MICROCLIMATE AND VEGETATION EDGE EFFECTS IN A FRAGMENTED PODOCARP-BROADLEAF FOREST IN NEW-ZEALAND

Microclimate (photosynthetically active radiation; air temperature; vapour pressure deficit) and vegetation edge effects were investigated in five podocarp-broadleaf forest fragments in the North Island of New Zealand Distinct forest edge microclimate regimes were found to exist for part of the year and these were associated with differences in vegetation composition and structure between the forest edge and interior. Some species-specific edge/interior differences could be related to timing of critical life history stages (e.g. germination and early establishment) relative to the temporal stability of edge microclimate regimes. Penetration of gross microclimatic edge effects was approximately 50 m regardless of fragment size. These results suggest that regularly shaped forest fragments < 9.0 ha are dominated by edge patterns and processes and that below 1.0 ha fragments do not support forest interior conditions or vegetation associations.