Since the summer of 1999, we have been investigating the impact of the invasive hay-scented fern, Dennstaedtia punctibobula, and of various environmental conditions on salamander populations in the Allegheny National Forest in McKean County, PA. Eight established 8 X 8 meter plots are being evaluated: 2 non-invaded (no hay-scented fern) terrestrial plots; 2 invaded (with hay-scented fern) terrestrial plots; 2 aquatic non-invaded plots, and 2 aquatic invaded plots. In addition 4 random plots are established each summer: 1 non-invaded terrestrial, 1 invaded terrestrial, 1 non-invaded aquatic, and one invaded aquatic. All terrestrial plots have similar topography and all aquatic plots have similar topography.

Four sets of sixteen 6 X 8 X 1 inch untreated, pine shelving boards were placed flush with the ground under the leaf litter in each plot and the duff replaced over the boards. The leaf litter covering the boards and the area under each board was examined for salamanders each sampling period. Salamanders were collected, tallied, identified, snout to vent length measured, and gravid females noted. The salamanders and litter were then replaced as found.

Various physical parameters were measured: water and soil pH; % moisture of both litter and soil; % canopy cover; air, soil, and water temperature; and relative humidity.

The number of hay-scented fern fronds in each plot was counted and recorded. In addition an inventory of the plants in each plot was done.

The salamander species found thus far are: Mountain Dusky, Red Back, Slimy, Wehrle's, Spring, and Northern Dusky.

Summer 2002:
We concluded the four-year monitoring study in August 2002. We are currently in the process of analyzing all the data collected and preparing a manuscript for journal submission.

Undergraduate Student Researchers:
Samuel Cercone, Biology major
Allison Charney, Geology & Environmental Science major
Kris Dominy, Geology & Environmental Science major
Hope Dotter, Biology major
Tracy Guenther

Summer 2001:

A three-year summary of the relationship between an invasive fern and salamander populations in the Allegheny National Forest

by Gretchen Sterba*, Hope Dotter*, John Skinner, Dessie Severson, and Thomas Pauley, Allegheny Institute of Natural History, University of Pittsburgh - Bradford, Bradford, PA 16701

We investigated the impact of the invasive hay-scented fern, Dennstaedtia punctibobula, and selective environmental conditions on salamander populations in the Allegheny National Forest in McKean County, PA. Eight plots were evaluated: 2 terrestrial non-invaded, 2 terrestrial invaded, 2 aquatic non-invaded, and 2 aquatic invaded. In both aquatic and terrestrial plots, the soil was more acidic in the invaded than in the non-invaded plots. For the terrestrial plots a positive correlation was found between the number of Desmognathus ochrophaeus, mountain dusky salamanders, and soil pH. The mountain dusky salamander was the most abundant salamander. The terrestrial invaded sites had significantly fewer salamanders than did the non-invaded sites. Although further experiments are needed to assign cause and effect, the results of this three-year study suggest that salamanders are sensitive to conditions characterizing habitats invaded by the hay-scented fern.

Undergraduate Student Researchers:
Hope Dotter, Biology major
Tracy Guenther, Biology major
John Skinner, Biology major
Gretchen Sterba, Biology major

Summer 2000:

An Investigation of the Relationship Between Invasive Plants and Salamander Populations in the Allegheny National Forest.

by Tracy Guenther*, Star Dunham, Dessie Severson, and Thomas Pauley, Allegheny Institute of Natural History, University of Pittsburgh at Bradford, Bradford, PA 16701

We investigated the impact of the invasive fern Dennstaedtia punctibobula and selective environmental conditions on salamander populations in the Allegheny National Forest in McKean County, PA. Eight plots were evaluated: 2 terrestrial non-invaded ( = 6.0 fronds/plot), 2 terrestrial invaded ( = 409.00 fronds/plot), 2 aquatic non-invaded ( = 20.0 fronds/plot), and 2 aquatic invaded ( = 208.66 fronds/plot). In aquatic and terrestrial plots, the soil was more acidic in the invaded than in the non-invaded plots (compared with t-tests, p<0.05, df=18 for both). For the terrestrial plots a positive correlation was found between the number of mountain dusky salamanders and soil pH (r=0.501, p< 0.03, n= 21), but soil pH was negatively correlated with the number of redback salamanders (r=-0.503, p<0.03, n=21). Although further experiments are needed to assign cause and effect, these results suggest that salamanders are sensitive to conditions characterizing habitats invaded by the fern.

Undergraduate Student Researchers:
Star Dunham, Biology major
Tracy Guenther, Biology major

Summer 1999:

Salamander populations in the Allegheny National Forest: the role of bryophytes.

by Tracy Guenther and Dessie Severson, Allegheny Institute of Natural History, University of Pittsburgh at Bradford, Bradford, PA 16701

Invasive plants influence biotic diversity. Management practices in the Alleghenies have created conditions for the spread of Dennstaedtia punctilobula (hay-scented fern.) We investigated the impact of D. punctilobula on bryophyte and salamander populations in the Allegheny National Forest in McKean County, PA. Four sites were compared: one terrestrial and one seep with an average of 1.1 hay-scented fern fronds per meter squared and one terrestrial and one seep with no invasive ferns. Both seep sites had more spatial heterogeneity and greater bryophyte and salamander diversity than the terrestrial sites. The invasive-fern sites had an average soil pH of 3.91 and one third fewer Desmognathus ochrophaeus (mountain dusky salamander) and fewer bryophytes than the no-invasive-fern sites, with an average soil pH of 4.78 (t=3.44, df=18, p<0.05). The terrestrial-invasive-fern site had 34 bryophyte censuses, with none on bare soil, compared to 43 censuses, with 6 on soil, in the fern-free site.

Salamander populations in the Allegheny National Forest: the role of invasive plants.

by Eileen Burley, Mariah Peterman, Lisa Van Gorden, Dessie Severson, and Thomas Pauley, Allegheny Institute of Natural History, University of Pittsburgh at Bradford, Bradford, PA 16701

Invasive plant species can influence plant and animal diversity. Timber and wildlife management practices in the Allegheny hardwood forest have created conditions for the spread of the hayscented fern (Dennstaedtia punctilobula). We investigated the impact of D. punctilobula on salamander populations in the Allegheny National Forest in McKean County, PA. Two sites, each surrounding a seep with standing water, were compared; one site had no hayscented ferns and few other fern species, and the second site averaged approximately 1.1 hayscented fern fronds per meter squared. The soil pH at the site with high fern density was lower than at the low fern density site (t=3.44, df=18, p<0.05). The mountain dusky salamander (Desmognathus ochrophaeus) was the most abundant salamander, but the terrestrial site with more ferns had only one third as many individuals as the site lacking ferns (X^2>10; df=1, P< 0.001).

Undergraduate Student Researchers:
Eileen Burley, Biology major
Tracy Guenther, Biology major
Mariah Peterman, Biology major
Lisa Van Gorden, Biology major