King Rail (Rallus elegans) presence in the Midwestern United States is predicted by local-scale factors and avian community.

The King Rail (Rallus elegans) is a wetland dependent species of conservation concern. Our objective was to gain a better understanding of the breeding habitat associations of King Rails in the Midwestern United States and the relationship of this species to other obligate marsh birds using occupancy and MaxEnt models. To collect data pertaining to occupancy, we placed trail cameras at 50 random points in coastal wetlands in the western Lake Erie basin where calls of King Rails were continuously broadcast at night. Data pertaining to other marsh bird species were collected via call-broadcast surveys and camera surveys at each sample point. For MaxEnt modeling, we obtained presence data for King Rails and other obligate marsh birds from eBird and habitat data from GIS databases. Trail cameras and call-broadcast surveys captured 10 detections of King Rails at nine sites, an 18% naive occupancy rate. King Rail occupancy was positively related to amount of interspersion, average water depth, and percent cover of emergent vegetation at local scales within a 5-m radius. Our MaxEnt models indicated that, at a broader scale, the presence of other rail species such as the Sora (Porzana carolina) may be more important for predicting King Rail presence than other marsh birds or coarse wetland categories such as "emergent vegetation." Our results could help wetland managers to predict where King Rails occur and to adapt management plans to incorporate King Rail conservation.

King rail (Rallus elegans) home range and microhabitat characteristics in western Lake Erie coastal marshes.

The king rail (Rallus elegans) is a secretive marsh bird that is threatened or endangered in eight of nine states and provinces in the Laurentian Great Lakes (Great Lakes) region. Available survey data suggests that this species has undergone population declines across this region and these are believed to have been driven by habitat loss and degradation. An improved understanding of the amount and type of habitat king rails require during the breeding season at sites within the Great Lakes region would inform and improve progress toward conservation goals. During 2019-2021, we caught and radio-tagged 14 king rails in northwestern Ohio and southeastern Michigan within impounded coastal wetlands of western Lake Erie. We used radio telemetry to identify breeding season (May-August) home-range characteristics and third order habitat selection within home ranges (hereafter microhabitat). For the birds whose home range stabilized (N = 10), we found a mean home-range size of 8.8 ha (±1.63 [SE]; range = 1.9 to 15.8). We generated a classification tree to determine which habitat characteristics were associated with king rail presence within home ranges in our study. We found that vegetative density within home ranges was particularly associated with king rail presence. Phragmites australis was also associated with king rail presence, despite its invasiveness and negative ecological impacts in the region, and could be selectively maintained to benefit king rails. Our results suggest that managers may be able to provide microhabitat for king rails by maintaining water depths of 6 to 17 cm and by promoting native, robust vegetation in the genera Carex and Juncus. Our findings could help inform wetland managers and conservation planners in the Great Lakes region, particularly in western Lake Erie coastal marshes, of patch sizes, water depths, plant communities, and vegetative structure preferred by king rails.

Genome sequencing in microfabricated high-density picolitre reactors.

The proliferation of large-scale DNA-sequencing projects in recent years has driven a search for alternative methods to reduce time and cost. Here we describe a scalable, highly parallel sequencing system with raw throughput significantly greater than that of state-of-the-art capillary electrophoresis instruments. The apparatus uses a novel fibre-optic slide of individual wells and is able to sequence 25 million bases, at 99% or better accuracy, in one four-hour run. To achieve an approximately 100-fold increase in throughput over current Sanger sequencing technology, we have developed an emulsion method for DNA amplification and an instrument for sequencing by synthesis using a pyrosequencing protocol optimized for solid support and picolitre-scale volumes. Here we show the utility, throughput, accuracy and robustness of this system by shotgun sequencing and de novo assembly of the Mycoplasma genitalium genome with 96% coverage at 99.96% accuracy in one run of the machine.

Fencerows, Edges, and Implications of Changing Connectivity Illustrated by Two Contiguous Ohio Landscapes.

We evaluated the amounts and implications of changes in habitat connectivity on rural land-scapes by modeling the colonization success and subsequent habitat colonization of a model edge organism within real landscapes. We first inventoried the changes in the fencerow and forest-edge network of two contiguous Ohio (U.S.A.) landscapes, an agriculturally dominated till plain and a more diverse and dynamic moraine landscape, from 1940 to 1988. On the moraine the number of fencerows changed little from 1940 to 1971. The number increased by 86 during 1971-1988 as marginal farms were subdivided. The total length of fencerows on the moraine increased 2.5-fold over 48 years. On the till plain the number and total length of fencerows remained relatively constant through the study period. The sum of fencerows and forest edges was used as a measure of total ecotonal edge. On the moraine total edge increased through the study period, whereas on the till plain it decreased. We selected two levels of landscape connectivity, low and high, to model animal habitat colonization success. As connectivity increased the earliest successful colonists preempted an increasingly large proportion of the total suitable habitat, and the probability of successful colonization by later-arriving individuals decreased. The changes in connectivity that resulted from changes in both the fencerow network and the proportion of forested land have resulted in contiguous landscapes that present very different colonization potentials to organisms with long-distance dispersal capability. Given the current uncertainty of the effects of corridors on species-preservation efforts, we suggest that further modeling of this type prior to field testing will add useful insights, especially if conducted using specific species and landscape types. Las cercas, los bordes y las connotaciones de los cambios en la conectividad ilustrados por dos paisajes contiguos de Ohio.

Resumen: Evaluamos la cantidad y las connotaciones de los cambios en la conectividad del hábitat, en paisajes rurales modelando el éxito en la colonización y la subsecuente colonización del hábitat en un organismo de los bordes modelo dentro de paisajes reales. En primer lugar, inventariamos los cambios en las cercas y el sistema de bordes del bosque de dos paisajes contiguos de Ohio, una planicie de tillita dominada por agricultura y un paisaje morenico más diverso y dinámico, durante 1940-1988. En la morena el número de cercas cambió poco entre 1940-1971. El número se incrementó en 86 durante 1971-1988, a medida que las granjas marginales fueron subdivididas. La extensión total de las cercas en la morena se multiplicó 2.5 veces durante un período de 48 años. En la planicie de tillita el número y la extensión total de las cercas permaneció relativamente constante a través del período de estudio. La suma de las cercas y el borde del bosque fue utilizado como medida del borde total del ecotono. En la morena el borde total se incrementó durante el período de estudio, mientras que en la planicie de tillita decreció. Seleccionamos dos niveles de conectividad del paisaje, bajo y alto, para modelar el suceso de la colonizacion del hábitat animal. En la medida en que la conectividad se incrementó, los colonizadores tempranos más exitosos se apropiaron de una gran proporción del hábitat total disponible y la probabilidad del éxito en la colonización de los individuos que fueron llegando más tarde decreció. Los cambios en conectividad que resultaron de los cambios en el conjunto de las cercas y la proporción de la tierra forestada, ha resultado en paisajes contiguous que presentan potenciales de colonización muy diferentes para los organismos con una capacidad de dispersión a gran distancia. Dada la incertidumbre actual sobre los efectos de los corredores sobre los esfuerzos de preservación de las especies, sugerimos que la intesificación en este tipo de modelado antes de ser probando en el campo puede adicionar información útil, especialmente si se conduce utilizando especies y tipos de paisajes específicos.