Proportion Of Acorns Research Articles

Impacts of human forest management on seed dispersal patterns by scatter-hoarding rodents

Abstract Scatter-hoarding rodents play a central role in seed dispersal, predating and dispersing seeds that affect many plant species’ population dynamics and influence forest regeneration. Anthropogenic changes in forest structure, such as clear-cutting in dense forests, may alter the ecological interactions between seeds and dispersers. This study compared predation and dispersal patterns of holm oak (Quercus ilex L.) acorns by wood mouse (Apodemus sylvaticus L.) in original dense forest [less managed forest (MF)] vs open MF (more MF) in north-eastern Spain. Results showed variations in the patterns of acorn predation and dispersal by wood mouse between forest types. In the MF, a greater fraction of acorns was harvested, and the acorns were being dispersed further than in the original forest. Despite the greater fraction of acorns dispersed in the MF, the proportion of acorns that survived and had the potential to grow was reduced in the MF because of increased predation. This shows that forest management has a significant influence on seed dispersal by rodents and thereby influences the natural regeneration potential of forests.

The effect of weevil and fungal attacks on the germination of Quercus robur acorns

Oak, Quercus robur, acorns are sometines attacked by a weevil or infested by fungi ( Murray, 1974). The number of acorns produced varies greatly from year to year. Acorns produced in the years between mast years may escape these weevil or fungal attacks, be dispersed and germinate. Acorns were collected annually from 1983 to 1989 from five oak trees in southern Sweden. The percentage of acorns attacked by a weevil or fungi, or both, were monitored and the acorns' ability to germinate was tested. Not all acorns were damaged in low crop years; the proportion of undamaged acorns varied between 33 and 69%. The proportion of weevil-attacked acorns differed significantly between the years. The proportion of acorns that were able to germinate in each category did not vary significantly between years. The germination ability was significantly higher in undamaged or fungi-infested acorns.