Geology topics

Brock Geary

Publications and source records attributed to Brock Geary.

3 recordsLinked to original sources

USGS2025

Piping Plover home ranges do not appear to be impacted by restoration of barrier islands and headlands

Restoration of barrier island and headland habitats can alter existing and create new habitats, which may impact wildlife occupying these areas such as the threatened Piping Plover ( Charadrius melodus ). We used resight data from banded birds to develop minimum convex polygon (MCP) and kernel density estimates (KDE) of individual Piping Plover home ranges to investigate whether changes in habitat use resulted from restoration activities at Whiskey Island and Caminada Headland, Louisiana. We quantified home range areas for each season and compared changes among pre-restoration, active restoration, and post-restoration phases at each site. We had sufficient sample sizes from Whiskey Island to compare home ranges derived by MCP during the pre-restoration phase to the active restoration phase. However, we did not have enough resight data to analyze post-restoration phase by MCP or any phase by KDE at Whiskey Island. For Caminada Headland, we were able to compare all phases of restoration using MCP, but only had sufficient data to compare pre-restoration and active restoration phases using KDE. Aside from one significant decrease in core (50% isopleth) home range at Caminada Headland when comparing MCPs between post-restoration (∼8 ha) and pre-restoration (∼11 ha) phases, we found no other differences in home range size across phases at either of our study sites. The sum of all evidence generally indicating no change to Piping Plover home range size suggests that barrier island and headland restoration did not have significant positive or negative impacts. The weak response to restoration activities further suggests that birds are using similar or smaller amounts of habitat after restoration is complete and may not need to expand their foraging range following restoration. Further study can help to understand how species of conservation concern respond to coastal restoration efforts, which is critical for establishing comprehensive conservation strategies aimed at species recovery.

BioRxiv↗

USGS2025

Understanding abundances and behaviors of shorebirds in coastal Louisiana

Barrier islands provide resources and ecological services that are integral to economic and environmental interests, such as protection of coastal infrastructure and provision of wildlife habitat. Over time, barrier islands may become eroded and experience land loss, which can require management actions to restore island integrity. Barrier island restoration can create or modify habitats, which can impact the organisms depending on them. Our objective was to understand how the abundance and behaviors of a suite of shorebird species responded to restoration and habitat factors at two restored sites in coastal Louisiana (USA). For five focal species, we used abundance from the breeding and non-breeding seasons as well as breeding, foraging, and maintenance behaviors as response variables in boosted regression tree models to determine the importance of various geospatial and remotely sensed predictor variables related to restoration. Across sites and species, remotely sensed variables, particularly a brightness index, tended to be more important than restoration phases as predictors of bird abundance and behavior. Our results suggest that sediment composition, moisture, and vegetative cover are related to shorebird coastal habitat selection, although the direction and strength of relationships differ among these variables and our focal species. Tying these remote sensing metrics to restoration design and management actions can help land managers better understand factors that attract and benefit birds. Additional research can advance understanding in how remote sensing can be used to monitor the availability of functional habitats for shorebirds.

BioRxiv↗

USGS2025

Early season tropical cyclones affect birds breeding on a barrier island

Animal populations often experience acute natural disturbances, most of which are connected to short—term weather events. Occurrences of early—season tropical cyclones during the peak of the avian breeding season are likely to increase with climate change, which can substantially impact populations of coastal breeding birds at multiple scales. To understand the acute impacts of severe tropical cyclones, we investigated how abundances of breeding birds changed before and after 4 early season named tropical cyclones on a barrier island in the Gulf of Mexico. We detected a change in pre— versus post—storm numbers of breeding birds after 2 out of 4 storms between 2015–2020. Following Tropical Storm Cindy and Hurricane Barry, significant declines in breeding adults ranged from a reduction of 32 Willets ( Tringa semipalmata ) to 105 Wilson’s Plover ( Anarhynchus wilsoni a) and 18 Willets to 1,794 Black Skimmer ( Rynchops niger ), respectively. The lack of response following 2 storms was likely due to the location of the storms relative to the island. Following the 2 storms that did elicit a response by breeding birds, we observed lower abundances in the majority of species after the storm passed. Species life histories and habitat restoration might explain the species—specific responses we observed. Our study documents occurrences of early—season tropical cyclones negatively affecting coastal breeding birds, which could be exacerbated with sea level rise. Additionally, our findings may provide insights regarding island design and nest susceptibility to flooding events, which may aid land managers as well as conservation and restoration planners.

Louisiana↗