The phenology of an enclosed pasture area with specific reference to the soil-vegetation interface
Permanent link to Research Commons versionhttps://hdl.handle.net/10289/15844
Over a seven year period (1966-1972) a systematic survey was made of an enclosed pasture area on the campus of the University of Waikato, Hamilton, New Zealand. Areas of similar soil type and floral composition were used for comparison at Newstead and Tamahere. Comparisons are made with shorter-term studies at Newstead and in other countries. None of the three sites had fertiliser applied during the survey period. Apart from sampling procedures, no vegetation was removed from Hillcrest, but Newstead and Tamahere were subjected to systematic mowing. Seasonal and long-term fluctuations of populations were determined for all major faunal groups, together with seasonal and successional development of the flora. Relationships between meteorological factors, faunal and floral composition have been subjected to computer analysis. Some correlations are suggested. The emphasis in the survey has been upon the fluctuations and relationships of groups rather than the precise responses of individual species to environmental variations. Feeding experiments with fauna in the laboratory have helped to add to the knowledge of the trophic position of some New Zealand species. The results of the survey show the effects of floral competition where Holcus lanatus, Bromus unioloides and Ranunculus sardous replace rosette and soft annual plants. The rate and sequence of succession are shown. An adaptation of the Berlese extractor was developed to give indications of the vertical distribution of fauna. Long term change in faunal composition are not clearly indicated. Changes which do occur are mostly at the soil surface, reflecting the state of vegetation and litter. As a result of the extended survey, it would seem that one of the most important influences in the ecology of light loam agricultural pastures is the quality of the soil/vegetation interface. When a litter layer is retained throughout the year, faunal numbers fluctuate less rapidly and to a lesser extent than in exposed short vegetation pastures. Basically, litter acts as an ecological buffer, dampens down extremes of microclimate change, and provides a greater number of niches for soil microfauna. Where vegetation removal does not occur, small low-growing plants and seedlings are suppressed. The smothering effects of the stems and leaves from taller plants maintain the dominance of perennial species.
The University of Waikato
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