Contribution of poplar plantations to bird conservation in riparian landscapes

Abstract

In Mediterranean areas, riparian zones are particularly important for maintaining biodiversity. Nevertheless,�thenativevegetationinthesezoneshasbeenmodifiedorlostatanalarmingrate � duringthelas tdecades . �Themainobjectiveofthiss tudyw astoinves tigatetheinfl uenceofpoplar� plantations on bird diversity in riparian zones, in order to estimate the ecological implications of a substantial expansion of poplar plantations. Breeding birds were sampled by the point-count method in twenty-four poplar plantations of I-214 clone, according to a factorial design combining stand age and understory management. Furthermore, the three native riparian forests remaining in the study area were also surveyed. Explanatory variables included (1) dendrometric, (2) understory and (3) landscape variables within six different radii of circular buffers. The species richness and abundance index were higher in riparian forests than in poplar plantations. Landscape variables (percentageofpopl arpl antationsi nt hesurroundi ngl andscape) �st ronglyi nfluencedbi rddi versity � in poplar plantations. Furthermore, at the local scale, understory cover was also a key factor in shaping bird assemblages. This suggests that poplar plantations should not be used as surrogates for native forests. Nevertheless, poplar plantations can still accommodate rich communities of forest bird species, providing that suitable management is applied at local and landscape levels.