Fig 1.
Second Pennsylvania Breeding Bird Atlas point count locations within the estimated range, delineated by dashed lines, of an example species, the Kentucky Warbler (Geothlypis formosa).
The inset depicts landscapes of multiple spatial scales centered on a count location. Land cover is from the 2006 National Land Cover Database [51].
Table 1.
The magnitude and spatial scale of the effect of urbanization intensity on the occurrences of forest bird species in Pennsylvania (USA).
Models of occurrence also accounted for other aspects of landscape heterogeneity, local habitat quality, and species detectability. Effect size was calculated as the model-averaged β coefficient of urbanization intensity at its scale of effect using models with ΔAIC ≤ 2. The sample size (N) for each species is the number of point locations surrounded by landscapes with radii equal to the scale of effect. Landscapes that intersected the state border were excluded from analyses, resulting in different numbers of landscapes at each scale.
Fig 2.
The effects of species traits on the magnitude of forest bird responses to urbanization intensity in Pennsylvania, USA.
Traits are those in the best models among models that included only traits with positive adjusted R2 values in univariate regressions or models that included only traits with values for all species. The larger effect is shown for traits included in both sets of best models.
Table 2.
The best models of the effects of species traits on the magnitude of forest bird responses to urbanization intensity in Pennsylvania, USA.
Evaluated models included traits with positive adjusted R2 values in univariate regressions.
Table 3.
The best models of the effects of species traits on the magnitude of forest bird responses to urbanization intensity in Pennsylvania, USA.
Evaluated models included traits with values for all species.
Fig 3.
The effects of species traits on the spatial scale of forest bird responses to urbanization intensity in Pennsylvania, USA.
Traits are those in the best models among models that included only traits with positive adjusted R2 values in univariate regressions or models that included only traits with values for all species. The larger effect is shown for traits included in both sets of best models.
Table 4.
The best models of the effects of species traits on the scale of effect of forest bird responses to urbanization intensity in Pennsylvania, USA.
Evaluated models included traits with positive adjusted R2 values in univariate regressions.
Table 5.
The best models of the effects of species traits on the scale of effect of forest bird responses to urbanization intensity in Pennsylvania, USA.
Evaluated models included traits with values for all species.