The standing mean of leaf variable-i (SLi, [i]) is given by (6) SL i = LD i / Δ T where Δ T is the length of the leaf growth period.
We used generalized linear mixed models (GLMM) fitted by the Laplace approximation with an assumed quasipoisson distribution and a log-link [38] to test for the effects of vertebrate exclusion on leaf damage (mean damage of leaf area and mean number of holes per leaf) by taking repeated samplings into account.
The exclusion of vertebrate predators led, in all cases, to a greater mean damage of leaf area and larger mean number of holes per leaf, suggesting that birds and bats significantly reduced the number of leaf-chewing arthropods and thus herbivory (Table 1 and 2).
In mature trees, the mean damage of leaf area (34%, Table 2) and mean number of holes per leaf (45% increase, Table 2, Fig. 2) were significantly higher on the Schwäbische Alb than in Hainich-Dün.
We show that the software provides an efficient and accurate means of analysing leaf area in large datasets in an automated or semi-automated work flow.
On young oaks, mean damage of leaf area (40%, Table 2, Fig. 1A) and mean number of holes per leaf (29% increase, Table 2, Fig. 1B) were significantly higher in netted trees than in controls.
Mean densities of leaf beetles and predators were compared between habitats using t-tests (PROC MEANS in SAS).
Similarly, on mature trees, mean damage of leaf area (Schwäbische Alb 23%, Hainich-Dün 44%, Table 2, Fig. 1A) and mean number of holes per leaf (Schwäbische Alb 16% increase, Hainich-Dün 39% increase, Table 2, Fig. 1B) were significantly greater within the exclusions than on control trees.
Most studies and available data on leaf deposition have been related to mean values of leaf surface pollen density over varied time periods.
In this example, the resulting expected mean value of leaf deposition close to the source (in-field conditions) is estimated to be 434 n/cm2 (326 n/cm2 × 1.33).
