Ecology and conservation of Eastern black rail: Road to recovery through management

Symposium

Organizers: Jim Lyons, USGS Eastern Ecological Science Center at Patuxent Research Refuge; Michelle Stantial, USGS; Abby Lawson, U.S. Geological Survey

This symposium will bring together ecologists and land managers to address a conservation crisis and promote research for best management practices for Eastern black rail, a small, cryptic marsh bird which historically ranged across the eastern, central, and southern United States. This species was recently listed as Threatened following population declines and range contraction in recent decades. The primary threats to the species include sea level rise, wetland loss and fragmentation, and incompatible use of prescribed fire and other habitat manipulations. Habitat requirements of this species are not well known, however, and additional research of habitat ecology and identification of best management practices are urgently needed to inform recovery planning. The first theme of the symposium is to address ecological uncertainty about habitat and populations. Speakers will present on innovative camera trap studies that are filling knowledge gaps about habitat use and nesting ecology, population and demographic studies from across the range, and species distribution modeling on the Atlantic coast. The second theme addresses management uncertainty about effective and efficient practices. Several lines of investigation with promising management actions to create and enhance habitat are ongoing. Symposium speakers will focus on applications of prescribed fire and hydrology manipulations. The third theme is to inform recovery planning with a synthesis of new knowledge of habitat ecology and habitat management practices being developed and tested to inform recovery planning, and an exploration of emerging threats, such as West Nile Virus, that may hinder recovery efforts.

 
Conservation challenges and the road to recovery through management of Eastern black rails
Jim Lyons, Abby Lawson, Michelle Stantial, Aimee Weldon
The Eastern Black Rail is a small, cryptic marsh bird which historically ranged across the eastern, central, and southern United States, and was recently listed as Threatened following population declines and range contraction. It occurs at low densities, is difficult to observe, and may be the least-studied rail in North America. The species thus presents challenges for recovery planning and conservation action that are rooted in uncertainty about population ecology and best management practices. We introduce our symposium with three themes: addressing ecological uncertainty, addressing management uncertainty, and prioritizing research and conservation for recovery planning. First, reducing ecological uncertainty will require generating new knowledge of populations and habitat requirements. Eastern Black Rails apparently prefer a specific combination of vegetation, hydrology, and topography found only in certain parts of coastal marshes and freshwater wetlands: a dense overstory of herbaceous vegetation cover, shallower water than other North American rails, and topography providing foraging micro-habitat and refuge from high water. Habitat requirements of this species are not well known, however, and seemingly suitable habitat is often unoccupied. Second, reducing management uncertainty will require new evidence of successful interventions. Prescribed fire of compatible timing and frequency, with unburned refugia, can reduce encroachment by woody vegetation and promote favored herbaceous species. Irrigation and water level management have also been used to promote shallow water conditions preferred by Eastern Black Rail. We review the history of relevant management techniques and describe the benefits of experimentation for well-informed decision making in complex ecosystems. Finally, recovery planning will require responses to historic and emerging threats. The primary threats to the species include sea level rise, wetland loss and fragmentation, and incompatible land management. Our symposium includes perspectives on emerging threats and lessons learned from conservation and management of other North American rails.
 
