The Areas of Ecology, Geology, Geomorphology, and Geophysics
Conservation Strategies: Matching Science and Management
the areas of ecology, geology, geomorphology, and geophysics. Methods include pedestrian surveys to locate the surface expression of cave systems, mapping of accessible tubes segments, correlating vegetation patterns with cave morphology or species ecological requirements, and refined geophysical techniques which provide non-invasive methods of mapping habitat without disturbing either the species of concern or sensitive archaeological resources. Case studies from the islands of Hawai‘i and Kaua‘i are discussed.
Poster 67 Kristin White Escarpment Environmental Consulting, Austin, TX Comparison of the Results of a Ground Penetrating Radar and Very Low Frequency Study Used to Detect Cold Lava Tubes (potential habitat for cave-adapted species), Hualālai Volcano, North Kona, Hawai‘i. This poster presents the procedures and results of surface geophysical surveys performed at three selected parcels at Hualālai Volcano, North Kona district, Hawai‘i County (Big Island) in 2006. This study contains general information about the environmental setting, lava tube morphology, anomaly descriptions, an overview of the geophysical methods used, data acquisition parameters, processing steps, interpretations of each method, and a comparison of the accuracy of the two methods. This report will be of interest to conservation biologists who are interested in identifying potential cold lava tubes and caves that may provide habitat for cave-adapted species. Currently, several geophysical methods exist to locate subsurface voids. Each geophysical method has limitations such as resolution and depth accuracy due to geological conditions, void size, shape, and orientation. Ground-penetrating radar (GPR) and very low frequency (VLF) data were collected over known cold lava tubes (caves) and along lines both perpendicular and parallel to known lava tubes. In some places where lava tube caves are known, geophysical measurements were conducted to establish the usefulness of GPR and VLF measurements in this setting. To help identify possible voids, non- invasive geophysical methods were used to (1) characterize the presence and range of vertical/ horizontal extent of voids, (2) to identify anomalies in the field and on a site map for planning purposes, and (3) to compare the results of two different geophysical methods (ground penetrating radar and very low frequency) to look for these features.
Session VIII Tracy Wiegner1, Randee Tubal1, Richard Mackenzie2, Mark Manuel1 Water Session 1University of Hawai‘i at Hilo, Hilo, HI, 2USDA Forest Service, Institute for Pacific Islands Forestry, Hilo, HI Concentrations and Bioavailability of Organic Matter and Nutrients During Base and Storm Flow Conditions in the Wailuku River, Hawai‘i. Hawai‘i’s economy relies on the quality of coastal waters. Thus, impacts of terrestrial inputs to coastal waters need to be quantified. Hilo Bay is an ecologically, culturally, and economically important estuary that is listed as impaired by USEPA. The Wailuku River is the largest source of surface water to Hilo Bay; however, little is known about it with regards to its organic matter and nutrient loads, and their effects on Hilo Bay’s water quality. Our study examined how the quantity and quality of dissolved organic matter (DOM) and nutrients from the Wailuku River differed spatially and temporally. Water collected from forested and developed regions of the Wailuku River during base and storm flow were analyzed for DOM and nutrient concentrations. Dark bioassays evaluated DOM quality. Forested and developed sites had similar water chemistries. During storms, dissolved organic nitrogen (DON) and carbon (DOC) concentrations tripled, while nitrate decreased by a third. Distribution of N and C forms changed between base and storm flow. The N pool was dominated by nitrate during base flow and particulate N during storms. DON comprised a similar percent of the N pool under base and storm flow. The C pool was dominated by DOC during base flow and particulate C during storms. Both DON and DOC bioavailability decreased during storms. Changes in DOM and nutrient concentrations and bioavailability with rainfall suggest that their sources differ under base and storm flow conditions. Our data will be used to develop a water quality management plan for Hilo Bay.
112 2007 Hawai‘i Conservation Conference