Nitrogen dynamics in an Alaskan salt marsh following spring use by geese
-
-
Authors: A. B. Zacheis, R. W. Ruess, and J. W. Hupp
Date: 2002
Journal: Oecologia
Volume: 130
Number: 4
Pages: 600-608
Summary of Methods: The effects of lesser snow geese and Canada geese grazing and trampling on nitrogen cycling and availability in the salt marsh communities of Upper Cook Inlet, Alaska (61° 15' N, 150° 30' W) were investigated . Paired plots were used to compare actively grazed sites to sites that had been excluded from grazing for at least 3 years. Net nitrogen mineralization, organic nitrogen pools and production, nitrogen fixation by cyanobacteria, soil temperature, moisture, salinity, pH, bulk density, C, N and C:N and litter characteristics were measured in the spring.
Article Summary / Main Points: The spring grazed areas had a higher rate of net nitrogen mineralization but organic nitrogen availability was not affected. Litter accumulated in exclosures, whereas, goose trampling increased litter integration into the soil and reduced litter accumulation on grazed plots. Therefore, grazing and trampling increased N pools and decreased soil C:N ratio, establishing an environment where N mineralization was enhanced. Bacterial N fixation and fecal deposition were greater on grazed plots and may have also altered N cycling. However, the effects of these factors appeared to be minimal compared to the effects of trampling in this environment on the nitrogen dynamics of the system, followed by nitrogen fixation leaving fecal input with little importance and influence.
Vegetation Types: Riparian and Wetlands
MLRA Ecoregions: Not Applicable
Agrovoc Control Words: Marshes Grazing Wildlife
Article Review Type: Refereed
Article Type: Experimental Research
Keywords: herbivory, nitrogen fixation, nitrogen mineralization, organic nitrogen, trampling
Annotation: Similar to previous studies of Zacheis et al. (2001, 2002) (RSIS database), the results of this replicated study conducted over three years are applicable to subarctic and arctic salt marshes and wetlands. As is true for all grazing research, the results are most directly applicable to areas with similar landscapes, similar goose species, and weather conditions. Grazing was not controlled by researchers; sites were only classified as grazed or ungrazed. The lack of a control or ungrazed pasture limits the strength of the findings and the strength of generalized statements made. Examination of various levels of goose grazing intensities and seasons of use on plant communities in different sites is needed. The results were analyzed only for spring season. Zacheis et al. (2001, J Ecol, 89:57-71) study examined the effects of annual browsing by migrating snow and Canadian goose on two salt marsh vegetation communities (herb and sedge meadow) and Zacheis et al. (2002, EcoScience, 9:320-331) studied the impacts of goose herbivory on plant biomass, tiller density, and tissue nitrogen concentration of salt marsh communities, also available within the RSIS database.
-
Get article
Cite article with DOI
-