Eastern black rail ecology and habitat management in South Carolina
Christy Hand, Wray Gabel, Spencer Weitzel, Rachel Bonafilia, Elizabeth Znidersic, Daniel Barrineau
Coastal South Carolina is among the few remaining strongholds for the Eastern black rail (Laterallus jamaicensis jamaicensis) along the Atlantic Coast of the USA. Managed wetlands in South Carolina offer unique conservation opportunities, however, basic life history information necessary to make informed management decisions has been lacking for the subspecies. Our ongoing study was initiated in 2015 and includes the objectives of 1) determining distribution and breeding status within the state, 2) investigating breeding ecology and natural history, and 3) developing habitat management strategies to increase reproductive success and survival. The study incorporates camera trapping in addition to traditional rail research tools and techniques such as call-response surveys, autonomous recording units, water level monitoring, and vegetation sampling. As part of the first study of breeding ecology, chick development, and flightless molt phenology for the subspecies, the project has revealed nest initiation began in mid-April and fledging concluded by the end of September. Two banded males raised two or more consecutive broods within a single breeding season. Flightless molt by adults occurred between mid-August and mid-September, overlapping with peak hurricane season. Black rails in an impounded wetland initiated nesting within 3 months following fires during February 2018 and 2019, suggesting regrowth of grasses in this habitat type may occur more rapidly compared to Gulf coast marshes. Fires resulted in increased rather than decreased encroachment of woody shrubs (Baccharis halimifolia). Deeply flooding the wetland (>50 cm water depth) throughout the winter of 2020-2021 was effective at killing the majority of the shrubs and appears to be an efficient shrub management practice where feasible. In addition to refining water level management within specific impoundments, we began testing the feasibility of using irrigation to create suitable habitat conditions in wet pastures during the 2021 breeding season and will share insights from our pilot season.
 
Black Rail Habitat Requirements in Louisiana
Erik Johnson, Justin Lehman
The enigmatic Eastern Black Rail (Laterallus j. jamaicensis) has been recently added to the Endangered Species List because of apparent low population sizes and rapid declines in part of its range. Little is known about its occurrence or status in Louisiana, where over 2,000 km2 of coastal wetlands, important to wildlife and the national economy, have been lost since the 1930s. Between May 2017 and April 2019, we conducted the first targeted survey effort in the state for this species, utilizing two survey methods: A) point counts (at 33 sites) and B) drag-line surveys (at 16 sites), the former during breeding season (April-July) and both during the non-breeding season (November-March). We tallied a total of 38 detections at 21 of 152 point count locations (at 33% of sites) during both the breeding and non-breeding seasons. Occupancy analyses from 1,239 point count surveys indicated a strong positive relationship with Spartina spartinae cover. Among 61 drag-line surveys, we tallied 36 detections, including 28 captures of 25 individuals at 43.8% of survey sites. We deployed 0.9-g VHF radio transmitters on 16 birds, and among 13 with sufficient data, we estimated the 95% minimum convex polygon home range size to be 0.71 ha (± 0.13 ha; range 0.22 – 1.59 ha). Our surveys efforts have demonstrated that the Black Rail is part of the core Louisiana avifauna, which has important implications for coastal restoration, wetland mitigation, and land management activities in a landscape threatened by sea level rise, subsidence, and coastal wetland loss.
 
Eastern Black Rail Occupancy and Habitat Use in Colorado
Jonathan Runge, Kevin Aagaard, Liza Rossi
Little information exists regarding Eastern black rail (Laterallus jamaicensis jamaicensis) occupancy or habitat use within marshes of the western Great Plains.  In order to learn more about site occupancy and persistence, Colorado Parks and Wildlife conducted repeated broadcast surveys to estimate occupancy and detection probability of black rails in southeastern Colorado.   We also conducted habitat measurements at call broadcast points.  Black rails are present at marshes of varying sizes along the lower Arkansas River valley, though probability of occupancy increases at points within larger contiguous marshes.  Detection probability in southeastern Colorado is higher during evening and night surveys compared to dawn surveys.  Estimated detection probability is also quite high, particularly when compared to other studies across the species’ range.  Our data indicate persistence at many of the call broadcast points across years.  Preliminary habitat measurements provide data for vegetation structure at sites occupied by black rails, which can then be used to inform black rail conservation in the Great Plains.
 
