Managed Habitats Increase Occupancy of Black Rails (Laterallus jamaicensis) and May Buffer Impacts from Sea Level Rise

Abstract

Global wetland degradation and loss are occurring at a rapid rate, and in the United States over 50 % of wetlands in the lower 48 states have been altered since European settlement. In some cases, wetlands that were historically transformed for agriculture are now managed as wetland habitat. We conducted occupancy surveys for black rails (Laterallus jamaicensis) in managed and unmanaged areas of coastal South Carolina. We modeled landscape and local variables potentially influencing black rail occupancy and we assessed whether these habitat associations indicated vulnerability following expected alterations from sea level rise. Black rails occupied 17 of 344 surveyed sites. Landscape factors had the strongest influence on black rail occupancy. Occupancy was associated with impounded marshes, decreasing distance to forest, and greater proportion of marsh landscape within a 200 m buffer. We mapped parameters from our top model to predict the amount of current and future suitable habitat under various sea level rise scenarios at Bear Island Wildlife Management Area, a black rail hotspot. Suitable habitat decreases in tidal marshes but increases in impounded areas. The current use of impoundments by black rails could represent a new management strategy for mitigating the loss of black rail habitat.

Habitat models to predict wetland bird occupancy influenced by scale, anthropogenic disturbance, and imperfect detection

“…Our validation metrics demonstrate that our occupancy models had good predictive ability. Without accounting for imperfect detection in validation data, the predictive ability of our models was similar to those from previous studies that used spatial habitat variables (and an independent validation dataset) to predict occupancy of other rail species: black rail ( Laterallus jamaicensis , AUC = 0.70; Roach and Barrett ) and king rail ( Rallus elegans , AUC = 0.72; Pickens and King ). However, when accounting for imperfect detection in the validation data, our occupancy models had substantially higher predictive ability than models from these studies.…”

“…, Rota et al. , Pickens and King , Comte and Grenouillet , Roach and Barrett ). However, the AUC values in these studies likely underestimated the true predictive ability of the occupancy models because some unknown proportion of unoccupied sites in the validation data were actually occupied.…”

Mapping habitat suitability at range‐wide scales: Spatially‐explicit distribution models to inform conservation and research for marsh birds

“…Example analyses illustrated the assessment of changes to the occupied breeding area for black rails, and suggested their breeding range has contracted by more than 70% in the 21st century. Additional analyses with black rails also demonstrated how to pair predictive habitat models with predictions of sea level rise, and indicated that breeding habitat for this species in low-lying coastal areas is vulnerable to future changes (see also Roach & Barrett, 2015). Both of these results are particularly alarming for black rail conservation given the existing concerns over their status (Conway & Sulzman, 2007;Roach & Barrett, 2015) and the recent recommendation to list the eastern subspecies under the Endangered Species Act.…”

“…Additional analyses with black rails also demonstrated how to pair predictive habitat models with predictions of sea level rise, and indicated that breeding habitat for this species in low-lying coastal areas is vulnerable to future changes (see also Roach & Barrett, 2015). Both of these results are particularly alarming for black rail conservation given the existing concerns over their status (Conway & Sulzman, 2007;Roach & Barrett, 2015) and the recent recommendation to list the eastern subspecies under the Endangered Species Act. Yet, data-driven assessments of marsh bird distributions and range contractions over their entire breeding ranges were not previously possible, and thus our models provide the ability to quantitatively assess changes in status over time.…”

Validating dispersal distances inferred from autoregressive occupancy models with genetic parentage assignments

“…Endangered Species Act. Yet, little is known about the species' life history and demography, aside from habitat requirements, because it is so secretive (Conway & Sulzman, 2007;Eddleman et al, 1994;Richmond et al, 2010a;Roach & Barrett, 2015). Black rails are rarely seen and appear to be weak flyers; however, similar species of rails have traveled great distances to colonize oceanic islands (Ripley & Beehler, 1985;Taylor, 1998).…”