Geology topics

Michael J. Budd

Publications and source records attributed to Michael J. Budd.

3 recordsLinked to original sources

USGS2025

Rallus elegans (King Rail) occupancy is stable, but habitat is in short supply in the Arkansas Delta

Secretive marsh birds experienced precipitous declines due to losses in wetland habitat across North America. However, from 1998 to 2004, wetland area increased, and between 2009 and 2019, the extent of emergent wetlands did not significantly decrease. This raises the question: how did secretive marsh birds, which are tied to emergent wetlands, respond to this period of relative stability in wetland area? Here, we use Rallus elegans (King Rail) occurrence data collected in 2005, 2006, 2012, and 2017 in the Arkansas Delta in the United States to test the hypothesis that a period of stability in wetland vegetation is linked to stable Rallus elegans occupancy. Specifically, we sought to (1) quantify relationships between R. elegans occupancy and land cover, (2) quantify temporal trends in R. elegans occupancy, and (3) characterize changes in land cover types linked to R. elegans occupancy. We developed spatial multi-season occupancy models, and our top model contained the categorical year effect but showed no trend in R. elegans occupancy between 2005 and 2017, instead showing high interannual variation in occupancy. We found strong associations between R. elegans occupancy and emergent wetlands (positive) and elevation (negative). From 2005 to 2017 in the ∼3.7 million ha Arkansas Delta, rice crop cover decreased by 294,750 ha, emergent wetlands increased by 6,719 ha, and all other cover types increased or decreased by < 7,500 ha. Thus, although emergent wetlands did increase, the total area of emergent wetlands in 2016 (22,262 ha) comprised <1% of the Arkansas Delta. Our results support the hypothesis that R. elegans occupancy stabilized during a time when the main habitat type R. elegans depend on, emergent wetlands, also stabilized in spatial extent. There is an opportunity to turn the tide in R. elegans declines by conserving extant emergent wetlands and creating new emergent wetlands.

Arkansas↗

USGS2011

Status and distribution of breeding secretive marshbirds in the Delta of Arkansas

We surveyed the Lower Mississippi Alluvial Valley of Arkansas ("the Delta") during the breeding seasons of 2005 and 2006 using the national marshbird monitoring protocol for secretive marshbirds. We detected and documented breeding by Podilymbus podiceps (Pied-billed Grebe), Ixobrychus exilis (Least Bittern), Rallus elegans (King Rail), and Gallinula chloropus (Common Moorhen). We detected but did not document breeding by Botaurus lentiginosus (American Bittern), Porphyrula martinica (Purple Gallinule), and Fulica americana (American Coot), all of which have been documented to breed in the Delta. Our estimated occupancy rates for breeding marshbirds in the study area ranged from a low of 6% for the King Rail in 2006 to a high of 27% for the Least Bittern in 2005. The range of these occupancy rates are low and reflect the rarity of secretive marshbirds in the Delta. Secretive marshbird occupancy rates were higher in the southern third of the Delta, probably because wetlands were more abundant or of higher quality there.

Southeastern Naturalist↗

USGS2010

Habitat use by Least Bitterns in the Arkansas Delta

Least Bittern ( Ixobrychus exilis ) occupancy surveys were conducted in the Arkansas Delta, USA, during April-July 2005-2006 to determine the proportion of area occupied and relate occupancy to habitat characteristics. Previous large-scale surveys indicated few Least Bitterns were present in the Delta. During surveys at 190 sites, Least Bitterns were detected at 15 sites in 2005 and at 16 sites in 2006. Several candidate models were tested to explain occupancy based on habitat variables. Emergent vegetation cover was positively related to occupancy while the proportion of forest within 400 m of a survey site was negatively related to occupancy. The study suggests that managing the breeding habitat of Least Bitterns for emergent vegetation cover and controlling forest cover near occupied sites may contribute to this species' recovery throughout its range.

Waterbirds↗