora, Sonora, Mexico

The Municipio de Yécora is in the Tropical Madrean zone of the Sierra Madre Occidental in eastern Sonora, Mexico. The flora is very diverse with 1777 taxa in 150 families and 687 genera. The most important families and genera are Asteraceae (14.5% of the flora), Poaceae (11.3%), and Fabaceae (10.6%), Muhlenbergia (38 taxa), Euphorbia (31 taxa), Cyperus (29 taxa), Ipomoea (26 taxa), Quercus (23 taxa including 7 hybrids), and Dalea (22 taxa). Herbaceous plants dominate the flora (71.3%).

Northern Sierra Madre Occidental and Its Apachian Outliers: A Neglected Center of Biodiversity

The Apachian-Madrean region is a zone of confluence and geographic termini of species and floras from the north and the south. Lower and intermediate elevations support many taxa of tropical plants and animals that are at their northernmost limits. It is a region of tremendous habitat diversity and species richness. Much of the region remains little known, and quantified data are scarce. This report offers brief synopses on the insect fauna, ichthyofauna, herpetofauna, avifauna, mammals, and vegetation and flora of the region.

Comparison of the Tropical Floras of the Sierra la Madera and the Sierra Madre Occidental, Sonora, Mexico

The floras of the tropical vegetation in the Sky Island Sierra la Madera (SMA) near Moctezuma in northeastern Sonora (30°00’N 109°18’W) and the Yécora (YEC) area in the Sierra Madre Occidental (SMO) in eastern Sonora (28°25’N 109°15”W) were compared. The areas are 175 km apart. Tropical vegetation includes foothills thornscrub (FTS) in both areas and tropical deciduous forest (TDF) in the Yécora area. A total of 893 vascular plant taxa are known from these areas with 433 taxa in FTS and 793 in TDF.

Status and conservation of old-growth forests and endemic birds in the pine-oak zone of the Sierra Madre Occidental, Mexico

The pine-oak forests of the Sierra Madre Occidental, a mountain range in NW Mexico, have recently been recognized as an area of high endemism and biodiversity. Selective logging threatens three bird species endemic to this habitat, who depend on standing dead trees (snags). This report is based on an 11 month field survey that aimed to locate old- growth remnants and to assess the status of the endemic birds. Old-growth is defined here as a forest that has never been logged mechanically.

Erpetogomphus molossus, a new species from Sonora, Mexico (Odonata: Anisoptera: Gomphidae)

Erpetogomphus molossus is described from 3 male and 3 female specimens (holotype and allotype in collection of Instituto Biologico de la Universidad Nacional Autónoma de México) from the intermittent pine-oak woodland of the Yécora municipio in east-central Sonora, Mexico. Diagnostic features of the new species include the seemingly bulbous tip (in lateral view) and prominent baso-ventral process of the male cerci and the notched and denticled posteromesal corners of the female subgenital plate.

From the High Sierra Madre to the Coast in Sonora - Changes in Vegetation Along Highway 16

Scenically spectacular, the Sierra Madre Occidental is challenging to researchers in ecology as well as in geology. Like mountain gradients elsewhere in tropical Mexico, it offers a variety of habitats and species. In this section we will introduce some ecological concepts related to the description of gradients, and picture some of the major features of the vegetation that stretches along the east-west transition drawn by the highway 16 from Maycoba to Hermosillo, in the state of Sonora.