Caging orchids after disturbance

Transect 9 was burnt in autumn 2014, and a caged-uncaged experiment in 2014-15 provided some evidence that cages protect plants in the newly burnt habitat. In 2015-16, we used a new stratified random allocation for cages to replicate the experiment. The results were very clear that cages made no significant difference to leaf emergence, flowering or fruiting outcomes.

Overall, the results of 2015 caging experiments are consistent and emphatic: caging has no effect on the grazing of plants, at least as measured by complete loss of leaves or flower stems. We have examined the direct observations of leaves as being grazed or ungrazed during the monitoring in very early season, early season and flowering time. This provides no evidence that caging protects the leaves. We have also compared leaf measurements between consecutive visits, and this also provides no evidence that caging protects the leaves. Finally, the direct observations of flower stems being grazed also provides no evidence that caging protects the flower stems.

These results are not consistent with some of our prior results that showed a benefit from caging immediately after disturbance. The stratification method employed for the first time is likely to have minimised some unwanted variation that was observed in 2014. As with all experiments that are repeated in different seasons and circumstances, it may be possible to piece the evidence together to form a more coherent picture over time.

Disturbance map 2015

Location map showing orchid transects at Rubicon. Map data: Google