The effects of simulated spring goose grazing on the growth rate and protein content of Phleum pratense leaves

Abstract

The effects of simulated goose grazing on Phleum pratense plants were tested in an Iceland hayfield during the spring goose staging period (19 April-11 May 1997). Plants in an area exclosed from the influence of grazing and the nutrient effects of goose faeces were subject to the removal of the youngest lamina once, three and four times during this period. Clipping three and four times resulted in 25-41% increases in cumulative elongation of youngest laminae compared with unclipped plants. Total cumulative lamina growth of entire plants showed no significant difference between unclipped plants and those clipped three and four times, hence no overcompensation occurred. Sequential clipping elevated the protein content of the youngest laminae from 20% to 27-33%, whereas there was no change amongst shoots clipped only once. Because geese only consume the youngest lamina of each Phleum plant, measurements from this experiment showed that regular physical removal of growing biomass doubled the biomass of preferred tissue available to geese and increased the potential protein intake 3.5 times at experimental clipping frequencies similar to levels of sequential harvesting observed amongst staging geese compared to less frequent harvesting. These increases were achieved without any fertilising effects of goose faeces implicated in such effects in previous studies.

Nitrogen dynamics in an Alaskan salt marsh following spring use by geese

“…This is in contrast to other studies that have found vegetation in grazed areas to have higher nitrogen concentrations than in ungrazed areas (e.g., Ydenberg and Prins 1981;Bazely and Jefferies 1985;Day and Detling 1990;Hik and Jefferies 1990;Fox et al 1998;Sirotnak and Huntly 2000). In several of the studies, higher shoot nitrogen concentrations in grazed areas only occurred with the addition of excreta (Bazely and Jefferies 1985;Day and Detling 1990;Hik and Jefferies 1990) and/or when vegetation was grazed multiple times by herbivores (Ydenberg and Prins 1981;Hik and Jefferies 1990;Fox et al 1998). The lack of a grazing effect on plant nitrogen concentrations in our study may possibly be explained by the minimal amounts of excreta added to grazed areas, and the fact that plants are grazed only one time during the growing season.…”

Travelling to breed

“…Effects of human disturbance (deliberate or otherwise) at restricted spring stopovers is having an impact at the population level and is a major complication in management aimed at setting defined limits on goose numbers (Calvert and Gauthier 2005). Evidence that the temporal and spatial pattern of grazing by geese at spring stopovers may have positive effects on their own food supply on the short-term (Fox et al 1998; Van der Graaf et al 2005 underlines the vulnerability of this 'fine-tuning' to external disturbance or other agents of change such as climate trends (Prop et al 1998;Tøttrup et al 2006, for an extensive overview see Møller et al 2004).…”

Staging site fidelity of Greenland White-fronted GeeseAnser albifrons flavirostrisin Iceland

“…However, it is only in the last 60 years that extensive creation of dry hayfields and the draining of wetlands has taken place on a large scale in a manner likely to affect the White-fronted Geese (Francis & Fox 1987). In recent decades, spring staging Greenland Whitefronted Geese in Iceland have increasingly used managed grasslands for food (Fox et al 1998(Fox et al , 1999b and their reliance on wetlands has decreased. Nevertheless, since farms were associated with wetlands (which in former times provided food for over-wintering livestock in the form of hay made from Carex lyngbyei), the creation of grass-sward hayfields in the vicinity of farms provides an alternative source of food for geese with established patterns of use for roost and feeding areas.…”