Ninety years and 535 miles : vegetation changes along the Mexican border.

Auteur :
HUMPHREY, R. R.

Description :
Photographs taken in 1892-1893 of the United States-Mexico international boundary monuments in the Chihuahuan and Sonoran Deserts were compared to repeat photos taken 90 years later as a way of determining vegetation changes. Many areas that supported grasses then now support only scrub due to grazing pressures and possibly increased aridity. - (DWG)


Type de document :
Monographie

Source :
nombre de pages : 448, Références bibliographiques : 62 réf.

Date :
1987

Identifiants :
isbn : 0-8263-0945-3

Editeur :
Pays édition : Etats-Unis, Albuquerque, University of New Mexico Press