Increasing the biodiversity in plantations of trees is an important issue because plantations have replaced many natural and semi-natural ecosystems worldwide. Therefore, identifying appropriate management techniques and key factors for enhancing biodiversity in plantations is required. We surveyed butterfly assemblages along forest trails in both plantations and natural forests and measured various environmental variables, including canopy, sub canopy and shrub stem densities, percentage of deciduous trees, flower plant richness, host plant richness, canopy openness and distance to forest edge. We hypothesized that (1) flower and host plant richness increase with an increase in the percentage of deciduous trees and canopy openness; (2) butterfly richness and abundance increase with an increase in forest structural complexity, butterfly resources, canopy openness and distance to forest edge; (3) the responses of plants and butterflies to canopy openness differ in plantations and natural forests; and (4) in plantations, tree-feeding butterflies respond to canopy openness less strongly than herbaceous plant feeding butterflies do because of the low diversity of trees in plantations. Our results generally support these hypotheses. Butterfly resources and butterfly richness and abundance all increase with increasing canopy openness; however, the increases were usually more dramatic in natural forests than in plantations and other factors are less important. In plantations, herbaceous plant feeding butterflies responded to increasing canopy openness more strongly than tree-feeding butterflies. The results of the present study indicate the importance of sunlit forest trails in enhancing butterfly resources, butterfly richness and abundance in plantations. Because at the stand-level management is labour- and cost-intensive, labour- and cost-saving trail management options need to be explored further in terms their effectiveness in increasing biodiversity in plantations.
Nest site preference of black stork nesting in the Dadia-Lefkimi-Soufli National Park, northeastern Greece was studied through the 2003 - 2004 field seasons. Seventeen nest-trees and their surroundings (0.1 ha circular plot centered at nest-tree) were described and compared to the characteristics of the same number of paired, randomly selected plots. Black storks usually nested in old pines, on branches at a mean distance 1.5 m from the trunk or against the trunk. Nest sites were located at slopes significantly steeper and significantly closer to small streams compared to random plots. The total tree density at nest sites was significantly lower and the mean canopy closure immediately adjacent to black stork nest trees was also significantly lower compared to that adjacent to the randomly selected trees. Nest sites had lower tree basal area than randomly selected sites, suggesting that the less wood volume sites were preferred for nesting by black storks in the study area.