Methods
We conducted the experiment in the Maliau Basin Protected Area in a
region of lowland old growth dipterocarp forest in Bornean Malaysia (the
area is described in (Griffiths et al. 2018) and in (Ashtonet al. 2019). In order to test the method, we buried 60 green tea
bags and 60 rooibos tea bags (of a known weight) at random within the
forest at a depth of 8 cm as recommended by Keuskamp et al. (2013). We
collected 20 of each type sacrifically at 7, 14 and 60 days. We weighed
each of the bags after collection and noted if they had been chewed
opened by macrofauna. We left them out for 60 days rather than the
recommended 90 days as our preliminary work showed that by 90 days most
of the bags had holes in them and many were emptied. Keuskamp et al 2031
recommended reducing incubation time in “extreme sites… with
extremely high k values (e.g. sites with high temperature and
precipitation like site 13 in their study – which was rainforest in
Panama).
In order to examine how effective the method is in tropical rain forest,
we investigated the relationship between weight loss, the time that the
bags were left out, and whether the bags had holes in them (i.e. opened
by macrofauna). We expressed this as a % mass loss per bag, which was
logit transformed for analysis (following (Warton & Hui 2011) so that
we could use standard Gaussian linear models. Using R (R core team,
2013), we also tested the following full-interaction model, using thelm command: