SUBMERGED AQUATIC VEGETATION IN A LOW-VISIBILITY LOW-SALINITY ESTUARY IN NORTH CAROLINA: IDENTIFYING TEMPORAL AND SPATIAL DISTRIBUTIONS BY SONAR AND LOCAL ECOLOGICAL KNOWLEDGE

Abstract

The rapid loss of Submerged Aquatic Vegetation (SAV) across the globe has prompted state and federal agencies to conduct SAV inventories and develop monitoring programs, which are vital to the conservation and management of ecosystems. Due to advances in optical remote sensing technologies, the distribution and status of SAV in higher salinity, less turbid regions have been better documented than in turbid, low-salinity waters. Hence, much less is known about the status and trends of low-salinity SAV. The objectives of this dissertation were to document SAV abundance, distribution, and temporal variation in Albemarle Sound (AS), so scientists and managers can detect SAV changes through time and develop adequate management strategies. In 2014, I sampled the AS, North Carolina shoreline utilizing a single-beam sonar system. The AS rapid assessment survey (RAS), guided me to identify three large SAV beds (>10 km in length) and smaller intermediate size beds (<10 km in length) throughout the Sound, most beds shallower than 2 m. The initial RAS allowed me to establish 10 permanent sentinel sites (SS) in the Sound. The purpose of establishing these sites was to examine SAV’s spatial and temporal variation at regional (sound-wide) and local (site) scales at different depths, and to examine intra-annual variation of SAV to determine the optimal SAV sampling time. I sampled the SS for two consecutive years (2015, 2016), in the spring and fall each year. SAV abundance in AS was highly asynchronous sound-wide and by site. The biological surveys were complemented by a social science study that utilized Local Ecological Knowledge (LEK) to study SAV stakeholders’ perception about SAV and to assess their historical SAV distribution knowledge in western AS. Often, biological surveys do not go far back in time, so historical information (e.g., social surveys, interviews with fishers) can help expand our habitat knowledge beyond data collected during traditional surveys. I carried out open-ended interviews and written surveys with coastal residents, commercial fishers, and fisheries managers. The three groups had unique perspectives about SAV’s ecological value and the effect of development on SAV. The LEK historical SAV distribution closely agreed with biological distribution data.