C. Cillero et al., Comparisons of riparian vs. over stream trap location in the estimation ofvertical litterfall inputs, HYDROBIOL, 416, 1999, pp. 171-179
Vertical inputs of allochthonous organic matter to streams can be estimated
directly with traps; traps may be placed over the stream, in the riparian
forest or at other locations in the catchment. In this study, we compared l
itter inputs estimated from traps located over the stream with those obtain
ed from traps placed on the stream bank in two stretches (orders 2 and 3) o
f the Mera stream, with similar tree species composition and riparian fores
t structure. The amount of annual litter input measured with the traps on t
he stream was similar in the two stretches, 748 and 730 g m(-2) yr(-1), for
orders 2 and 3, respectively. However, there appeared to be differences in
the composition of litter; a lower percentage of leaves and a higher perce
ntage of wood was found in the stretch of order 3 than in the stretch of or
der 2. In both sites, the mean input measured under the riparian forest was
lower than the input recorded with the traps placed over the stream by app
roximately 10%. In relation to the traps located over the stream, the traps
located on the bank overestimated the input from adjacent terrestrial tree
species and, therefore, underestimated the input from riparian species.