Irene M. Rossell

The seed banks of a southern Appalachian fen and an adjacent degraded wetland

Bogs and fens are rare communities in the southern Appalachians of the USA. Many have been degraded, and little ecological information beyond cursory floral inventories is available to help guide conservation and restoration efforts. The seedling emergence technique was used to examine the soil seed banks of open and closed canopy regions of a southern mountain fen in North Carolina. We also examined the seed bank of an adjoining portion of the floodplain, which had been drained and cleared for a golf fairway and is now slated for restoration. A total of 32 taxa emerged, with graminoids (particularlyJuncus spp.) dominating all three seed banks. Seedlings were assigned to one of five plant types: woody, rush, sedge, grass, or forb. Significantly more woody seedlings emerged in soils from the closed canopy fen than in soils from the other two areas. Most rush seedlings emerged in open canopy fen soils, more sedge and forb seedlings emerged in floodplain soils, and more grass seedlings emerged in floodplain soils than in closed canopy fen soils. A discriminant function analysis separated the open canopy fen from the closed canopy fen and floodplain by seedlings of woody plants and rushes. The floodplain was separated from the open and closed regions of the fen by sedge and grass seedlings. These patterns in seed bank composition bore little similarity to the standing vegetation in the three areas. Restoration activities planned for the floodplain are intended to restore its hydrology and microtopography, which will strongly influence recruitment from the seed bank and surrounding seed sources.

Vascular Flora of a Southern Appalachian Fen and Floodplain Complex

Abstract A survey of vascular flora was completed at wetland sites in the Tulula Creek floodplain in Graham County, North Carolina as part of a comprehensive ecological study. The vegetation survey was conducted in forested and unforested fen and floodplain wetlands in 1994 and 2001, and in a forested floodplain wetland in 2001 in order to document plant species occurring in these rare mountain habitats. A total of 107 taxa representing 52 families were identified. More than 66% of the taxa also have been reported in other non-alluvial wetlands in the region; about 31% of the taxa identified in the Tulula Creek wetland complex have been reported in non-alluvial wetlands in West Virginia and about 12% have been reported in the non-alluvial wetlands of northeastern United States and adjacent Canada. This paper documented the vascular plant communities within this rare wetland complex before intensive stream restoration began in 2001.

Impacts of Dogwood Anthracnose (Discula destructiva Redlin) on the Fruits of Flowering Dogwood (Cornus florida L.): Implications for Wildlife

Abstract Flowering dogwood (Cornus florida L.) fruits are an important fall food for many species of birds and mammals throughout the eastern United States. However, the rapid spread of the fungal disease dogwood anthracnose (Discula destructiva Redlin) has caused extensive mortality of dogwoods throughout the Appalachians. We examined the impacts of dogwood anthracnose on the production of inflorescences by flowering dogwoods in western North Carolina as an indication of fruit production. We also collected ripe fruits in the fall, weighed the pulps and analyzed them for protein, lipids, Ca, K, Mg and P. Only one-third of 173 live trees flowered. Large trees were significantly more likely to flower than small trees, and as disease severity increased, the probability of flowering decreased. Neither the mean number of inflorescences per tree nor mean pulp weight differed among two size classes or three disease categories of trees. However, pulps from moderately infected trees contained significantly more Ca and P than pulps from lightly infected trees. Pulps from severely infected trees also contained higher levels of Ca than pulps from lightly diseased trees. A discriminant function analysis examining all six nutritional variables separated lightly diseased pulps from the other two categories along an axis represented by Ca, P and lipids. Moderately diseased pulps were separated from severely diseased pulps by K, P and protein. The most significant impact of dogwood anthracnose on frugivores will likely be the loss of flowering dogwoods from the landscape, with the concomitant loss of actual and potential fruit production.

The Influence of Woody Encroachment Upon Herbaceous Vegetation in a Southern Appalachian Wetland Complex

ABSTRACT Small isolated wetlands in the southern Appalachian mountain region contain a disproportionate amount of the regions rare and uncommon herbaceous species. Many of these herbaceous communities may be threatened by invading trees and shrubs. We investigated changes in vegetative communities between 1994 and 2001 and the impact of woody encroachment upon herbaceous wetland communities in a southern Appalachian wetland complex in western North Carolina. We conducted a quantitative investigation of herbaceous, shrub and tree vegetation in forested and unforested fen and floodplain wetland sites. Additionally, soil chemistry, water level and precipitation data were collected. We found that woody encroachment was the strongest predictor of diminished herbaceous wetland communities, while water levels had the strongest positive relationship with herbaceous coverage.

