Using lidar to detect the breeding habitat characteristics of the Cerulean Warbler (setophaga cerulea) and identify potential habitat at the landscape-level

Open Access
Author:
Carlton, Alissa Marie
Graduate Program:
Forest Resources
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
January 05, 2016
Committee Members:
  • Eric Zenner, Thesis Advisor
Keywords:
  • Cerulean Warbler
  • Setophaga cerulea
  • lidar
  • habitat selection
  • habitat model
  • suitability
  • vegetation structure
  • conservation
Abstract:
Habitat loss and degradation play a major role in the population decline of many Neotropical migrant birds. One such Neotropical migrant, the Cerulean Warbler (Setophaga cerulea (Wilson, 1810)), is a species of high conservation concern due to its significant and steady decline. Cerulean Warblers have specific breeding habitat needs, such as a diverse vegetation structure with well-established upper-canopy and understory layers along with canopy gaps. As an area-sensitive species, management of large tracts of mature forest is essential to any conservation plan. Field surveys for suitable breeding habitat at the landscape-level, however, are labor intensive and prohibitively expensive. Light detection and ranging (lidar) is a more efficient tool of describing, in fine detail, the topography and vertical vegetation structure at large scales. Metrics derived from airborne leaf-off topographic lidar were therefore combined with bird survey data from the latest Breeding Bird Atlas (BBA) to create predictive habitat models at two spatial scales for two physiographic provinces in Pennsylvania. At both spatial scales, the model demonstrated the importance of elevation, slope, aspect, and vegetative complexity to the habitat selection of Cerulean Warblers. However, the landscape-level models performed better than those at the territory-level for predicting the habitat where Cerulean Warblers were observed. At the landscape-level, differences among provinces were also noted. In the Appalachian Plateau Province study area, birds were positively associated with a denser upper-canopy than midstory, whereas in the Ridge and Valley Province study area a less dense upper-canopy and relatively more dense midstory was preferred. Overall, Cerulean Warblers were detected in areas with steeper slopes, east-facing aspects, and a more diverse vegetation structure. The latter was indicated by a greater standard deviation or interquartile distance of lidar return heights, a higher rumple index, or differences in lidar return proportions within various vegetative strata. The additional information gained from lidar could prove critical to the conservation of Cerulean Warblers and other species that rely on similar habitat by identifying potential habitat at a landscape scale while taking into consideration regional preferences.