A possible experimental artefact associated with leaf tethering in crab herbivory studies

The rate at which crabs consume leaves and propagules in mangrove forests is often measured by tethering the leaves of propagules to the forest floor using a lengths of nylon fishing line. This technique was used to estimate rates of crab consumption of leaves of Avicennia marina in two temperature mangrove forests near Sydney, Australia. Rates of herbivory were low compared to those in tropical forests. An experimental artefact was identified, in that unbaited lines were also found trailing down burrows, suggesting that tethers may be inadvertently intercepted by crabs.