The impacts of water buffalo and cattle ranching on the Lower Amazon floodplain: An ecological and socio-economic comparison

Ranching is the dominant land use activity on the floodplains of the Brazilian Amazon. The proliferation of cattle and water buffalo on floodplain ecosystems has generated interest in their production capacities and management, as well as concern about their socio-economic and ecological impacts on the floodplains of the Brazilian Amazon. The goals of this dissertation are to: (1) report the production and management characteristics of cattle and water buffalo ranching on floodplains in the Lower Amazon, Brazil; (2) document the habitat and forage selection of free-ranging cattle and water buffalo on floodplain ecosystems; (3) quantify the effects of cattle and water buffalo on floodplain forest structure, light environment, and soil physical properties; and (4) determine the effect of soil compaction and percent canopy openness on the growth of floodplain tree seedlings.; Based on the results of survey with floodplain ranchers, it was found that the management of water buffalo was nearly identical to that of cattle, with the exception that water buffalo were kept grazing on floodplain ecosystems significantly longer than cattle.; Cattle and water buffalo activity in floodplain forests was related to changes in floodplain forest structure, vegetation composition, and soil and light properties. Forest stands with different intensities of cattle and water buffalo activity were inventoried to determine the relationship between livestock use and soil physical properties, canopy openness, and vegetation composition and structure. Livestock activity was negatively related to seedling and sapling density, and positively related to soil bulk density, soil compaction, and canopy openness. In stands with heavy livestock activity, low adult tree stem diversity was found, yet no significant differences in stem diversity were found between stands with moderate and light livestock activity.; Soil compaction and percent canopy cover affected the growth of floodplain tree seedlings in the floodplain forests. Based on results from a 2 x 2 factorial experiment, seedlings were found to generally grow best in areas with uncompacted soil and “high” light environments. Areas with high light environments were found to contain a large percent cover of native grass species.; The rapid expansion of livestock ranching on the Amazon floodplain emphasizes the need to understand how livestock may alter ecosystems and disrupt other land-use activities in floodplain regions. (Abstract shortened by UMI.)...