Large-scale distribution models for optimal prediction of Eastern black rail habitat suitability
Bryan Stevens, Courtney Conway
Eastern black rails inhabit estuarine and inland emergent wetlands and are among the rarest and least understood birds in North America. This species was recently listed as threatened under the U.S. Endangered Species Act, and spatial models to predict habitat quality over broad spatial extents are needed to inform conservation. We leveraged data from >47,000 field surveys collected at >15,000 sites and spanning 3 decades to build species distribution models that predict eastern black rail breeding habitat quality within tidally-influenced wetlands at a fine spatial resolution (30-m) over the entire eastern seaboard of the U.S. We used predictive Bayesian model selection to develop optimally-predictive multi-scale occupancy models that account for failed detection of these rare birds during field surveys. The models predict quality of breeding habitat as a function of wetland attributes, hydrologic modification, and disturbance from human development measured over multiple spatial scales. We used raster regression techniques and geographic information systems to translate the optimal statistical model into maps of habitat suitability. We found that breeding habitat quality (and hence eastern black rail breeding distribution) was negatively influenced by amount of human disturbance, and was also affected by local wetland attributes and human-altered hydrology. This work provides an example of integrating large-scale field sampling with modern statistical methods to build predictive distribution models for rare species inhabiting estuarine ecosystems, and provides the first large-scale assessment of breeding habitat quality for the threatened eastern black rail along the eastern coast of the U.S. These models will enable identification of important wetlands and threats to species recovery for eastern black rails, and thus will facilitate strategic habitat conservation over large scales.
 
Fire ecology and knowledge transfer from uplands to wetlands
James Cox
Fires have a Jekyll-and-Hyde relationship with Black Rails.  Fires can be key to sustaining the grass-dominated areas where rails occur; fires also have the capacity to do harm, especially when land managers are asked to sustain this rare bird on a small fraction of its former range. Land managers manipulate 5 key variables when they conduct prescribed burns: (1) frequency with which fire returns to an area; (2) season in which fires are applied; (3) extent of the area treated; (4) ignition techniques used to launch a fire, and (5) the specific weather conditions under which a fire is initiated.  Data on the effects each of these factors can have are discussed for several ground-dwelling birds associated with fire-dependent uplands.  The effects these factors may have on Black Rails and the wetlands they occupy need more study, but fire frequency ranks highest in importance for upland birds and likely has similar importance for Black Rails  Ignition patterns and weather are likely more important for Black Rails than season and extent.  A focus on mimicking the season and extent of natural fire regimes can also have unintended consequences for some  upland species. 
 
Have preferred weather conditions for prescribed fire changed over time?
Chelsea Kross, J. Andrew Nyman, Robert Rohli, Jena Moon
Coastal marsh habitat is the optimal habitat type associated with Eastern Black Rail presence, but most coastal marsh habitat has been severely degraded for human use. The precipitous decline of the black rail necessitates the restoration and management of their habitat. One of the most common tools used to improve and maintain coastal marsh habitat is prescribed fire. Due to climate change and other anthropogenic factors, the preferred conditions for applying a burn prescription have likely changed. Thus, the objective of our research was to determine if weather type and frequency associated with prescribed fire have changed over time across the United States Gulf Coast. Additionally, we sought to identify the weather conditions preferred by land managers for implementing prescribed fire. To do this, we gathered prescribed fire data from 1979 to 2017 across the Gulf Coast regions including the five Gulf Coast Joint Venture Initiative Areas, as well as several USGS Biological Planning Units along the Alabama and Florida Gulf Coast. We estimated the frequency of different weather types across all years and then estimated the frequency of each weather type used by prescribed burners. We also calculated manager preference and avoidance indices for each weather type. Preliminary analysis from the Chenier Plains Initiative Area suggest that there has been no real change in the frequency of weather types over time. However, managers do show a preference for type 3 weather conditions (cool dry winds from the northwest) and avoidance of type 8 weather conditions (onshore winds). Understanding how the availability of preferred weather conditions has changed and manager preference will allow for a more accurate understanding of when and why prescribed fire might be implemented for coastal marsh habitat management.
 
