Early effects of restoration practices within a historically fire-suppressed mountain longleaf pine ecosystem on vegetative and bird community structure

Background/Question/Methods Logging, land conversion, and fire suppression has decreased longleaf pine (Pinus palustris) ecosystems to only a fraction of their original range. Fire suppression, in particular, has led to overcrowding by hardwoods and litter buildup, leading to indirect effects on the native plant and animal community. In 2001, efforts were initiated to re-establish Berry College’s (Floyd County, Georgia) fire-suppressed mountain longleaf pine forest. Various management techniques have been implemented, including prescribed burning, clear-cutting, planting, and herbicide applications, in an effort to restore parts of this forest to its historically open state. Very little is known about the biotic and abiotic effects of ecological restoration in these systems. This study was designed to determine the effects of management practices thus far on vegetation structure and on the native bird community. In 2009, we collected data on vegetation structure in five (4 ha) stands in each of three management classes ranging from low to high intensity management: 1) fire suppressed (UNM), 2) hack-and-squirt herbicided/burned (HSB) and 3) clear-cut/foliar herbicided/hack-and-squirt herbicided/burned/planted (CCH). Auditory and visual bird censuses were taken six times in each study stand in summer 2009, fall/winter 2009-2010, and spring 2010. Bird species contributions to differences among management classes were evaluated using non-metric multidimensional scaling, and subsequently related to vegetative differences among the management classes.

Results/Conclusions

Based upon multiple analysis of variance, significant differences were found among the management classes for all vegetative variables except tall shrubs. There were more herbs, grasses, and small shrubs, and lower tree cover, litter cover, litter dry mass, and litter moisture level as management intensity increased. Fire suppressed stands were strongly correlated with birds of mixed woodlands. These species forage for insects on trees or within accumulated leaf litter, variables characteristic of unmanaged stands. HSB stands contained a roughly even mixture of insectivores and granivores common to open woodlands, their mixed diet supported by the relative abundance of herbaceous undergrowth and standing dead trees. CCH stands were most strongly associated with granivores of open woods and thickets. Because clear-cut stands were virtually absent of leaf litter they contained relatively fewer insectivores. The prevalent grass and shrub cover was easily conducive to granivorous activity, fostering ground dwelling birds. Severity of management was thus positively correlated with area openness, degree of undergrowth, and litter reduction, and was subsequently a major determining factor of resident bird species. Keywords: birds, ecological restoration, fire suppression, longleaf pine, management, vegetative structure.