Assessing the extent and diversity of riparian ecosystems in Sonora, Mexico
Source: Biodiversity and Conservation, Volume 18, Number 2, February 2009 , pp. 247-269(23)
Abstract:Conservation of forested riparian ecosystems is of international concern. Relatively little is known of the structure, composition, diversity, and extent of riparian ecosystems in Mexico. We used high- and low-resolution satellite imagery from 2000 to 2006, and ground-based sampling in 2006, to assess the spatial pattern, extent, and woody plant composition of riparian forests across a range of spatial scales for the state of Sonora, Mexico. For all 3rd and higher order streams, river bottomlands with riparian forests occupied a total area of 2,301 km2. Where forested bottomlands remained, on average, 34% of the area had been converted to agriculture while 39% remained forested. We estimated that the total area of riparian forest along the principal streams was 897 km2. Including fencerow trees, the total forested riparian area was 944 km2, or 0.5% of the total land area of Sonora. Ground-based sampling of woody riparian vegetation consisted of 92, 50 m radius circular plots. About 79 woody plant species were noted. The most important tree species, based on cover and frequency, were willow species Salix spp. (primarily S. goodingii and S. bonplandiana), mesquite species Prosopis spp. (primarily P. velutina), and Fremont cottonwood Populus fremontii. Woody riparian taxa at the reach scale showed a trend of increasing diversity from north to south within Sonora. Species richness was greatest in the willow-bald cypress Taxodium distichum var. mexicanum—Mexican cottonwood P. mexicana subsp. dimorphia ecosystem. The non-native tamarisk Tamarix spp. was rare, occurring at just three study reaches. Relatively natural stream flow patterns and fluvial disturbance regimes likely limit its establishment and spread.
Document Type: Research Article
Affiliations: 1: Fort Science Center, US Geological Survey, 2150 Centre Ave., Bldg. C, Fort Collins, CO, 80526, USA, Email: email@example.com 2: Southwest Biological Science Center, Sonoran Desert Research Station, US Geological Survey, University of Arizona, School of Natural Resources, 125 Biological Sciences East, Tucson, AZ, 85721, USA 3: Environmental Research Laboratory, University of Arizona, 2601 East Airport Drive, Tucson, AZ, 85706, USA 4: Pronatura Noroeste, Juárez 8, Plaza de Armas. Apdo. P. 64, Alamos, Sonora, 85760, Mexico 5: Fort Science Center, US Geological Survey, 2150 Centre Ave., Bldg. C, Fort Collins, CO, 80526, USA 6: Angela Peralta 61, Colonia Periodista, Hermosillo, Sonora, 83156, Mexico
Publication date: February 1, 2009