Qualitative value of information provides a transparent and repeatable method for identifying critical uncertainty regarding the use of prescribed fire to benefit Black Rails and other marshbirds
Michael Runge, Mark Woodrey, Jim Lyons, Michelle Stantial, Abby Lawson, Auriel Fournier, Peter Kappes, Chelsea Kross
Conservation decisions are often made in the face of uncertainty because the urgency to act can preclude delaying management while uncertainty is resolved. In this context, adaptive management is attractive, allowing a balance between management and learning. The adaptive program design requires the identification of critical uncertainties that impede the choice of management action. Quantitative evaluation of critical uncertainty, using the expected value of information, may require more resources than are available in the early stages of conservation planning. We demonstrate the use of a new qualitative value of information (QVoI) analysis to prioritize which sources of uncertainty to reduce regarding the use of prescribed fire to benefit Eastern Black Rails (Laterallus jamaicensis jamaicensis), Yellow Rails (Coturnicops noveboracensis), and Mottled Ducks (Anas fulvigula; hereafter, focal species) in high marsh habitats of the Gulf of Mexico. Prescribed fire has been used as a management tool in Gulf of Mexico high marshes throughout the last 15-20 years; however, it is not known how periodic burning affects these focal species, and the optimal conditions for burning marshes to improve habitat remains unknown. We followed a structured decision-making framework to develop conceptual models, which we used to identify sources of uncertainty and articulate alternative hypotheses about prescribed fire in high marshes. We used QVoI to prioritize the sources of uncertainty based on their magnitude, relevance for decision making, and reducibility. We found that hypotheses related to the optimal fire return interval and season were the highest priorities, whereas hypotheses related to predation rates and interactions among management techniques were lower. These results suggest that learning about the optimal fire frequency and season to benefit the focal species might produce the greatest management benefit.
 
The Eastern Black rail Irrigation Planner: a tool to plan freshwater wetland creation for metapopulation persistence along the Atlantic Coast
Nathan Van Schmidt, Maureen Correll
The Eastern black rail (Laterallus jamaicensis jamaicensis) was recently federally listed as a threatened subspecies. This subspecies depends almost entirely on shallow water within the intertidal zone of salt marshes along the Atlantic coast of the United States, habitat which is severely threatened by sea level rise under climate change. Black rail populations in California utilize not only salt marshes but also wetlands characterized by shallow ( < 3 cm) sheets of flowing water released from irrigation ditches onto slopes of the Sierra Nevada foothills. The creation of such irrigated wetlands along the Eastern coast may represent an opportunity to create habitat for the Eastern subspecies that is resilient to climate change. We created the Eastern black rail Irrigation Planner (EBIP), a planning tool that allows users to (1) place irrigation releases on topographic map and estimate the water flows and resulting wetland habitat creation, and (2) simulate black rail persistence likelihood within the created wetlands. The tool runs as an agent-based model parameterized from field data on irrigation releases from n = 28 wetlands. Black rail persistence was based on a multi-season occupancy model fit to field data from n = 273 California wetlands surveyed from 2002-2016. We provide an overview of the tool, discuss challenges in translating field data from California to a novel system, and describe applications of the tool for management.
 
Black rail research and management in inland Florida
Amy Schwarzer, Graham Williams, Bryan Watts, Mike Legare
On the Atlantic coast, eastern black rails (Laterallus jamaicensis jamaicensis) have historically occurred in and largely remain a salt marsh dependent species. However, the species has seen sharp declines in coastal areas in recent history, with sea level rise the likely cause. Thus, conservation planning has centered strategies focused on expanding existing inland populations and establishing new inland populations. Among the Atlantic states, Florida is the only state with a significant portion of its rail population supported by a broad variety of freshwater wetlands in addition to salt marsh sites. Many of these inland areas have had both historical and extant use, suggesting that there are lessons to be learned about habitat requirements in freshwater systems as we move toward an inland-based recovery strategy. Multiple sites within these habitats are managed using a variety of tools, providing an ideal environment for experimental management treatments as well as observational studies. This talk will focus on the state of research and possible management strategies within inland Florida and what features may or may not be transferrable to inland habitat creation and management elsewhere.  
 
