The comparative effects of landscape-level forest fragmentation, forest area and local habitat measures on Connecticut bird communities

I studied how breeding and wintering forest bird communities across Connecticut responded to variation in habitat characteristics and particularly such landscape attributes as forest fragmentation. I surveyed birds at 1,815 points along 121 transects that traversed ca. 400 km of forest. I also made 12705 habitat measurements at survey points and computed areas of forest, non-forest, core forest and perimeter/area ratios of forest for 31,550 ha of study area. I computed sampled species richness and community density as well as individual species’ population densities for each transect. Moreover, I classified species encountered as to their nest site selection, macrohabitat use, microhabitat use, migratory strategy and trophic affiliation. Based on observations of 36,702 summering individuals of 123 species and 13,742 wintering individuals of 63 species, declines in community density occurred with increasing fragmentation although species richness was often more closely associated with ha..., I established 121 bird survey transects, with each traversing 3.2−4 km of forest depending upon terrain and other local conditions.  Each transect had 15 survey points—the maximum I could visit during the peak of morning bird activity.  Routes began at first light (05:15 in summer, 07:00 in winter) and lasted 3.5−4 hr.  I used the Variable Circular Plot (VCP) technique to survey. I computed population densities with Distance 7.3 software.
I visually evaluated habitat to a 70 m radius from each sampling station for: 1) forest type, 2) moisture regime, 3) diameter of canopy trees at breast height (dbh), 4) canopy cover, 5) understory density and 6) elevation at the location of the survey point. I also summed canopy and understory measures to provide a measure of 7) vertical vegetation complexity. To characterize the landscapes within which the survey transects were situated, I employed QGIS 3.16 geographic information systems software to analyze aerial orthophotos. I plotted the survey po..., , # The comparative effects of landscape-level forest fragmentation, forest area and local habitat measures on Connecticut bird communities

[https://doi.org/10.5061/dryad.tht76hf5v](https://doi.org/10.5061/dryad.tht76hf5v)

The dataset contains summer and winter results of variable plot surveys of birds.  Column heads for survey data are: Global =  state location; Region = NECT (northeast CT), SECT (southeast CT), CECT (central CT), NWCT (northwest CT), SWCT (southwest CT); an additional S = summer and an additional W = winter; Season = summer, winter; Transect = transect number; Station = station number along transect; Species = U.S. Fish and Wildlife Service species code; Observation = distance from survey point in m; Flock = flock size for flocking species, otherwise = 1; Forest = 1 (deciduous), 2 mixed, 3 (conifer); Moisture = 1 (hydric, 2 (mesic), 3 (xeric); dbh = 1 (< 15 cm), 2 (15-45 cm), 3 (> 45 cm); Canopy = 1 (< 40% cover), 2 (50-60% cover), 3 (> 70% cover); Underst...