Department
Renewable Natural Resources
Document Type
Dissertation
Abstract
Restoration and conservation of coastal Louisiana hinges on understanding the patterns and processes underlying habitat heterogeneity on the landscape and therefore the species that inhabits this region, including secretive marshbirds. Elusive in nature, this guild of birds has evolved under dynamic hydroperiods, and myriad plant communities present within wetlands. Only recently, however, has research focused on the role of hydrologic dynamics and vegetative structure and distribution on abundance, movement and detection of marshbirds, specifically within southeastern Louisiana. This study aimed to quantify the ecological patterns and processes, particularly hydrologic processes and landscape structure, driving breeding secretive marshbird movement, abundance and distribution across southeastern Louisiana at different spatial and temporal scales. The effects of water depths and variability on temporary emigration and detection probability of marshbirds during surveys were also quantified. Different temporal water depth and water depth variability measurements demonstrated species-specific effects on displacement and home range with strong seasonal correlations apparent. Additionally, water depths, water depth variability, and vegetation structure affected abundance, but whether positively or negatively differed by species, specifically by where marshbirds occurred on the estuarine gradient. Availability for detection increased with water depth variability in fresh marshes but availability began to decrease as salinity increased. These findings underscore the importance of dynamic processes and patterns on the landscape and the need to incorporate metrics of temporary emigration into detection probability for marshbird abundance estimates. Habitat heterogeneity in the form of proportion of temporary water, proportion of edge, flooding heterogeneity and vegetation denseness were the most informative predictors of the presence of marshbirds, outperforming salinity values for all species except clapper rail. Dynamic hydrological processes and habitat structure on the landscape play important roles in marshbird movement, abundance, and distribution but the dynamic and fluctuating landscape of southeastern Louisiana makes modeling difficult within the region, highlighting the need for multi-temporal and spatial scale variables to better understand the patterns and processes influencing marshbird use and needs.
Date
7-25-2025
Recommended Citation
Moran, Leah, "Patterns and Processes Behind Secretive Marshbird Movement, Abundance, and Distribution Across Southeastern Louisiana" (2025). LSU Doctoral Dissertations. 6877.
https://repository.lsu.edu/gradschool_dissertations/6877
Committee Chair
King, Sammy
DOI
10.31390/gradschool_dissertations.6877