Proportion Of Bird Species Research Articles

Stand-level management practices increase occupancy by birds in exotic Eucalyptus plantations

Managing for wildlife in human-dominated matrices outside natural reserves has great importance to improve the efficacy of conservation efforts aiming to protect and restore biodiversity. As such, it is critical to understand which features of the matrix enhance habitat suitability to the remaining species and also to evaluate species responses to alternative management practices. We used hierarchical modeling to estimate the effect of stand level management practices adopted in Eucalyptus plantations on site occupancy by birds while accounting for species detection failure. Our models incorporated site-specific traits, such as management practice type and landscape attributes of each sampling unit. They also incorporate species-specific traits, particularly main foraging stratum. The major factor associated with differences in site occupancy by birds within our study site is the management practice type. Scattered native trees and early successional stage understory within mature stands were associated with an increase in the proportion of bird species from the regional pool that was able to occupy the silvicultural matrix. Landscape attributes had a relatively minor effect on site occupancy in our study area. We concluded that site occupancy by birds is positively associated with increasing spatial complexity within Eucalyptus stands, with species responding to the retention of native scattered trees and understory presence. Forestry managers interested in improving the conservation value for birds of Eucalyptus plantations in tropical areas should maintain existing native trees and adopt practices that trigger understory regeneration during site preparation and stand rotation.

Birds on novel island environments. A case study with the urban avifauna of Tenerife (Canary Islands)

AbstractWe analyzed the variation in island bird communities of urban environments related to habitat characteristics, using regression/classification tree analyses. Data from field censuses in cities/towns representing the urban heterogeneity of the whole island were obtained in Tenerife (Canary Islands, Spain). Urban bird abundance in Tenerife was negatively affected by altitude and the cover of dry Euphorbia shrubs and positively influenced by the height and cover of the tree layer. Species richness was negatively associated with building cover and positively related to tree height and altitude. Data from field censuses in Tenerife were compared with that of similar urban environments in the mainland (Madrid Province, central Spain). Species diversity was higher in the urban sample of Tenerife than in that of Madrid and the proportion of bird species from the regional pool ‘captured’ by urban environments was higher in the island than in the mainland. Nine native species and three alien species were more abundant in island urban environments than in the continent (densities, at least, 100% higher), the converse occurring for only five species. At a biogeographic scale, we conclude that the avifauna of Tenerife Island is more prone to occupy a new artificial environment than the mainland bird fauna of central Spain.