Behavioral Responses of Black Bears to Gypsy Moth Infestation in Shenandoah National Park, Virginia

1994 ◽  
Vol 9 ◽  
pp. 461 ◽  
Author(s):  
John W. Kasbohm ◽  
Michael R. Vaughan ◽  
James G. Kraus
Keyword(s):  
Gypsy Moth ◽  
National Park ◽  
Behavioral Responses ◽  
Black Bears ◽  
Shenandoah National Park

Food habits and nutrition of black bears during a gypsy moth infestation

1995 ◽  
Vol 73 (9) ◽  
pp. 1771-1775 ◽  
Author(s):  
John W. Kasbohm ◽  
James G. Kraus ◽  
Michael R. Vaughan
Keyword(s):  
Gypsy Moth ◽  
Food Habits ◽  
National Park ◽  
Crude Protein ◽  
Ursus Americanus ◽  
Substantial Reduction ◽  
Black Bear ◽  
Black Bears ◽  
Phytolacca Americana ◽  
Shenandoah National Park

During 1988–1991 we determined food habits and indices of diet quality for a black bear (Ursus americanus) population in Shenandoah National Park, Virginia, experiencing a severe gypsy moth (Lymantria dispar) defoliation event, and compared the results with data collected prior to defoliation (1982–1984). Gypsy moth infestation resulted in extensive summer overstory canopy loss and a complete acorn failure in affected areas. As in predefoliation years, analysis of scats collected during defoliation indicated that bears ate primarily herbaceous vegetation in spring, followed by squawroot (Canopholis americana) and fruits of black and sweet cherry (Prunus serotina and P. avium) in summer. However, in early and late fall bears switched from consuming predominantly acorns before defoliation to pokeweed (Phytolacca americana) berries and grapes (Vitis spp.), respectively, during defoliation. Despite acorn loss, no decline in dietary nutritional quality was observed in comparisons of the percentages of crude protein, crude fat, and crude fiber in seasonal diets before and during defoliation. When it is available, bears can successfully exploit soft mast as a fall food source and do not necessarily experience a substantial reduction in food quality if acorn crops fail.

scholarly journals Computation and Visualization of Regional-Scale Forest Disturbance and Associated Dissolved Nitrogen Export from Shenandoah National Park, Virginia

2001 ◽  
Vol 1 ◽  
pp. 539-547 ◽  
Author(s):  
Keith N. Eshleman ◽  
Daniel A. Fiscus ◽  
Nancy M. Castro ◽  
James R. Webb ◽  
J Jr. Deviney
Keyword(s):  
Gypsy Moth ◽  
Computer Animation ◽  
National Park ◽  
Forest Disturbance ◽  
Regional Scale ◽  
Forested Watersheds ◽  
Shenandoah National Park ◽  
Dissolved Nitrogen ◽  
Second Growth ◽  
Forest Streams

Long-term watershed research conducted in Shenandoah National Park (SNP) in Virginia and elsewhere in the eastern U.S. indicates that annual export of dissolved nitrogen (N) from gaged forested watersheds to surface waters increases dramatically in response to vegetation disturbances. Dissolved N leakage is a common, well-documented response of small forested watersheds to logging in the larger region, while recent defoliation outbreaks of the gypsy moth (Lymantria dispar) larva in the deciduous forests of SNP have been shown to generate similar biogeochemical responses. A recent modeling analysis further suggests that a parsimonious, empirical, unit N export response function (UNERF) model can explain large percentages of the temporal variation in annual N export from a group of small gaged forested watersheds in the years following disturbance. The empirical UNERF modeling approach is completely analogous to the unit hydrograph technique for describing storm runoff, with the model representing annual N export as a linear deterministic process both in space and in time. The purposes of this analysis are to (1) test the applicability of the UNERF model using quarterly streamwater nitrate data from a group of ungaged watersheds in SNP; (2) demonstrate a park-wide application of a regional UNERF model that references the geographic distributions of bedrock geology and the timing and extent of gypsy moth defoliation over the entire SNP area; and (3) visualize the temporal and spatial patterns in vegetation disturbance and annual dissolved N export through the use of computer animation software. During water year 1992, the year of peak defoliation, our modeling study suggests that park-wide export had transiently increased by 1700% from a baseline rate of about 0.1 kg/ha/year. SNP forests appear to be characteristic of other N-limited second-growth forests in the eastern U.S. that leak little N under undisturbed conditions, despite receiving relatively large inputs of N from atmospheric deposition sources. Vegetation disturbances can apparently cause major changes in N input-output balances with potentially important ramifications for low-order forest streams and downstream receiving waters.

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