Soil-plant-herbivore interactions and nutrient dynamics in semi-arid grazing systems in northeastern Brazil and western USA

Nutrient cycling, availability, and use efficiency are key issues of sustainability and control important aspects of ecosystem function. In the series of studies in this dissertation, we evaluate how human-induced disturbances and interactions between soil, plants, and herbivores influence nutrient cycling, productivity, and ecosystem structure in semi-arid grazing systems in northeastern Brazil and Colorado, USA. We found that the presence of tree species within pastures of C. ciliaris in northeastern Brazil led to increases in soil nutrient levels, cycling rates, and availability in comparison to areas where all trees were removed. In Rocky Mountain National Park (RMNP), Colorado, we found that herbivores had a significant influence on nutrient pools, fluxes between pools, and also on ecosystem structure by possibly reducing the ability of Salix shrubs to take up N from the groundwater, which may affect the regeneration of Salix communities in that site. Overall, our findings indicate that the presence and preservation of trees or shrubs in the semi-arid grazing systems in northeastern Brazil and RMNP contributed to the maintenance of ecosystem function by increasing the capture, retention, and availability of nutrients and plant productivity in comparison to disturbed systems where the density of trees or shrubs was reduced.

Name thesis:degree_name

Doctor of Philosophy (Ph.D.)

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Soil and Crop Sciences

Grantor dc:publisher

Colorado State University. Libraries

Year dc:date.issued

1999

Authors dc:creator

• Menezes, Rômulo Simões Cezar, author
• Elliott, Edward T., advisor
• Peterson, Gary A., advisor
• Coughenour, Michael B., committee member
• Paustian, Keith, committee member

• ecology
• soil sciences
• zoology

Statement dc:rights

• Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.

Language dc:language.iso

eng, English

Identifier URI

https://doi.org/10.25675/3.026693

OAI identifier oai:identifier

oai:mountainscholar.org:10217/244027