Can autonomous recording units be used to detect non-breeding black rails?
Jennifer Wilson
The eastern black rail (Laterallus jamaicensis jamaicensis) is most frequently detected through its vocalizations.  Multiple studies have estimated its occupancy using acoustic surveys.  Acoustic surveys are normally conducted during the breeding season when vocalization rates are expected to be greatest.  This species is known to vocalize during the winter months, but the degree to which this occurs is not well understood.  Greater understanding of the timing and frequency of black rail vocalizations during non-breeding periods could support the development of survey options outside the breeding season.   In addition, if autonomous recording units can be used to survey during non-breeding months, this would further increase survey options.  At San Bernard National Wildlife Refuge in coastal Texas, a small number of autonomous recording units was used to passively record acoustic data during the 2019-2020 fall and winter seasons.  Kaleidscope Pro software was used to search the collected acoustic data for black rail vocalizations.  We will discuss detection rates and summarize the steps used to identify black rail vocalizations for this pilot study.
 
Winter interspecific density relationships between black rails and yellow rails in the context of fire in coastal Texas
Amanda Haverland, Butch Weckerly, Jennifer Wilson, M. Green
Prescribed fire is widely used as a management tool in Texas coastal ecosystems. During winter, coastal marshes at San Bernard National Wildlife Refuge in Texas provide habitat for Black Rails (Laterallus jamaicensis) and Yellow Rails (Coturnicops novaboracensis). The populations of these species are believed to be influenced by fire regime, but information is lacking for these species in Texas. In 2017 and 2018, systematic bottle-line surveys targeting Black Rails and Yellow Rails were conducted in six plots at SBNWR that differed in months post-burn ranging from 3 to >86. Effects of months post-burn and habitat variables on the density of each species were assessed using generalized linear mixed models. Over two winters, for all plots combined we captured 75 Rails: 12 Black Rails and 63 Yellow Rails. There was no correlation between months post-burn and density of either rail species. Plots varied most in woody frequency and herbaceous vegetation density. There was a positive correlation between woody frequency and months post-burn, however there was no correlation between herbaceous vegetation density and months post-burn. The differences in growth rates of herbaceous vegetation among plots signifies the complex dynamic between fire regime and herbaceous growth. None of the measured habitat covariates were able to explain density of Black Rails within burn-plots. Black Rail density in burn-plots may have been affected by variables not directly measured in this study like food availability, low detectability, or territoriality. Yellow Rails tolerated a relatively wide range of burn regimes. Yellow Rail density was best explained by herbaceous vegetation density where lower density of vegetation in plots provided conditions attractive to Yellow Rails. Results indicate burn regime did not act independently to influence habitat dynamics. On San Bernard National Wildlife Refuge, habitat characteristics are more indicative of rail density rather than simply the number of months post-burn.
 
Best-case scenario planning: evaluating tradeoffs among abundance and occupancy monitoring frameworks to detect eastern black rail population trends in optimal habitat
Jim Lyons, Adam Smith, Abby Lawson, Michelle Stantial
Occupancy and N-mixture modeling frameworks are widely used in wildlife management to analyze spatiotemporally replicated detection/non-detection and count data, respectively. Choosing among these two frameworks ultimately depends on management objectives, available resources, and density or detectability of the focal species. We evaluated tradeoffs in abundance- and occupancy-based monitoring program designs for eastern black rail (Laterallus jamaicensis jamaicensis; hereafter black rail) populations in optimal habitat on the Atlantic coast. Due to their cryptic nature and low detectability, rails are frequently monitored using occupancy frameworks. However, it is unclear how occupancy-based parameters translate into number of individuals or pairs (commonly used in setting recovery criteria) and the efficacy of occupancy-based monitoring to detect population declines. To address these uncertainties, we conducted call-broadcast surveys at sites that were likely to contain rails based on habitat characteristics within three national wildlife refuges located in North Carolina and Florida. Selecting only optimal sites we meant to increase the feasibility of obtaining reliable parameter estimates through both occupancy and N-mixture frameworks, in which the latter typically requires higher detectability and spatiotemporal replication. Using the estimated parameters from each analysis, we simulated a series of black rail populations that were subject to varying degrees of population decline. We then simulated survey data according to different monitoring frameworks (occupancy and N-mixture), survey designs (spatiotemporal replication), and detectability scenarios. Here we present the baseline demographic parameters estimated from field data, and the ability of each monitoring design to detection rail population declines.
 
