Geology topics

Emily J. Lain

Publications and source records attributed to Emily J. Lain.

4 recordsLinked to original sources

USGS2026

Sediment dredging influences the seasonal biomass and community composition of microphytobenthos on a sandy shoal

Microphytobenthos on sand shoals of continental shelves support biogeochemical cycles and trophodynamics and can be affected by sediment dredging. Therefore, our goal was to assess seasonal (spring, summer, fall) microphytobenthic biomass and composition over two years (2021 and 2022) at three areas (reference, relic dredged pit, and new dredged pit) of Ship Shoal off the coast of Louisiana, USA. Surface sediment was collected for algal pigment analysis to estimate microphytobenthic biomass and community composition using high-performance liquid chromatography. The average seasonal biomass ranged from 0.2 to 16.7 μg chlorophyll a g dry sediment −1 across the three regions and was consistently high in the relic dredged pit, with peak biomass during summer 2022. All regions contained benthic diatoms, cyanobacteria, and green algae, with diatoms significantly higher in the reference shoal region compared to the other regions. Benthic cyanobacteria and green algae dominated the biomass in relic pit. Enhanced deposition of organic-rich material in the relic pit, likely drives high seasonal biomass and shifts the community to benthic cyanobacteria and green algae. New and active dredging may suppress biomass despite changes in community composition. Thus, dredging-related changes could impact the autotrophic base of the benthic food web and have potential cascading effects.

Louisiana↗

USGS2025

Blowing in the wind: Anemochory in blackbrush habitat of South Texas

Wind dispersal has the potential to carry seeds long-distances and could inform the management and restoration of natural vegetation along the U.S.-Mexico Border. Plant species with the potential to disperse seeds in arid landscapes fragmented by border barrier infrastructure include foundational native, invasive, and federally endangered plant species. Wind dispersal traps constructed of cloth were set facing into the prevailing wind direction (SE) to characterize the role of wind in transporting soil particles, pebbles, plant debris, and seeds in blackbrush habitat during maximum events of wind speed (km per hour), and precipitation (cm). Shrubs, native grasses, the invasive Pennisetum ciliare (buffelgrass), soil particles, and pebbles dispersed in the wind, especially during maximum wind and/or precipitation events. Natural blackbrush areas supported the wind dispersal of twelve native species including grasses and woody shrubs. Sites disturbed by border infrastructure (barrier, roads, waterways) had higher seed numbers of invasive species such as P. ciliare captured in the wind traps. While modifications in passages through waterways and other structures have been proposed to improve the movement of organisms influenced by the barrier, the restoration of native plant species in damaged areas might further aid in the maintenance of blackbrush ecosystems by reducing invasive plant species dispersal into natural habitats.

Texas↗

USGS2024

Review of the life history and conservation of federally endangered plant species of the Lower Rio Grande Valley, Texas, U.S.A.

This review aims to summarize information critical to the conservation of the federally listed endangered species of South Texas, which occur along the border of Texas and Mexico. This paper describes the characteristics, habitat, population status, distribution, life history, threats, and restoration of endangered plant species of the Lower Rio Grande Valley, Texas, which includes Cameron, Willacy, Hildago, and Starr County. Seven federally listed species are considered including Ambrosia cheiranthifolia, Asclepias prostrata, Astrophytum asterias, Ayenia limitaris, Manihot walkerae, Lesquerella thamnophila (syn. Physaria thamnophila), and Thymophylla tephroleuca. An eighth species, Physostegia correllii is under consideration for federal listing by the U.S. Fish and Wildlife Service. This paper assembles information on the background, biological status, major threats, and conservation to aid managers and the scientific community in restoring and managing these species.

Texas↗

USGS2023

A Buteo sp. hawk predates a hummingbird (Trochilidae) during autumn migration

Predation can play a significant role on survival during migration as birds find themselves competing for resources in unfamiliar habitats. Here we describe the first documented observation of a Buteo platypterus (Broad-winged Hawk) predating an Archilochus colubris (Ruby-throated Hummingbird) during autumn migration. To our knowledge, this is the first documented record of any Buteo sp. hawk predating any Trochilidae (hummingbird). While predation on hummingbirds likely represents a minor source of mortality, identifying sources of predation and mortality is important in understanding the risk of migration for any species.

Southeastern Naturalist↗