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.
Sierra Madre Occidental
Aldo Leopold's son, Starker Leopold, reviews changes to the Rio Gavilan region in the northern Sierra Madre since he was a kid.
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 is described from 3 male and 3 female specimens (holotype and allotype in collection of Insti- tuto 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.
This wildfire was likely human caused and was burning in pine and oak forest primarily in the understory.
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.
We studied annual variation in reproductive activity and productivity of the Thick-billed Parrot (Rhynchopsitta pachyrhyncha) during a five year period (1997-2001), in five nesting areas at the Sierra Madre Occidental in Mexico. Two breeding areas continue to be the breeding strongholds for the species. We documented 491 nesting pairs and determined the outcome of 162 accessible nests. A nesting pair laid in average 2.7 eggs, and produced 1.6 fledlings per egg-laying pair.