As herbaria collaborate to bring their collections online, we are starting to see a clearer picture of the history of biological collection efforts and the emergence of a biogeographical map of species over the recent past. Since the Louisiana State Herbarium began manually databasing in the early 1990s, it has been charting digitization efforts. Today national collection consortiums, some of which the LSU herbarium is associated, have accelerated efforts to digitize and manual databasing has become semi-automated. Currently, digitized collections at Louisiana State University Herbarium (LSU) and The Bernard Lowy Mycological Herbarium (LSUM) have increased to include 74% of vascular plants, 68% of lichens, 78% of bryophytes, and 31% of fungi, for a total collection of approximately 225,000 specimens. Georeferencing these records has just begun and will increase our spatial understanding of these collections. Though each herbarium has unique circumstances for imaging and databasing, several methods have been established at LSU in order to increase efficiencies. Overall, digitization will result in collections being studied in a whole new way as new scientific queries can be answered. Collection Consortiums are asking broad questions such as 1) effects of Climate Change on North American lichen and bryophyte distributions and 2) the impact of human land use on fungi globally. More specifically, LSU is interested in creating a regional flora and finding localities for which where there is a paucity of data in order to direct further collection efforts. In general, the efforts to digitize biological collections will increase their value and help to direct future scientific research.
Management decisions about aquatic habitats are often made based on results of biomonitoring for macroinvertebrate fauna, fish, and/or algae. We chose to assess the invertebrate community for abundance and diversity of taxa found in different aquatic habitat types. We collected freshwater invertebrates from four different kinds of vegetated habitats present in Lake Hollingsworth in Lakeland, Florida. We hypothesized that the type of habitat would affect the diversity and abundance of invertebrates living in Lake Hollingsworth. We also expected that vegetated habitats would have greater diversity and abundance of invertebrates compared to non-vegetated habitats. We found that habitat type does affect the diversity and abundance of invertebrate species. Further investigations are underway to determine seasonal shifts in community structure, geographical differences among lakes in the region, and to tease apart some of the causal processes that result in observed patterns of community structure.
Diatom Biodiversity of North Branch Pawpaw Creek, a Stream Near Reelfoot Lake, Northwest Tennessee
PawPaw Creek is adjacent to the Reelfoot Lake watershed south of Samburg, TN. Very little is known about diatom communities from Reelfoot Lake and the surrounding aquatic habitats. Our goal was to describe the diatom communities from the major microhabitats in PawPaw Creek. Qualitative samples were taken during June 2012 and 2013 from epipsammon, epilithon, epiphyton from vascular plants and epiphyton from mats of the filamentous xanthophyte alga Vaucheria. Permanent diatoms slides were made and diatom frustules from 10 transects or 300 diatom frustules from each slide were identified to species. Non-metric multidimensional scaling was performed on arcsine square-root transformed relative abundance data to assess differences in communities among microhabitats. Over 20 genera and 40 species of diatoms were identified. Gomphonema parvulum, G.truncatum var. capitata, Navicula lanceolata, Nitzschia amphibia, and Rhoicosphenia curvata were among the dominant species. Communities from inorganic substrata regardless of year were more similar to each other than they were to communities from epiphytic substrata. Communities from the two types of epiphytic substrata were similar to each other within the same year, and showed strong differences between years.
Dept of Biological Sciences, University of Tennessee at Martin, Martin, TN
P49 • Jonathan Brink, Eddie Barnett, Nicholas Stacy, Alex Collier, Brett Larson
Palatable Species of Amphibians are More Heavily Impacted by Visual and Chemical Cues of Predatory Fish
In this study, relatively unpalatable toad larvae (Bufo terrestris) and palatable leopard frogs (Lithobates sphenocephala) were reared in 20 cm diameter PVC pipes drilled with aeration holes to allow water flow. These PVC chambers were submerged in 75 L aquaria. In half of the treatments, the chambers were white, preventing any visual cues between predators and prey. A second group of tadpoles were reared in clear chambers that permitted visual cues. Predatory bluegill (Lepomis macrochirus) or largemouth bass (Micropterus salmoides) swam freely between the chambers. The predators were offered a diet of conspecific prey that they were paired with although toad tadpoles were rarely consumed. Control tadpoles were isolated in both clear and white PVC chambers in aquaria with no fish. The length (mm) and weight (g) of tadpoles were recorded at regular sampling invtervals throughout their developmental period. In both the non-visual and visual treatments, toad tadpoles did not statistically differ from control animals regardless of predator species. The most significant impact on prey growth was observed among leopard frog tadpoles reared in visual chambers with largemouth bass. These tadpoles were significantly smaller than control animals and suffered heavy mortality during the study. These results support the notion that prey palatability can affect the impact of visual and chemical cues of predatory fish.
