Fig 1.
Map of Field Sites used in this study.
Map of forest patches (grey shaded areas) in which herbivory data were collected in 2011 and 2012. Patches are located in southern Quebec, Canada just east of Montreal. Individual size and connectivity metrics for each patch are outlined in the figure. Size is reported in hectares, and connectivity is reported as a proximity index (PROX) described in [54]. Large sites are indicated by squares, while small sites are indicated by circles. Connected sites are indicated by solid shapes, isolated sites are indicated by hollow shapes. Black shapes indicate sites that were used in both years, light grey shapes are sites that were used only in 2011, and dark grey shapes are sites that were used only in 2012. Complete site characteristics and GPS coordinates are included in S2 Table.
Fig 2.
Herbivory by patch connectivity and location within patch.
Mean herbivory index (+/-SE) for patches with different connectivities (connected vs. isolated), and for different locations within patches (edge vs. interior understory, and canopy vs interior understory). Means and standard errors are back-transformed predicted values from the mixed effects model with trees nested within patches as random effects. Significant results of multiple comparisons tests are indicated by a star (*), with Interior Connected > Edge Connected in 2011 (p<0.05), and Canopy Isolated < Edge Isolated (p<0.0001) and < Interior Isolated (p<0.05) in 2012.
Table 1.
Results of mixed effects models testing the effects of sampling period, landscape characteristics and locations within forest patches on herbivory.
Fig 3.
Herbivory by forest patch landscape characteristics.
Mean herbivory index (+/- SE) for different forest patch sizes (large vs. small) and connectivity (isolated vs. connected) for both 2011 and 2012. There were no significant differences among treatments when data for the different locations were pooled.
Fig 4.
Herbivory over the course of the sampling season.
Mean herbivory index (+/-SE) for each of 5 sampling rounds performed throughout the spring and summer in 2011 and 2012. In both years, herbivory was measured on 12 understory trees and 2 canopy trees in 20 forest patches throughout southern Quebec. There was a significant increase in herbivory with time of season in both 2011 and 2012 (p<0.0001).