Vascular plants and plant habitats of Brush Creek Island, Lewis County, Kentucky, U.S.A.

A descriptive survey of the vascular flora and plant habitats of Brush Creek Island, a 6.7-ha Ohio River island in Lewis County, Kentucky, was conducted during 1995–1996 and 2012. Brush Creek Island (BC), one of three Ohio River islands politically a part of Kentucky, is currently under private ownership and projected as a future part of the Ohio River Islands National Wildlife Refuge. Two major habitats in 2012 were Vegetated Unconsolidated Shoreline and Bottomland Hardwood Forest, a final sere of Late Old Field and Immature Bottomland Hardwood Forest. Two additional 1996 habitats, a seasonal Riverine Emergent Wetland and Late Old Field, were altered through fluvial action and secondary succession processes by 2012. An annotated list consists of 330 species in 220 genera from 82 families. Taxa are composed of one Monilophyte, four Magnoliids, 76 Monocots, and 249 Eudicots. Ninety-three taxa (28.2%) are non-native adventive or naturalized spe-cies. Forty-eight taxa (54%) are classified as Kentucky invasive plants. A total of 189 species (57.3%) are hydrophytes. Ninety-five native or non-native taxa (28.8%) are Lewis County distribution records.

Diversity or Redundancy in Leaf Physiological and Anatomical Parameters in a Species Diverse, Bottomland Hardwood Forest?

Research Highlights: Bottomland hardwood forests exhibit seasonal flooding, are species diverse, and provide numerous ecosystem services including floodwater storage, wildlife habitat and nutrient mitigation. However, data are needed to adequately predict the potential of individual species to achieve these services. Background and Objectives: In bottomland hardwood forests, increasing tree species richness may increase functional diversity unless species exhibit an overlap in physiological functioning. Therefore, the objectives of this study were to (1) compare physiological and anatomical leaf parameters across species, (2) determine if leaf anatomical and nutrient properties were correlated with physiological functioning, (3) determine intra-species variability in leaf stomatal properties and determine how whole crown metrics compare with leaves measured for gas exchange and (4) measure soil nitrogen for evidence of denitrification during inundation periods. Materials and Methods: We measured gas exchange, leaf nutrients and anatomical properties in eight bottomland hardwood species including Carya ovata, Fraxinus pennsylvanica, Quercus michauxii, Quercus nigra, Quercus pagoda, Quercus phellos, Ulmus alata and Ulmus americana. Additionally, we quantified soil ammonium and nitrate content during winter inundated conditions to compare with non-inundation periods. Results: We found that leaf-level water use parameters displayed greater variability and diversity across species than photosynthesis and leaf nitrogen parameters, but green ash and shagbark hickory exhibited generally high leaf N concentrations and similar physiological functioning. Elms and oaks displayed larger variability in leaf physiological functioning. Stomatal density was significantly correlated with photosynthetic capacity and tree-level water use and exhibited high intra-species variability. Conclusions: This bottomland hardwood forest contains more diversity in terms of water use strategies compared with nitrogen uptake, suggesting that differences in species composition will affect the hydrology of the system. Green ash and shagbark hickory exhibit higher leaf nitrogen concentrations and potential for nutrient mitigation. Finally, leaf anatomical parameters show some promise in terms of correlating with leaf physiological parameters across species.