Geology topics

W. P. Johnson

Publications and source records attributed to W. P. Johnson.

2 recordsLinked to original sources

USGS2022

Using automated telemetry to identify population connectivity and migration phenology of Snowy Plovers breeding in the Southern Great Plains

Within-breeding season movements have not been quantified for Snowy Plovers ( Charadrius nivosus ) breeding on the Southern Great Plains (SGP), where suitable breeding habitat can range from less than 10 km to more than 600 km apart. This mosaic distribution of discrete patches of breeding habitat, combined with weather stochasticity and low densities of Snowy Plovers in Texas and New Mexico, increases the risk of local and regional extirpation. Further, little is known about SGP Snowy Plover migration phenology or winter habitat. We used the Motus Wildlife Tracking System to examine population connectivity, migration phenology, and winter habitat locations of adult Snowy Plovers in the SGP. Movements of Snowy Plovers during the 2017 and 2018 breeding seasons suggest little to no connectivity between the Salt Plains National Wildlife Refuge population in Oklahoma and populations in Texas and New Mexico. However, several Snowy Plovers in Texas moved to a lake formed by freshwater springs that may have provided higher-quality breeding and foraging habitat. Migrating primarily at night, we found that Snowy Plovers from a breeding area in Oklahoma made migratory movements to Texas and the Louisiana Gulf Coast. These data may be important to long-term conservation and planning efforts relative to understanding regional persistence and connectivity among breeding populations of Snowy Plovers in the SGP. Our results also highlight the need for future studies of wintering habitats used by SGP Snowy Plovers.

Journal of Field Ornithology↗

USGS2020

Detectability and abundance of snowy plovers at Salt Plains National Wildlife Refuge, Oklahoma

In the past two decades, Salt Plains National Wildlife Refuge has been increasingly recognized as important habitat for both breeding and migratory shorebirds. North American snowy plovers Charadrius nivosus in particular rely on the nearly 5,000-ha salt flat at Salt Plains National Wildlife Refuge, which thousands use as breeding and stopover habitat. Elsewhere on the Southern Great Plains, decadal declines up to 75% within snowy plover subpopulations have been documented and attributed to vegetation encroachment, increased rates of nest predation, and decreased availability of fresh surface water. Despite many attempts to estimate this species' abundance across the continent, to date, no known attempt at distance sampling of snowy plovers has occurred. To address this paucity of data, we assessed feasibility of distance sampling methods to accurately estimate snowy plover abundance and detectability. Distance sampling surveys (2017–2018) indicated high detection probability ( P = 0.80) and the population abundance estimate across the salt flat extrapolated to 3,307 individuals. The distance-sampling population abundance estimate is lower than population abundance estimates determined by two previous studies within the past decade but far greater than 2,105 estimated for a study in 2006. Overall, distance sampling snowy plovers at Salt Plains National Wildlife Refuge proved to be an effective addition to pre-established survey protocols but further investigation is needed to compare accuracy and precision of methods used in this study, annual surveys conducted by Salt Plains National Wildlife Refuge, and other potential snowy plover surveys.

Oklahoma↗