A community-driven general session on community ecology.
Lead Organizer: María González, Miami University (gonzalmj@miamioh.edu)
Presentations
09:00 AM
Using passive acoustic monitoring to document differences in lake soundscapes (8205)
Primary Presenter: Catherine O'Reilly, Illinois State University (oreilly@ilstu.edu)
Identifying population and community characteristics of ecosystems is often necessary for conseration and restoration. Although passive acoustic monitoring (PAM) is being used to identify features of ecological communities in terrestrial and marine environments, these approaches have not yet been widely employed in freshwater systems. Previous freshwater work wtih PAM and bioacoustic metrics has been done primarily in urban invertebrate-dominanted ponds. Here, we assessed whether acoustic indices from PAM correspond with freshwater community compositions as the North Temperate Lakes LTER site. We recorded underwater sound environments across a gradient of communities, from near-fishless bogs to larger, deeper lakes with more complex food webs. We calculated the acoustic diversity index (ADI), the acoustic complexity index (ACI), and the normalized difference soundscape index (NDSI) using 15-minute intervals of the acoustic recordings. In addition, we explored the potential for diel cycles in lake soundscapes. There were relationships between lake depth and ADI and ACI, but not with NDSI. Crystal Bog had distinct diurnal patterns, due to insect-generated sounds no audible above water. By comparing various acoustic indices across a range of lakes where community composition has been established, we determined that current terrestrial bioacoustic indices may be applicable for aquatic ecosystems.
09:15 AM
Use of Passive Acoustic Monitoring to detect diurnal and lunar fish community activity cycles in fish hatchery ponds and public reservoirs in Illinois (8235)
Primary Presenter: William Perry, Illinois State University (wlperry@ilstu.edu)
The use of sound by marine fishes to communicate has been widely studied, and we know species-specific calls are commonly used for communication. Passive sound monitors are used to assess biological activity and even ecosystem health in marine systems. However, the extent to which freshwater fishes or invertebrates use sound is relatively unknown. We used passive acoustic monitoring (PAM) of two fish hatchery ponds and two reservoirs. From these recordings, we calculated several bioacoustics indices that are commonly used in terrestrial bioacoustics monitoring, e.g., the acoustic diversity index (ADI), acoustic complexity index (ACI), and normalized difference soundscape index (NDSI). We found no significant difference in ADI, ACI or NDSI between reservoirs and the fish hatchery ponds. However, ADI and ACI were significantly higher during the full moon. ADI had higher values during the day than night, while ACI was higher during the dawn and day periods relative to night. NDSI was higher during the new moon but did not have diurnal patterns. We were also able to specifically identify fathead minnow (Pimephales promelas) sounds and identify periods when this species was active as an example of the applicability of this approach. Our results suggest that passive acoustic monitoring may be an effective tool in monitoring community assemblages in freshwater systems and even identifying individual species.
09:30 AM
Examining Temporal and Spatial Variation of Invertebrate Biodiversity in Lake Maurepas, an Oligohaline Lake in Southeastern Louisiana (8102)
Primary Presenter: Alexander Mott, Southeastern Louisiana University (alexander.mott@selu.edu)
Lake Maurepas, an oligohaline lake in southeastern Louisiana, USA, lies on the westernmost edge of the socio-ecologically important Lake Pontchartrain Basin. Relative to Lake Pontchartrain, our knowledge of the invertebrate community in Lake Maurepas is sparse. We aim to establish a baseline dataset on the spatio-temporal variability of the invertebrate community within Lake Maurepas, including shrimp, blue crabs, Rangia clams, and other benthic macroinvertebrates. Our techniques include stratified-random crab trap setting to estimate abundance and measure the width and weight of blue crabs, otter trawl pulling to investigate the nekton community, and petite PONAR grab dredging to collect benthic macroinvertebrates. We will spatio-temporally compare species richness, abundance, and community changes. Our preliminary analyses indicate interesting spatial patterns in blue crab and Rangia clam densities, and invertebrate species richness and abundance, potentially influenced by three freshwater river inflows and one channel (in- and out-flow) connected to Lake Pontchartrain—the more brackish and estuarine component of the basin. Our data provide baseline information on the diversity and abundance of invertebrates in Lake Maurepas, which is important in light of future and ongoing anthropogenic impacts on the lake.
09:45 AM
LIGHT SPECTRUM IS AN IMPORTANT DETERMINANT OF DIVERSITY AND TROPHIC TRANSFER IN FRESHWATER COMMUNITIES (8054)
Primary Presenter: Jeff Dudycha, University of South Carolina (dudycha@biol.sc.edu)
More than a century of work has shown how light availability influences differences among aquatic communities and drives the dynamics of populations they contain. But even when available, light is not uniform. Light attenuation depends on wavelength, creating wide differences in the spectrum of available light within and among waterbodies. The consequences of this spectral variation has received much less investigation than those of light availability. We sought to experimentally evaluate the potential for light spectrum to influence freshwater communities. In particular, we were interested in how light spectrum altered algal communities, whether the effect of spectrum interacted with phosphorus availability, and whether any effects reverberated up the food web through changes to trophic transfer to zooplankton. We applied four different light spectra to replicate experimental mesocosms containing an algal community derived from relatively high- and low-phosphorus lakes. We crossed light spectrum with phosphorus level to test for interactions with nutrient availability. We then used a growth bioassay with Daphnia to assess trophic transfer to zooplankton. We found that spectrum was an important determinant of both algal diversity and trophic transfer to zooplankton. Algal diversity and composition were also influenced by the interaction between spectrum and phosphorus, whereas trophic transfer to zooplankton was not affected by phosphorus or an interaction. Our results provide new insights into the effect of spectrum on multiple trophic levels in a freshwater food web.
10:00 AM
LOCAL ADAPTATION OF CHAOBORUS PUNCTIPENNIS TO SEASONAL AND CONSTANT PREDATION REGIMES (8194)
Primary Presenter: Petra Wakker, Yale University (pabwakker@gmail.com)
Species adapt to seasonality in their environment through a complex arrangement of life history events around the yearly cycle. Populations in the same climatic conditions are usually assumed to be adapted to similar seasonality. However, the behavior of other species can modify or create different seasonality in the biotic environment. We studied the adaptation of an invertebrate mesopredator, Chaoborus punctipennis, to the seasonal or constant presence of migratory and landlocked alewife, a zooplanktivorous fish. Alewife prey directly on Chaoborus larvae and strongly structure the zooplankton community when present, affecting prey availability for Chaoborus. We intensively sampled the abundance and size distribution of two populations of Chaoborus occupying one lake with landlocked alewife (constant predation and prey availability) and one with migratory alewife (highly seasonal predation and prey availability) weekly from June–October 2021, and monthly in three other lakes. We found that populations differed in their life history and morphology: Chaoborus in the lakes with migratory alewife exhibited one major reproductive event each summer, and grew to a larger terminal fourth instar size, while Chaoborus in the lakes with landlocked alewife reproduced twice a summer and reached a smaller fourth instar size. This shows that biotic seasonality can strongly and differentially structure lakes experiencing nearly identical environmental seasonality, and that this specific community context can lead to drastic differences in the characteristics of local populations.
CS09 - Community Ecology
Description
Time: 9:00 AM
Date: 3/6/2024
Room: Hall of Ideas I