If a rail dies in a marsh, would anyone know? The role of West Nile Virus in the decline of the black rail
Steven Beissinger, Nathan Van Schmidt, Jerry Tecklin, Sean Peterson, Laurie Hall, Tony Kovach, A Kilpatrick, Orien Richmond
Conservation attention has focused on the Black Rail with the recent ESA listing of the eastern population segment. The USFWS concluded that populations have declined over 75% during the last 10-20 years due to habitat destruction and climate change (sea level rise, tidal flooding, and increased storm intensity and frequency). But because the Black Rail is incredibly secretive, its demography is unknown and the cause of decline is based on circumstantial evidence. An 18-year study of the metapopulation dynamics of Black Rails inhabiting small, freshwater wetlands of California’s Sierra Nevada foothills shows a different threat is likely involved. Surveying hundreds of small wetlands (mean 0.5 ha) annually allowed us to understand the site-level factors related to colonization and extinction, using occupancy models to correct for imperfect detection. From 2002-2006 the Black Rail metapopulation was in dynamic equilibrium. Turnover occurred frequently but occupancy was stable due to probabilities of local extinction (0.19) and colonization (0.16) that did not differ. A dramatic extinction event occurred in 2007, when extinction rates rose to 0.40, colonization was low (0.04), and occupancy plummeted from around 0.60 to 0.40. The timing coincides with the arrival of West Nile Virus (WNV) in the study area, which spiked in August 2006. Subsequent studies verified the presence of WNV in mosquito pools in foothills wetlands and in rails throughout the region, and found that Black Rail extinction rates were strongly related to the potential for recurrent WNV outbreaks, as well as drought. Coupled human-natural system models of the metapopulation indicated that rails were strongly regulated by precipitation, and the Black Rail’s decade-long decline was caused by the combination of West Nile virus and drought. The decline of the eastern Black Rail segment coincides with the arrival of WNV in New York (1999) and its rapid spread after 2002. 
 
A review of ecology and management of North American rails: lessons learned for management and recovery of Eastern Black Rails
Courtney Conway
Rails are circumpolar, occur on all continents except Antarctica, and inhabit every biome except deserts and tundra.  Rails have high rates of endemism and high rates of extinction and there are 152 extant species worldwide and 10 in the U.S. All rails share one obvious habitat characteristic (they all inhabit dense vegetation) and all 10 species in the U.S. are closely tied to emergent marshes and, hence, have been disproportionately affected by human development. Most species of rails have little sexual dimorphism and are secretive/shy.  For all of these reasons, most research, monitoring, and management efforts rely heavily on recording their presence and abundance based on their vocalizations.  However, we know relatively little about the breeding behavior of most rails and almost nothing about the function of their unique calls.  I will review the seasonal phenology of black rail calls (and calls of other rails) and discuss the implications of seasonal phenology in vocalizations for management, monitoring, and recovery efforts.   Eastern black rails were recently listed under the Endangered Species Act and join 3 other federally listed subspecies of rails in the U.S. Black rails are the least well-known of the 10 species of rails and the most difficult to study, so lessons learned from other rails can help direct management, monitoring, and research priorities for eastern black rails.  Based on call-broadcast surveys, prescribed fires appear to benefit California black rails but the benefit isn’t manifested until >2 years post-fire. Moreover, black rails are very sensitive to changes in water depth and do not tolerate marshes when water gets too deep.

Symposium
Location: Virtual Date: November 3, 2021 Time: 1:00 pm - 2:00 pm