COLONIZATION AND ESTABLISHMENT OF RED MAPLE (ACER RUBRUM) IN A SOUTHERN APPALACHIAN WETLAND

We characterized the post-disturbance recruitment window for red maple (Acer rubrum) in a southern Appalachian wetland using size-class distributions and forest stand models. The DBH and core age of understory and overstory trees were measured in 108 plots in forested (closed) and unforested (open) fen and floodplain sites at the Tulula Creek wetland complex (a southern Appalachian wetland in Graham County, North Carolina) in 1994 and 2001 as part of a larger ecological study. In addition, the heights of red maple seedlings were measured in 379 quadrats in an unforested floodplain in 1996 and 2001. We examined the temporal patterning of wetland recruitment using red maple size-class data in order to determine (1) the recruitment window for seedling colonization and (2) temporal recruitment patterning based on the size/age structure of established tree stands. Diameter and height distribitions were compared with power function, negative exponential and quadratic models in order to determine goodness of fit using the coefficient of determination (R2). Diameter distributions and stand models showed that recruitment continued (at a diminishing rate) at sites that were last cleared 7, 14, and approximately 30 years earlier and ceased at a fourther site cleared approximately 45 years earlier. While there were minor recruitment fluctuations that possibly coincided with water-level changes, the unimodal size class distribution indicated that recruitment did not pulse subsequent to initial canopy disturbance. These results show that red maple readily colonized wetland habitats and that the recruitment window lasts at least twice as long as that reported in terrestrial systems. In addition, size-class distribution and regression analysis indicate that the colonization window is directly impacted by canopy disturbance and only indirectly influenced by water levels.

Microhabitat Selection by Eastern Box Turtles (Terrapene c. carolina) in a North Carolina Mountain Wetland

Abstract We investigated microhabitat selection by Terrapene carolina carolina in a North Carolina mountain wetland. We monitored a total of 21 radio-tagged turtles in 1997 and 1998. Turtles were located at least weekly from mid-May until they entered their overwintering sites. Microhabitat characteristics were quantified at each turtle location and at a corresponding random location < 25 m away. Weather varied during the study: 1998 was much hotter and drier than 1997. Microhabitat did not differ between males and females, except that females selected form locations with greater amounts of exposed soil. Overall, turtles constructed forms in areas that were more humid than the surrounding environment. Box turtles also used habitats with lower surface temperatures and higher humidity levels than the surrounding environment, particularly during hot and dry periods. This likely helped them regulate body temperature and prevent desiccation. During the summer of 1997 and all monitoring seasons in 1998, turtles were located at sites with moderate canopy cover and less understory plant cover than expected. Sites with less understory cover may have greater air circulation than those with more cover, thus allowing turtles to dissipate heat more rapidly. Amounts of woody debris, leaf litter, and canopy cover at turtle locations were similar to those available in the surrounding environment. Our results indicate that the attributes most important for defining the microhabitat of T. carolina (surface temperature, relative humidity, and understory plant cover) are related to thermoregulation and minimizing water loss.

Attributes of Rock Crevices Selected by Allegheny and Eastern Woodrats in the Zone of Contact in the Appalachian Mountains of North Carolina

Abstract We investigated the attributes of rock crevices selected by Allegheny (Neotoma magister) and eastern woodrats (N. floridana haematoreia) in their zone of contact in the Appalachian Mountains of North Carolina. In North Carolina, N. magister and N. f. haematoreia both occur in rocky habitats above 300 m, and are listed as species of special concern. We studied 14 active sites (N. magister: n  =  9; N. f. haematoreia: n  =  5) where woodrats had been captured 1 y prior to our study and identified to species using the mitochondrial DNA D-loop analysis. At each site, we measured the attributes of 10 crevices used by woodrats and 10 corresponding random crevices located < 15 m from each used crevice. Neotoma magister and N. f. haematoreia selected crevices with larger dimensions (height, width and depth) and more internal fissures (openings >5 cm in diameter) than those available in the surrounding environments. All crevices used by N. magister (n  =  90) and N. f. haematoreia (n  =  50) were dry. Neotoma magister were more specialized than N. f. haematoreia, as they selected crevices that were south-facing. These results suggest that both N. magister and N. f. haematoreia are habitat specialists in the southern Appalachians, preferring crevices with larger dimensions and more internal fissures to enhance their protection against severe weather and predators. The preference for south-facing crevices by N. magister suggests that they may be better adapted at surviving colder climatic conditions, thus enabling them to inhabit higher elevations in the mountains. Based on these specialized habitat preferences, we suggest that suitable rock crevices may be a limiting factor to both species in the southern Appalachians. In addition, the similarity in attributes of rock crevices selected by these species suggests that habitat is not a factor that will prevent hybridization between these species where they co-occur in the mountains of North Carolina.

The Habitat and Plant Associates of Eriocaulon decangulare L. in Three Southern Appalachian Wetlands

Abstract Eriocaulon decangulare is a wetland species that is rare in the North Carolina mountains. The mountain populations are disjunct from those in the Coastal Plain, where the species is more common. We investigated the habitat and plant associates of E. decangulare in three mountain wetlands during summer 2002. We centered 40, 0.25-m2 quadrats around randomly selected E. decangulare plants (8–20 quadrats per wetland), and estimated the percent cover occupied by all species within the quadrat. We also measured photosynthetically active radiation in each quadrat and determined the soil pH at each site. For seven plant types, only the coverage of woody plants differed significantly among sites. Most of the woody plants occurred as seedlings, small sprouts, or trailing stems. Overall, E. decangulare appeared to favor open, acidic, sunny conditions with abundant Sphagnum mosses. We documented four other unique and uncommon wetland plant species occurring with E. decangulare, and recommend continued management of all three wetlands to suppress woody species and increase the sunlight available to smaller herbaceous plants.