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oai:mountainscholar.org:10217/2440272026-04-07T11:04:54Zcom_10217_100532com_10217_100000com_10217_100511com_10217_100303col_10217_100536col_10217_100514

Menezes, Rômulo Simões Cezar, author Elliott, Edward T., advisor Peterson, Gary A., advisor Coughenour, Michael B., committee member Paustian, Keith, committee member 2026-04-06T18:25:15Z 1999 https://hdl.handle.net/10217/244027 https://doi.org/10.25675/3.026693 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. doctoral dissertations English eng Colorado State University. Libraries 1980-1999 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. Per the terms of a contractual agreement, all use of this item is limited to the non-commercial use of Colorado State University and its authorized users. ecology soil sciences zoology Soil-plant-herbivore interactions and nutrient dynamics in semi-arid grazing systems in northeastern Brazil and western USA Text Doctor of Philosophy (Ph.D.) Doctoral Soil and Crop Sciences Colorado State University This Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). open.access